But they could still obtain accurate radar measurements of its orbit; and the more they observed, the more puzzled they be- came.

By comparing successive radar measurements, the navigation system identifies stationary and moving objects in the vicinity.

Vehicle speed and radar measurement are rarely the same for this reason.

Work on the glacier included radar measurements and seismic surveys.

Although radar measurements do not detect visible light they can determine the distance and size of an object with a high degree of accuracy.

The software performs match-up of ground- and space-based radar measurements.

This can include coordinates, radar measurements (including velocity), or an IR image of the target.

Using radar measurements, the French Air Force is able to spot satellites orbiting the Earth and determine their orbit.

As with all radar measurements, these rely on measuring the time taken for photons to be reflected from an object.

Direct radar measurements of the distances to Venus and Mars became available in the early 1960s.