Sub-surface radar imaging
AssigneeThe Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
InventorRoger Tredegar Biggs
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Abstract
Detailed is radar imaging apparatus including a single transmit antenna and at least one receive antenna, scanning apparatus (e.g. a pantograph) for mechanically scanning the antennas over a surface of interest, position providing apparatus (e.g. a computer driving the pantograph via an X-Y drive and a stepper motor) providing a position signal indicative of the instantaneous position of the transceiver and a control system for operating the transmit antenna in a stepped frequency continuous wave mode. The amplitude and phase components of the receive antenna signal are analysed and the output combined with the position signal as in a synthetic aperture array to provide a radar image signal of the surface and underlying features. The scan is two-dimensional (random or boustrophedral).
Claims36
Radar imaging apparatus comprising a transceiver including a single transmit antenna and at least one separate receive antenna, control means for operating the transmit antenna in a stepped frequency continuous wave mode, scanning means for mechanically scanning said transceiver across a surface of interest, position providing means providing a position signal indicative of the instantaneous position of the transceiver, signal analysing means for analysing amplitude and phase components of the receive antenna signal, and signal combining means for combining the output of said signal analysing means with said position signal as in a synthetic aperture array to provide a radar image signal of the surface and underlying features, characterised in that (a) the apparatus is arranged for operation over a bandwidth of at least 8 GHz;
- and (b) part of the scanning means in use is located at a fixed position relative to said surface and the position providing means is arranged to provide a position signal as a function of the instantaneous position of the transceiver relative to the said fixed position.
A method of imaging sub-surface features comprising the steps of providing a transceiver including a single transmit radar antenna and at least one separate receive radar antenna, operating the transmit antenna in a stepped frequency continuous wave mode to irradiate a surface of interest, providing a scanner for mechanically scanning the transceiver across said surface, providing a position signal indicative of the instantaneous position of the transceiver relative to the stationary part of the scanning means, analysing the phase and amplitude of the receive antenna signal and combining the resulting information with said position signal as in a synthetic aperture array to provide a radar image signal of the surface and underlying features, characterised in that (a) the apparatus is operated over a bandwidth of at least 8 GHz;
- and (b) part of the scanning means in use is maintained at a fixed position relative to a surface of interest and the position signal is determined as a function of the instantaneous position of the transceiver relative to the said fixed position.
Dependencies are inferred from the claim text.