NMEA Checksum always wrong for 2/2 GSV

Reach Module / M+ / M2 RTK / PPK configuration
1

I’m running multiple Reach RS+ (2.22.1) units and recently started parsing the *GSV NMEA strings. What I’m finding is that the 2nd of 2 msgs always has the wrong checksum.

Received a sentence with an invalid checksum:
$GAGSV,2,2,05,36,26,147,38,,,,,,,,,,,,*41

Using https://nmeachecksum.eqth.net/ it is clear that it should be 55.

I can provide more examples if needed but what I have noticed is that the GSV is a multi-part message. The first message has the correct checksum. The second, third, etc always has the wrong one.

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,3,09,30,35,306,43,,,,,,,,,,,,*4E'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GLGSV,2,2,05,87,52,104,49,,,,,,,,,,,,*44'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GAGSV,2,2,05,36,26,147,38,,,,,,,,,,,,*41'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,2,2,07,23,19,181,36,27,36,048,38,30,35,306,37,,,,*37'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,2,09,11,39,134,44,23,19,181,40,27,36,048,43,28,16,258,38*04'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,3,09,30,35,306,44,,,,,,,,,,,,*49'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GLGSV,2,2,05,87,52,104,49,,,,,,,,,,,,*44'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GAGSV,2,2,05,36,26,147,38,,,,,,,,,,,,*41'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,2,09,11,39,134,44,23,19,181,40,27,36,048,43,28,16,258,37*0B'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,3,09,30,35,306,44,,,,,,,,,,,,*30'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GLGSV,2,2,05,87,52,104,49,,,,,,,,,,,,*46'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GAGSV,2,2,05,36,26,147,38,,,,,,,,,,,,*41'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,2,2,07,23,19,181,36,27,36,048,38,30,35,306,37,,,,*4E'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,2,2,07,23,19,181,35,27,36,048,38,30,35,306,37,,,,*4D'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,2,09,11,39,134,44,23,19,181,40,27,36,048,43,28,16,258,37*0B'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,3,09,30,35,306,44,,,,,,,,,,,,*30'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GLGSV,2,2,05,87,52,104,49,,,,,,,,,,,,*46'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GAGSV,2,2,05,36,26,147,38,,,,,,,,,,,,*41'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,2,09,11,39,134,44,23,19,181,40,27,36,048,43,28,16,258,37*0B'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GPGSV,3,3,09,30,35,306,44,,,,,,,,,,,,*30'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GLGSV,2,2,05,87,52,104,49,,,,,,,,,,,,*46'

WARN2020.02.21 14:50:06Received a sentence with an invalid checksum. Sentence was: '$GAGSV,2,2,05,36,26,147,38,,,,,,,,,,,,*41'

Thanks,

Kyle

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2

Hi Kylelanman

The same problem is here

1 Like
3

Hey everyone,

We confirm there’s an issue with checksum in the latest ReachView. In the nearest time we’ll post more specific information on what is causing this and ETA on fix for it.

Sorry for inconvenience.

3 Likes
4

Thanks for the quick response. I’ll tweak my logging while I wait.

6

Hey there,

We’ve just released the v2.22.3 firmware update that should fix the issue with the incorrect checksums. You can check other fixes of the update in this community forum thread.

7

V2.22.3 still gives check sum errors.

for example:

$GNRMC,192902.80,A,5036.5308492,N,00449.2435799,E,0.01,,070320,,,A*5F CORRECT!
$GNGGA,192902.80,5036.5308492,N,00449.2435799,E,1,14,0.0,163.424,M,45.832,M,0.0,*51CORRECT!
$GPGSA,A,3,08,10,16,20,21,26,27,,,,,,0.0,0.0,0.0*3C CORRECT!
$GLGSA,A,3,68,69,75,76,84,85,86,,,,,,0.0,0.0,0.0*23 CORRECT!
$GPGSV,2,1,07,08,22,283,43,10,28,151,47,16,72,222,46,20,46,117,47*70 CORRECT!
$GPGSV,2,2,07,21,50,062,46,26,49,177,47,27,55,289,49,,,,*30  ERROR! Should be 4E
$GLGSV,2,1,07,68,16,019,42,69,28,072,45,75,50,234,48,76,40,312,49*61 CORRECT!
$GLGSV,2,2,07,84,30,058,42,85,71,328,48,86,24,263,48,,,,*34 ERROR! Should be 5B

it seems that only some GSV messages give the error; my guess is only for GSV with “empty” data at the end of the message.

Could you please check and fix it asap? Our applications are out of services…!

thanks

Stef

8

Hi @stefdas,

Would you mind elaborating on the way you get the NMEA position? Is the data you provided directly output from Reach?

9

Hello Polina,

The issue was on version 2.22.0.

The update to V2.22.3 didn’t succeed at the first attempt; and i didn’t notice that i was still using version 2.22.0.

After correct installation of 2.22.3; no checksum error! Good!

I thought to have deleted my previous post; but it seems not; sorry for that disturbance.

thank anyway for your feedback.

regards

stef

10

Stef,

Thanks for the update!

I’ve double-checked the checksums and couldn’t find any errors. So we can confirm that the checksums of the NMEA messages are correct.

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