Abstract: A radar screening system that detects an object in a region of interest by transmitting coded signals having a first polarization and receiving coded return signals having at least a second polarization. Suitably the transmitted signals have one polarization and some return signals have the same polarization and other return signals have an orthogonal polarization. The return signals are processed into voxels to calculate at least a cross-polar value at each voxel. Voxels are identified as being from an object of interest if an indicator using at least the cross-polar value exceeds a threshold. Preferably the indicator uses at least a ratio of the cross-polar value and the co-polar value. The radar screening system may also perform automatic target recognition by taking into account shape and location of the object of interest.

Abstract: According to one aspect of the present invention, a radar system is provided which accurately measures the surface profile in a wide sector beneath and forward of a helicopter, to aid low level transit and landing in poor visibility. This uses an electronic beam synthesis technique to form multiple beams directed at the area of interest, each measuring the distance to the first reflected signal received by each beam. These distances represent the profile of the ground and any objects on the ground. A processor then compares the measured profile with the ideal ground profile for safe landing. If the deviations from straight and level exceed the specified requirement for safe landing, or if sufficient rotor clearance is not detected, then a warning is given to the operator. A display will show the measured ground profile highlighting the unsafe regions, allowing the operator to seek a safe region to land.

Abstract: According to one aspect of the present invention, there is provided a radar altimeter which utilizes a downward looking MIMO phased array to form multiple beams, covering a relatively wide sector, e.g., +/?60 degrees or thereabouts. The distance to the ground is then measured in each beam allowing the ground profile to be formed. The beams may be tilted forward to cover from about +90 degrees forward (horizontal) to about 30 degrees behind nadir. The provision of such a forward tilt gives a greater degree of coverage in the direction of approach vector to the ground. This additional cover enables the altimeter to more accurately detect other vehicles in the proximity to the current approach vector of the vehicle to the desired landing zone.

Abstract: A surveillance apparatus (100) is provided, said apparatus including a linear sub-array (101) of N omnidirectional transmitter elements (103) and a planar sub-array (102) of M receiver elements (104). A plurality of the transient elements (105) are generated by separating out at each of the receivers (104) the signals transmitted from the antenna elements (103) of the transmitter sub-array (101). This allows the geometry of each path (from each transmitter antenna element, to the point being imaged and back to the receiver antenna elements) to be converted to a delay or phase shift to focus on the particular point being imaged. The transient elements (105) form a cylindrical array (106) at the mid points between transmitter and receiver sub-arrays. Such a configuration enables a full 360 degrees of cover in azimuth and typically +/?60 degrees in elevation.

Abstract: A radar imaging system for capturing an image of an object within an area of interest through at least one visual impairment. The radar imaging system comprises at least one radar array. The radar array includes a plurality of transmitter elements and a plurality of receiver elements for receiving a plurality of coded return signals from an object through the at least one visual impairment.

Abstract: A collision avoidance system for use with an unmanned vehicle, the system includes a plurality of radar elements arranged parallel to the longitudinal axis of the unmanned vehicle, wherein the radar elements transmit a plurality of pulses about the vehicle and receive a plurality of return signals from one or more objects within the range of the vehicle. Upon detecting the one or more objects within range of the vehicle, the system determines if an object is on a course which requires evasive action and suitably alters the vehicle's course in order to avoid collision.