error in RMC parsing

[ser]

My device (Ublox ZED-F9P) submits an empty course value when the device is stationary, for example:

['GNRMC', '051003.00', 'A', '100', 'N', '100', 'E', '0.124', '', '080122', '', '', 'A', 'V']

which fact invalidates current parser here:

micropython-async/v3/as_drivers/as_GPS/as_GPS.py

Line 328 in c10a5c2

course = float(gps_segments[8])

I do not know what is your favourite solution to that so I am not submitting a pull request, but it should be fixed in some way :)

[peterhinch]

Thanks for that. The solution that comes to mind is

course = float(gps_segments[8]) if gps_segments[8] else 0.0

If you agree with this, please could you test with your unit. Or do you have a better approach?

[ser]

it's perfect, thank you!

[peterhinch]

Thanks for the feedback. Change now pushed.

[romeocontrol]

Dear Peter Hinch, you are fast … as usual. But. A vehicle, that does not move, has a heading, i.e. the direction its nose points to. To get from a compass. It has no course, as the course is the direction a vehicle MOVES on. No Move, no course. Greetings romeo tango

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Am 08.01.2022 um 10:12 schrieb Peter Hinch ***@***.***>: Thanks for that. The solution that comes to mind is course = float(gps_segments[8]) if gps_segments[8] else 0.0 If you agree with this, please could you test with your unit. Or do you have a better approach? — Reply to this email directly, view it on GitHub <#71 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEI5EA3IU5LSJXJQ7Y4SQQTUU75XJANCNFSM5LQG5RYA>. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.

[ser]

I've noticed it before but I do not see a problem with heading 0 if stationary. It really does not matter whilst parsing the file later. But I would love to hear your solution :)

[romeocontrol]

Hallo, heading and course are different! A gps-unit can only calculate a course, when it is moving. No move no course. And it can not calculate a heading. It is correct, not to send a course, when not moving. Or if the speed os zero, then the course is not usable. Greetings romeotango

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Am 08.01.2022 um 11:19 schrieb ᎠᎡ. Ѕϵrgϵ Ѵictor ***@***.***>: I've noticed it before but I do not see a problem with heading 0 if stationary. It really does not matter whilst parsing the file later. — Reply to this email directly, view it on GitHub <#71 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEI5EA4OJIAXHGLX4E6YTPLUVAFULANCNFSM5LQG5RYA>. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you commented.

[ser]

I think you convinced me, Romeo, I will propose more subtle solution in few days after testing it, then. Thanks :)

[romeocontrol]

Thank you for the reply. What do you use it for? I looked for some use cases with GPS and SAPOS to minimise the errors to some cm. But it is a bit to complicated for me to use this system. It ist just for Germany, either. romeotango

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Am 08.01.2022 um 17:33 schrieb ᎠᎡ. Ѕϵrgϵ Ѵictor ***@***.***>: I think you convinced me, Romeo, I will propose more subtle solution in few days after testing it, then. Thanks :) — Reply to this email directly, view it on GitHub <#71 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEI5EA7Y27MH6MDLVSMAMVTUVBRN5ANCNFSM5LQG5RYA>. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you commented.

[peterhinch]

To get heading you need a compass (e.g. an IMU with a magnetometer).

You might try to infer it from the direction of the last motion, but this wouldn't work for a platform like a boat which can rotate around a point. Even a car can change its heading at the last moment before becoming stationary.

[ser]

We do not have any other data than content of GNRMC message. What I am working on currently is to have no value which would work with other parts of the code.