关键词: 无线电高度表, 线性调频连续波, 数字信号处理器, 快速傅立叶变换, 线性调频Z变换

Abstract: In order to meet the needs of small and medium grazing sea aircraft on the radio altimeters, a transceiver integrated radio altimeter was designed based on the IVS948 module. The influence of the sawtooth wave and the symmetrical triangular wave modulated signal on the measurement height was analyzed and compared with the linear frequency modulated continuous wave system. The selection of other main parameters was also calculated and analyzed. The key aspects of each working mode in the software operation flow were specified Description, and FFT-CZT algorithm into the height measurement. After the project prototype with the fly test, the measurement data and GPS differential height data consistent. The results show that the radio altimeter is reliable, the measurement data is credible and the precision is high. It can be used in flight control system of small and medium size skimming sea-based aircraft.

Key words: Radio altimeter, Linear Frequency Modulated Continuous Wave（LFMCW）, Digital Signal Processor（DSP）, Fast Fourier Transform（FFT）, Chirp Z-Translation（CZT）