What kind of sensor can be used for finding the relative position between 2 satellites? Thanks.
Welcome to the PF.
On schoolwork questions like this, we require that you show some effort on your part first, before we can offer any tutorial hints. What kind of sensors do you think could be used? What would be their advantages and disadvantages? How far apart are the 2 satellites, and what is their expected relative motion?
Radar, laser from the satellites themselves.
From the ground, more options, including optical tracking.
It depends on the desired precision as well... If mapping Earth's gravitation field you demand more, to detect gravitation waves even more.
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