[time-nuts] Galileo and GPS

[Magnus Danielson]

Martyn,

Martyn Smith wrote:
> Hello,
> 
> Will exisitng GPS receivers (Motorola M12M for example) be able to work 
> with the new Galileo system when it comes on line.
> 
> I know the systems are compatible, but not sure about older GPS receivers.

Simple answer: No.

Little longer answer:
Most existing GPS receiver such as the M12M has correlators that 
supports the L1 C/A signal only, possibly also GLONASS L1 C/A signal 
(such as the Zarlink chipsets). The Galileo signal structure does not 
use the L1 C/A signal structure, but has two L1 BOC signals, which the 
digital frontents of older receivers does not support.

Also, support for Galileo signal overhead needs to be there, along with 
expecting the signals to be there in the first place.

You can buy (expensive) receivers that will support Galileo and some 
even track the Giove test satellites. But those receivers will give you 
GPS and GLONASS L1 & L2 tracking, so for the moment a Galileo sat here 
or there doesn't make much difference.

However, if you look at L2C signals and L5 signals similarities will be 
much better. That's where the future compability will be.

Cheers,
Magnus