RAK5205 - Invalid LPP GPS payload

(kastayou) #1


I am using firmware.
The RAK5205 is registered in TheThingsNetwork

I have setup my TTN application to decode the payload as LPP payload.
All the data sent by the RAK5205 are correctly decoded by TTN application excepted the GPS data.

After looking at the data, the data frame is too long compared to what is specified by LPP format.

By looking at the source code, I can see that you have added the speed at the end of the frame but it is not inline with the LPP format thus TTN is not able to decode the payload.

Unfortunately, since you only provide the project for Keil and I do not have it, I cannot correct the issue.

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RAK5205 BreakBoard software version: 1.1.16 r120
(Fomi Tong) #2

Thank you! @kastayou
We’ll check and fix this issue ASAP and update the new version source code and firmware on Github.

(elpis) #3

Hello i have the same problem i have the keil full versions if you want pm you email and i will send it :slight_smile:

(kastayou) #4

The payload containing the GPS data is sent on the port 2. This is not the one shown in your screenshot.

The following lines (232 & 233) in app.c should be commented out:

> app_data[11] = ((uint16_t)(speed*100)>>8)& 0xFF;; //high byte speed   
> app_data[12] = ((uint16_t)(speed*100))& 0xFF;; //low byte speed    

And the line 234 :

*size = 13;

should be modified to:

*size = 11;

(elpis) #5

I get gps load on TTN but not on cayene how i can fix that ?

(kastayou) #6

Like I said in my initial message.
The message (payload) sent by the RAK5205 for the GPS data on port 2 is not compliant with LPP specification.
When cayenne receives the data, they cannot decode the payload so they cannot display the GPS position.
The other messages are OK so you can see the data on Cayenne.

To correct the issue, you need to :

  • Wait the bug fix and new firmware published by RAK
  • Modify the source code yourself and recompile the source to create the new firmware by yourself. You can see on my previous messgae the modification to be done on the source
(elpis) #7

i am uploading keil to my drop box and i am sending it to you in 10 minutes :>please fix this for me also :> thanks

(elpis) #8

here it is

(Todor Velev) #9

As @kastayou said, there is a problem with LPP format. Here are the fixed bins for RAK5205, based of version. Download

Tested and working fine.
Pls note that this is not RAK official fix :smiley: . If you can, wait for @Fomi fix in git.

(Fomi Tong) #10

That’s great! @velev :handshake:

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(Vladislav Yordanov) #11

Damn son, that’s my boy for ya :grin:

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