Coherent analysis of horizontally-polarized monostatic and bistatic sea clutter

Abstract

This paper compares the statistical properties of multiple simultaneous recordings of coherent monostatic and bistatic sea clutter data at two different bistatic angles. Differences in the Doppler spectra characteristics are highlighted as well as quantifiable amplitude statistics differences between the monostatic and bistatic data at each angle.

Analysis of polarimetric bistatic sea clutter using the NetRAD radar system

“…9 c . This extends to the Doppler domain the conclusion highlighted in the previous section regarding amplitude statistics, and appears to be in line with previous results with other NetRAD data [5, 6, 33]. The characterisation of micro‐Doppler signatures of sea clutter, the effect of the sea surface micro‐motions as a function of the sea state, and the use of this knowledge for detection of maritime targets, especially those presenting low observability, was also investigated in [38, 39].…”

“…Several methods have been proposed in the literature to estimate the shape parameter of the K distribution. A first approach uses the relation between the second normalised moment of the time series and the shape parameter ν , as indicated in chapters 6 and 13 of [15] and in [23], and used for instance in [5, 6]. The formula is reported in (3).…”

“…exo-clutter), the K distribution was used as it was observed that in the former case the effect of the noise was practically negligible when fitting the data, and in the latter case a K distribution with high shape parameter, i.e. a previous results with other NetRAD data [5,6,33]. The characterization of micro-Doppler signatures of sea clutter, the effect of the sea surface micro-motions as a function of the sea state, and the use of this knowledge for detection of maritime targets, especially those presenting low observability, was also investigated in [38,39].…”

“…Previous work on the characterisation of bistatic sea clutter has been presented within the collaboration between University College London (UCL) and the University of Cape Town (UCT) to collect and analyse data on multistatic sea clutter and maritime targets, using the netted radar system NetRAD [2]. These data have provided significant results for the characterisation of bistatic sea clutter radar cross section [3], amplitude statistics [4], and Doppler spectra [5, 6], and highlighted the potential advantageous properties of sea clutter in bistatic geometries, in particular the reduced effects of spike events in the amplitude and Doppler domain comparing simultaneous monostatic with bistatic data. The data analysed in these papers were collected in October 2010 and included different bistatic angles (15°, 30°, 60°, 90°, and 120°) and VV and HH co‐polarised measurements, plus a single cross‐polarised measurement reported in [3, 4].…”

“…A unique aspect of the data analysed is that for each transmitted and received polarisation combination, the data were collected over a relatively short amount of time at seven different bistatic angles from 60° to 120°. This allows a smoother analysis of clutter characteristics and trends as a function of bistatic angle for each polarisation compared to previous dataset analysis [3, 4, 6, 7], where the slow evolution of sea parameters might have had an effect. Some of the measurement programmes on bistatic clutter discussed in chapter 9 of [1] recorded simultaneous co‐polarised and cross‐polarised bistatic data, such as in [8] by Pidgeon at C‐band and in [9] by Kochanski at X‐band, but there is no clear reference to simultaneous monostatic clutter data for a proper comparison.…”