Detect/sniff GPS signals
 

After dealing with an issue in work this thought struck me. First i'll explain the issue i had first.

We had a GPS tracking system attached to the inside of a steel container, the Antennae was on the inside also. The GPS system was functional but we found that our hardware that was inside the container kept having problems and after replacing everything we disconnected the GPS system and we stopped having faults with our hardware. We had the company who managed the GPS systems investigate and it turns out the Antennae was causing problems with the electronics on our hardware.

What i'm wondering is if we can use the gps on the n900 like we use the wifi in monitor mode and detect the signal strength or if there's some way we can detect how strong the signal is in a particular transmitter. I know you can buy devices for checking the different radio waves and other information about it etc but would be a cool ability to do this with the n900. i'm not an expert in radiowave's so excuse the ignorance.

Re: Detect/sniff GPS signals
 

I hope I understood you well. Yes, there are many utilities to do that on N900. One of the best is Columbus... which allows a pc to access N900 gps.

Of course, gps on N900 isn't one of the best

Re: Detect/sniff GPS signals
 

Would Columbus show GPS raw data?

Re: Detect/sniff GPS signals
 

i don't want to see my own gps data but another devices gps data? the main thing i would like to know is what radio waves (mainly gps) how strong they are (for checking if they would interfere with devices)

I'm looking up this columbus now.

Edit:

just looked at columbus and it's for the n900's gps not being in eg monitor mode to detect other device's gps signals/transmissions

Re: Detect/sniff GPS signals
 

once you have columbus, go to Tools... and choose a method that suits your needs.

Re: Detect/sniff GPS signals
 

@smegheadz,

I'm not sure I understand your question. GPS is basically downstream. A GPS receiver receives the GPS signals transmitted off the satellites.

What you had as far as I can understand was a system with a GPS receiver and some transmitter sending the location data to somewhere.

The transmitter itself is not a GPS but whatever proprietary radio signal you are using. The transmitter is however not sending data to the GPS satellites.

So with your N900 you can of course receive GPS signals from the satellites, but in order to be able to receive (sniff) things that are sent by your containers you would need to know how the stuff is being sent. At most you could get lucky with the FM receiver, but it's very unlikely that you are using FM for this (it's mostly illegal in most countries).

If I've misunderstood your question, please feel free to clarify it!

Re: Detect/sniff GPS signals
 

The only part in the GPS system that emit anything is in the satellite... the GPS unit on earth only listen to timestamps send by these satellites.
Unless I misanderstood you, I'm affraid what you want is no more possible than sniffing your neighbour's FM receiver.

Re: Detect/sniff GPS signals
 

so with GPS tracking devices it's not the GPS signal thats transmitting but some other signal eg gsm or some other signal. so it may be possible to detect these with the n900 and confirm dB levels from said signal.

I think it would interesting to display the signals that the n900 can pick up, their frequency, and dB etc, and what card it's picking it up through, gps,wifi,bt,cell etc, making the n900 into an all round signal checker with raw data of those signals.

Re: Detect/sniff GPS signals
 

What probably happened here is that the oscillator that is used to downmix the received GPS signal was causing interference with the other electronics. Which is kinda weird though, that must have been some very badly shielded electronics (either the GPS receiver or the other board).

It would be possible to 'detect' such an oscillator from close distance, but it's a static signal.. there's no data in there. It's not possible with the N900 though.. mostly because you don't have direct access to the receiver through software as it's on the other side of the phone hardware from software point of view.

Re: Detect/sniff GPS signals
 

You can't access the radio devices directly on the N900, so you get only some parsed data from the modules.