[time-nuts] 5370B on eBay, carrier phase tracking GPS receiver
didier at cox.net
Sun Feb 18 21:56:01 EST 2007
I read about the uncertainty of absolute position because the carrier
phase data has no absolute reference, but that still gives a very
precise relative position (and speed) information.
The point is that for timing, absolute position information is probably
unnecessary. The benefit is that the hardware is capable of tracking the
signal at a much finer level and therefore provide a better timing
At least that's what I gathered from the various posts.
I am bidding on an Ashtech receiver too, but not a Z12. We'll see what
this one brings :-)
Brooke Clarke wrote:
> Hi Didier:
> Many GPS receivers output carrier phase data but it's usually used in
> post processing to get survey grade position accuracy. Since the code
> phase position accuracy is larger than a wavelength the receiver does
> not know how many integer wavelengths to add. But because of satellite
> movement this can be figured out later.
> The exception is the "in development" carrier phase timing which as far
> as I know can only be done using the Ashtech Z12.
> The Motorola GPS receivers have carrier phase data available, but when
> the 8 channel models were current there was no way to use it without
> spending a small fortune. I think today there's a Motorola binary to
> RINEX converter.
> Have Fun,
> Brooke Clarke
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