GPS recognition doesn't work

[miran]

Hi

Please can you send me one example of RMC sentence.

I try to connect my GPS Receiver without success. I attempt with RMC protocol.
After first connection my GPS send a few sentence and they are not $GNRMC. Is that the problem?
The first few sentence You can see below.

19:42:03 $GNRMC,194203.00,A,4631.01884,N,01612.10637,E,0.054,,200318,,,D*6D
19:42:03 $GNTXT,01,01,02,u-blox AG – http://www.u-blox.com*4E
19:42:03 $GNTXT,01,01,02,HW UBX-M8030 00080000*60
19:42:03 $GNTXT,01,01,02,ROM CORE 3.01 (107888)*2B
19:42:03 $GNTXT,01,01,02,FWVER=SPG 3.01*46
19:42:03 $GNTXT,01,01,02,PROTVER=18.00*11
19:42:03 $GNTXT,01,01,02,GPS;GLO;GAL;BDS*77
19:42:03 $GNTXT,01,01,02,SBAS;IMES;QZSS*49
19:42:03 $GNTXT,01,01,02,GNSS OTP=GPS;GLO*37
19:42:03 $GNTXT,01,01,02,LLC=FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFD*2F
19:42:03 $GNTXT,01,01,02,ANTSUPERV=AC SD PDoS SR*3E
19:42:03 $GNTXT,01,01,02,ANTSTATUS=OK*25
19:42:03 $GNTXT,01,01,02,PF=3FF*4B
19:42:04 $GNRMC,194204.00,A,4631.01908,N,01612.10629,E,0.103,,200318,,,D*63
19:42:05 $GNRMC,194205.00,A,4631.01932,N,01612.10622,E,0.113,,200318,,,D*61
19:42:06 $GNRMC,194206.00,A,4631.01957,N,01612.10616,E,0.130,,200318,,,D*67
19:42:07 $GNRMC,194207.00,A,4631.01984,N,01612.10610,E,0.116,,200318,,,D*6A
and so one

Please help me. This is really a great improvement of practical use of yours spectrum analyzers.

Regards, Miran

[Andrew]

Miran,

Are you seeing the “CommErr” message in the Spike application?

If you haven’t already, verify the baud rate is correct.

It looks like after a few seconds, only the RMC string is being transmitted? It only transmits the other NMEA sentences on the first second? I believe in my code I pattern match everything between the string “RMC” and a newline, which means if the RMC sentence was the only sentence in the message it wouldn’t parse properly. I will need to account for this case for the next release.

Regards,
Andrew

[Andrew]

Here is an RMC string from our shop GPS. If I match it successfully (as per my previous post) I only look for the first 7 comma separated values, and ignore the rest.

$GPRMC,174641.000,A,4552.763046,N,12235.011607,W,0.011,142.26,210318,,,A*47

[miran]

After setting the correct Port number (13) and correct speed (I tray all standard speed) and pressing the button Connect I receive
immediately the message: “Unable to Connect GPS”

I Also change RMC format from $GPRMC (neutral-all satellite not only GPS) to $GPRMC and add some extra sentences. Without success

20:16:01 $GPTXT,01,01,02,u-blox AG – http://www.u-blox.com*50
20:16:01 $GPTXT,01,01,02,HW UBX-M8030 00080000*7E
20:16:01 $GPTXT,01,01,02,ROM CORE 3.01 (107888)*35
20:16:01 $GPTXT,01,01,02,FWVER=SPG 3.01*58
20:16:01 $GPTXT,01,01,02,PROTVER=18.00*0F
20:16:01 $GPTXT,01,01,02,GPS;GLO;GAL;BDS*69
20:16:01 $GPTXT,01,01,02,SBAS;IMES;QZSS*57
20:16:01 $GPTXT,01,01,02,GNSS OTP=GPS;GLO*29
20:16:01 $GPTXT,01,01,02,LLC=FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFD*31
20:16:01 $GPTXT,01,01,02,ANTSUPERV=AC SD PDoS SR*20
20:16:01 $GPTXT,01,01,02,ANTSTATUS=OK*3B
20:16:01 $GPTXT,01,01,02,PF=3FF*55
20:16:08 $GPRMC,201608.00,A,4631.01796,N,01612.11149,E,0.012,,210318,,,A*76
20:16:08 $GPGNS,201608.00,4631.01796,N,01612.11149,E,NN,00,1.20,186.5,41.5,,*73
20:16:08 $GPGGA,201608.00,4631.01796,N,01612.11149,E,1,00,1.20,186.5,M,41.5,M,,*59
20:16:08 $GPGSV,1,1,00*79
20:16:08 $GPZDA,201608.00,21,03,2018,00,00*60
20:16:09 $GPRMC,201609.00,A,4631.01798,N,01612.11146,E,0.031,,210318,,,A*77
20:16:09 $GPGNS,201609.00,4631.01798,N,01612.11146,E,NN,00,1.20,186.4,41.5,,*72
20:16:09 $GPGGA,201609.00,4631.01798,N,01612.11146,E,1,00,1.20,186.4,M,41.5,M,,*58
20:16:09 $GPGSV,1,1,00*79
20:16:09 $GPZDA,201609.00,21,03,2018,00,00*61
20:16:10 $GPRMC,201610.00,A,4631.01798,N,01612.11143,E,0.038,,210318,,,A*73
20:16:10 $GPGNS,201610.00,4631.01798,N,01612.11143,E,NN,00,1.22,186.4,41.5,,*7D
20:16:10 $GPGGA,201610.00,4631.01798,N,01612.11143,E,1,00,1.22,186.4,M,41.5,M,,*57
20:16:10 $GPGSV,1,1,00*79
20:16:10 $GPZDA,201610.00,21,03,2018,00,00*69
20:16:11 $GPRMC,201611.00,A,4631.01797,N,01612.11142,E,0.036,,210318,,,A*72
20:16:11 $GPGNS,201611.00,4631.01797,N,01612.11142,E,NN,00,1.20,186.3,41.5,,*77
20:16:11 $GPGGA,201611.00,4631.01797,N,01612.11142,E,1,00,1.20,186.3,M,41.5,M,,*5D
20:16:11 $GPGSV,1,1,00*79
is repeated

Please send me all NMEA sentences that are used in the program.

thank you for helping me!

Regards, Miran

[miran]

Dear Adrew

New information!
I just change the port number; from 13 to 2 without any other changes from the last GPS settings and now I get position. “GPS Connectect”.
I dont have Altitude, Sat. in View and SNR.
If you send my all NMEA sentences that are used in the program I can fix that.

Many new GPS receiver received also other satellite. For this reason i recommend also to use also $GNxxx sentences.

Regards Miran

[Andrew]

Miran,

If you are seeing the “Unable to Connect GPS” then this is not an issue with the NMEA data, it is an issue with attempting to open a file handle with the GPS. We use the CreateFile() function to open the GPS with a fileName of “COM#” where # is the COM port number you provided. Can you think of a reason why the GPS would be unable to open this way? Is it being interfaced in another application?

To answer your question, we only look at the RMC, GSV, and GGA sentences, but we only require the RMC to be present, if the others aren’t present then we ignore those values, but these sentences are only going to be looked at if the GPS is successfully connected, which it doesn’t sound like it is.

Regards

[Andrew]

It doesn’t look like your GSV sentence contains the SNR value, so it will stay empty.
Also I used this sentence format for the GGA string.
http://aprs.gids.nl/nmea/#gga
It looks like your message contains the data when it is emitted. Is it possible it is not emitting the GGA sentence in it’s current configuration?

[miran]

Andrew,

Thank you for the very quick response.

Now I get all GPS information.

The solution: I just change the port from 13 to 2. Is there any limitation for port number (except max 255)?
I also switch in GPS receiver: GSV, and GGA sentences.

Miran

Regards

[Andrew]

Hi Miran,

I’m not sure of the limitation. You can determine the COM port number of a device in the device manager.

Regards

[JasonS]

Andrew

Seems like there is more too this. I also struggled to get the GPS comms going.

My GPS created a COM35 port. This was the first available COM port. No connection in Spike.

I changed it to COM2 manually in Device Manager and all was good!

So there is a limitation somewhere …

Cheers

[Justin Crooks]

AJ,
I remember running into this before. I think this is the bug fix:
https://stackoverflow.com/questions/11775185/open-a-com-port-in-c-with-number-higher-that-9
Also, here:
https://support.microsoft.com/en-us/help/115831/howto-specify-serial-ports-larger-than-com9

• This reply was modified 8 years, 4 months ago by Justin Crooks.

[Andrew]

Hello Jason and Miran,

It looks like Justin is correct. There is something additional I needed to do to get port numbers above 9 to work properly. I can now get Spike to connect to higher port number devices properly. You should see this in the next version of Spike (no timeframe yet). Apologies for the difficulties and thanks for the feedback so we could get this fixed.

Regards,
Andrew

[Author]

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