It was found that a newly developed portable collision alert radar receives reflections from the ground while flying. In this paper a method is developed that uses range and Doppler information from these reflections. This information is used to compute height and velocity information relative to the terrain, something which is not possible with existing hardware. The method was tested on a local flight in the Netherlands, with a prototype of the radar. Flight state results were compared with those of a GPS tracker on board. It was found that the velocity can be computed within meters-per-second accuracy. Height differences are due to the measurement method, measuring directly from the ground surface (radar) or relative to a database (GPS). If developments in microwave sensing techniques continue to improve the hardware, flight state estimation by radar can become an option for pilots who do not want to be dependent on the correctness of a terrain model, but who measure the terrain shape independently.

人们发现，新开发的便携式碰撞预警雷达在飞行时会接收地面反射。在本文中，开发了一种使用来自这些反射的距离和多普勒信息的方法。该信息用于计算相对于地形的高度和速度信息，这是现有硬件无法实现的。该方法已在荷兰的一次本地飞行中使用雷达原型进行了测试。将飞行状态结果与机上GPS追踪器的结果进行了比较。发现可以以米/秒的精度计算速度。高度差是由于测量方法所致，是直接从地面（雷达）或相对于数据库（GPS）进行测量。如果微波感应技术的发展继续改善硬件，