thoughts on A-GPS offline

mqy meng.qingyou at
Sun Mar 1 23:25:14 CET 2009

>From [

UBX-AID-EPH and UBX-AID-ALM Messages for Satellite without valid Orbits
When polling UBX-AID-EPH or UBX-AID-ALM messages, satellites without valid
ephemeris or almanac data will 
return a complete UBX-AID-EPH or UBX-AID-ALM message with all data words set
to zero. This doesn’t comply 
with the protocol specification. Furthermore, u-blox 5 receivers with
firmware V5.00 and earlier can run into a 
floating-point exception when fed with such “empty” ephemeris. 

Is that the cause :D

Daniel Willmann wrote:
> Yes and that's what ogpsd does already. It has been saving/restoring
> almanac for months, ephemeris was disabled up until recently because
> there was a bug that prevented the GPS chip from doing anything useful
> after they were restored to the chip.
> ... ...
> Regards,
> Daniel Willmann
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> Openmoko community mailing list
> community at

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