Is there any library that can help me determine one mobiles devices position in relation to other?
For example:
Can one iPhone determine that there is another one laying next to it and if so which way is it facing?
I don't know of a way to do what you are asking.
NFC requires the devices to basically touch. Wifi and GPS location services probably don't have the granularity to determine location to that precise level. It would probably be possible to use the location services to determine if two phones were in the same room (not table), and which location. I think in real world, this would with variable results, and not be feasible.
I wonder if the new Wifi Direct technologies provide anything like that.
On Android you can use Near Field Communication
Related
I'm trying to find a good way to track location of people in a building. I would ultimately like to be able to create a graphic on demand showing where employees are in a building - which floor (elevation), and where on the floor they are located (lat/lon). I have read that elevation is relative to the WGS84 ellipsoid, not sea level necessarily, which is fine. I can define a baseline of where the first floor is, for example, and then calculate the difference of a person's current location from there. If I understand correctly, the general precision lat/lon for a GPS is as fine as 1m, which should be sufficient for me.
Part of my problem is finding a device to use for employees to carry around. The other is finding a device with a supported API (read: "free API") or other programming options. I would like this to be manufacturer-independent.
I would love to do cross-platform development - iOS, Android, PC, web, etc.
Does anyone have experience with something like this, and what recommendations can you offer on where to start? I know this is a little open ended but I'm not sure where to start.
Thanks.
This all does not work (tracking within a building).
GPS Signal is very poor or non existent within a building.
(Next time search here on Stackoverflow. It has been asked some times.)
The only robust and working solution, are BlueTooth beacons.
Such small hardware pieces are mounted within the building.
Such beacons (search for iBeacon) just send out an id.
The phone receives the id, and the approximate distance to it.
You have to administrate and know which id is at which level of the building.
Even when having good reception the GPS signal is not precise enough to determine the floor a person is location.
Some phones have a barometer, like the ipHone, this can track relative heigh changes, and may be used to determine level within a building. (Once calibrated before entering the buulding)
I would like to make an app which is keep tracking various points in a room in 3D and can tell where to look up the tracked points again.
The problem is: I can't use GPS and Wifi points to determine my phone's location and orientation.
So far I know two things which can be useful in this case, the gravitation force, and magnetic north. It is not a problem if there is some misleading fake magnetic north unless it is too close to the room where I want to locate things.
I found that the gyro + acceleration isn't accurate enough to use, is there a "ready made" API what I can use for that? I have the feeling I am reinventing the wheel.
Thanks in advance.
There is only one "ready made" API - Fused locations ( https://developer.android.com/google/play-services/location.html ). But currently it relies on GPS/WiFi/Cell-tower data. I don't beleive there is easy/cheap solution for your problem.
You could use bunch of Bluetooth devices, maybe some BT4 low power tags. Place them everywhere in the room and measure signal strength of each.
I want to develop an application in which I need to know the position of my device within a building (the room in which the device currently is). GPS is not working in the building. Is there any way to find the position of the device in building? If yes how? Can i use position or motion sensors or combination of these for this purpose?
There is no general solution. In case you can place WiFi hotspots/repeaters in the building (preferably in every room), you can triangulate the position from the WiFi signal strengths. But that's also not straightforward, because of different signal losses through the walls and floors. You'll need to survey the building and make a signal strength map in advance and then, based on the signals you receive, look up your location on the map.
Motion sensors are also not precise enough and compass, if you are inside a steel construction, is inaccurate, too.
You can try using the Network to locate the user. If the signal is strong enough, it should return a decent location fix, though not as accurate as GPS
Unfortunately there is no easy solution. Network location is out of the question, since it is not precise enough to show buildings, not even mentioning rooms.
The only way I could think of for this to work is to use external sensors in building and somehow connect them with the device.
I am developing a project that is intended to use the GPS capabilities of an Android phone and a nearby station to compute positioning to a much more precise degree (cm), using RTK DGPS technology.
So far, I haven't been able to see anyone saying they actually managed to perform a similar task (apart from #GPSmaster, who doesn't explain how), and the APK doesn't seem to offer any information from the GPS chip other than location and NMEA message updates. I need, if possible, pseudo-ranges and carrier phases.
I was wondering if:
It would be possible to look for lower level hooks on my phone using native code, or other lower level snooping;
It would be possible to send RTCM corrections to the GPS chip present on one of these devices;
Any ideas?
Generally speaking DGPS is a technique that improves real position accuracy by canceling out most of the atmospheric effects on the GPS signal. In a typical direct GPS measurement there is about a random error in the ranges computed to the satellites due to atmospheric effects. This is why a GPS receiver that is left collecting data in a fixed location will seem to wander with in an error ellipse. For two receiver stations in the same area the atmospheric effects are almost identical and they will wander in parallel within their similarly sized and oriented error ellipses. If one of the two receivers is at a know location then the differences in their apparent GPS locations can be taken and plotted from the true location of the known station to find the true location of the unknown station.
Back in the day (circa 1992) when we had to accomplish DGPS by "post processing" we used to take the raw NEMA data collected at the two stations match up the times, compute the baseline vector and apply it to the known point to find the unknown point. I think the NEMA data we were using was only recorded to the nearest 10 sec. The math isn't really that hard.
I suspect that NEMA GPS messages [http://developer.android.com/reference/android/location/GpsStatus.NmeaListener.html ] from a tablet at a known point (with a clear sky view) could probably be sent over an internet socket to a smart phone (also with a clear sky view), which could then compute the difference and achieve a sub-meter relative location over a distance of few km, even if the assumed Internet transit times were ignored. This technique would probably still work even if the tablet and smart phone were both applying broadcast DGPS adjustments.
With the andvent of Android 7.1, the raw data from GPS chips will be available to developers. (http://gpsworld.com/google-to-provide-raw-gnss-measurements/)
Others seem to have done something similar to what you wish to accomplish (http://gpsworld.com/innovation-precise-positioning-using-raw-gps-measurements-from-android-smartphones/)
No, it is not practical to get any lower level access to the GPS device by an Android application. This has several reasons:
The application has no other means of accessing the GPS device as through the Java based API. Native code is forbidden to use most devices and usually needs a Java wrapper to tunnel through the sandbox for Android sensor devices. This makes up the main security concept.
If native code would have access to the GPS device on a lower level, it would have to cope with several different manufacturers protocols now not abstracted by the API. Best chances are to get access to custom NMEA codes, which may still have device dependent caveats.
Even if lower level access would be possible, one loses the integrated merging of other location sources like WLAN and cellphone carrier, that are presumably merged in native code below the Java API but above the NMEA protocol.
You can use DGPS corrections in Europe via custom application for SISnet receiving correction signals from EGNOS augmentation satellites(http://egnos-portal.gsa.europa.eu/news/egnos-gets-invite-your-smartphone-11). It does however need a subscription (which isn't really open to public yet) to SISnet to obtain username and password for connection to their servers. There's some of SDK published which you may find useful. Just remember that you are limited to C/A signals only (pseudoranges) and you CANNOT get phase data (L1/L2) from those cheap chips inside smartphones.You'd need a precision GNSS receiver such as Trimble BD910 (http://www.trimble.com/gnss-inertial/bd910.aspx?dtID=overview) to be able to access L1 carrier phase signal for GPS & GLONASS. There are however cheaper chips that support SBAS but none are yet installed natively in phones.
Umm. Your android probably has such a crap GPS antenna that achieving cm accuracy is impossible. Maybe if you average the position for days.. usually DGPS support is not published and not many chipsets support it. Last time I saw DGPS implemented it involved hacking the actual GPS chip firmware to add support. Even getting A-GPS to work on a random chipset is iffy since they might not support a documented way of feeding the assistance data.
It should be related with the hardware implementation , rather than the software implementation.
In the reality, GPS is usually accompanied with Wi-Fi or 3G to assist in searching the current position.
RTCM correction can be sent to your android phone using NTRIP 'provider'. Then you need to apply it to your raw GPS in your android.
I was wondering if it were possible to have two cellphones interact with one another like a radar/sonar device to be able to find one another or be accurate within maybe 500 yards or so? Also, if there is a way to do it without the GPS or connecting to a cell tower (like being indoors or out in a desert)? Are there any technologies resident in a cellphone that can bounce off each other link radar to find one another basically without the need for gps/cell tower triangulation? Im trying to create a fun app similar to the Ghostbuster's EKG Meter :-)
Wifi direct can reach further than Bluetooth and also transmit data faster http://developer.android.com/guide/topics/wireless/wifip2p.html
But 500 yards seems to be too far for the technology reside in the current mobile phone.
No.
Even going through all the other ways a phone could possibly connect to another phone(bluetooth, ad-hoc networking, wireless network...), you have no frame of reference to calculate distance. You couldn't possibly "ping" another phone, and derive distance from that ping like you could with sonar/radar. You need another fixed point to derive the distance like you could with triangulation, or 2 fixed points with GPS.
Sorry.. doesn't sound feasible.
You can't use Wifi or Bluetooth for this (there is a reason why when installing a pro-network, they do wave propagation models of the building). Sound won't work also, as the sampling rates in iPhone are limited as explained here.