[time-nuts] TruePosition GPSDO Holdover Issues

[Björn]

There are sometimes rapidly varying ionospheric conditions in some tropical/equator areas - older generation surveying receivers could loose phase look (cycle slips) due to temporal variation. Spatial variation can break the assumption that two receivers doing “RTK” will not have equal iono delay for each satellite - this would reduce base line lengths that could be achieved.

Don’t have a reference at hand, but there are publications about CORS station networks in Brazil discussing these phenomena behind the ION paywall.

/Björn 

>> Neat.  Thanks.  That raises several questions.
>> How high do satellites get if you are at a pole?
>> What is the best or worst latitude for timing?
>> What is the best/worst latitude for doing a survey?
> 
> 
> The answer for both timing and survey is that you want to be on the equator as far
> as sat elevation / tracks go. As long as you are “in the tropics” it is just about as good.
> 
> Bob
> 
> 
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
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