[Gta04-owner] GPS fix?

[Dr. H. Nikolaus Schaller]

Am 15.11.2011 um 15:39 schrieb Boudewijn:

> On Tuesday 15 November 2011 14:46:03 Neil Jerram wrote:
> > On 15.11.2011 13:40, Dr. H. Nikolaus Schaller wrote:
> > > But the module starts sending NMEA records (with 0 satellites and
> > > void
> > > location data) on /dev/ttyS1 as soon as you give one  impulse on the
> > > on/off line.
> > > Please compare (slightly updated):
> > > 	http://projects.goldelico.com/p/gta04-kernel/page/GPS/
> After a few minutes next to a window, my log quite resembles Neils:
> 
> $GPGGA,000919.031,,,,,0,00,,,M,0.0,M,,0000*55

This shows the internal time.

> $GPGSA,A,1,,,,,,,,,,,,,,,*1E

The A means: no fix

> $GPRMC,000919.031,V,,,,,,,130806,,,N*42
> $GPGGA,000920.031,,,,,0,00,,,M,0.0,M,,0000*5F
> $GPGSA,A,1,,,,,,,,,,,,,,,*1E
> $GPRMC,000920.031,V,,,,,,,130806,,,N*48
> $GPGGA,000921.041,,,,,0,00,,,M,0.0,M,,0000*59
> $GPGSA,A,1,,,,,,,,,,,,,,,*1E
> $GPGSV,3,1,12,20,00,000,,10,00,000,,25,00,000,,27,00,000,*79
> $GPGSV,3,2,12,19,00,000,,07,00,000,,04,00,000,,24,00,000,*76
> $GPGSV,3,3,12,16,00,000,,28,00,000,,26,00,000,,29,00,000,*78

These records indicate the 12 satellites

> $GPRMC,000921.041,V,,,,,,,130806,,,N*4E
> $GPGGA,000922.031,,,,,0,00,,,M,0.0,M,,0000*5D
> $GPGSA,A,1,,,,,,,,,,,,,,,*1E
> $GPRMC,000922.031,V,,,,,,,130806,,,N*4A
> 
> > > What test did not check is if the internal antenna switch and power
> > > supply is working
> > > well enough and does not have too much attenuation for good
> > > reception.
> I have an external antenna, but with an oldfashioned connector, ie, about 3 times the diameter of the one on the GTA02/04. I haven't been able to find an adapter. For a new antenna goes the same as Neil: see if I can pick up one for a nice price.
> 
> Might opening the battery cover help? Are best results expected while pointing the antenna up, keeping it vertical or horizontal?

Best result should be antenna outdoors towards the sky.

> 
> > > 
> > > A common problem of the internal GPS antenna module is that the cable
> > > may
> > > break at the end that is soldered to the module during some
> > > disassembly of
> > > the units.
> Is a broken cable easily recognized? The cable is quite stiff, does it become less stiff if it's broken? The connector gave a little "snap" when pressing it on, so that side seems ok.
> 
> Now, a few minutes later, comparable results:
> $GPGGA,001612.043,,,,,0,00,,,M,0.0,M,,0000*55
> $GPGSA,A,1,,,,,,,,,,,,,,,*1E
> $GPRMC,001612.043,V,,,,,,,130806,,,N*42
> $GPGGA,001613.031,,,,,0,00,,,M,0.0,M,,0000*51
> $GPGSA,A,1,,,,,,,,,,,,,,,*1E
> $GPRMC,001613.031,V,,,,,,,130806,,,N*46
> $GPGGA,001614.031,,,,,0,00,,,M,0.0,M,,0000*56
> $GPGSA,A,1,,,,,,,,,,,,,,,*1E
> $GPRMC,001614.031,V,,,,,,,130806,,,N*41
> $GPGGA,001615.039,,,,,0,00,,,M,0.0,M,,0000*5F
> $GPGSA,A,1,,,,,,,,,,,,,,,*1E
> $GPRMC,001615.039,V,,,,,,,130806,,,N*48
> $GPGGA,001616.031,,,,,0,00,,,M,0.0,M,,0000*54
> $GPGSA,A,1,,,,,,,,,,,,,,,*1E
> $GPGSV,3,1,12,20,00,000,,10,00,000,,25,00,000,,27,00,000,*79
> 
> I'll read up on what the signals mean, so I got some idea myself as well what is going on.

Looks as if the GPS chip works but have no satellite fix.

I will try to find out what other reasons may be.

Nikolaus

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