GPS-enabled navigation is common. There are softwares for locating a person by his cellphone signal(other than GPS), but can we do realtime tracking also as in the case of GPS navigation systems?
Cell phones use a concept known as Assisted GPS, meaning that the network assists the phone in acquiring a GPS lock by providing assistance data about where the base stations are and what satellites are visible in the sky from their location. A stand-alone GPS (e.g. your Garmin receiver for your car) doesn't have this additional information and thus takes longer to find the satellites the first time (obtain a first fix) and is more likely to get lost.
Beyond that, the primary purpose for A-GPS is for the carriers to provide location based services (LBS) including the mandated e911. Thus, the location information is fed back to the network to provide customized LBS including emergency location, turn-by-turn directions, etc. So yes, it's possible to remotely track a cell phone using LBS.
Michael Sir, I intend to track my cellphone located inside a pipeline 1 m below the soil. I have tested that the cell phone signal reaches there, but GPS signal doesn't
Assisted GPS to track the UE requires the receiving of the GPS signals. Therefore, if you could not receive any GPS signal, A-GPS most likely could not help. In this case, you need some other tech. to track the UE movement. There are many studies (e.g., wifi) and companies work on this issues, e.g., the famous Google Maps Geolocation API. Such kinds of researches locate the UE by the already known radio nodes, including wifi APs, cell towers, or even possibly by those UEs next to the tracking one.
Therefore, for your questions:
(1) Can we do realtime tracking also as in the case of GPS navigation systems? Yes.
(2) Could we do that in the pipeline below the soil? Yes, if there are enough radio nodes and signals.
Hope this info would help.
Most land based approaches for positioning use time-of-flight calculations to triangulate the distance between various base stations. This works pretty well for TDD signals like Wi-Fi and TDMA signals like GSM. It's not as practical for CDMA and the like.
The bigger concern is about what you're trying to do. In another post you indicated it was a metal pipe. Metal pipe = shield. Lots of earth tends to be a pretty good shield too. However, you also indicate you've been able to receive cellular signals in the pipe. How was that detected? I'm doubting you crawled to the middle of a pipeline and were sealed in at both ends. Open ended pipe also = waveguide. Signals entering the end of the pipe will bounce down the pipe and propagate a significant distance with less loss (assuming a good conductor) than you'd get in free space. However, in terms of location, the data will be useless. Any time of flight information will be covering the distance from the cell towers to the end of the pipe, and from there to the radio in the pipe along the length of the pipeline. Thus all signals will have the same distance in the pipeline. Any triangulation algorithm assuming line of sight from the tower will go nuts trying to triangulate (A+X, B+X, C+X) where A, B, and C are distances from three towers to the opening in the pipe and X is the distance of the radio down the pipe. Assuming it can get a solution, it won't be where the device is!
Now, if I were to assume that someone knows WHERE the pipe is buried and you're primarily trying to determine where your device is in the pipe, you could use this sort of technology to determine the distance to the radio from another radio in the pipe. For that you could probably just use Wi-Fi and some of the experimental TOF software that's out there.
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