[LEAPSECS] LEAPSECS Digest, Vol 51, Issue 22
Richard B. Langley
lang at unb.ca
Mon Feb 7 15:25:03 EST 2011
GPS Time actually come from a "paper clock" composed of all satellite
and ground station clocks: <http://tycho.usno.navy.mil/gpstt.html>.
Quoting Tony Finch <dot at dotat.at>:
> On Mon, 7 Feb 2011, Steve Allen wrote:
>> Until there is an ensemble of cesium chronometers not on the surface of
>> the earth there is no easy way to measure the potential depth to 1e-10,
>> so the corrections currently being used to compensate for the NIST and
>> PTB chronometers being about a mile high are as good as things can get.
> The PTB campus is at about 75m above sea level.
> Also, doesn't the GPS count as an ensemble of atomic clocks?
> f.anthony.n.finch <dot at dotat.at> http://dotat.at/
> HUMBER THAMES DOVER WIGHT PORTLAND: NORTH BACKING WEST OR NORTHWEST, 5 TO 7,
> DECREASING 4 OR 5, OCCASIONALLY 6 LATER IN HUMBER AND THAMES. MODERATE OR
> ROUGH. RAIN THEN FAIR. GOOD.
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> LEAPSECS at leapsecond.com
Richard B. Langley E-mail: lang at unb.ca
Geodetic Research Laboratory Web: http://www.unb.ca/GGE/
Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142
University of New Brunswick Fax: +1 506 453-4943
Fredericton, N.B., Canada E3B 5A3
Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/
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