Framing error using Sparkfun Venus GPS with Binary Commands

GPS/GNSS Development Boards
1

Hello,

I have the SparkFun Venus GPS (https://www.sparkfun.com/products/retired/11058) and I connected it to a MyRio 1900 from National Instruments.

My problem is that the sensor does not work consistently. I use the Binary Command Protocol to change some parameters:

  • First I increase the baudrate

  • then I increase the frequency at which messages are sent

  • then I configure the NMEA messages so that only the RMC messages get sent

I am rather sure that the messages itself are correct since sometimes it works perfectly.

But sometimes they don’t work and then a framing error occurs.

I managed to get less errors by introducing some wait times between reading and writing the binary commands. So now I write a config message and wait a second and then read the reply. Also after sending all the messages I wait one second before starting normal operations mode.

But that only made the framing error occur less often.

Is there some special timings that I have to comply to in the byte command protocol or do you know what can cause this? It works in about 80 percent of the cases but I would like more consistency in the way it works since it is a vital part of my data aquisition program.

Best regards

Thies

2

Hi Thies,

This is a bit beyond the scope of our support but I have a feeling the issue is caused by the increased message frequency. What are you setting that to? From what I can tell, it works perfectly at, say, 10Hz but setting it to anything beyond that (especially maxing it out at 20Hz) will cause issues with the packets’ spacing. [This comment from another user on the product page explains that issue and outlines some other quirks of the Venus638 module.](https://www.sparkfun.com/products/retired/11058#comment-524a2a36ce395f12598b4567)