 But with our one second clock delay the situation
in our imperfect world would look like this:
The thick circles in the drawing show the "pseudo-ranges" caused by our
clock's error. The word "pseudo-range" is used in
the GPS world to describe measurements that contain errors.
Notice that while Sat A and B's pseudo ranges intersect at point XX, Sat C's pseudo
range cannot go through that point. This discrepancy alerts the receiver's computer that
there is a clock error.
Since any clock error or offset would affect all measurements, the computer looks for a
single correction factor that would allow all the measurements to intersect at one point.
In our example, it would discover that by subtracting a second from each measurement
the ranges would all intersect at one point.
With that correction factor determined, the receiver can then apply the correction to
all measurements from then on.
And from then on its clock is synced to universal time. Of course this correction
process would have to be repeated constantly to make sure the receiver's clocks stay
synced. But with it, even the lowliest GPS receiver turns into an atomic-accuracy clock.
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