Re: "The Truth about GPS. Co-inventor of GPS says Relativity Not Required." by Brent Shadbolt

Den 06.02.2025 01:25, skrev LaurenceClarkCrossen:

Source:
https://brentshadbolt.substack.com/p/the-truth-about-gps-relativity-not
 "Mar 18, 2024
 GPS is used to pinpoint locations on the Earth’s surface and relies on
radio signals sent from satellites in space. The signals carry coded
information about the satellite’s location and the signal's time. A GPS
receiver on Earth collects this information from three or four
satellites simultaneously and calculates the distance to each satellite.
The receiver then calculates where these distances intersect to
determine its location in three-dimensional space. The coordinates of
longitude, latitude and altitude are given in reference to a
three-dimensional mathematical model of the Earth's ellipsoid shape (a
slightly squashed sphere) called the ‘Conventional Inertial Frame’ or
‘World Geodetic System 1984’ (WGS 84)1 (figure 12).
 The positioning system's success relies on radio signals' ability to
transmit extremely precise information. To this end, GPS satellites
carry caesium atomic clocks that are correct to less than 5 parts in
1014, or about 4 billionths of a second per day.2 As the satellites are
orbiting 20,184 km above the Earth, they are in a much weaker
gravitational field than clocks on the Earth, and general relativity
predicts that the satellite clocks will tick more quickly by 45
microseconds per day.3
 Since the satellite clocks are moving relative to receivers on Earth,
special relativity predicts the satellite clocks will tick more slowly
by some amount compared to ground-based clocks. Satellite orbital speeds
are cited as 3,874 m/s; thus, satellite atomic clocks are reported to
experience a time dilation of about 7 microseconds per day.3
 When the slowing effect of special relativity on a GPS satellite clock
rate is subtracted from the speeding-up effect of general relativity,
the result is about 38 microseconds of increase per day (45-7). GPS
engineers adjust the clock rates before they are placed into orbit to
correct this time increase in satellite atomic clocks. The clocks are
given a rate offset of 4.465 parts in 1010 from their nominal frequency
of 10.23 MHz so that, on average, they appear to run at the same rate as
a clock on the ground. The actual frequency of the satellite clocks
before launch is thus 10.22999999543 MHz.3 In other words, the clocks
are pre-tuned to count a different number of caesium oscillations per
second compared to the standard on Earth so that in space, they measure
the same duration of time for one second as on Earth.

So the clocks are tuned to run slow by the factor -4.4647e-10 ,
or -38 μs/day because that's what the General Theory of Relativity
say must be done to make the GPS work.
And then the GPS does work.
GPS without relativity? :-D
https://paulba.no/pdf/Clock_rate.pdf
--
Paul
https://paulba.no/