Hello everyone, I have a very important question about GPS modules, does not all gps modules work inside the building, because I have a NEO6MV2 type module in my project and in the game improvement I have a part that deals with INDOOR
In general, GPS units do not work without a clear view of most of the sky.
For indoor localization, there is Poszyx.
Most GPS modules do work to some extent indoors. The GPS signals can go around corners a little and they are pretty good at going through window glass.
But remember how GPS works: it measures the distance to each satellite. So if you are sitting indoors near a window, the distance is measured to the window and then direct to the satellite. The best solution for those weird distances is to subtract the distance to the window from every satellite. So the GPS will show you sitting at the window, no matter how far away you are. If you walk towards another window, it starts to see signals coming in that window, with even more distance errors. Maybe it will 'snap' to that window or maybe it will show you a position that's underground.
Car GPS's are particularly good at 'snapping' - they snap to roads. So if it gets a weird bunch of distances, it will try to show you on the nearest road.
None of the seven GPS units I own work indoors, in a single story dwelling.
Three are high end commercial Garmin units, one is an Android, three others are various GPS modules, including one NEO6MV2.
The large Ublox GPSs with the 25mm ceramic patch antenna, do sometimes work indoors and more so if they are near a Window.
It varies so much however, and often does not work at all, that it would be pointless planning a project that depended on these types of GPS working indoors.
I read a paper about warehouse robots using 2D barcodes on the floor for indoor positioning. The barcodes are spaced about 1 meter apart.
GPS doesn't work indoors(*). It used not to work much in cities (restricted view of sky) until newer chipsets
that managed to do a better job in the face of multipath reception, and there were more satellites in the sky.
(*) Unless you're in a loft/roofspace!
Ok thank you everyone, so the gps maybe work in door and maybe no it depended of antenna No?
You should just plan on a GPS NOT working indoors.
It depends on what you mean by "work".
You can get a really good time signal from GPS. Great for synchronizing data loggers without having to set the clock on each one.
Under favourable conditions or if you just wait long enough to see enough satellites through the windows, you will probably know where you are to about 200m accuracy. In the city, that won't tell you which building you're in but you do know which street.
I have an Adafruit Ultimate GPS. It works reasonably well on the main floor of my house but it works much better when I attach an active antenna. It takes longer to get a lock without the external antenna but once it has a lock it gives the position within about 5 metres with or without the active antenna.
Pete
it gives the position within about 5 metres
Excellent. That should be good enough to determine whether you are actually in the house, at least some of the time.
el_supremo:
It takes longer to get a lock without the external antenna but once it has a lock it gives the position within about 5 metres with or without the active antenna.
How did you check the accuracy ?
When a GPS tells you the predicted accuracy, thats a guess, it does not know.
jremington:
None of the seven GPS units I own work indoors, in a single story dwelling.Three are high end commercial Garmin units, one is an Android, three others are various GPS modules, including one NEO6MV2.
This is probably more a function of the building than the particular GPS receiver.
I've done testing indoors with a GPS located near a window and it worked well enough to give me time sync. I'd expect both the time and position accuracy are degraded in this situation.
How did you check the accuracy ?
I just left my logger running with the GPS sitting on the dining room table (with just the ceramic patch antenna) and then loaded the GPX file into Google Earth. It does seem to get within 5m although there are occasional glitches outside this range. You clearly can't count on a single reading.
My house is primarily constructed of wood with vinyl/plastic siding. The same house with aluminium siding would probably obtain very different results.
Pete
This is probably more a function of the building than the particular GPS receiver.
That is the entire point, although some GPS receivers and antenna combinations are considerably more sensitive than others.
None of us has a clue what sort of building the OP is in, so it is pointless to encourage the OP to use a GPS "indoors", especially for positioning a robot.
Robot? Cool!
jremington:
None of us has a clue what sort of building the OP is in, so it is pointless to encourage the OP to use a GPS "indoors", especially for positioning a robot.
Agreed.
Planning a project assuming that something (like a GPS) might possibly work, sometimes maybe, or probably not, is a waste of time and effort.