"Time mark is not valid" and also missing marks

Hello, I have a problem with an M2 in PPK mode mounted on a fixed wing drone. I had several missing time marks on a flight (the flight gave fix all the flight).
When reviewing the rinex file, I see the message “Time mark is not valid” on all shots and ALSO I have about 30% of missing shots . I am using the latest version of Emlid Studio and the M2 is updated to the latest firmware as well.
Could you help me find the problem? When I test the camera, cable and hot shoe before flight, always work right.
I attach the .ubx
Thank you very much

Hi Augusto,

Thank you for the log!

The only thing I can confirm is that your log contains two time marks and 650 time marks that aren’t valid. As for post-processing, I don’t have a base log to reproduce it in Emlid Studio.

Such issues are usually caused by poor log’s quality. In its turn, it’s caused by electromagnetic interference affecting Reach. The drone components or wires may produce a lot of RF noises and act as interference sources. Reach has to be properly isolated from all potential interference sources for normal operation.

Please share your hardware setup photos to check what may cause interference. On top of thay, you can take Reach out of the drone, connect it with the camera, and trigger. Then, I can check the time marks’ number in the log. It will show whether the issue is related to electronics nearby or the receiver itself.

Hi Kirill, I attach the base log so you can process it. Analyzing the data, I don’t see many cycle slips, except in the satellites of the Glonnas constellation, maybe it would be convenient to disable this constellation here in Argentina?
I would appreciate it if you could evaluate the quality of the data collected, since at first glance they do not seem to me to be of poor quality, but perhaps I am wrong. In addition to insulating the M2 (I’m using aluminum foil for this), is it convenient to insulate the cable that goes from the hotshoe to the M2? Is kitchen aluminium foil enough to isolate EMI or do you recommend some other better method? I don’t have much room to move the M2 around, so I want to improve the insulation as much as possible. What do you think of copper foil?

Thank you very much for your quick response, regards.

Hi Augusto,

Thank you for the log! I’ve post-processed in Emlid Studio and obtained 652 time marks. It matches with the time marks’ number I mentioned in my previous comment. But I also see these slips that look like some events are missing.

Regarding raw data quality, it indeed looks not so bad at first glance. However, I see that SNR values periodically oscillate much during the whole log, take a look at the screenshot:

You can see these fluctuations as alternation of orange and purple bars. It can be indirect sign of interference impact.

You can try copper foil as well as cable insulation. But how about to test Reach M2 out of the drone? Or probably you have another hot shoe adapter for testing? The POS file quality is indeed good enough, so I assume that hot shoe adapter may be the reason for missing time marks.


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