[time-nuts] Carrier phase tracking
brooke at pacific.net
Mon Feb 19 15:45:35 EST 2007
The interfering signals to GPS are:
1) other satellites, they all transmit on the same frequency.
2) ground based transmitters, through harmonic radiation.
3) defective ground based equipment, like the active TV antenna on a
ship in Monterey bay.
There are now GPS+Glonass (spelling?) receivers. The European system is
not yet operational.
Having 30 active satellites instead of the minimal 24 makes surveyors
happy since they get more hours when there's good geometry.
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
Hal Murray wrote:
>>But... as marketing people thinks that 'more satellites, better' some
>>manufactures are commercializing small GPS receivers with 16 and even
>>20 channels... and obviously, no advantage over 12-channel ones.
>>Perhaps they expect the Navstar constellation to be so crowded in the
>>near future to don't let the Sun rays reach the Earth :-)
>How many satellites are there in the Russian or European systems? Or will
>there be if/when everything gets fully deployed?
>How close are the frequencies?
>What's the bandwidth of the signal? How far does doppler shift things?
>Is there spectrum set aside for this use, or is it shared with other
>applications and the receiver has to dig the signal out of a mess that's
>worse than just noise?
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