Mapping bathymetry using X-band marine radar data recorded from a moving vessel

Abstract

Marine radars mounted on ships can provide remarkable insights into ocean behaviour from distances of several kilometres, placing other in situ observations and the environment around a ship into a wider oceanographic context. It has been known for some time that it is possible to map shallow water bathymetry and currents using radar image sequences recorded from shore based stations. However, a long standing question from military and hydrographic communities has been whether such techniques can be applied to radar data collected by moving vessels. If so, this presents the possibility of mapping large areas of shallow or coastal seas (albeit with a somewhat coarse horizontal resolution of 50-100 m) prior to the surveying vessel actually having to travel into potentially uncharted or dangerous shallow water areas. Trial sets of radar data were recorded by the Canadian Forces Auxiliary Vessel Quest using a Wamos radar digitiser connected to a Decca navigation radar during a number of deployments around Nova Scotia in 2008 and 2009. Georeferencing corrections derived from the existing ship navigation systems were sufficient to allow the application of the existing depth inversion analysis designed for static radar installations. This paper presents the results of bathymetry analyses of two datasets recorded from CFAV Quest while the vessel was travelling at speeds of up to 14 knots. The bathymetry derived from the radar data compare favourably with independent surveys and with the on-board echo sounder to depths of approximately 50 m.

Proof of Feasibility of the Sea State Monitoring from Data Collected in Medium Pulse Mode by a X-Band Wave Radar System

“…Accordingly, the function F w k x , k y , ω retrieved from the analysis of the radar data represents a "scaled version" of the actual sea wave spectrum. Therefore, a calibration stage is required; see Equation (3).…”

“…In recent decades, X-band marine radar has been also employed as a remote sensing tool for sea state monitoring, not only on ships [1][2][3][4][5][6] but also in coastal areas [7][8][9][10][11][12][13]. The wavelength of X-band radar signal is approximatively equal to the wavelength of ripples present on the sea surface when a wind speed higher than 3 m/s is present.…”

“…Afterwards, the 3D sea-wave spectrum is obtained from this filtered radar spectrum through an equalization step based on the radar Modulation Transfer Function (MTF) [17]; see Equation (3).…”

Ocean Wind and Wave Measurements Using X-Band Marine Radar: A Comprehensive Review

“…Radar backscatter from the sea surface is primarily generated by Bragg resonance [9] interactions between the radar-transmitted electromagnetic microwaves and the high frequency gravity-capillary waves which are influenced by the effects of gravity and surface tension. For X-band radar operating Due to its high spatial and temporal resolutions, X-band marine radar has been used in many other oceanic applications, which involve target tracking [21], oil spill detection [22], internal wave analysis [23], wave group retrieval [24], surface current determination [25][26][27][28], upwelling observation [29], tide estimation [30], bathymetry mapping [31,32], surface elevation approximation [33,34] and prediction [35,36], coastal erosion [37], and detection of marine mammals [38]. In this paper, only the work related to sea surface wind and wave measurements is reviewed.…”

A simple method for retrieving significant wave height from Dopplerized X-band radar

“…In recent years, X-band marine radars have been utilized to measure spectral wave parameters (Nieto-Borge et al, 1999), wave groups (Dankert et al, 2003), individual waves (Dankert and Rosenthal, 2004;Nieto-Borge et al, 2004), surface currents (Senet et al, 2001;Huang et al, 2016), bathymetry (Senet et al, 2008;Bell and Osler, 2011) as well as surface winds (Dankert and Horstmann, 2007;VicenBueno et al, 2013). However, to retrieve significant wave heights, the relative radar image spectrum has to be transferred to a real wave amplitude spectrum using a modulation transfer function (Nieto-Borge et al, 1999).…”