Patent ID: 7463187
Filing Date: 2008-12-09
Classification: G01S

Abstract:
1. A method to control a track gate and a level gate in an altimeter tracking an altitude of an airborne vehicle, the method comprising: emitting signals from the airborne vehicle, the signals directed toward a terrain; receiving terrain echo signals, wherein the terrain echo signals comprise reflections of the emitted signals from the terrain, and wherein each terrain echo signal has a rising edge and a peak amplitude; positioning the track gate in a temporal location to a selected reference amplitude on the rising edge of the terrain echo signals; positioning the level gate in a temporal location to within a selected range of the peak amplitude level of the terrain echo signals; measuring a change in a temporal location of the peak amplitude between sequentially received terrain echo signals; and varying a temporal separation between the track gate temporal location and the level gate temporal location based on the measured change in the temporal location of the peak amplitude.