Intermittent GPS Dropouts with simpleRTK3B Compass on ArduPilot

ArduRover
1

Hi all,

I’m integrating the simpleRTK3B Compass into my BlueBoat platform and encountering intermittent GPS dropouts in ArduPilot, despite stable readings in other tools.

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Setup

Hardware:

Software:

  • ArduRover
  • Ground station: QGroundControl
  • GPS status cross-verified using UPrecise tool

ArduPilot Parameters Set

Based on the official ArduSimple guide:

  • COMPASS_ENABLE = 0
  • COMPASS_USE = 0
  • COMPASS_USE2 = 0
  • COMPASS_USE3 = 0
  • EK3_MAG_CAL = 5
  • EK3_SRC1_YAW = 2
  • GPS_AUTO_CONFIG = 0
  • GPS_AUTO_SWITCH = 0
  • GPS_RATE_MS = 100
  • GPS_TYPE = 5
  • SERIAL1_BAUD = 115
  • SERIAL1_PROTOCOL = 5

Issue Observed

  • Using UPrecise, the GPS position and heading update continuously and correctly.
  • But in QGroundControl, ArduPilot intermittently reports:
    • GPS Count = 28, 3D Fix
    • Then drops to GPS Count = 0, No Fix for ~9 seconds or more
    • Then recovers again, and repeats this cycle

Has anyone successfully configured a simpleRTK3B Compass with ArduPilot?
Any help or shared experiences would be greatly appreciated!

Best regards,
Yan-Liang Chen

2

I don’t think ArduSimple provides very good instructions on their site. I’ve used UM982 based hardware very successfully, though not the one from ArduSimple.

The ArduPilot GPS driver supports UM982 configuration. Set:

  • GPS_AUTO_CONFIG,1
  • GPS_RATE_MS,200

Then follow the instructions here for “Common Parameter Setup” and those marked for UM982:

3

Hello.

I used UM982 and didn’t experience any problems.

However, in my previous experiences, I encountered the same problem because the GPS was not at the correct Hz.

GPS1_TYPE = 25 (for UM982)

GPS_RATE_MS=200 (Default)

It should work when you do this.

I don’t understand why GPS AUTO CONFIG is turned off.

4

Hi @Yuri_Rage,

Thank you for your advice.

I’m using ArduRover, and the firmware version might be slightly different from the one in the example. Based on the instructions, I’ve set GPS_TYPE to NMEA, and configured the GPS receiver to send GNGGA, GNRMC, and GPHDT to COM3 at either 10Hz (0.1) or 5Hz (0.2) by adjusting GPS_RATE_MS accordingly.

Unfortunately, the issue persists. The GPS signal still drops intermittently. When a fix is received, it shows good values (24–28 satellites, HDOP ~0.5, 3D fix), but the signal can drop out completely for over a minute, making it unusable for stable operation.

I’m attaching a log file in case it helps with diagnosing the issue. Any further suggestions or insights would be greatly appreciated!

GPS_log.log (91.4 KB)

5

Hi @idris,

Following up on my reply to @Yuri_Rage — I’ve set GPS_RATE_MS to 200, and on the GPS receiver side I configured:

GNGGA COM3 0.2
GNRMC COM3 0.2
GPHDT COM3 0.2

Unfortunately, the issue still persists.

Additionally, after enabling GPS_AUTO_CONFIG, ArduPilot stopped receiving GPS entirely, and continuously shows “EKF waiting for GPS config data.” I’ve since disabled GPS_AUTO_CONFIG to restore signal input.

6

What is GPS1_TYPE?

Can you share a log?