A Feasibility Study on Multiple Frequency CW for Landing Radar

摘要

Landing radar that measures the velocity and the altitude of the airframe has been developed for the sensor, which helps safe landing. In applications where the observation range is limited to a very short range such as the final stage of landing, we can expect to obtain a high signal-to-noise (S/N) ratio. In these situations, the multiple frequency continuous wave (CW) with MUSIC (MUltiple SIgnal Classification) algorithm is considered to be useful for achieving a high resolution with a low sampling rate of several tens of kilohertz and relatively low-speed signal processing. In this paper, the multiple frequency CW with 1D and 2D MUSIC algorithm to measure the altitude is described. The simulation shows that the bias errors in both methods are less than 1% of the altitudes. The random errors of 1D MUSIC and 2D MUSIC are 1.3%-1.7% and 0.8%-1.0%, respectively. The random errors of 2D MUSIC are smaller than those of 1D MUSIC. We also show the fundamental experimental results obtained in an athletic field using the radar fitted on a cage lifted by a crane. We could obtain stable estimation results on altitudes between 1.0m and 7.0m. These results indicate that the multiple frequency CW radar is one of the effective tools for landing radar in the final phase of landing.