LRRP & LOCN

[tuky]

Hello, have DSD+ Fastlane and run well.
In Italy when I listen a service I red always LOCN (please look attach) and look the position, the number etc but no direction and speed.
I have seen on web (please look attach) LRRP and it's possible look position, number but also direction and speed.
I must change DSD+ setting or how it's possible?
Can You help me?

 

[stevensmithe4th]

In your DSD base files should be a program called "FMP-MAP". That should populate the LRRP/LOCN.

 

[tuky]

I don'use FMP because it's difficult!!! I use only DSDPlus because it'more eazy!!!
Why I red ONLY locn data and no lrrp data. You know the differences from locn data to lrrp data.
In the attach ONLY locn word it's my file; the other it's from web!!!!

 

[slicerwizard]

LRRP is a specific location request/reporting protocol created by Motorola; LRRP position reports typically include track angle and speed, but, IIRC, position requests can ask only for location (lat/long).

LOCN likely refers to other location (GPS fix) reporting messages that have been created by other DMR vendors. Those messages either don't contain direction and speed information or the DSD+ developers don't have enough information to reverse engineer the entire contents of the GPS fix messages.

If a DMR radio was just parroting an entire NMEA message, like GPRMC, I have no doubt that DSD+ would report track angle and speed:

NMEA-0183 message: RMC

If it's a different message, like GPGGA, there is no track angle or speed to report:

NMEA-0183 message: GGA

Start by looking at the raw data that DSD+ displays. That might provide your answer.

If it's not a NMEA message, I'd be gathering messages and looking at lat/long changes to work out the track angles and speeds and then go looking for them in the raw data. Or I'd be sending all that data to the DSD+ team and let them figure it out. If they're not in Italy, they won't have access to that data unless you send it to them. The easiest thing to do would be to record 15 minutes of raw audio, zip it up, then upload it to a service like SendSpace.

 

[tuky]

Hello,
I have written to DSD+ Fastlane team and I have sent them (by WeTransfer) an audio file.
DSD+ has written this:
============================================================================================
Hello,

We can not identify any additional GPS data fields.

LOCN

Data Header DPF=[13:SD-Def] Tgt=600118 Src=611018
Conf=1 SAP=[10:Short Data] Blocks=5 Format=Binary PadBits=88

01 00 08 C0 03 00 38 00 00 00 C5 0A 09 52 CA FF ......8......R..
FF FF FF FF FF FF FF 41 31 30 34 33 31 34 30 39 .......A10431409
30 36 32 31 4E 34 35 33 36 2E 32 38 33 30 45 30 0621N4536.2830E0
31 33 34 38 2E 35 32 36 31 30 2E 30 31 32 33 2B 1348.52610.0123+
03 .

LOCN; Tgt=600118 Src=611018 45.60472 13.80877 2021/06/09 10:43:14



A

10 43 14 time

09 06 21 date

N4536.2830 latitude

E01348.5261 longitude

0.0123+
============================================================================================

ThankYou
Walter

 

[AM909]

Does anyone else see where the Target ID is in the message? The source ID, 611018 (0x0952CA) can be seen at position 0x0C, but the target ID 600118 (0x092836) doesn't seem to appear anywhere. I'd expect it to be in the previous three bytes (0x00C50A), but I don't see any relation in the bit patterns.

There's also the string "0.0123+" at the end (position 0x39) that means what? I'm guessing the trailing 0x03 is a CRC?

 

[slicerwizard]

The target ID is in the header block. It doesn't have to be in the payload data.