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Topic: GNSS GN808 GPS chip issue (Read 1 time) previous topic - next topic

yerzhik

Hello, I've bought the "Ublox NEO-M8N GNSS chip GPS Module,GPS GLONASS Dual mode " chip.
On top I see the GNSS RECEIVER GN-808 from STOTON. On the stoton web site I found that chip but no datasheets found.

I connected it to arduino uno and just reading what I get from rx/tx.

Here is what I get:
Code: [Select]
$GNRMC,,V,,,,,,,,,,N*4D
$GNVTG,,,,,,,,,N*2E
$GNGGA,,,,,,0,00,99.99,,,,,,*56
$GNGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*2E
$GNGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*2E
$GPGSV,2,1,06,14,,,13,15,,,20,17,,,20,19,,,07*76
$GPGSV,2,2,06,20,,,22,21,,,22*7E
$GLGSV,1,1,00*65
$GNGLL,,,,,,V,N*7A


I also ran the tinygps and saw nothing but stars like:
Code: [Select]
**** **** ********* ********** **** ********** ******** **** ****** ****** ***** ***   *******  ****** ***   3564  0   

Seems like soemthing is wrong with the data I'm getting. Could someone point out on what is wrong and where can I download the datasheet?

-dev

The newest GPS devices emit NMEA sentences that have different "talker IDs".  The older libraries look for a talker ID of "GP", so they expect "$GPRMC", not "$GNRMC".  These new devices can emit a mix of sentences, and you may want to know when GPS satellites (USA) are being used vs. GLONASS satellites (Russia).  There are other constellations, too.

This is one of the reasons I wrote NeoGPS.  I also made it smaller, faster, more reliable and more accurate than all other GPS libraries.  It can parse all Talker IDs, so it can handle GNRMC as quickly as GPRMC, or even a mix of talkers.  NeoGPS is available from the Arduino IDE Library Manager, under the menu Sketch -> Include Library -> Manage Libraries.

A secondary problem with other libraries is their example programs.  They are usually not correctly structured and frequently break when modified.  There are other advantages, related to the GPS quiet time, printing too much data and coherency.  Even if you don't use it, there are lots of tips on the Troubleshooting page and the Installation page (see Choosing a Serial Port).

Cheers,
/dev
Really, I used to be /dev.  :(

yerzhik

The newest GPS devices emit NMEA sentences that have different "talker IDs".  The older libraries look for a talker ID of "GP", so they expect "$GPRMC", not "$GNRMC".  These new devices can emit a mix of sentences, and you may want to know when GPS satellites (USA) are being used vs. GLONASS satellites (Russia).  There are other constellations, too.

This is one of the reasons I wrote NeoGPS.  I also made it smaller, faster, more reliable and more accurate than all other GPS libraries.  It can parse all Talker IDs, so it can handle GNRMC as quickly as GPRMC, or even a mix of talkers.  NeoGPS is available from the Arduino IDE Library Manager, under the menu Sketch -> Include Library -> Manage Libraries.

A secondary problem with other libraries is their example programs.  They are usually not correctly structured and frequently break when modified.  There are other advantages, related to the GPS quiet time, printing too much data and coherency.  Even if you don't use it, there are lots of tips on the Troubleshooting page and the Installation page (see Choosing a Serial Port).

Cheers,
/dev
I've just tried it. Do I need additional steps for running NMEATest and other examples?
Because I get some compilation errors like:
Code: [Select]
Arduino: 1.6.9 (Windows 7), Board: "Arduino/Genuino Uno"

NMEAtest:58: error: #error NMEAGPS_PARSE_GGA, GLL, GSA, GSV, RMC, VTG and ZDA must be defined in NMEAGPS_cfg.h!

   #error NMEAGPS_PARSE_GGA, GLL, GSA, GSV, RMC, VTG and ZDA must be defined in NMEAGPS_cfg.h!

    ^

NMEAtest:74: error: #error GPS_FIX_LOCATION_DMS must be defined in GPSfix_cfg.h!

   #error GPS_FIX_LOCATION_DMS must be defined in GPSfix_cfg.h!

    ^

NMEAtest:94: error: #error GPS_FIX_HDOP must be defined in GPSfix_cfg.h!

   #error GPS_FIX_HDOP must be defined in GPSfix_cfg.h!

    ^

NMEAtest:98: error: #error GPS_FIX_GEOID_HEIGHT must be defined in GPSfix_cfg.h!

   #error GPS_FIX_GEOID_HEIGHT must be defined in GPSfix_cfg.h!

    ^

exit status 1
#error NMEAGPS_PARSE_GGA, GLL, GSA, GSV, RMC, VTG and ZDA must be defined in NMEAGPS_cfg.h!

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

yerzhik

I uncommented some of define lines, should work but seems like arduino ide is not seeing those changes. Anyway thank you, will try to get it to work.

-dev

Why are you trying the benchmark NMEAtest? That doesn't even use a GPS device.  See comments at the top.

Try the sketches in the order listed in the Installation instructions: NMEA and NMEAorder.

If they work, you could then try NMEAsimple, NMEAloc, NMEAtimezone, NMEAdistance... be sure to read the comment blocks at the top so you know what they are supposed to do.  And what you might need to do.
Really, I used to be /dev.  :(

srnet

#5
Nov 10, 2017, 10:06 pm Last Edit: Nov 10, 2017, 10:08 pm by srnet
Seems like soemthing is wrong with the data I'm getting. Could someone point out on what is wrong and where can I download the datasheet?
Nothing wrong with the data you are getting, but its likley the Arduino GPS library you are using does not recognise the format the data is in. That is not the GPSs fault and it would have been helpful if you had said which GPS library you are using.


The data sheets for the Ublox GPSs are easy to find, look on the Ublox website.

By default the Modern Ubloxes are listening and using most GPS satellite systems, although the location data is put in the GLONASS (GN) format.

To make a Ublox GPS put out sentences in the 'normal' GP format, send this command (string of bytes) to the GPS;

0xB5, 0x62, 0x06, 0x3E, 0x0C, 0x00, 0x00, 0x00, 0x20, 0x01, 0x06, 0x08, 0x0E, 0x00, 0x00, 0x00, 0x01, 0x01, 0x8F, 0xB2
http://www.50dollarsat.info/
http://www.loratracker.uk/

srnet

I also ran the tinygps and saw nothing but stars like:

**** **** ********* ********** **** ********** ******** **** ****** ****** ***** ***   *******  ****** ***   3564  0   

And you will get the stars in any case, even when the GPS format is recognised. In the example you gave the GPS does not have a fix so there is not meaningful data to display.

From the exerpt you showed, its clear the GPS satellite signals are extremly weak, are you perhaps testing the GPS indoors ?   

A GPS need to be outdoors to work properly.
http://www.50dollarsat.info/
http://www.loratracker.uk/

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