[time-nuts] how good an oscillator do you need for a GPS simulator
Magnus Danielson
magnus at rubidium.dyndns.org
Sun Dec 18 03:55:03 UTC 2011
Hi Brooke,
On 12/18/2011 03:30 AM, Brooke Clarke wrote:
> Hi Magnus:
>
> Exactly. The main problem with the Transit system was that the receiver
> needed a Cs clock for the system to work at all. GPS removed that
> requirement.
Indeed. Most of that was due to the long observations times as I recall it.
The 4 satellite requirement of a normal navigation GPS receiver is there
to allow for a complete (X, Y, Z, T) solution for a portable receiver
which can't afford the weight and continuous power consumption of atomic
references... at it's time of design.
> It's my understanding that a GPS receiver that uses a Cs clock has much
> more capability.
The main capability would be to either provide correction/ephemeris data
(widely used) or to provide good navigation even under severe methods,
as well as direct-Y locking.
Cheers,
Magnus
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