Here 3 Noisly Sat counts

Here GPS
1

Hello Everyone

During the cruise flight of our UAV, we observed very noisy sat counts. I am attaching a screenshot below.

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We are using Here 3 x 2.
one Here 3 is connected directly to the CAN-1 port
another Here 3 is connected to the CAN splitter port, connected to CAN-2, and powered with external 5v bec.

We have shielded the GPS signal wire and the shield is connected to the ground.

What could be possible reasons for this?

Here GPS Cube Autopilot

Thanks in advance.

2

That looks nominal sat count for Ublox m8p.
Fluctuations could be because of bad switching regulator. What regulators are you using?
Shielding wires has nothing to do with this. What kind of CAN cable are you using? Refer CAN wire specs instead of jumping to shielding.

3

We are using Castle 2.0 BEC.

We are using the CAN wires that come with the module. Apart from that CAN wire comes with a pixhawk kit. i.e., 28AWG.

Is there anything else you can recommend to look into to find the root cause?

Thanks!

4

Try switch to different regulator.
Google CAN wire speciation for wire specs.

5

@Ashesh_Rai This is normal, unless you see a large jump in Sat counts like 5+, this is not an issue, look how your hdop, vdop and other values are. Most of the time the GPS sat count is only varying by +/- 1

6

Hi @sidbh

Thanks for your suggestion I’ve looked into logs again here are the snapshots
Parameter: HDOP

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Parameter: VDOP

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Paramenter: Delta

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Frequent up-downs can be observed on hdop going up to 0.75. Do you recommend some other parameters that can be checked to see if there is anything wrong with the GPS?

Thanks!

7

It’s fine unless you have errors shown on mission planner or qgc.

8

Hi

I’m more concerned about the frequent drop and climb of the sat counts.