In Section 3.9.3, the point was made that a radar receiver performs a cross-correlation between the received signal and a reference of the transmitted waveform. Furthermore, the received signal may differ from the transmitted signal on account of being time delayed and Doppler shifted. The design of a matched receiver usually entails designing the receiver to match the transmitted waveform and so may no longer match the received signal on account of the time and frequency displacements of the received signal over the transmitted one. Matched reception is tantamount to autocorrelation of the received signal at a particular time shift. In radar, it is most convenient to think of the particular time shift associated with a given range cell. While the autocorrelation function handles shifts in time, it offers no provision for handling shifts in frequency. The ambiguity function describes the response of a matched receiver to a finite duration signal. The use of the ambiguity function in ambiguity analysis considers the receiver to be matched to a signal received from a target at a given time delay (range cell) and frequency. The ambiguity function describes the matched receiver response as a function of any additional time delay and any additional Doppler frequency.

Chapter Contents:

• 5.1 Ambiguity Diagrams
• 5.2 Peak and Integrated Sidelobe Levels

Inspec keywords: correlation methods; radar receivers; Doppler shift; radar signal processing

Other keywords: transmitted signal; ambiguity function analysis; frequency displacements; Doppler shift; radar receiver; received signal; Doppler frequency; time delay; cross-correlation analysis; finite duration signal; time displacements; matched receiver design; range cell

Subjects: Radar equipment, systems and applications; Signal processing and detection