New Methods of Range Measuring Doppler Radar

This paper describes several methods of phase modulation radar in which the Doppler effect provides a carrier for range information. It is shown that these methods yield simple radar systems capable of measuring both the range and the speed of a target down to essentially zero distance. In contrast to conventional radars, only a nominal transmission bandwidth is required even under conditions where the echo is much weaker than the direct transmitter to receiver leakage signal. Special emphasis is given to the case where the phase modulation on the radar signal is accompanied by a certain amount of incidental amplitude modulation. Even then, however, a simple radar system results, the operating principles of which are experimentally verified. It is thus indicated that range can be measured down to a few feet using a transmission bandwidth of less than 1 Mc.