On Monday 07 July 2008, Kai R=F6mer wrote:
quoted text
> Hi Al,
> If you need testers, please contact me. I have several gta02v5
> available and can do tests in Germany Munich.

=46irst stab uses the example perl functions from ublox for generating the=
=20
aid-ini data, replacing their hardcoded x,y,z with values for my location.=
=20
The copyright notice on the example code says you can't do anything with it=
=20
without permission so I can't give you the script, but I can tell you how t=
o=20
reproduce it ;-)

Get the AssistNow online client application note from:
http://people.openmoko.org/matt_hsu/ImplementationAssistNowServerAndClient(=
GPS.G4-SW-05017-C).pdf

Create a new script aid-ini.pl and start with:

#!/usr/bin/perl
print(clientdata_prepare());

Go to section B - Sample Server implementation and append subroutines=20
clientdata_prepare and ubx_checksum to aid-ini.pl

You need to replace the $posx, $posy and $posz values in clientdata_prepare=
=20
with some that match your location. These are ECEF coordinated in m. There'=
s=20
an explanation of the calculation method in:
http://www.u-blox.com/customersupport/docs/GPS.G1-X-00006.pdf

Alternatively you can use the attached spreadsheet if it survives the list.=
=20
Just replace the lat and lon with values for your location.

You probably want to change the time accuracy to reflect the accuracy of th=
e=20
=46reerunner clock, and possibly the accuracy of your location estimate.

Now copy the script to somewhere suitable on the Freerunner and make it=20
executable. I'm using /usr/local/bin. You need to install perl if you don't=
=20
have it already:
opkg install perl

Switch on the GPS then run the script:
/usr/local/bin/aid-ini.pl > /dev/ttySAC1

If you cat /dev/ttySAC1 you should be able to see it using the current time=
=20
according to your Freerunner. TangoGPS makes it easier to see what it's=20
doing. In the only test I've managed so far it got a fix with a poor view o=
f=20
the sky, while my Garmin Geko was still struggling to see 3 sats. It wasn't=
=20
quick, but it was better than the Garmin. It would be interesting if you=20
could try 2 units side by side, one with aid-ini and one without, to see if=
=20
it really makes a difference or if I was just lucky. I'll try to get some=20
more testing in, but the weather isn't good here, and I don't want to get m=
y=20
new toy wet ;-)