[time-nuts] Re: Composite sky GPS

[Bob Camp]

Hi

This is sort of several questions rolled into one. Various answers:

1) Are there dual antenna receivers? Sure there are/ They *assume* you can see all the 
sats from both antennas at the same time. 

2) Can you get 3D fixes from multiple independent antennas? Sure, but not with a stock 
receiver. The delays and phase shifts into multiple receivers from multiple inputs via multiple
cables really mess with things. 

3) Can receivers chat with each other? Yes, it’s RTK mode. Like 1 above to be useful, it
wants both receivers looking at the same set of sat’s. 

Bottom line, AFIK, you need an antenna that can see at least 4 sats all at the same time. It
needs to do that long enough to get a reasonable location fix. Once you have that fix, you
can go over to fixed location / timing mode. That will give you timing information. This mode
is not available on all GPS receivers or modules. 

Bob



> On Jun 30, 2023, at 1:36 AM, glen english LIST via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> talking about GNSS, someone here might know....
> 
> I have a problem which I can see either one hemisphere or the other, but not both simultaneously  - from the one antenna.
> 
> It takes two antennas. Consequently, my 3D fixes are in the toilet.
> 
> Is there a mode where two receivers  separately correlate all the sats they can see independently and then talk to each other to use the sats from the 'other' receiver to get a better all sky 3D fix ? or get  enough raw data out of them and post process elsewhere ?
> 
> glen.
> 
> 
> On 22/06/2023 10:31 am, Lux, Jim via time-nuts wrote:
>> On 6/21/23 10:11 AM, Erik Kaashoek via time-nuts wrote:
>>> John, thanks
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