Triangulate a signal source with 3 dongles in different locations with time of flight analysis like with KiwiSDR?

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Record
Posts: 6
Joined: Wed Dec 30, 2020 12:38 am

Triangulate a signal source with 3 dongles in different locations with time of flight analysis like with KiwiSDR?

Post by Record » Sun Jan 17, 2021 11:48 pm

I've found this very interesting article https://www.rtl-sdr.com/kiwisdr-tdoa-di ... ublic-use/ on how to triangulate a signal with KiwiSDRs with GPS connected.
In that article they use a continious signal so they compare samples to get the time of flight and locate the transmitter.

Im my case there are only some short bursts so no need to compare signals. Time of burst can be easily recorded.
But how accurate is this? Are there some buffers in the RTL-SDR dongle which differ between devices and thus would change time? Suppose we take a raspberry pi as receiver and GPS as time source. According to this https://stackoverflow.com/questions/403 ... -gps-clock GPS can be as excat as 40 ns which would be 12 meters of accuracy. Suppose it takes the GPS receiver some time to send the signal to Raspberry PI so we get 1 µS of timing accuracy. That still would be 300 m of accuracy which is quite high.

So the final question is how accurate is an RTL-SDR? Would it be possible to build a high accuracy tracking system of short burst signals?

alanzfq
Posts: 200
Joined: Thu Oct 04, 2018 11:18 am

Re: Triangulate a signal source with 3 dongles in different locations with time of flight analysis like with KiwiSDR?

Post by alanzfq » Mon Jan 18, 2021 9:31 am

Any receiver can be used provided accurate time calibration is done.
When the exact time of arrival is known then triangulation.
Simple, but making it accurate maybe not so simple.
Alan

ckoval7
Posts: 90
Joined: Fri Sep 27, 2019 8:54 pm

Re: Triangulate a signal source with 3 dongles in different locations with time of flight analysis like with KiwiSDR?

Post by ckoval7 » Tue Jan 19, 2021 11:16 am

This guy has done extensive work with what you're describing: http://www.panoradio-sdr.de/tdoa-transm ... -rtl-sdrs/

Record
Posts: 6
Joined: Wed Dec 30, 2020 12:38 am

Re: Triangulate a signal source with 3 dongles in different locations with time of flight analysis like with KiwiSDR?

Post by Record » Tue Jan 19, 2021 11:58 pm

Thanks for the link. That helps a lot.

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