Fwd: How to read status and NMEA standard message string(RMC,GGA..)

[Bhavna Harani]

---------- Forwarded message ---------
From: Bhavna Harani <haranibhavna111@gmail.com>
Date: Wed, Aug 3, 2022 at 7:37 PM
Subject: Re: How to read status and NMEA standard message string(RMC,GGA..)
To: Gary E. Miller <gem@rellim.com>

Hi ,

please find below information.

What version of gpsd?  : 3.24 release
What model GNSS receiver? - LC79D Quectl
How are you "reading" gpsd? - using a sample application which I have attached.

I have attached a log file also. In which I am getting status 0 ( STATUS_UNK ).  

I have also attached a log from gpsd ,which shows status 1(STATUS_GPS).

Both status are conflicting .

Is there any way to get the only first field of a NEMA packet using libgps API ?

For example, In below packet , how to get GNRMC or RMC ?

$GNRMC,141325.359,A,1834.587127,N,07353.248946,E,21.4,82.7,240722,,,*2C

Thanks,

Bhavna

On Tue, Aug 2, 2022 at 8:57 PM Gary E. Miller <gem@rellim.com> wrote:

Yo Bhavna!

On Tue, 2 Aug 2022 13:12:13 +0530
Bhavna Harani <haranibhavna111@gmail.com> wrote:

> I have below questions:

The problem with starting out with questions is that you have given
us zero context.

What version gpsd?

What model GNSS receiver?

How are you "reading" gpsd?

> 1) I am able to read lat/long/mode but when I have tried to read
> status, every time I was getting zero but I can see it was actually
> one.


Garbage in, garbage out.  Almost no GNSS receiver outputs a valid "status",
so it is rare to see gpsd pass that on.

> Below is a snippet.

Rather thatn reading your bad code, how about you read the working
and annotated gpsd example first:

    https://gpsd.io/gpsd-client-example-code.html

Then we can discuss the myriad issues with your code.

> logs in which I can see status is one.

gpsd never report a status of 1 when the NMEA status is 1.  They
are unrelated variables.  An NMEA status of 1 is meaningless.

See : include/gps.h lines 185-200

> Is there anything wrong I am doing here?

Many things.

> *2) How can I know the respective NEMA string type like GGA,RMC,etc
> in a client code?*

How does anyone know anything?

RGDS
GARY
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gnss_log.txt
Description: Text document

GNSS_SamplRead.c
Description: Text Data