RSGEC Terrestrial Altimetry(3)

In the last section, it has been mentioned that a series of photons has a super short time interval. The shorter they are, the more accurate the measurement is. Why? If following up the illustration given in Figure 1, it can be easily found that the time spent on photons’ travelling in space at speed of light and interacting with atoms and molecules of substances on sub-trace is less than one second! That is why stellate measurement is so accurate.

However, ones are always confused by radar frequency. That is defined as the frequency of sending photons out. In other words, for SAR the higher frequency radar has, the larger density of photons spreading on the surface is. That ensures that non-surface is missed while one satellite is flying over one location.

However, the scattered photons generated by interaction are uncontrollable although they travel in space in the form of EM wave as well and are received by receiver installed in the satellite as a series of signals.