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szechyjs / dsd

Digital Speech Decoder
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*Feature* MotoTRBO GPS is been used #37

Open francisuk opened 10 years ago

francisuk commented 10 years ago

Hi. I would like to see a feature of the MotoTRBO GPS Not to tell me where abouts but to say on DSD that GPS is been used.

Francis.

szechyjs commented 10 years ago

I don't have any details on how the gps data is transmitted. If anyone has any documentation for this it seems like a pretty easy feature to implement.

playaspec commented 2 years ago

If anyone has any documentation for this it seems like a pretty easy feature to implement.

I've been scratching at the net to see if there was any other prior art that such information could be extracted from. Surprisingly, there's little directly applicable source still, but I think I've scrounged enough to maybe get you going in the right direction.

The best piece I found was US Patent No.: US 2013/0246659 A1. which details the packet format, and describes the methodology used to encode the location to save bandwidth.

There's a post on RadioReference that appear to have reverse engineered LRRP decoding, addressing both lat/long and time stamps.

So you don't spend so much time reinventing the wheel, there's a number of projects on Github that appear to grok relevant parts of XCMP and LRRP like Moto.NET (written in C#). The file Moto.Net/Mototrbo/LRRP/ImmediateLocationResponsePacket.cs appears to implement a parser that will return the desired data. It should be fairly straight forward to refactor into C++.

Hopefully this is enough to add this feature. If there's anything missing you don't have the time to chase down, I don't mind scrounging to find it if it can be had.