Abstract: A targetless tracking device has a detector configured to receive scattered radiation indicative of the presence of an object. The device also has a processor which is configured to calculate a positional relationship between the device and the object based on the scattered radiation, receive an indication of a desired positional relationship to the object, and output an error signal indicative of the positional relationship versus the desired positional relationship so that the device position is able to be controlled to reduce the error signal. The processor creates first and second images at first and second points in time, respectively, and compares the first and second images in order to calculate the positional relationship.

Abstract: A vehicle positioning and tracking radar system includes a rotating antenna with a pair of spatially separated transmit feeds for simultaneously transmitting a pair of frequency-modulated continuous-wave (FMCW) electromagnetic signals having a first polarisation and a pair of spatially separated receive feeds for receiving an electromagnetic signal having a second polarisation, wherein the first and second polarisations are different from one another, such that the transmit feed and receive feed at the rotating antenna are isolated from each other; and a coded modulated transponder receives transmit signals from the rotating antenna with the first polarization and transmits a receive signal to the rotating antenna with the second polarization.