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Satellites of external Bluetooth Device not shown anymore
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I've just updated the FW of my Ublox F9P to 1.13, but since then, LocusMaps isn't able to show all satellites anymore.
It seems that the coordinates etc are correct, but it shows for example that it is connected to 0 of 6 satellites, while I see in u-center or in SWMaps, that I'm connected to 17/23 satellites. Also the skyview flashes intermittently as if LocusMaps tries to update and show all satellites but fails - some satellites briefly light up and disappear again.
SWMaps shows all satellites correctly, so it cannot be an issue with the ublox but something that LocusMaps does not understand in the protocol.
What NMEA versions does locus support? By default NMEA 4.10 is used
The same question
Hello Matthias,
somehow original topic is corrupted and I'm unable to answer there correctly, so I made a copy manually.
Back to topic: may you please share with me some short NMEA file I may use for testing? Thanks, this should help to identify the problem.
Menion
Hello Matthias,
somehow original topic is corrupted and I'm unable to answer there correctly, so I made a copy manually.
Back to topic: may you please share with me some short NMEA file I may use for testing? Thanks, this should help to identify the problem.
Menion
Hi Menion
Thanks for your quick reply. I've enabled NMEA logging in locus maps, here's the result of about a minute recording.
LocusMaps sometimes showed 6/8 satellites, sometimes 10/13 (often flickering between the two very quickly), wherease sw-maps showed the more correct 18/22 (which may or may not be a coincidence that it just about sums up?)
Matt
On 13.07.2020 08:40, Locus Map wrote:
Hi Menion
Thanks for your quick reply. I've enabled NMEA logging in locus maps, here's the result of about a minute recording.
LocusMaps sometimes showed 6/8 satellites, sometimes 10/13 (often flickering between the two very quickly), wherease sw-maps showed the more correct 18/22 (which may or may not be a coincidence that it just about sums up?)
Matt
On 13.07.2020 08:40, Locus Map wrote:
Hello Matthias,
thanks for the NMEA file. Simple: I think that it's a problem with your device. Seems you understand NMEA messages a little bit, so you may simply look into send NMEA file. Since start are visible reported GSV sentences that display invalid values > repeated GPGSV, GLGSV, GAGPS with information about sats in view.
I made an improvement, so it should be better in the next version 3.48.
Hello Matthias,
thanks for the NMEA file. Simple: I think that it's a problem with your device. Seems you understand NMEA messages a little bit, so you may simply look into send NMEA file. Since start are visible reported GSV sentences that display invalid values > repeated GPGSV, GLGSV, GAGPS with information about sats in view.
I made an improvement, so it should be better in the next version 3.48.
Hi Menion
Thanks for your reply. I've just read myself in to NMEA GSV messages. Do you mean that additional number that appears at the end of each GSV sequence just before the checksum? Or do you mean the missing values especially at the beginning of the file where the receiver was still picking up satellites so a lot of values (especially coordinates) are just empty? Or to what invalid values do you refer?
I've just tested it with another device with FW 1.11 and the sequences look quite alike but the display does display a sensible total number of sats
Example from 1.11:
$GPGSV,2,1,06,02,41,289,28,04,36,065,47,07,51,169,43,09,75,048,37,1*67
$GPGSV,2,2,06,16,14,064,43,30,23,193,41,1*69
Hi Menion
Thanks for your reply. I've just read myself in to NMEA GSV messages. Do you mean that additional number that appears at the end of each GSV sequence just before the checksum? Or do you mean the missing values especially at the beginning of the file where the receiver was still picking up satellites so a lot of values (especially coordinates) are just empty? Or to what invalid values do you refer?
I've just tested it with another device with FW 1.11 and the sequences look quite alike but the display does display a sensible total number of sats
Example from 1.11:
$GPGSV,2,1,06,02,41,289,28,04,36,065,47,07,51,169,43,09,75,048,37,1*67
$GPGSV,2,2,06,16,14,064,43,30,23,193,41,1*69
Message (example) you wrote is ok, but in the next moment comes another message
$GPGSV,3,1,09,02,35,252,29,04,12,080,38,05,42,304,29,06,23,208,34,1*64
$GPGSV,3,2,09,07,74,118,35,09,48,075,49,15,,,08,16,13,036,38,1*5B
$GPGSV,3,3,09,30,54,194,42,1*55
Which means that previous two lines are no longer valid because here are new three lines that inform about current satellites. Problem is simply that your GNSS unit print too much information about satellites. Just look into your file on lines 15, 16, 17, here are three lines with sats. Oki, but right next on line 18 are new fresh data, but just for 4 sats.
Anyway if problem is really just visible sats in skyplot screen, it should be improved in next version. Location is still displayed correctly right?
Message (example) you wrote is ok, but in the next moment comes another message
$GPGSV,3,1,09,02,35,252,29,04,12,080,38,05,42,304,29,06,23,208,34,1*64
$GPGSV,3,2,09,07,74,118,35,09,48,075,49,15,,,08,16,13,036,38,1*5B
$GPGSV,3,3,09,30,54,194,42,1*55
Which means that previous two lines are no longer valid because here are new three lines that inform about current satellites. Problem is simply that your GNSS unit print too much information about satellites. Just look into your file on lines 15, 16, 17, here are three lines with sats. Oki, but right next on line 18 are new fresh data, but just for 4 sats.
Anyway if problem is really just visible sats in skyplot screen, it should be improved in next version. Location is still displayed correctly right?
I think we've just found the real culprit! This device is a multi frequency device. Therefore it receives GPS and Galileo on two frequences; here are the 4 lines in question (lines 15-18 in the original file):
$GPGSV,3,1,11,01,,,15,02,,,24,04,14,079,39,05,,,25,1*50
$GPGSV,3,2,11,06,,,25,07,74,124,42,09,49,074,46,12,,,16,1*60
$GPGSV,3,3,11,15,,,16,16,13,038,36,30,52,194,41,1*61
$GPGSV,1,1,04,04,14,079,34,07,74,124,29,09,49,074,37,30,52,194,35,6*6A
The first three lines define 11 satellites with the first requencey (Signal ID 1); the last line defines 4 potentially additional Satellites on another frequency (Signal ID 6).
So the first requency saw sats 01, 02, 04, 05, 06, 07, 09, 12, 15, 16 and 30 and the second frequency saw sats 04, 07, 09 and 30. So the second package shouldn't overwrite the first but augment it (in this case, there's nothing to augment because all those 4 sats were already seen using the first frequency, but in other cases that might be the case. In particular, the second package should not remove any seen satellites from the other frequency...
Location appears to be correct, at least I wouldn't be able to get 1.3m accuracy with only the sometimes displayed 6 satellites. Since LocusMaps does not display VDOP/PDOP/HDOP values I also cannot compare it directly with swmaps other than the coordinates and estimated accuracy.
I think we've just found the real culprit! This device is a multi frequency device. Therefore it receives GPS and Galileo on two frequences; here are the 4 lines in question (lines 15-18 in the original file):
$GPGSV,3,1,11,01,,,15,02,,,24,04,14,079,39,05,,,25,1*50
$GPGSV,3,2,11,06,,,25,07,74,124,42,09,49,074,46,12,,,16,1*60
$GPGSV,3,3,11,15,,,16,16,13,038,36,30,52,194,41,1*61
$GPGSV,1,1,04,04,14,079,34,07,74,124,29,09,49,074,37,30,52,194,35,6*6A
The first three lines define 11 satellites with the first requencey (Signal ID 1); the last line defines 4 potentially additional Satellites on another frequency (Signal ID 6).
So the first requency saw sats 01, 02, 04, 05, 06, 07, 09, 12, 15, 16 and 30 and the second frequency saw sats 04, 07, 09 and 30. So the second package shouldn't overwrite the first but augment it (in this case, there's nothing to augment because all those 4 sats were already seen using the first frequency, but in other cases that might be the case. In particular, the second package should not remove any seen satellites from the other frequency...
Location appears to be correct, at least I wouldn't be able to get 1.3m accuracy with only the sometimes displayed 6 satellites. Since LocusMaps does not display VDOP/PDOP/HDOP values I also cannot compare it directly with swmaps other than the coordinates and estimated accuracy.
Hello Matthias,
ah very useful info, thanks! Makes sense, nice.
It also fit the change I made. Sats are now grouped and may be "reset" only once a while when GGA messages is read. So it should now correctly merge multiple frequencies at once.
Accuracy from GSA sentence is not visible, indeed. Accuracy was really bad few years ago, so it wasn't worth it to display separated values. Now it starts to be interesting. I'll reconsider this and probably improve visible accuracy somehow. Thanks for this tip.
Menion
Hello Matthias,
ah very useful info, thanks! Makes sense, nice.
It also fit the change I made. Sats are now grouped and may be "reset" only once a while when GGA messages is read. So it should now correctly merge multiple frequencies at once.
Accuracy from GSA sentence is not visible, indeed. Accuracy was really bad few years ago, so it wasn't worth it to display separated values. Now it starts to be interesting. I'll reconsider this and probably improve visible accuracy somehow. Thanks for this tip.
Menion
Ah great that it helped (and I learned a lot about NMEA I didn't even knew it existed a few days ago :) ). Looking forward to your fix then!
Well, for most people, accuracy in meters is probably more than enough, but a way to see the other values would be nice (I could imagine a small popup when clicking the accuracy on the satellites view or the contents could switch between meters and dop values; but screen estate might be a problem here)...
If you have a donation link somewhere, I'd be happy to donate something for the great support and quick replies given! (I've already purchased pro quite a while ago, sorry ;) )
Thanks and keep up the great work!
Matt
Ah great that it helped (and I learned a lot about NMEA I didn't even knew it existed a few days ago :) ). Looking forward to your fix then!
Well, for most people, accuracy in meters is probably more than enough, but a way to see the other values would be nice (I could imagine a small popup when clicking the accuracy on the satellites view or the contents could switch between meters and dop values; but screen estate might be a problem here)...
If you have a donation link somewhere, I'd be happy to donate something for the great support and quick replies given! (I've already purchased pro quite a while ago, sorry ;) )
Thanks and keep up the great work!
Matt
Hello Matthias,
really do not know? You look like a professional ;).
Anyway, donation ... no, not needed, but thanks for the offer!
Have a nice day and in case of any problem with the next version, feel free to contact me (us).
Menion
Hello Matthias,
really do not know? You look like a professional ;).
Anyway, donation ... no, not needed, but thanks for the offer!
Have a nice day and in case of any problem with the next version, feel free to contact me (us).
Menion
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