What is required to make GPS signals available indoors?Does GPS work at ISS?How does GPS work exactly?Would GPS work above the GPS satellites?GPS constellation for MarsHow does GPS module gets time even before a fix?How many satellites would be required for Solar System GPS?What are RAIM Service Outage, RNP and EnRoute on GPS DOP maps? What does the red line mean?Do operating GPS satellites ever make orbital maneuvers for station-keeping?Does the Soyuz spacecraft really try to achieve attitude accuracy of 0.5° from GLONASS and GPS signals?GPS PPS stable signal
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What is required to make GPS signals available indoors?
Does GPS work at ISS?How does GPS work exactly?Would GPS work above the GPS satellites?GPS constellation for MarsHow does GPS module gets time even before a fix?How many satellites would be required for Solar System GPS?What are RAIM Service Outage, RNP and EnRoute on GPS DOP maps? What does the red line mean?Do operating GPS satellites ever make orbital maneuvers for station-keeping?Does the Soyuz spacecraft really try to achieve attitude accuracy of 0.5° from GLONASS and GPS signals?GPS PPS stable signal
$begingroup$
GPS satellites don't transmit strong enough to reach indoors, through the roofs and walls of buildings, like cell phones do. GPS signals that enter buildings through windows are unreliable since they often have bounced and thus give the wrong distance measures by even hundreds of meters. Since cell phones work fine indoors, and GPS uses the same frequency, I suppose there's no need to use another frequency.
Would it suffice for today's kind of GPS satellites to orbit in low Earth orbits, such as planned communication satellites constellations like Starlink? Would it be feasible to equip them with larger solar arrays, or would nuclear generators be required?
One can imagine many commercial applications for precision indoor navigation (like more efficient robotic vacuum cleaners ;-) Just reaching through the roofs of single storage factories and shopping centers should make for a great market. The alternative today is to install radio or ultrasound beacons (or perhaps a camera system) in every room where one wants to have a location service. A single ubiquitous system that's already standard would have economic advantages.
gps radio
edited 2 days ago
Glorfindel
2111210
asked 2 days ago
LocalFluffLocalFluff
12.9k450167
$endgroup$
|
show 4 more comments
$begingroup$
GPS satellites don't transmit strong enough to reach indoors, through the roofs and walls of buildings, like cell phones do. GPS signals that enter buildings through windows are unreliable since they often have bounced and thus give the wrong distance measures by even hundreds of meters. Since cell phones work fine indoors, and GPS uses the same frequency, I suppose there's no need to use another frequency.
Would it suffice for today's kind of GPS satellites to orbit in low Earth orbits, such as planned communication satellites constellations like Starlink? Would it be feasible to equip them with larger solar arrays, or would nuclear generators be required?
One can imagine many commercial applications for precision indoor navigation (like more efficient robotic vacuum cleaners ;-) Just reaching through the roofs of single storage factories and shopping centers should make for a great market. The alternative today is to install radio or ultrasound beacons (or perhaps a camera system) in every room where one wants to have a location service. A single ubiquitous system that's already standard would have economic advantages.
gps radio
edited 2 days ago
Glorfindel
2111210
asked 2 days ago
LocalFluffLocalFluff
12.9k450167
$endgroup$
1
$begingroup$
Not all cell phones work fine indoors and not in every building. There are metall roofs and steel construction buildings. Multi path distribution of satellite signals does harm the GPS position precision. The speed of electric waves is different in air and in solid materials ( non metallic solids ). But GPS even handles different speed of light in vacuum and air. But how to handle the much lower speed in solids?
$endgroup$
– Uwe
2 days ago
4
$begingroup$
All you have to do is construct your building appropriately. GPS works perfectly well inside my (wood frame, single story, non-metal roof) house.
$endgroup$
– jamesqf
2 days ago
$begingroup$
@jamesqf Really? It's been some years since I disappointingly tried out GPS inside a hut, and maybe with already then old equipment. The receivers have been getting alot better. But how far could that development go?
$endgroup$
– LocalFluff
2 days ago
1
$begingroup$
There is no need to install radio beacons for a indoor positioning system. Wifi access points which are ubiquitous these days can do that job. Wifi positioning system (en.wikipedia.org/wiki/Wi-Fi_positioning_system) is already used extensively by mobile phones and laptops and have a better accuracy than GPS indoors.
$endgroup$
– Kevin Selva Prasanna
yesterday
1
$begingroup$
The comparison with phones is really unhelpful. You yourself state why: "since they often have bounced". While that is a problem for GPS, your phone doesn't care at all, hence it works
$endgroup$
– Hobbamok
yesterday
|
show 4 more comments
$begingroup$
GPS satellites don't transmit strong enough to reach indoors, through the roofs and walls of buildings, like cell phones do. GPS signals that enter buildings through windows are unreliable since they often have bounced and thus give the wrong distance measures by even hundreds of meters. Since cell phones work fine indoors, and GPS uses the same frequency, I suppose there's no need to use another frequency.
Would it suffice for today's kind of GPS satellites to orbit in low Earth orbits, such as planned communication satellites constellations like Starlink? Would it be feasible to equip them with larger solar arrays, or would nuclear generators be required?
One can imagine many commercial applications for precision indoor navigation (like more efficient robotic vacuum cleaners ;-) Just reaching through the roofs of single storage factories and shopping centers should make for a great market. The alternative today is to install radio or ultrasound beacons (or perhaps a camera system) in every room where one wants to have a location service. A single ubiquitous system that's already standard would have economic advantages.
gps radio
edited 2 days ago
Glorfindel
2111210
asked 2 days ago
LocalFluffLocalFluff
12.9k450167
$endgroup$
GPS satellites don't transmit strong enough to reach indoors, through the roofs and walls of buildings, like cell phones do. GPS signals that enter buildings through windows are unreliable since they often have bounced and thus give the wrong distance measures by even hundreds of meters. Since cell phones work fine indoors, and GPS uses the same frequency, I suppose there's no need to use another frequency.
Would it suffice for today's kind of GPS satellites to orbit in low Earth orbits, such as planned communication satellites constellations like Starlink? Would it be feasible to equip them with larger solar arrays, or would nuclear generators be required?
One can imagine many commercial applications for precision indoor navigation (like more efficient robotic vacuum cleaners ;-) Just reaching through the roofs of single storage factories and shopping centers should make for a great market. The alternative today is to install radio or ultrasound beacons (or perhaps a camera system) in every room where one wants to have a location service. A single ubiquitous system that's already standard would have economic advantages.
gps radio
gps radio
edited 2 days ago
Glorfindel
2111210
asked 2 days ago
LocalFluffLocalFluff
12.9k450167
edited 2 days ago
Glorfindel
2111210
asked 2 days ago
LocalFluffLocalFluff
12.9k450167
edited 2 days ago
Glorfindel
2111210
edited 2 days ago
Glorfindel
2111210
edited 2 days ago
Glorfindel
2111210
2111210
asked 2 days ago
LocalFluffLocalFluff
12.9k450167
asked 2 days ago
LocalFluffLocalFluff
12.9k450167
asked 2 days ago
LocalFluffLocalFluff
12.9k450167
12.9k450167
1
$begingroup$
Not all cell phones work fine indoors and not in every building. There are metall roofs and steel construction buildings. Multi path distribution of satellite signals does harm the GPS position precision. The speed of electric waves is different in air and in solid materials ( non metallic solids ). But GPS even handles different speed of light in vacuum and air. But how to handle the much lower speed in solids?
$endgroup$
– Uwe
2 days ago
4
$begingroup$
All you have to do is construct your building appropriately. GPS works perfectly well inside my (wood frame, single story, non-metal roof) house.
$endgroup$
– jamesqf
2 days ago
$begingroup$
@jamesqf Really? It's been some years since I disappointingly tried out GPS inside a hut, and maybe with already then old equipment. The receivers have been getting alot better. But how far could that development go?
$endgroup$
– LocalFluff
2 days ago
1
$begingroup$
There is no need to install radio beacons for a indoor positioning system. Wifi access points which are ubiquitous these days can do that job. Wifi positioning system (en.wikipedia.org/wiki/Wi-Fi_positioning_system) is already used extensively by mobile phones and laptops and have a better accuracy than GPS indoors.
$endgroup$
– Kevin Selva Prasanna
yesterday
1
$begingroup$
The comparison with phones is really unhelpful. You yourself state why: "since they often have bounced". While that is a problem for GPS, your phone doesn't care at all, hence it works
$endgroup$
– Hobbamok
yesterday
|
show 4 more comments
1
$begingroup$
Not all cell phones work fine indoors and not in every building. There are metall roofs and steel construction buildings. Multi path distribution of satellite signals does harm the GPS position precision. The speed of electric waves is different in air and in solid materials ( non metallic solids ). But GPS even handles different speed of light in vacuum and air. But how to handle the much lower speed in solids?
$endgroup$
– Uwe
2 days ago
4
$begingroup$
All you have to do is construct your building appropriately. GPS works perfectly well inside my (wood frame, single story, non-metal roof) house.
$endgroup$
– jamesqf
2 days ago
$begingroup$
@jamesqf Really? It's been some years since I disappointingly tried out GPS inside a hut, and maybe with already then old equipment. The receivers have been getting alot better. But how far could that development go?
$endgroup$
– LocalFluff
2 days ago
1
$begingroup$
There is no need to install radio beacons for a indoor positioning system. Wifi access points which are ubiquitous these days can do that job. Wifi positioning system (en.wikipedia.org/wiki/Wi-Fi_positioning_system) is already used extensively by mobile phones and laptops and have a better accuracy than GPS indoors.
$endgroup$
– Kevin Selva Prasanna
yesterday
1
$begingroup$
The comparison with phones is really unhelpful. You yourself state why: "since they often have bounced". While that is a problem for GPS, your phone doesn't care at all, hence it works
$endgroup$
– Hobbamok
yesterday
1
1
$begingroup$
Not all cell phones work fine indoors and not in every building. There are metall roofs and steel construction buildings. Multi path distribution of satellite signals does harm the GPS position precision. The speed of electric waves is different in air and in solid materials ( non metallic solids ). But GPS even handles different speed of light in vacuum and air. But how to handle the much lower speed in solids?
$endgroup$
– Uwe
2 days ago
$begingroup$
Not all cell phones work fine indoors and not in every building. There are metall roofs and steel construction buildings. Multi path distribution of satellite signals does harm the GPS position precision. The speed of electric waves is different in air and in solid materials ( non metallic solids ). But GPS even handles different speed of light in vacuum and air. But how to handle the much lower speed in solids?
$endgroup$
– Uwe
2 days ago
4
4
$begingroup$
All you have to do is construct your building appropriately. GPS works perfectly well inside my (wood frame, single story, non-metal roof) house.
$endgroup$
– jamesqf
2 days ago
$begingroup$
All you have to do is construct your building appropriately. GPS works perfectly well inside my (wood frame, single story, non-metal roof) house.
$endgroup$
– jamesqf
2 days ago
$begingroup$
@jamesqf Really? It's been some years since I disappointingly tried out GPS inside a hut, and maybe with already then old equipment. The receivers have been getting alot better. But how far could that development go?
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@jamesqf Really? It's been some years since I disappointingly tried out GPS inside a hut, and maybe with already then old equipment. The receivers have been getting alot better. But how far could that development go?
$endgroup$
– LocalFluff
2 days ago
1
1
$begingroup$
There is no need to install radio beacons for a indoor positioning system. Wifi access points which are ubiquitous these days can do that job. Wifi positioning system (en.wikipedia.org/wiki/Wi-Fi_positioning_system) is already used extensively by mobile phones and laptops and have a better accuracy than GPS indoors.
$endgroup$
– Kevin Selva Prasanna
yesterday
$begingroup$
There is no need to install radio beacons for a indoor positioning system. Wifi access points which are ubiquitous these days can do that job. Wifi positioning system (en.wikipedia.org/wiki/Wi-Fi_positioning_system) is already used extensively by mobile phones and laptops and have a better accuracy than GPS indoors.
$endgroup$
– Kevin Selva Prasanna
yesterday
1
1
$begingroup$
The comparison with phones is really unhelpful. You yourself state why: "since they often have bounced". While that is a problem for GPS, your phone doesn't care at all, hence it works
$endgroup$
– Hobbamok
yesterday
$begingroup$
The comparison with phones is really unhelpful. You yourself state why: "since they often have bounced". While that is a problem for GPS, your phone doesn't care at all, hence it works
$endgroup$
– Hobbamok
yesterday
|
show 4 more comments
4 Answers
4
active
oldest
votes
$begingroup$
There are some big differences between GPS and cell phone signals:
GPS relies on the exact timing of a signal (1 nanosecond off = 30 cm of position inaccuracy). Cell phones are much more tolerant to variations in signal timing. Basically they don't care as long as the packets arrive quickly enough not to cause a gap in the audio.
GPS transmitters are 18,000 km away, cell phone towers are less than 5 km away. So a cell phone signal is much stronger at the receiver.
item 2 could be solved with a stronger transmitter, but that would make #1 worse: with a stronger signal, you get more multipathing: more reflections that are still strong enough to be picked up by the receiver.
You can't really use indoors transmitters either. Many buildings have a steel structure which reflects radio waves, so you get lots of multipathing when the transmitter is inside.
answered 2 days ago
HobbesHobbes
95.5k2272426
$endgroup$
8
$begingroup$
"... with a stronger signal, you get more multipathing..." This sounds like something that's made up and not based in EE fact. Any digital radio receiver system will have automatic gain control (AGC) before the ADC. So as far as the digital signal is concerned, the multipathed reflections will have the same strength relative to the direct path signal no matter what the strength of the satellite's signal is.
$endgroup$
– uhoh
2 days ago
4
$begingroup$
if your signal is weak to begin with, reflections can drop below the noise floor. Strong signal->more reflections make it to the receiver above the noise floor.
$endgroup$
– Hobbes
2 days ago
4
$begingroup$
It doesn't work like that. It's not like there is a "floor" and signals below it disappear. Every signal (of a given type, e.g. L1) from every GPS satellite in the sky, plus every reflection of every signal from every satellite in the sky plus all sources of noise, all go through one single front end amplifier and then one ADC, where it is digitized into one digital stream of 1's and 0's. That stream is then copied to dozens of identical correlaters, each looking for a different Gold code from a different satellite.
$endgroup$
– uhoh
2 days ago
2
$begingroup$
@uhoh, would need to find a reference, and is a analog artifact but was taught a potential solution for en.wikipedia.org/wiki/Ghosting_(television) where the cause was proximity to the transmitter allowing reflections to be above noise floor was adding an attenutor or just making the antenna less effective. Thinking through may have also been result of of doing AGC later in the signal path than GPS.
$endgroup$
– GremlinWranger
2 days ago
2
$begingroup$
@uhoh, other place I've met power reduction to reduce multipathing is in Sonar, which also does not say anything useful at all about GPS and their somewhat unique receiver design so think I get to learn something today.
$endgroup$
– GremlinWranger
2 days ago
|
show 7 more comments
$begingroup$
There is existing technology for this, termed "Active,Passive GPS Repeater". It is composed of both an antenna outside and inside, with optionally active or passive components to forward the signal. My introduction to it was within an ocean-going vessel, and it worked fine.
http://www.terrisgps.com/how-do-gps-repeaters-work/
https://www.tri-m.com/index.php/product/tri-m/gps-networking/gps-re-radiators/l1-gps-repeater-kit
https://electronics.stackexchange.com/a/7798/216525
answered 2 days ago
Tyson HilmerTyson Hilmer
692
New contributor
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
9
$begingroup$
Note that a GPS repeater doesn't actually give you indoor navigation - everything receiving the repeated signal computes approximately the same position, that of the outside antenna. (Source: we use these repeaters to be able to do indoor testing of GPS-based equipment that we make.)
$endgroup$
– jasonharper
2 days ago
1
$begingroup$
A cite from your first link: "It should be noted that all the repeaters in a single network will transmit the coordinates of the outdoor antenna and not the position of the repeater unit itself."
$endgroup$
– Uwe
2 days ago
$begingroup$
@jasonharper If they have chosen to transmit the computed GPS position directly to the GPS receivers (so that crew and cruise passenger easily can see on their phones where they are at sea when under deck) instead of via e.g. WiFi, that speaks for the advantage of GPS, as a dominating standard, over indoor positioning systems requiring specific hardware and software.
$endgroup$
– LocalFluff
2 days ago
add a comment |
$begingroup$
In general, if you need a local indoor navigation system, then you are better off implementing your own. Generally speaking these are called Indoor Positioning Systems. There isn't yet a standard, but there has been some work to making one. It would be MUCH cheaper, more accurate, and overall just better.
GPS satellites are expensive, they are all space rated atomic clocks, some of the most accurate clocks ever created, and the most accurate in orbit. Making thousands of them would be very expensive, and not really gain a lot.
All that being said, there are a few things that can be done. The way indoor GPS typically works is by estimating your location from other means, and looking for the very low signal strength signal coming at the right time.
answered 2 days ago
PearsonArtPhoto♦PearsonArtPhoto
84.2k16243465
$endgroup$
$begingroup$
Low altitude GPS satellites do have conceptual problems with time in sight and Earth's shadow. But I'm pretty sure that putting nuclear reactors on the GPS satellites to up their power (if that would be a solution) is cheaper than installing and maintaining unstandardized indoor systems in billions of buildings. Just changing the beacons' batteries or cabling them to the power grid is a pain. GPS isn't more expensive than EU, Russia, China, Japan and India all have gotten their own (redundant) positioning satellite constellations.
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@LocalFluff Nuclear reactors in LEO ?!!
$endgroup$
– Antzi
2 days ago
$begingroup$
@Anzi Nuclear rather as the alternative to having GPS satellites in LEO. With enough power generation they could beam their radio the more powerful from 30 times further away,
$endgroup$
– LocalFluff
2 days ago
$begingroup$
They may not be cheaper though. Suppose you can either include an extra stage in your mobile phone's chipset to (somehow) pick up GPS indoors, or install an indoor positioning system. The former is cheap (add to a handful of chip designs => solved for most devices within 2 years, similar to adding GALILEO or GLONASS, low cost). The latter needs every building to buy new hardware and install it, effectively billions of individual boxes to buy, install, and run on mains power for the rest of time.
$endgroup$
– Stilez
2 days ago
2
$begingroup$
No satellite from far far away will possibly give the precision that a local system would require. Also, indoor will always suffer from multipath, which will degrade the accuracy further. One of the interesting ideas I've heard in this regard is to use the local wifi signals as a kind of GPS signal, which would be totally doable.
$endgroup$
– PearsonArtPhoto♦
2 days ago
|
show 2 more comments
$begingroup$
1. Assuming that your application can (or does) use an external GPS antenna, keep in mind that they are not all the same. They are available in different gains.
I use them for two lightningmaps.org receivers. One is far more sensitive than the other, and I might be able to get away from using it indoors (though I have never tried to).
2. Many have had success by placing GPS antennas next to windows. Glass does not attenuate the signals like foil-backed building insulation, wiring, etc. does.
A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
answered 2 days ago
Mike WatersMike Waters
1215
New contributor
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Question did not ask for GPS indoor receiption only, it was about GPS indoor navigation too. A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
$endgroup$
– Uwe
yesterday
$begingroup$
@Uwe Thanks. Comment edited to include that.
$endgroup$
– Mike Waters
yesterday
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
There are some big differences between GPS and cell phone signals:
GPS relies on the exact timing of a signal (1 nanosecond off = 30 cm of position inaccuracy). Cell phones are much more tolerant to variations in signal timing. Basically they don't care as long as the packets arrive quickly enough not to cause a gap in the audio.
GPS transmitters are 18,000 km away, cell phone towers are less than 5 km away. So a cell phone signal is much stronger at the receiver.
item 2 could be solved with a stronger transmitter, but that would make #1 worse: with a stronger signal, you get more multipathing: more reflections that are still strong enough to be picked up by the receiver.
You can't really use indoors transmitters either. Many buildings have a steel structure which reflects radio waves, so you get lots of multipathing when the transmitter is inside.
answered 2 days ago
HobbesHobbes
95.5k2272426
$endgroup$
8
$begingroup$
"... with a stronger signal, you get more multipathing..." This sounds like something that's made up and not based in EE fact. Any digital radio receiver system will have automatic gain control (AGC) before the ADC. So as far as the digital signal is concerned, the multipathed reflections will have the same strength relative to the direct path signal no matter what the strength of the satellite's signal is.
$endgroup$
– uhoh
2 days ago
4
$begingroup$
if your signal is weak to begin with, reflections can drop below the noise floor. Strong signal->more reflections make it to the receiver above the noise floor.
$endgroup$
– Hobbes
2 days ago
4
$begingroup$
It doesn't work like that. It's not like there is a "floor" and signals below it disappear. Every signal (of a given type, e.g. L1) from every GPS satellite in the sky, plus every reflection of every signal from every satellite in the sky plus all sources of noise, all go through one single front end amplifier and then one ADC, where it is digitized into one digital stream of 1's and 0's. That stream is then copied to dozens of identical correlaters, each looking for a different Gold code from a different satellite.
$endgroup$
– uhoh
2 days ago
2
$begingroup$
@uhoh, would need to find a reference, and is a analog artifact but was taught a potential solution for en.wikipedia.org/wiki/Ghosting_(television) where the cause was proximity to the transmitter allowing reflections to be above noise floor was adding an attenutor or just making the antenna less effective. Thinking through may have also been result of of doing AGC later in the signal path than GPS.
$endgroup$
– GremlinWranger
2 days ago
2
$begingroup$
@uhoh, other place I've met power reduction to reduce multipathing is in Sonar, which also does not say anything useful at all about GPS and their somewhat unique receiver design so think I get to learn something today.
$endgroup$
– GremlinWranger
2 days ago
|
show 7 more comments
$begingroup$
There are some big differences between GPS and cell phone signals:
GPS relies on the exact timing of a signal (1 nanosecond off = 30 cm of position inaccuracy). Cell phones are much more tolerant to variations in signal timing. Basically they don't care as long as the packets arrive quickly enough not to cause a gap in the audio.
GPS transmitters are 18,000 km away, cell phone towers are less than 5 km away. So a cell phone signal is much stronger at the receiver.
item 2 could be solved with a stronger transmitter, but that would make #1 worse: with a stronger signal, you get more multipathing: more reflections that are still strong enough to be picked up by the receiver.
You can't really use indoors transmitters either. Many buildings have a steel structure which reflects radio waves, so you get lots of multipathing when the transmitter is inside.
answered 2 days ago
HobbesHobbes
95.5k2272426
$endgroup$
8
$begingroup$
"... with a stronger signal, you get more multipathing..." This sounds like something that's made up and not based in EE fact. Any digital radio receiver system will have automatic gain control (AGC) before the ADC. So as far as the digital signal is concerned, the multipathed reflections will have the same strength relative to the direct path signal no matter what the strength of the satellite's signal is.
$endgroup$
– uhoh
2 days ago
4
$begingroup$
if your signal is weak to begin with, reflections can drop below the noise floor. Strong signal->more reflections make it to the receiver above the noise floor.
$endgroup$
– Hobbes
2 days ago
4
$begingroup$
It doesn't work like that. It's not like there is a "floor" and signals below it disappear. Every signal (of a given type, e.g. L1) from every GPS satellite in the sky, plus every reflection of every signal from every satellite in the sky plus all sources of noise, all go through one single front end amplifier and then one ADC, where it is digitized into one digital stream of 1's and 0's. That stream is then copied to dozens of identical correlaters, each looking for a different Gold code from a different satellite.
$endgroup$
– uhoh
2 days ago
2
$begingroup$
@uhoh, would need to find a reference, and is a analog artifact but was taught a potential solution for en.wikipedia.org/wiki/Ghosting_(television) where the cause was proximity to the transmitter allowing reflections to be above noise floor was adding an attenutor or just making the antenna less effective. Thinking through may have also been result of of doing AGC later in the signal path than GPS.
$endgroup$
– GremlinWranger
2 days ago
2
$begingroup$
@uhoh, other place I've met power reduction to reduce multipathing is in Sonar, which also does not say anything useful at all about GPS and their somewhat unique receiver design so think I get to learn something today.
$endgroup$
– GremlinWranger
2 days ago
|
show 7 more comments
$begingroup$
There are some big differences between GPS and cell phone signals:
GPS relies on the exact timing of a signal (1 nanosecond off = 30 cm of position inaccuracy). Cell phones are much more tolerant to variations in signal timing. Basically they don't care as long as the packets arrive quickly enough not to cause a gap in the audio.
GPS transmitters are 18,000 km away, cell phone towers are less than 5 km away. So a cell phone signal is much stronger at the receiver.
item 2 could be solved with a stronger transmitter, but that would make #1 worse: with a stronger signal, you get more multipathing: more reflections that are still strong enough to be picked up by the receiver.
You can't really use indoors transmitters either. Many buildings have a steel structure which reflects radio waves, so you get lots of multipathing when the transmitter is inside.
answered 2 days ago
HobbesHobbes
95.5k2272426
$endgroup$
There are some big differences between GPS and cell phone signals:
GPS relies on the exact timing of a signal (1 nanosecond off = 30 cm of position inaccuracy). Cell phones are much more tolerant to variations in signal timing. Basically they don't care as long as the packets arrive quickly enough not to cause a gap in the audio.
GPS transmitters are 18,000 km away, cell phone towers are less than 5 km away. So a cell phone signal is much stronger at the receiver.
item 2 could be solved with a stronger transmitter, but that would make #1 worse: with a stronger signal, you get more multipathing: more reflections that are still strong enough to be picked up by the receiver.
You can't really use indoors transmitters either. Many buildings have a steel structure which reflects radio waves, so you get lots of multipathing when the transmitter is inside.
answered 2 days ago
HobbesHobbes
95.5k2272426
answered 2 days ago
HobbesHobbes
95.5k2272426
answered 2 days ago
HobbesHobbes
95.5k2272426
answered 2 days ago
HobbesHobbes
95.5k2272426
95.5k2272426
8
$begingroup$
"... with a stronger signal, you get more multipathing..." This sounds like something that's made up and not based in EE fact. Any digital radio receiver system will have automatic gain control (AGC) before the ADC. So as far as the digital signal is concerned, the multipathed reflections will have the same strength relative to the direct path signal no matter what the strength of the satellite's signal is.
$endgroup$
– uhoh
2 days ago
4
$begingroup$
if your signal is weak to begin with, reflections can drop below the noise floor. Strong signal->more reflections make it to the receiver above the noise floor.
$endgroup$
– Hobbes
2 days ago
4
$begingroup$
It doesn't work like that. It's not like there is a "floor" and signals below it disappear. Every signal (of a given type, e.g. L1) from every GPS satellite in the sky, plus every reflection of every signal from every satellite in the sky plus all sources of noise, all go through one single front end amplifier and then one ADC, where it is digitized into one digital stream of 1's and 0's. That stream is then copied to dozens of identical correlaters, each looking for a different Gold code from a different satellite.
$endgroup$
– uhoh
2 days ago
2
$begingroup$
@uhoh, would need to find a reference, and is a analog artifact but was taught a potential solution for en.wikipedia.org/wiki/Ghosting_(television) where the cause was proximity to the transmitter allowing reflections to be above noise floor was adding an attenutor or just making the antenna less effective. Thinking through may have also been result of of doing AGC later in the signal path than GPS.
$endgroup$
– GremlinWranger
2 days ago
2
$begingroup$
@uhoh, other place I've met power reduction to reduce multipathing is in Sonar, which also does not say anything useful at all about GPS and their somewhat unique receiver design so think I get to learn something today.
$endgroup$
– GremlinWranger
2 days ago
|
show 7 more comments
8
$begingroup$
"... with a stronger signal, you get more multipathing..." This sounds like something that's made up and not based in EE fact. Any digital radio receiver system will have automatic gain control (AGC) before the ADC. So as far as the digital signal is concerned, the multipathed reflections will have the same strength relative to the direct path signal no matter what the strength of the satellite's signal is.
$endgroup$
– uhoh
2 days ago
4
$begingroup$
if your signal is weak to begin with, reflections can drop below the noise floor. Strong signal->more reflections make it to the receiver above the noise floor.
$endgroup$
– Hobbes
2 days ago
4
$begingroup$
It doesn't work like that. It's not like there is a "floor" and signals below it disappear. Every signal (of a given type, e.g. L1) from every GPS satellite in the sky, plus every reflection of every signal from every satellite in the sky plus all sources of noise, all go through one single front end amplifier and then one ADC, where it is digitized into one digital stream of 1's and 0's. That stream is then copied to dozens of identical correlaters, each looking for a different Gold code from a different satellite.
$endgroup$
– uhoh
2 days ago
2
$begingroup$
@uhoh, would need to find a reference, and is a analog artifact but was taught a potential solution for en.wikipedia.org/wiki/Ghosting_(television) where the cause was proximity to the transmitter allowing reflections to be above noise floor was adding an attenutor or just making the antenna less effective. Thinking through may have also been result of of doing AGC later in the signal path than GPS.
$endgroup$
– GremlinWranger
2 days ago
2
$begingroup$
@uhoh, other place I've met power reduction to reduce multipathing is in Sonar, which also does not say anything useful at all about GPS and their somewhat unique receiver design so think I get to learn something today.
$endgroup$
– GremlinWranger
2 days ago
8
8
$begingroup$
"... with a stronger signal, you get more multipathing..." This sounds like something that's made up and not based in EE fact. Any digital radio receiver system will have automatic gain control (AGC) before the ADC. So as far as the digital signal is concerned, the multipathed reflections will have the same strength relative to the direct path signal no matter what the strength of the satellite's signal is.
$endgroup$
– uhoh
2 days ago
$begingroup$
"... with a stronger signal, you get more multipathing..." This sounds like something that's made up and not based in EE fact. Any digital radio receiver system will have automatic gain control (AGC) before the ADC. So as far as the digital signal is concerned, the multipathed reflections will have the same strength relative to the direct path signal no matter what the strength of the satellite's signal is.
$endgroup$
– uhoh
2 days ago
4
4
$begingroup$
if your signal is weak to begin with, reflections can drop below the noise floor. Strong signal->more reflections make it to the receiver above the noise floor.
$endgroup$
– Hobbes
2 days ago
$begingroup$
if your signal is weak to begin with, reflections can drop below the noise floor. Strong signal->more reflections make it to the receiver above the noise floor.
$endgroup$
– Hobbes
2 days ago
4
4
$begingroup$
It doesn't work like that. It's not like there is a "floor" and signals below it disappear. Every signal (of a given type, e.g. L1) from every GPS satellite in the sky, plus every reflection of every signal from every satellite in the sky plus all sources of noise, all go through one single front end amplifier and then one ADC, where it is digitized into one digital stream of 1's and 0's. That stream is then copied to dozens of identical correlaters, each looking for a different Gold code from a different satellite.
$endgroup$
– uhoh
2 days ago
$begingroup$
It doesn't work like that. It's not like there is a "floor" and signals below it disappear. Every signal (of a given type, e.g. L1) from every GPS satellite in the sky, plus every reflection of every signal from every satellite in the sky plus all sources of noise, all go through one single front end amplifier and then one ADC, where it is digitized into one digital stream of 1's and 0's. That stream is then copied to dozens of identical correlaters, each looking for a different Gold code from a different satellite.
$endgroup$
– uhoh
2 days ago
2
2
$begingroup$
@uhoh, would need to find a reference, and is a analog artifact but was taught a potential solution for en.wikipedia.org/wiki/Ghosting_(television) where the cause was proximity to the transmitter allowing reflections to be above noise floor was adding an attenutor or just making the antenna less effective. Thinking through may have also been result of of doing AGC later in the signal path than GPS.
$endgroup$
– GremlinWranger
2 days ago
$begingroup$
@uhoh, would need to find a reference, and is a analog artifact but was taught a potential solution for en.wikipedia.org/wiki/Ghosting_(television) where the cause was proximity to the transmitter allowing reflections to be above noise floor was adding an attenutor or just making the antenna less effective. Thinking through may have also been result of of doing AGC later in the signal path than GPS.
$endgroup$
– GremlinWranger
2 days ago
2
2
$begingroup$
@uhoh, other place I've met power reduction to reduce multipathing is in Sonar, which also does not say anything useful at all about GPS and their somewhat unique receiver design so think I get to learn something today.
$endgroup$
– GremlinWranger
2 days ago
$begingroup$
@uhoh, other place I've met power reduction to reduce multipathing is in Sonar, which also does not say anything useful at all about GPS and their somewhat unique receiver design so think I get to learn something today.
$endgroup$
– GremlinWranger
2 days ago
|
show 7 more comments
$begingroup$
There is existing technology for this, termed "Active,Passive GPS Repeater". It is composed of both an antenna outside and inside, with optionally active or passive components to forward the signal. My introduction to it was within an ocean-going vessel, and it worked fine.
http://www.terrisgps.com/how-do-gps-repeaters-work/
https://www.tri-m.com/index.php/product/tri-m/gps-networking/gps-re-radiators/l1-gps-repeater-kit
https://electronics.stackexchange.com/a/7798/216525
answered 2 days ago
Tyson HilmerTyson Hilmer
692
New contributor
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
9
$begingroup$
Note that a GPS repeater doesn't actually give you indoor navigation - everything receiving the repeated signal computes approximately the same position, that of the outside antenna. (Source: we use these repeaters to be able to do indoor testing of GPS-based equipment that we make.)
$endgroup$
– jasonharper
2 days ago
1
$begingroup$
A cite from your first link: "It should be noted that all the repeaters in a single network will transmit the coordinates of the outdoor antenna and not the position of the repeater unit itself."
$endgroup$
– Uwe
2 days ago
$begingroup$
@jasonharper If they have chosen to transmit the computed GPS position directly to the GPS receivers (so that crew and cruise passenger easily can see on their phones where they are at sea when under deck) instead of via e.g. WiFi, that speaks for the advantage of GPS, as a dominating standard, over indoor positioning systems requiring specific hardware and software.
$endgroup$
– LocalFluff
2 days ago
add a comment |
$begingroup$
There is existing technology for this, termed "Active,Passive GPS Repeater". It is composed of both an antenna outside and inside, with optionally active or passive components to forward the signal. My introduction to it was within an ocean-going vessel, and it worked fine.
http://www.terrisgps.com/how-do-gps-repeaters-work/
https://www.tri-m.com/index.php/product/tri-m/gps-networking/gps-re-radiators/l1-gps-repeater-kit
https://electronics.stackexchange.com/a/7798/216525
answered 2 days ago
Tyson HilmerTyson Hilmer
692
New contributor
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
9
$begingroup$
Note that a GPS repeater doesn't actually give you indoor navigation - everything receiving the repeated signal computes approximately the same position, that of the outside antenna. (Source: we use these repeaters to be able to do indoor testing of GPS-based equipment that we make.)
$endgroup$
– jasonharper
2 days ago
1
$begingroup$
A cite from your first link: "It should be noted that all the repeaters in a single network will transmit the coordinates of the outdoor antenna and not the position of the repeater unit itself."
$endgroup$
– Uwe
2 days ago
$begingroup$
@jasonharper If they have chosen to transmit the computed GPS position directly to the GPS receivers (so that crew and cruise passenger easily can see on their phones where they are at sea when under deck) instead of via e.g. WiFi, that speaks for the advantage of GPS, as a dominating standard, over indoor positioning systems requiring specific hardware and software.
$endgroup$
– LocalFluff
2 days ago
add a comment |
$begingroup$
There is existing technology for this, termed "Active,Passive GPS Repeater". It is composed of both an antenna outside and inside, with optionally active or passive components to forward the signal. My introduction to it was within an ocean-going vessel, and it worked fine.
http://www.terrisgps.com/how-do-gps-repeaters-work/
https://www.tri-m.com/index.php/product/tri-m/gps-networking/gps-re-radiators/l1-gps-repeater-kit
https://electronics.stackexchange.com/a/7798/216525
answered 2 days ago
Tyson HilmerTyson Hilmer
692
New contributor
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
There is existing technology for this, termed "Active,Passive GPS Repeater". It is composed of both an antenna outside and inside, with optionally active or passive components to forward the signal. My introduction to it was within an ocean-going vessel, and it worked fine.
http://www.terrisgps.com/how-do-gps-repeaters-work/
https://www.tri-m.com/index.php/product/tri-m/gps-networking/gps-re-radiators/l1-gps-repeater-kit
https://electronics.stackexchange.com/a/7798/216525
answered 2 days ago
Tyson HilmerTyson Hilmer
692
New contributor
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 2 days ago
Tyson HilmerTyson Hilmer
692
New contributor
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 2 days ago
Tyson HilmerTyson Hilmer
692
answered 2 days ago
Tyson HilmerTyson Hilmer
692
692
New contributor
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Tyson Hilmer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
9
$begingroup$
Note that a GPS repeater doesn't actually give you indoor navigation - everything receiving the repeated signal computes approximately the same position, that of the outside antenna. (Source: we use these repeaters to be able to do indoor testing of GPS-based equipment that we make.)
$endgroup$
– jasonharper
2 days ago
1
$begingroup$
A cite from your first link: "It should be noted that all the repeaters in a single network will transmit the coordinates of the outdoor antenna and not the position of the repeater unit itself."
$endgroup$
– Uwe
2 days ago
$begingroup$
@jasonharper If they have chosen to transmit the computed GPS position directly to the GPS receivers (so that crew and cruise passenger easily can see on their phones where they are at sea when under deck) instead of via e.g. WiFi, that speaks for the advantage of GPS, as a dominating standard, over indoor positioning systems requiring specific hardware and software.
$endgroup$
– LocalFluff
2 days ago
add a comment |
9
$begingroup$
Note that a GPS repeater doesn't actually give you indoor navigation - everything receiving the repeated signal computes approximately the same position, that of the outside antenna. (Source: we use these repeaters to be able to do indoor testing of GPS-based equipment that we make.)
$endgroup$
– jasonharper
2 days ago
1
$begingroup$
A cite from your first link: "It should be noted that all the repeaters in a single network will transmit the coordinates of the outdoor antenna and not the position of the repeater unit itself."
$endgroup$
– Uwe
2 days ago
$begingroup$
@jasonharper If they have chosen to transmit the computed GPS position directly to the GPS receivers (so that crew and cruise passenger easily can see on their phones where they are at sea when under deck) instead of via e.g. WiFi, that speaks for the advantage of GPS, as a dominating standard, over indoor positioning systems requiring specific hardware and software.
$endgroup$
– LocalFluff
2 days ago
9
9
$begingroup$
Note that a GPS repeater doesn't actually give you indoor navigation - everything receiving the repeated signal computes approximately the same position, that of the outside antenna. (Source: we use these repeaters to be able to do indoor testing of GPS-based equipment that we make.)
$endgroup$
– jasonharper
2 days ago
$begingroup$
Note that a GPS repeater doesn't actually give you indoor navigation - everything receiving the repeated signal computes approximately the same position, that of the outside antenna. (Source: we use these repeaters to be able to do indoor testing of GPS-based equipment that we make.)
$endgroup$
– jasonharper
2 days ago
1
1
$begingroup$
A cite from your first link: "It should be noted that all the repeaters in a single network will transmit the coordinates of the outdoor antenna and not the position of the repeater unit itself."
$endgroup$
– Uwe
2 days ago
$begingroup$
A cite from your first link: "It should be noted that all the repeaters in a single network will transmit the coordinates of the outdoor antenna and not the position of the repeater unit itself."
$endgroup$
– Uwe
2 days ago
$begingroup$
@jasonharper If they have chosen to transmit the computed GPS position directly to the GPS receivers (so that crew and cruise passenger easily can see on their phones where they are at sea when under deck) instead of via e.g. WiFi, that speaks for the advantage of GPS, as a dominating standard, over indoor positioning systems requiring specific hardware and software.
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@jasonharper If they have chosen to transmit the computed GPS position directly to the GPS receivers (so that crew and cruise passenger easily can see on their phones where they are at sea when under deck) instead of via e.g. WiFi, that speaks for the advantage of GPS, as a dominating standard, over indoor positioning systems requiring specific hardware and software.
$endgroup$
– LocalFluff
2 days ago
add a comment |
$begingroup$
In general, if you need a local indoor navigation system, then you are better off implementing your own. Generally speaking these are called Indoor Positioning Systems. There isn't yet a standard, but there has been some work to making one. It would be MUCH cheaper, more accurate, and overall just better.
GPS satellites are expensive, they are all space rated atomic clocks, some of the most accurate clocks ever created, and the most accurate in orbit. Making thousands of them would be very expensive, and not really gain a lot.
All that being said, there are a few things that can be done. The way indoor GPS typically works is by estimating your location from other means, and looking for the very low signal strength signal coming at the right time.
answered 2 days ago
PearsonArtPhoto♦PearsonArtPhoto
84.2k16243465
$endgroup$
$begingroup$
Low altitude GPS satellites do have conceptual problems with time in sight and Earth's shadow. But I'm pretty sure that putting nuclear reactors on the GPS satellites to up their power (if that would be a solution) is cheaper than installing and maintaining unstandardized indoor systems in billions of buildings. Just changing the beacons' batteries or cabling them to the power grid is a pain. GPS isn't more expensive than EU, Russia, China, Japan and India all have gotten their own (redundant) positioning satellite constellations.
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@LocalFluff Nuclear reactors in LEO ?!!
$endgroup$
– Antzi
2 days ago
$begingroup$
@Anzi Nuclear rather as the alternative to having GPS satellites in LEO. With enough power generation they could beam their radio the more powerful from 30 times further away,
$endgroup$
– LocalFluff
2 days ago
$begingroup$
They may not be cheaper though. Suppose you can either include an extra stage in your mobile phone's chipset to (somehow) pick up GPS indoors, or install an indoor positioning system. The former is cheap (add to a handful of chip designs => solved for most devices within 2 years, similar to adding GALILEO or GLONASS, low cost). The latter needs every building to buy new hardware and install it, effectively billions of individual boxes to buy, install, and run on mains power for the rest of time.
$endgroup$
– Stilez
2 days ago
2
$begingroup$
No satellite from far far away will possibly give the precision that a local system would require. Also, indoor will always suffer from multipath, which will degrade the accuracy further. One of the interesting ideas I've heard in this regard is to use the local wifi signals as a kind of GPS signal, which would be totally doable.
$endgroup$
– PearsonArtPhoto♦
2 days ago
|
show 2 more comments
$begingroup$
In general, if you need a local indoor navigation system, then you are better off implementing your own. Generally speaking these are called Indoor Positioning Systems. There isn't yet a standard, but there has been some work to making one. It would be MUCH cheaper, more accurate, and overall just better.
GPS satellites are expensive, they are all space rated atomic clocks, some of the most accurate clocks ever created, and the most accurate in orbit. Making thousands of them would be very expensive, and not really gain a lot.
All that being said, there are a few things that can be done. The way indoor GPS typically works is by estimating your location from other means, and looking for the very low signal strength signal coming at the right time.
answered 2 days ago
PearsonArtPhoto♦PearsonArtPhoto
84.2k16243465
$endgroup$
$begingroup$
Low altitude GPS satellites do have conceptual problems with time in sight and Earth's shadow. But I'm pretty sure that putting nuclear reactors on the GPS satellites to up their power (if that would be a solution) is cheaper than installing and maintaining unstandardized indoor systems in billions of buildings. Just changing the beacons' batteries or cabling them to the power grid is a pain. GPS isn't more expensive than EU, Russia, China, Japan and India all have gotten their own (redundant) positioning satellite constellations.
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@LocalFluff Nuclear reactors in LEO ?!!
$endgroup$
– Antzi
2 days ago
$begingroup$
@Anzi Nuclear rather as the alternative to having GPS satellites in LEO. With enough power generation they could beam their radio the more powerful from 30 times further away,
$endgroup$
– LocalFluff
2 days ago
$begingroup$
They may not be cheaper though. Suppose you can either include an extra stage in your mobile phone's chipset to (somehow) pick up GPS indoors, or install an indoor positioning system. The former is cheap (add to a handful of chip designs => solved for most devices within 2 years, similar to adding GALILEO or GLONASS, low cost). The latter needs every building to buy new hardware and install it, effectively billions of individual boxes to buy, install, and run on mains power for the rest of time.
$endgroup$
– Stilez
2 days ago
2
$begingroup$
No satellite from far far away will possibly give the precision that a local system would require. Also, indoor will always suffer from multipath, which will degrade the accuracy further. One of the interesting ideas I've heard in this regard is to use the local wifi signals as a kind of GPS signal, which would be totally doable.
$endgroup$
– PearsonArtPhoto♦
2 days ago
|
show 2 more comments
$begingroup$
In general, if you need a local indoor navigation system, then you are better off implementing your own. Generally speaking these are called Indoor Positioning Systems. There isn't yet a standard, but there has been some work to making one. It would be MUCH cheaper, more accurate, and overall just better.
GPS satellites are expensive, they are all space rated atomic clocks, some of the most accurate clocks ever created, and the most accurate in orbit. Making thousands of them would be very expensive, and not really gain a lot.
All that being said, there are a few things that can be done. The way indoor GPS typically works is by estimating your location from other means, and looking for the very low signal strength signal coming at the right time.
answered 2 days ago
PearsonArtPhoto♦PearsonArtPhoto
84.2k16243465
$endgroup$
In general, if you need a local indoor navigation system, then you are better off implementing your own. Generally speaking these are called Indoor Positioning Systems. There isn't yet a standard, but there has been some work to making one. It would be MUCH cheaper, more accurate, and overall just better.
GPS satellites are expensive, they are all space rated atomic clocks, some of the most accurate clocks ever created, and the most accurate in orbit. Making thousands of them would be very expensive, and not really gain a lot.
All that being said, there are a few things that can be done. The way indoor GPS typically works is by estimating your location from other means, and looking for the very low signal strength signal coming at the right time.
answered 2 days ago
PearsonArtPhoto♦PearsonArtPhoto
84.2k16243465
edited 2 days ago
answered 2 days ago
PearsonArtPhoto♦PearsonArtPhoto
84.2k16243465
answered 2 days ago
PearsonArtPhoto♦PearsonArtPhoto
84.2k16243465
answered 2 days ago
PearsonArtPhoto♦PearsonArtPhoto
84.2k16243465
84.2k16243465
$begingroup$
Low altitude GPS satellites do have conceptual problems with time in sight and Earth's shadow. But I'm pretty sure that putting nuclear reactors on the GPS satellites to up their power (if that would be a solution) is cheaper than installing and maintaining unstandardized indoor systems in billions of buildings. Just changing the beacons' batteries or cabling them to the power grid is a pain. GPS isn't more expensive than EU, Russia, China, Japan and India all have gotten their own (redundant) positioning satellite constellations.
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@LocalFluff Nuclear reactors in LEO ?!!
$endgroup$
– Antzi
2 days ago
$begingroup$
@Anzi Nuclear rather as the alternative to having GPS satellites in LEO. With enough power generation they could beam their radio the more powerful from 30 times further away,
$endgroup$
– LocalFluff
2 days ago
$begingroup$
They may not be cheaper though. Suppose you can either include an extra stage in your mobile phone's chipset to (somehow) pick up GPS indoors, or install an indoor positioning system. The former is cheap (add to a handful of chip designs => solved for most devices within 2 years, similar to adding GALILEO or GLONASS, low cost). The latter needs every building to buy new hardware and install it, effectively billions of individual boxes to buy, install, and run on mains power for the rest of time.
$endgroup$
– Stilez
2 days ago
2
$begingroup$
No satellite from far far away will possibly give the precision that a local system would require. Also, indoor will always suffer from multipath, which will degrade the accuracy further. One of the interesting ideas I've heard in this regard is to use the local wifi signals as a kind of GPS signal, which would be totally doable.
$endgroup$
– PearsonArtPhoto♦
2 days ago
|
show 2 more comments
$begingroup$
Low altitude GPS satellites do have conceptual problems with time in sight and Earth's shadow. But I'm pretty sure that putting nuclear reactors on the GPS satellites to up their power (if that would be a solution) is cheaper than installing and maintaining unstandardized indoor systems in billions of buildings. Just changing the beacons' batteries or cabling them to the power grid is a pain. GPS isn't more expensive than EU, Russia, China, Japan and India all have gotten their own (redundant) positioning satellite constellations.
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@LocalFluff Nuclear reactors in LEO ?!!
$endgroup$
– Antzi
2 days ago
$begingroup$
@Anzi Nuclear rather as the alternative to having GPS satellites in LEO. With enough power generation they could beam their radio the more powerful from 30 times further away,
$endgroup$
– LocalFluff
2 days ago
$begingroup$
They may not be cheaper though. Suppose you can either include an extra stage in your mobile phone's chipset to (somehow) pick up GPS indoors, or install an indoor positioning system. The former is cheap (add to a handful of chip designs => solved for most devices within 2 years, similar to adding GALILEO or GLONASS, low cost). The latter needs every building to buy new hardware and install it, effectively billions of individual boxes to buy, install, and run on mains power for the rest of time.
$endgroup$
– Stilez
2 days ago
2
$begingroup$
No satellite from far far away will possibly give the precision that a local system would require. Also, indoor will always suffer from multipath, which will degrade the accuracy further. One of the interesting ideas I've heard in this regard is to use the local wifi signals as a kind of GPS signal, which would be totally doable.
$endgroup$
– PearsonArtPhoto♦
2 days ago
$begingroup$
Low altitude GPS satellites do have conceptual problems with time in sight and Earth's shadow. But I'm pretty sure that putting nuclear reactors on the GPS satellites to up their power (if that would be a solution) is cheaper than installing and maintaining unstandardized indoor systems in billions of buildings. Just changing the beacons' batteries or cabling them to the power grid is a pain. GPS isn't more expensive than EU, Russia, China, Japan and India all have gotten their own (redundant) positioning satellite constellations.
$endgroup$
– LocalFluff
2 days ago
$begingroup$
Low altitude GPS satellites do have conceptual problems with time in sight and Earth's shadow. But I'm pretty sure that putting nuclear reactors on the GPS satellites to up their power (if that would be a solution) is cheaper than installing and maintaining unstandardized indoor systems in billions of buildings. Just changing the beacons' batteries or cabling them to the power grid is a pain. GPS isn't more expensive than EU, Russia, China, Japan and India all have gotten their own (redundant) positioning satellite constellations.
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@LocalFluff Nuclear reactors in LEO ?!!
$endgroup$
– Antzi
2 days ago
$begingroup$
@LocalFluff Nuclear reactors in LEO ?!!
$endgroup$
– Antzi
2 days ago
$begingroup$
@Anzi Nuclear rather as the alternative to having GPS satellites in LEO. With enough power generation they could beam their radio the more powerful from 30 times further away,
$endgroup$
– LocalFluff
2 days ago
$begingroup$
@Anzi Nuclear rather as the alternative to having GPS satellites in LEO. With enough power generation they could beam their radio the more powerful from 30 times further away,
$endgroup$
– LocalFluff
2 days ago
$begingroup$
They may not be cheaper though. Suppose you can either include an extra stage in your mobile phone's chipset to (somehow) pick up GPS indoors, or install an indoor positioning system. The former is cheap (add to a handful of chip designs => solved for most devices within 2 years, similar to adding GALILEO or GLONASS, low cost). The latter needs every building to buy new hardware and install it, effectively billions of individual boxes to buy, install, and run on mains power for the rest of time.
$endgroup$
– Stilez
2 days ago
$begingroup$
They may not be cheaper though. Suppose you can either include an extra stage in your mobile phone's chipset to (somehow) pick up GPS indoors, or install an indoor positioning system. The former is cheap (add to a handful of chip designs => solved for most devices within 2 years, similar to adding GALILEO or GLONASS, low cost). The latter needs every building to buy new hardware and install it, effectively billions of individual boxes to buy, install, and run on mains power for the rest of time.
$endgroup$
– Stilez
2 days ago
2
2
$begingroup$
No satellite from far far away will possibly give the precision that a local system would require. Also, indoor will always suffer from multipath, which will degrade the accuracy further. One of the interesting ideas I've heard in this regard is to use the local wifi signals as a kind of GPS signal, which would be totally doable.
$endgroup$
– PearsonArtPhoto♦
2 days ago
$begingroup$
No satellite from far far away will possibly give the precision that a local system would require. Also, indoor will always suffer from multipath, which will degrade the accuracy further. One of the interesting ideas I've heard in this regard is to use the local wifi signals as a kind of GPS signal, which would be totally doable.
$endgroup$
– PearsonArtPhoto♦
2 days ago
|
show 2 more comments
$begingroup$
1. Assuming that your application can (or does) use an external GPS antenna, keep in mind that they are not all the same. They are available in different gains.
I use them for two lightningmaps.org receivers. One is far more sensitive than the other, and I might be able to get away from using it indoors (though I have never tried to).
2. Many have had success by placing GPS antennas next to windows. Glass does not attenuate the signals like foil-backed building insulation, wiring, etc. does.
A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
answered 2 days ago
Mike WatersMike Waters
1215
New contributor
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Question did not ask for GPS indoor receiption only, it was about GPS indoor navigation too. A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
$endgroup$
– Uwe
yesterday
$begingroup$
@Uwe Thanks. Comment edited to include that.
$endgroup$
– Mike Waters
yesterday
add a comment |
$begingroup$
1. Assuming that your application can (or does) use an external GPS antenna, keep in mind that they are not all the same. They are available in different gains.
I use them for two lightningmaps.org receivers. One is far more sensitive than the other, and I might be able to get away from using it indoors (though I have never tried to).
2. Many have had success by placing GPS antennas next to windows. Glass does not attenuate the signals like foil-backed building insulation, wiring, etc. does.
A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
answered 2 days ago
Mike WatersMike Waters
1215
New contributor
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Question did not ask for GPS indoor receiption only, it was about GPS indoor navigation too. A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
$endgroup$
– Uwe
yesterday
$begingroup$
@Uwe Thanks. Comment edited to include that.
$endgroup$
– Mike Waters
yesterday
add a comment |
$begingroup$
1. Assuming that your application can (or does) use an external GPS antenna, keep in mind that they are not all the same. They are available in different gains.
I use them for two lightningmaps.org receivers. One is far more sensitive than the other, and I might be able to get away from using it indoors (though I have never tried to).
2. Many have had success by placing GPS antennas next to windows. Glass does not attenuate the signals like foil-backed building insulation, wiring, etc. does.
A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
answered 2 days ago
Mike WatersMike Waters
1215
New contributor
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1. Assuming that your application can (or does) use an external GPS antenna, keep in mind that they are not all the same. They are available in different gains.
I use them for two lightningmaps.org receivers. One is far more sensitive than the other, and I might be able to get away from using it indoors (though I have never tried to).
2. Many have had success by placing GPS antennas next to windows. Glass does not attenuate the signals like foil-backed building insulation, wiring, etc. does.
A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
answered 2 days ago
Mike WatersMike Waters
1215
New contributor
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited yesterday
answered 2 days ago
Mike WatersMike Waters
1215
New contributor
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 2 days ago
Mike WatersMike Waters
1215
answered 2 days ago
Mike WatersMike Waters
1215
1215
New contributor
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Mike Waters is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
$begingroup$
Question did not ask for GPS indoor receiption only, it was about GPS indoor navigation too. A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
$endgroup$
– Uwe
yesterday
$begingroup$
@Uwe Thanks. Comment edited to include that.
$endgroup$
– Mike Waters
yesterday
add a comment |
1
$begingroup$
Question did not ask for GPS indoor receiption only, it was about GPS indoor navigation too. A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
$endgroup$
– Uwe
yesterday
$begingroup$
@Uwe Thanks. Comment edited to include that.
$endgroup$
– Mike Waters
yesterday
1
1
$begingroup$
Question did not ask for GPS indoor receiption only, it was about GPS indoor navigation too. A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
$endgroup$
– Uwe
yesterday
$begingroup$
Question did not ask for GPS indoor receiption only, it was about GPS indoor navigation too. A GPS receiver connected to an external (outdoor) antenna would determine the position of that outdoor antenna.
$endgroup$
– Uwe
yesterday
$begingroup$
@Uwe Thanks. Comment edited to include that.
$endgroup$
– Mike Waters
yesterday
$begingroup$
@Uwe Thanks. Comment edited to include that.
$endgroup$
– Mike Waters
yesterday
add a comment |
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1
$begingroup$
Not all cell phones work fine indoors and not in every building. There are metall roofs and steel construction buildings. Multi path distribution of satellite signals does harm the GPS position precision. The speed of electric waves is different in air and in solid materials ( non metallic solids ). But GPS even handles different speed of light in vacuum and air. But how to handle the much lower speed in solids?
$endgroup$
– Uwe
2 days ago
4
$begingroup$
All you have to do is construct your building appropriately. GPS works perfectly well inside my (wood frame, single story, non-metal roof) house.
$endgroup$
– jamesqf
2 days ago
$begingroup$
@jamesqf Really? It's been some years since I disappointingly tried out GPS inside a hut, and maybe with already then old equipment. The receivers have been getting alot better. But how far could that development go?
$endgroup$
– LocalFluff
2 days ago
1
$begingroup$
There is no need to install radio beacons for a indoor positioning system. Wifi access points which are ubiquitous these days can do that job. Wifi positioning system (en.wikipedia.org/wiki/Wi-Fi_positioning_system) is already used extensively by mobile phones and laptops and have a better accuracy than GPS indoors.
$endgroup$
– Kevin Selva Prasanna
yesterday
1
$begingroup$
The comparison with phones is really unhelpful. You yourself state why: "since they often have bounced". While that is a problem for GPS, your phone doesn't care at all, hence it works
$endgroup$
– Hobbamok
yesterday