Contents
What is ambiguity function in radar?
The radar ambiguity function is defined as the absolute value of the envelope of the output of a matched filter when the input to the filter is a Doppler-shifted version of the original signal, to which the filter was matched. Ambiguity functions are usually analyzed on a single pulse basis.
What is cross ambiguity function?
The cross-ambiguity function is a time (𝜏) and frequency (𝜈) analysis technique employed to solve many signal processing problems such as interference mitigation and the location of emitters.
What is ambiguity diagram?
An ambiguity diagram is a three-dimensional plot that shows the results of convolving a range of frequency-shifted signals with a fixed reference signal. DETAILED EXPLANATION: The Ambiguity diagram uses the waveform that is sent out by a RADAR as its reference waveform.
How does pulse compression work?
Pulse compression is a signal processing technique commonly used by radar, sonar and echography to increase the range resolution as well as the signal to noise ratio. This is achieved by modulating the transmitted pulse and then correlating the received signal with the transmitted pulse.
Why is it called pulse compression?
this signal is designed so that after matched filtering, the width of the intercorrelated signals is smaller than the width obtained by the standard sinusoidal pulse, as explained above (hence the name of the technique: pulse compression).
How is pulse compression gain calculated?
The pulse compression ratio can be expressed as the ratio of the range resolution of an unmodulated pulse of length τ to that of the modulated pulse of the same length and bandwidth B. The compression ratio is equal to the number of sub pulses in the waveform, i.e., the number of elements in the code.
Which is the maximum value of the ambiguity function?
The asterisk (*) denotes the complex conjugate. The ambiguity function describes the effects of time delays and Doppler shifts on the output of a matched filter. The magnitude of the ambiguity function achieves maximum value at (0,0). At this point, there is perfect correspondence between the received waveform and the matched filter.
How is the ambiguity function represented in radar?
A more concise way of representing the ambiguity function consists of examining the one-dimensional zero-delay and zero-Doppler “cuts”; that is, , respectively. The matched filter output as a function of time (the signal one would observe in a radar system) is a Doppler cut, with the constant frequency given by the target’s Doppler shift: .
How is the ambiguity function of a pulse determined?
The ambiguity function is determined by the properties of the pulse and the matched filter, and not any particular target scenario.
The ambiguity function plays a key role in the field of time–frequency signal processing, as it is related to the Wigner–Ville distribution by a 2-dimensional Fourier transform.