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Pulse Compression Radar
Published in Habibur Rahman, Fundamental Principles of Radar, 2019
The ambiguity function is defined as the absolute value of the complex envelope of the output signal obtained when the matched filter is fed by a Doppler-shifted version of the original signal, to which the filter is matched. The mathematical functions called time-frequency autocorrelation functions or ambiguity functions were first introduced by Woodward2 to allow representation of the time response of a signal processor when a target has significant radial velocity. The radar ambiguity function is used by radar designers to obtain a better insight about how different radar waveforms may be suitable for the various radar applications. It is also used to determine the range and Doppler resolution for a specific radar waveform.
Signal Processing
Published in Lawrence J. Ziomek, Fundamentals of Acoustic Field Theory and Space-Time Signal Processing, 2020
The auto-ambiguity function is used as a measure of the range and Doppler resolving capabilities of different transmitted electrical signals (amplitude- and angle-modulated carriers) used in active sonar (and radar) systems. We shall derive and provide an interpretation of the auto-ambiguity function by considering the following binary hypothesis-testing problem of trying to detect a slowly fluctuating point-target return in the presence of noise: () H0:r˜(t)=n˜(t),−∞<t<∞, () H1:r˜(t)=y˜T(t)+n˜(t),−∞<t<∞,
The Design and Analysis of the Sidelobe Reduction Filter for Polyphase Frank Codes
Published in IETE Journal of Research, 2023
A Balaraju, S. P. Singh, Dhiraj Sunehra
In the case of a moving target, the output of the matched filter is generally represented by the complex function , where represents the Doppler shift due to the velocity of the moving target and τ represents the time delay. is the ambiguity function. Mathematically the ambiguity function is represented as follows: In other words, the Ambiguity function is a tool to check the detection efficiency of the transmitted signal when the signal is received with a Doppler shift. That is the signal is received with time-delay τ and Doppler shift relative to the nominal values (0,0) [1].