Piksi RTK seems to work, but is pixhawk using it?

ArduRover Sensors -- deprecated
1

Hey guys,

i have a rover platform thats working good.
now i added a piksi rtk and it seems to work as second gps.

now how can i validate that pixhawk uses that rtk data ?
it does not show “RTK” in gps status just “DGPS”

usind the 3.01 beta of ardurover and that settings:

thanks !

Max

2

Hi Max. DGPS is the RTK gps - the D stands for differential which is RTK.
You could always unplug the primary GPS and see if the Rover still works.
And I think in the dataflash logs there is a flag showing which GPS is being used. Maybe in one of the EKF logs - hmm in EKF4 the last field is GPS - I think that show’s which one is being used.
Make sure you have AUTO_SWITCH enabled.
Note much better if you attach a raw .tlog or .bin dataflash log rather then just your params. We can learn much more from the logs.
Thanks, Grant.

3

Hey Grant,
thanks for the fast answer!

i will upload a log if it helps, if you want to know anything specific just ask i will be glad to help you out!
Max

4

so i tryed it out, if i remove the gps1 it shows "no gps"
AUTO_SWITCH is enabled

hdop is always better on the gps1 (status4) but the rtk gps (a littel less hdop sometimes onlz 0.1, gps status5) is not used :frowning:

any command to “force” gps 2 to be used?

log of the last automission:

5

There is no way to tell ArduPilot which GPS to use unless you set GPS_TYPE to 0 for the GPS you don’t want to use and then it will use the remaining one. Make sense? In other words disable the one you don’t want to use via the GPS_TYPE or GPS_TYPE2 parameters.

If you have a look at your dataflash log in the GPS2 you will see “U : 1” - that U is the “used” field and if set to 1 it means its using that GPS.

2016-06-15 18:16:05.37: GPS2 {TimeUS : 948817277, Status : 5, GMS : 288980400, GWk : 1901, NSats : 10, HDop : 0.75, Lat : 60.700843, Lng : 10.8691285, Alt : 296.67, Spd : 0.795392990112, GCrs : 11297796.1, VZ : -0.124000005424, U : 1}

So yes looks like your second GPS is being used.

You can also see that the first GPS was used so it did switch over
2016-06-15 18:17:34.85: GPS {TimeUS : 1038297099, Status : 4, GMS : 289069800, GWk : 1901, NSats : 11, HDop : 0.75, Lat : 60.7011557, Lng : 10.8693849, Alt : 259.04, Spd : 0.019999999553, GCrs : 180.0, VZ : -0.109999999404, U : 1}

I’ve attached a log which has the record when each respective GPS was used. Not sure if that’s of any use to you.
gps-used.txt.zip (181.4 KB)

Thanks, Grant.

6

great :slight_smile: thanks ! now i can find out myself

7

DGPS is not RTK:smiley:, RTK not just differential GPS! Satus bar of Mission Planner you can see gps_status2, 4=dgps,5=rtk