Analysis of calibrated sea clutter and boat reflectivity data at C- and X-band in south african coastal waters

Abstract

The temporal characteristics of low grazing angle sea clutter and boat reflectivity are considered for both fixed and stepped frequency waveforms under a range of environmental conditions and geometrical configurations. Detectability of boats using an asymptotically optimal detector is evaluated empirically, as well as the influence of the local sea on boat reflectivity. Measurements were conducted with a calibrated, coherent, staring, pulsed radar system at C-and X-band frequencies ranging from 6.9 GHz to 10.3 GHz.

An Analysis of X‐Band Calibrated Sea Clutter and Small Boat Reflectivity at Medium‐to‐Low Grazing Angles

“…Only in a fully developed sea can the wave height be directly related to the present wind speed and can the significant wave height H s be accurately inferred from the average sea clutter reflectivity [3]. In transient sea conditions, the best fit for the Georgia Institute of Technology (GIT) mean sea clutter reflectivity model [4] is found if the sea state is related to the local mean wind speed rather than H s [5,6]. It can therefore be deduced that it is possible to also infer local wind conditions from X-band sea clutter.…”

Small Boat Detection Using OFDM Radar

“…Without loss of generality, the effect of thermal noise W from (15) is ignored, since, the power spectrum of noise is usually 20 dB below that of the clutter [29], [30]. Statistically, the sea clutter follows a non-Gaussian distribution [3], [4]. In particular, K-distribution, which describes the spherically invariant random process (SIRP), is considered as a suitable fit for the distribution of sea clutter.…”

“…Waves produced by the motion of a boat introduce interference of high spikes which cause degradation in the performance of conventional radar systems [1], [2]. Sea waves cause sea clutter which makes detection of small targets in an ocean difficult [3], [4]. Typically, sea clutter follows a non-Gaussian distribution [3], which affects detection and tracking of a small boat in the sea.…”

“…Sea waves cause sea clutter which makes detection of small targets in an ocean difficult [3], [4]. Typically, sea clutter follows a non-Gaussian distribution [3], which affects detection and tracking of a small boat in the sea. For small boat detection in a high clutter environment, many algorithms [3][4][5][6][7][8][9] have been proposed in the literature.…”

Boat Speed Monitoring Using Artificial Vision

“…An example of this application has been presented by Blake in [1] but unfortunately, like described in [2] and [3] using a radar-based method, it is difficult to recognize small boats, because their doppler spectrum is similar to sea waves' spectrum. Vision based detectors offer great advantages since the classification capabilities are more precise than a radar (in a complex scene objects can be better distinguished and further classifications are possible).…”