A Doppler’s range rate refers to the rate of change of the distance (range) between a radar system and a target over time. It is often expressed in meters per second (m/s) and indicates how quickly the target’s distance from the radar changes. Range rate is a crucial parameter in radar systems, especially in applications such as tracking moving targets or measuring relative speeds. It is calculated based on the Doppler shift observed in the target’s radar return signals.
Doppler rate, in radar terminology, refers to the rate of change of the Doppler shift of a signal. It quantifies how quickly the frequency of the received signal changes due to relative movement between the radar and the target. Doppler rate is significant in radar signal processing for tracking moving targets because it provides information about the speed acceleration of the target, which can help distinguish between different types of targets and detect specific movements.
The typical range of Doppler shift depends on several factors, including the relative speed between the radar and the target, the operating frequency of the radar, and the maximum detectable speed range of the radar system. Doppler shifts can range from very low values, indicating stationary or slow-moving objects, to higher values corresponding to rapidly moving targets. For example, in radar systems operating in the microwave frequency range, Doppler shifts can range from fractions of a Hertz (Hz) for slow-moving objects to several kilohertz (kHz) or more for fast-moving objects such such as planes or vehicles. The range of Doppler shift observed in practice is influenced by the specific application requirements and technical capabilities of the radar.