Synthetic-Aperture Radar Based on Nonsinusoidal Functions: IV-Tracking Radar and Beam Rider

Basic features of synthetic-aperture radar based on nonsinusoidal functions have been discussed in three previous papers [1]. This paper investigates the application of the principles to tracking radars and beam riders. The main area of application is for high-resolution all-weather radar. In this case, the highest significant frequency used is two orders of magnitude lower than for a radar using a sinusoidal carrier, if the same absolute bandwidth and thus the same information flow are used in both cases. Data for the angular resolution and the accuracy of angle measurement are obtained as functions of timing errors and mechanical tolerances. Angle measurements are based directly on the measurement of time diffemces, while radar with a sinusoidal carrier derives angles from the measurement of phase differences, which yield time differences with an ambiguity of multiples of the carrier period. The need to remove this ambiguity by spacing radiators or receptors no more than half a wavelength apart is a major reason for the very different design of radars with and without a sinusoidal carrier.