A new algorithm for long range FMCW radar altimeter

The altitude information is very important for the safety of aircraft. Among many types of modulation, the Frequency Modulated Continuous Wave (FMCW) was the most common used in radar altimeter. Although classical Fast Fourier Transform (FFT) method has been successfully used in short range measurement for Radar Altimeter [1], the problem of altitude estimation in long distance for Radar Altimeter is still an opening issue. Main problem of the existing methods for long range measurement is that they easily lose the current altitude or require the long searching time. This paper proposes a novel algorithm for radar altimeter to estimate the altitude of an aircraft in both cases of long and short range measurements. By increasing the searching interval of spectrum of beat frequency, the proposed method can real-time track the altitude changes of the aircraft in a complex Dynamic Environment. The simulation results verify the proposed method.