Synthetic-Aperture Radar Based on Nonsinusoidal Functions: VII-Thumbtack Ambiguity Functions

Abstract

In the sixth paper of this series, an approximation was used for certain correlation functions, but its justification was postponed. These correlation functions are investigated in more detail in the present paper. The theory of pulse-position and pulse-shape coding of radio signals is further advanced toward correlation and ambiguity functions with low or no sidelobes, and block diagrams of receivers are derived. It is shown how signals can be constructed that have a large average-to-peak power ratio of the radiated wave, and avoid at the same time large antenna currents. A class of signals and their receivers is derived whose ambiguity functions have theoretically no sidelobe in a selectable section of the range-Doppler domain. Such signals are ideal for the detection of low-flying aircraft and cruise missiles by means of an all-weather, look-down radar, the discrimination of radar decoys from an ICBM, and other uses calling for extreme resolution under any weather conditions.