GlobalSat nd-105C GPS

[Wadoadi]

Hi All,
     I have been having trouble with my ubox GPS for sometime, I even spoke to someone from Pilotaware at the Flying Show last year as it has always been very slow to get a fix even outside and indoors it would seldom work, I was told by the PAW team member that it would not work indoors. Now it has also let me down twice in flight, requiring a reboot to get it back, which is less then ideal.

So having always had a good experience with Globalsat GPSs in the past I ordered a ND-105C it connects via a micro USB port but comes with an adaptor.

Trying it on my PC indoors it got a fix first time and straight out of the packet in around 5 seconds.

It doesn't auto detect when plugged into PaW however i manually set the port and it came up with a fix in around 2 seconds. Great time for a flight test!

the location was working great however the altitude seems around 800ft off comparing it with the inbuilt GPS on both the iPad (Cellular) and iPhones inbuilt GPS which both were close to the altimeter.

Any ideas?

[Admin]

Sounds very strange, I have found the ublox receivers to be very good, but there could be a fault here.

Is this a PilotAware Classic ?

Which GPS, is this - the Dongle or Mouse ?

and finally, which software release are you using (reported on home page) ?

There was an issue in an earlier software version which was erroneously reporting there was no satellite fix, when in fact there was - if you have not updated this could be the case.

If this is a Classic, we would be happy to provide an alternate GPS to see if this is the source of the problem.

So having always had a good experience with Globalsat GPSs in the past I ordered a ND-105C it connects via a micro USB port but comes with an adaptor.
...
the location was working great however the altitude seems around 800ft off comparing it with the inbuilt GPS on both the iPad (Cellular) and iPhones inbuilt GPS which both were close to the altimeter.

This would be very concerning, because of course the relative altitude when reporting surrounding traffic using a GPS reference would be way off.
Also its strange that the GPS was close to the Altimeter, but depends totally on the Pressure setting you selected, and the pressure on that particular day

Thx
Lee

[Paul_Sengupta]

That's odd, that GPS is supposed to be WAAS/EGNOS capable. Maybe leave it outside with a good clear view towards the south for a while to allow it to get the EGNOS satellite and maybe calibrate itself.

Lee - the altimeter will have been set to the pressure setting, so the GPS and pressure altitudes should be similar. It's showing altitude, not flight level. The calibration/compensation will be done by twiddling the altimeter knob. Using my PAW GPS tends to get me within about 20ft of what my altimeter reads.

[Admin]

Lee - the altimeter will have been set to the pressure setting, so the GPS and pressure altitudes should be similar. It's showing altitude, not flight level. The calibration/compensation will be done by twiddling the altimeter knob. Using my PAW GPS tends to get me within about 20ft of what my altimeter reads.

Duuuurrrh
re-engage brain - yes, this is what happens when you spend so much time thinking about comparing Pressure Altitude at 1013.25mb versus GPS Altitude !

Thx
Lee

[Wadoadi]

Thanks Lee and Paul,
     this the USB UBox VK172 not the usb mouse. no not part of a classic kit, I was one of the originals using the wireless thing and then traded it in for the PaW bridge board...

I do also have the USB Ubox mouse which is better but still not as quick as the GlobalSat and doesn't get a fix indoors...

The height did improve over the duration of the flight but I can't remember where it ended up.

PaW version is  20170223

extract from the GlobalSat taken from indoors with the gps connected to my laptop not Paw.

$GPGSV,4,3,15,30,13,312,15,01,11,248,,07,10,276,26,15,09,029,13*75
$GPGSV,4,4,15,28,04,329,,32,02,127,,26,01,169,*47
$GPRMC,194152.000,A,5244.4711,N,00033.0033,E,0.23,354.70,110517,,,A*67
$GPGGA,194153.000,5244.4711,N,00033.0033,E,1,8,1.47,4.3,M,47.0,M,,*5D
$GPGSA,A,3,08,11,07,27,21,18,10,15,,,,,1.70,1.47,0.85*0E
$GPGSV,4,1,15,27,72,125,19,08,67,291,30,10,57,104,36,18,41,064,27*7E
$GPGSV,4,2,15,11,25,266,20,16,25,179,,36,23,142,,21,15,072,27*77
$GPGSV,4,3,15,30,13,311,15,01,11,248,,07,10,276,26,15,09,029,13*76
$GPGSV,4,4,15,28,04,329,,32,02,127,,26,01,169,*47
$GPRMC,194153.000,A,5244.4711,N,00033.0033,E,0.16,354.70,110517,,,A*60
$GPGGA,194154.000,5244.4710,N,00033.0032,E,1,8,1.47,4.3,M,47.0,M,,*5A
$GPGSA,A,3,08,11,07,27,21,18,10,15,,,,,1.70,1.47,0.85*0E
$GPGSV,4,1,15,27,72,125,19,08,67,291,30,10,57,104,36,18,41,064,27*7E
$GPGSV,4,2,15,11,25,266,21,16,25,179,,36,23,142,,21,15,072,27*76
$GPGSV,4,3,15,30,13,311,15,01,11,248,,07,10,276,26,15,09,029,13*76
$GPGSV,4,4,15,28,04,329,,32,02,127,,26,01,169,*47
$GPRMC,194154.000,A,5244.4710,N,00033.0032,E,0.14,354.70,110517,,,A*65
$GPGGA,194155.000,5244.4710,N,00033.0032,E,1,8,1.47,4.3,M,47.0,M,,*5B
$GPGSA,A,3,08,11,07,27,21,18,10,15,,,,,1.70,1.47,0.85*0E

[Wadoadi]

Made the same trace from my PC with the uBlox it seems to have corruption every so often, or is this normal for uBlox?!

$GPZDA,205744.00,11,05,2017,00,00*67
$GPGBS,205744.00,4.9,5.5,17.8,,,,*72
µb
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tË ;ê$GPRMC,205745.00,A,5244.47159,N,00033.00500,E,0.137,,110517,,,A*7B
$GPVTG,,T,,M,0.137,N,0.253,K,A*22
$GPGNS,205745.00,5244.47159,N,00033.00500,E,AN,06,1.37,13.5,45.8,,*49
$GPGGA,205745.00,5244.47159,N,00033.00500,E,1,06,1.37,13.5,M,45.8,M,,*6C
$GPGSA,A,3,01,10,32,22,18,08,,,,,,,2.55,1.37,2.15*03
$GPGSV,3,1,09,01,42,267,33,08,72,171,20,10,41,058,20,11,58,278,*75
$GPGSV,3,2,09,18,15,050,27,22,31,206,31,27,36,141,08,28,28,313,11*75
$GPGSV,3,3,09,32,27,104,20*43
$GPGLL,5244.47159,N,00033.00500,E,205745.00,A,A*64
$GPGRS,205745.00,1,0.3,-0.3,1.3,-1.3,1.9,-9.7,,,,,,*64
$GPGST,205745.00,42,,,,4.9,5.6,18*79
$GPZDA,205745.00,11,05,2017,00,00*66
$GPGBS,205745.00,4.9,5.6,18.0,,,,*77
µb
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\Ï R$GPRMC,205746.00,A,5244.47167,N,00033.00492,E,0.168,,110517,,,A*75
$GPVTG,,T,,M,0.168,N,0.310,K,A*2E
$GPGNS,205746.00,5244.47167,N,00033.00492,E,AN,07,1.18,13.4,45.8,,*40

looks like it could be uBlox binary protocol is on, how do i turn it off?

[Wadoadi]

@Lee does the out from Ublox look correct or is there a way to turn off the binary message assuming that is what it is?

interestingly when plugged into the PC and using the Ublox software it gets a fix inside my house and very quickly which is greatly different from when its pluged into my PaW!

Also do the messages from the ND-105C look ok?

thanks

[Admin]

@Lee does the out from Ublox look correct or is there a way to turn off the binary message assuming that is what it is?

I'm sorry I have no idea, you could try the uBlox tech support.

interestingly when plugged into the PC and using the Ublox software it gets a fix inside my house and very quickly which is greatly different from when its pluged into my PaW!

That does not make sense.
How do you determine 'fix' ?
do you mean 2D/3D and how many satellites ?
I cannot see how this is any different to the data it provides to PilotAware - the NMEA messages are the same.

Also do the messages from the ND-105C look ok?

I think that is covering all the required messages - difficult to know if the content is OK
I would need to get out the NMEA spec and decode.

Thx
Lee

[JCurtis]

That binary data is the U-Blox AssistNow Aiding Messages packets, they start 0xB5 which is the ASCII "µ" you see in the data.  So you need to look at the commands to disable that feature in the module.  You might be able to turn it off in the UBlox config tool and save it to the flash in the GPS module.

[JCurtis]

Further to my last post, it looks like they enable the dumping of almanac data every so often so their app can display the various sat positions etc. I doubt this can be disabled I'm afraid.

[Wadoadi]

Thanks Lee and Jeremy,
          Lee the fix is indicated in the UBlox software and says 3D, as attached. I think this was about 40 - 60 secs after I plugin it in to the laptop in the center of my home and where it doesn't get a fix when plugged into the Pi.

Thank you Jeremy for your input too, I assume this is therefore the the same for all and thus nothing to do with the poor reception of the GPS.

May be it is interference from the Pi!?

[Admin]

Can you try an experiment on your pc ?
Rather than connecting using the ublox utility, try connecting using putty
Settings are
9600 baud
8 bits
1 stop bit
No parity

Would be interested in what you see

Thx
Lee

[Wadoadi]

sure no problem...
taken from Putty at 9600,8,1,N

$GPVTG,,T,,M,0.138,N,0.255,K,A*2B
$GPGNS,210018.00,5244.47035,N,00033.00790,E,AN,09,1.07,27.8,45.8,,*44
$GPGGA,210018.00,5244.47035,N,00033.00790,E,1,09,1.07,27.8,M,45.8,M,,*61
$GPGSA,A,3,11,08,10,22,01,27,18,28,32,,,,2.63,1.07,2.40*0A
$GPGSV,3,1,12,01,50,272,27,03,12,215,,08,63,165,26,10,33,055,25*75
$GPGSV,3,2,12,11,66,277,14,14,24,118,25,18,08,050,14,22,39,208,34*76
$GPGSV,3,3,12,24,01,026,,27,28,144,28,28,31,305,22,32,32,096,30*7F
$GPGLL,5244.47035,N,00033.00790,E,210018.00,A,A*6F
$GPGRS,210018.00,1,8.3,-5.2,-0.9,-0.1,3.7,-4.5,39.5,-1.8,4.6,,,*72
$GPGST,210018.00,44,,,,5.1,4.4,19*7F
$GPZDA,210018.00,15,05,2017,00,00*69
$GPGBS,210018.00,5.1,4.4,19.5,,,,*72
▒b0}▒
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      ▒▒▒▒▒▒▒▒}▒        ▒!*-7▒▒$GPRMC,210019.00,A,5244.47031,N,00033.00795,E,0.209,,150517,,,A*7A
$GPVTG,,T,,M,0.209,N,0.387,K,A*24
$GPGNS,210019.00,5244.47031,N,00033.00795,E,AN,09,1.07,28.0,45.8,,*43
$GPGGA,210019.00,5244.47031,N,00033.00795,E,1,09,1.07,28.0,M,45.8,M,,*66
$GPGSA,A,3,11,08,10,22,01,27,18,28,32,,,,2.63,1.07,2.40*0A
$GPGSV,3,1,12,01,50,272,27,03,12,215,,08,63,165,25,10,33,055,25*76
$GPGSV,3,2,12,11,66,277,12,14,24,118,24,18,08,050,14,22,39,208,35*70
$GPGSV,3,3,12,24,01,026,,27,28,144,28,28,31,305,21,32,32,096,30*7C
$GPGLL,5244.47031,N,00033.00795,E,210019.00,A,A*6F
$GPGRS,210019.00,1,10.5,-5.9,-1.8,0.3,0.9,-4.5,38.5,-1.9,4.8,,,*6B
$GPGST,210019.00,48,,,,5.1,4.4,19*72
$GPZDA,210019.00,15,05,2017,00,00*68
$GPGBS,210019.00,5.1,4.4,19.4,,,,*72
▒b0▒▒
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!7▒▒▒▒

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      ▒▒▒▒▒▒E▒b▒        ▒!17▒#$GPRMC,210020.00,A,5244.47028,N,00033.00799,E,0.222,,150517,,,A*7D
$GPVTG,,T,,M,0.222,N,0.411,K,A*25
$GPGNS,210020.00,5244.47028,N,00033.00799,E,AN,09,1.07,28.1,45.8,,*4C
$GPGGA,210020.00,5244.47028,N,00033.00799,E,1,09,1.07,28.1,M,45.8,M,,*69
$GPGSA,A,3,11,08,10,22,01,27,18,28,32,,,,2.63,1.07,2.40*0A
$GPGSV,3,1,12,01,50,272,27,03,12,215,,08,63,165,25,10,33,055,25*76
$GPGSV,3,2,12,11,66,277,10,14,24,118,24,18,08,050,13,22,39,208,35*75
$GPGSV,3,3,12,24,01,026,,27,28,144,28,28,31,305,21,32,32,096,29*74
$GPGLL,5244.47028,N,00033.00799,E,210020.00,A,A*61
$GPGRS,210020.00,1,4.5,-3.9,-1.0,0.0,0.5,-0.6,40.4,-1.5,6.6,,,*5C

[JCurtis]

Well there is defiantly some binary data in there, but without a hex dump it's hard to pick out the actual data being sent. It can be ignored though.

Note the dongles whilst they say UBlox are very probably clones, the one I was supplied defiantly is, they also have a small cell battery in them to maintain almanac data for faster acquisition, I don't think its rechargeable, and if that gets low it will be doing a full cold start each time. Depends on the quality of the cell when it was put together. If I get time I'll open mine up again and see what's what.

[Admin]

There is a problem in the setup there for sure.
The dongles we have do not generate the binary data, no idea what is happening there, but would upset the NMEA parser in Pilotaware

In fact if you look at tge logging page, I would guess there would be sone error messages

I think you have identified your issue

Thx
Lee