Moitessier HAT - No GPS

[jamieFL]

Hello,

After assembling my project, I'm now trying to get things working.  I have a Pi 4 with the Moitessier HAT.  I've been able to get everything configured, but have no GPS signal.  I've been working from inside the house, so thought that might be the problem, so today I took my project outside.

It has a direct view of the sky now and has been powered up for about 1/2 hour.  I purchased an external antenna, but it is not attached at the moment.  Both of the green LED's are lit solid and the red is off.  From the instructions, I believe I'm not receiving any GPS data.  Incidentally, I also tried with the external GPS antenna and get the same results.  There is also no GPS fix or GPS satellites showing in Open CPN.

What do I need to do?   

jamieFL

[Sailoog]

Is the HAT well configured? what "moitessier hat - check configuration" says?

If all is configured ok, what "opencpn - options - connections - show NMEA debug window" says? do you see data there?

[jamieFL]

Please see the attached images.  I started with a new OP Moitessier HAT image last week when I updated the Pi's firmware before reading the warning that it will prevent the Pi from booting.  As far as I can tell, everything seems to be configured and working.  I have no red warnings.  The temp, barometer, compass, and accelerometer on the HAT seem to be working fine.

I ordered the Motessier HAT 2,  QYUQHROMP on 04/29/2020 and just last week got my project put together.  I've attached the debug screen.  Unfortunately, I don't know how to read it.

[SkipperEarly]

I had similar hiccups but they eventually went away. Dont recall what helped most but try:
- check powersupply for pi is sufficient (my observation is that most problems start with bad power
- check Moitessier hat with cmd prompt (may need a sudo in front)
cat /dev/moitessier.tty
cat /dev/moitessier.spi
- let the gps antenna see the sky without any destruction for prolonged time (2hrs)
- if all doesnt help try reinstalling the op-moitessier kernel as per manjual

good luck in your endeavors

[serh11]

Do you have any USB 3.0 devices connected? I'm experiencing issues caused by USB 3.0 interference, mainly with 2.4GHz WiFi and GPS. To get GPS working I had to shield raspberry  with Moitessier HAT and connect external GPS antenna.
So I would suggest to try to disconnect USB and reset Moitessier HAT and see if you get an improvement.

[jamieFL]

SkipperEarly,

- check power supply for pi is sufficient (my observation is that most problems start with bad power
          I am powering the Pi with an old 19V Dell laptop power supply through an MCS board.  I have an 
          SSD plugged into one of the Pi's USB 3 ports, and a powered USB hub plugged into the second.
          Power shouldn't be a problem.
- check Moitessier hat with cmd prompt (may need a sudo in front)
cat /dev/moitessier.tty
cat /dev/moitessier.spi
          I've not had time to do this yet, but will soon.  I'll post the results; however, I think that they,
          correct me if I'm wrong, will show the same thing as the photos above from the Moitessier HAT
          configs and the OpenCPN Debug.
- let the GPS antenna see the sky without any destruction for prolonged time (2-hrs)
          I was hoping this would help.  This morning I put my project outside for three hours and never
          had a GPS signal.
- if all doesn't help try reinstalling the op-moitessier kernel as per manual
          This is a option, but since I have the compass, accelerometer, and barometer data showing up
           I'll wait.  I suspect that the temp is working too, but I renamed it to inside.openplotter and 
           have not seen it since.

good luck in your endeavors
          Thanks for your input.


serh11,

Do you have any USB 3.0 devices connected? 
          Actually I do.  The 4 port hub in the photo is a powered USB 3 hub that is powered by a
          step down regulator.  I suppose both could be putting out RF-interference.

I'm experiencing issues caused by USB 3.0 interference, mainly with 2.4GHz WiFi and GPS. 
          Funny you should mention that.  I've been working in the house about 10 feet from my internet 
          router and have not had any WiFi problems.  Yesterday when I took my project outside, I could not 
          keep the WiFi connected.  After doing a little reading online, I thought it might be my monitor
          connected via HDMI being too close to the project.  This morning, when I took my project outdoors,
          I placed the monitor about 5 feet away and seemed to have better WiFi.

To get GPS working I had to shield raspberry with Moitessier HAT and connect external GPS antenna.
          I already bought a GPS antenna and had it hooked up, but when I didn't see any GPS data, I 
          disconnected it for fear it was the cause.  All further tests used the Moitessier HAT's antenna.  


          How did you shield your Raspberry Pi?  I posted a photo of my project in the first post.  This
          is a likely cause as nothing is shielded.

So I would suggest to try to disconnect USB and reset Moitessier HAT and see if you get an improvement.
          Currently, the only device attached to the hub is the WiFi dongle.  The other two cables connect to 
          USB ports on the case and currently have nothing plugged in.  I can un-power the hub and plug the 
          WiFi dongle directly into pi to test this.  I will try later when I have time and post the results.


Thanks for the help so far.  I'd really like to get this stable so I can begin configuring it for my boat.

[serh11]

For the test it's important that no USB 3.0 5Gbps activity happening, so if WiFi dongle is USB 2.0 then it should probably be ok for the test.
As for interference with 2.4GHz WiFi, I was mainly talking about RPI's WiFi, but it could affect nearby WiFi devices as well.
Here are some technical details regarding violent USB 3.0: https://www.intel.com/content/www/us/en/...paper.html

[holgerw]

Use only shielded DC-DC Converters in your Setup, maybe better install them in an Distance to the High Frequency Receivers. Use only one centralized Point to Ground/-5V all your Parts! Sometimes Ferrite Rings around the Power Cables near the DC-Converter may also help.

Good Luck
Holger

[glowntiger]

Hi holgerw,
the MCS is a DC-DC converter. It has enough power for the Moitessier hat and a good, stable performance.
Further it is testet for CE and there are many such configurations on water... ;-)

---

I have heared from trubbles wit external SD cards? Did you use one? If yes, try it without...

[jamieFL]

I use the DC converter to power the USB hub. I am using a USB SSD. All grounds, except for the USB hub which has a 5v and ground terminal on the DC converter, are led to a grounding block on the fuse block.

Things to try:
--Unplug all the USB 3 devices and plug them into the USB 2 ports.
--remove the SSD and boot from the SD card.
--ferrite rings on the power wires.

I won't be able to work on my project till Sunday. I'll post results then. Thanks for all the suggestions.