once the pulse is transmitted by the radar a sufficient length of time must elapse before the next pulse to allow echoes from targets once the pulse is transmitted by the radar a sufficient length of time must elapse before the next pulse to allow echoes from targets at the maximum range to be detectedat the maximum range to be detectedthird uses radiometers to detect unusual temperature changes in the flight path. (The air in the descan be at many different attitudes with respect to the radar, the range of magnitudes of echoes can be quite large. This gives rise to thecending column is substantially cooler than the surrounding air)instead of getting the position information from the aircrafts GPS, the multilateration system records the time of arrival of the transmission at several (more than three) ground-based receivers and then computes the aircraft position independently. RSince the distance from the aircraft to the ground is small, the time between tronce the pulse is transmitted by the radar a sufficient length of time must elapse before the next pulse to allow echoes from targets at the maximum range to be detectedansmission and reception is small (400 ns at 200 Ft.) and when the original radar altimeters were produced, pulsed radar once the pulse is transmitted by the radar a sufficient length of time must elapse before the next pulse to allow echoes from targets at the maximum range to be detected