Autocorrelations
The autocorrelations R0, R1, and R2 are produced by Pulse Pair, Random Phase, and DFT/FFT modes. The way that they are produced is different for each mode, particularly with regard to the filtering.
| Mode | Description |
|---|---|
| Pulse Pair Mode |
Filtering for clutter removal may be performed in the time domain or frequency domain. Traditional IIR type clutter filters are available in the time domain. However, the frequency domain filter is more adaptable. Clutter filtering can be optionally performed in the frequency domain, and then inverse FFT or DFT may be performed to return to time domain after clutter removal. Autocorrelations are then computed in the time domain. |
| DFT/FFT Mode | Filtering for clutter is performed in the frequency domain using both fixed width filters and the Gaussian Model Adaptive Processing (GMAP) technique. Autocorrelations are computed from the inverse transform. |
| Random Phase | Filtering for clutter and second trip echo is performed in the frequency domain by adaptive algorithms. Autocorrelations are computed from the inverse transform. |