Abstract: A radar surveillance system includes a plurality of satellites a plurality of medium earth orbit satellites to provide continuous, long dwell coverage of a region of interest. Each satellite has an antenna having a main reflector and a subreflector electromagnetically coupled to the main reflector. A phased array generates multiple electromagnetic beams positioned so the electromagnetic beams reflect from the subreflector onto said main reflector. The system may be used in determining slow moving targets using a combination of monopulse anomaly and target spectral width measurements. The system also performs synthetic aperture radar imagery and focussed area fast moving target detection using alternating slope linear frequency modulated pulses. The plurality of medium Earth orbit satellites include a self-contained communications system consisting of high bandwidth self-relay crosslinks, high bandwidth downlink, and direct broadcast downlinks for processed data.

Abstract: A radar surveillance system includes a plurality of satellites a plurality of medium earth orbit satellites to provide continuous, long dwell coverage of a region of interest. Each satellite has an antenna having a main reflector and a subreflector electromagnetically coupled to the main reflector. A phased array generates multiple electromagnetic beams positioned so the electromagnetic beams reflect from the subreflector onto said main reflector. The system may be used in determining slow moving targets using a combination of monopulse anomaly and target spectral width measurements. The system also performs synthetic aperture radar imagery and focussed area fast moving target detection using alternating slope linear frequency modulated pulses. The plurality of medium Earth orbit satellites include a self-contained communications system consisting of high bandwidth self-relay crosslinks, high bandwidth downlink, and direct broadcast downlinks for processed data.

Abstract: A radar surveillance system includes a plurality of satellites a plurality of medium earth orbit satellites to provide continuous, long dwell coverage of a region of interest. Each satellite has an antenna having a main reflector and a subreflector electromagnetically coupled to the main reflector. A phased array generates multiple electromagnetic beams positioned so the electromagnetic beams reflect from the subreflector onto said main reflector. The system may be used in determining slow moving targets using a combination of monopulse anomaly and target spectral width measurements. The system also performs synthetic aperture radar imagery and focussed area fast moving target detection using alternating slope linear frequency modulated pulses. The plurality of medium Earth orbit satellites include a self-contained communications system consisting of high bandwidth self-relay crosslinks, high bandwidth downlink, and direct broadcast downlinks for processed data.

Abstract: A passive imaging system that uses an antenna having two antenna elements. The system cross-correlates received signals with a reference function to achieve high resolution. The antenna elements are rectangular with their long dimensions oriented normal to the longitudinal axis of a carrying vehicle and the elements are separated by a distance consistent with image resolution requirements. Additionally, the antenna elements are frequency scanned in the cross-track dimension. The channel for the forward antenna element has a time delay relative to that of the rear antenna element. This time delay achieves pointing of the antenna at a particular forward angle relative to the normal to the velocity vector. Outputs of IF filters of the antenna elements are synchronously detected to provide in-phase and quadrature (I/Q) components of their phase modulated product.

Abstract: A synthetic array processing system which simultaneously develops a plurality of parallel synthetic beams, each beam being spaced in time along a flight path and having different effective phase centers. Means are provided for storing and reading out a plurality of doppler history signals from each of a plurality of range positions and in one embodiment of the subject invention the read out sweep lengths are programmed as a function of the square root of range to allow use of a constant slope focusing oscillator. The center frequency of the doppler histories are offset as a predetermined function of range and applied through a focusing mixer to a time compression filter circuit. A plurality of compressed pulses provided at the output terminal of the compression filter circuit, each represent a doppler history of a point reflector and a synthetic beam and these signals are applied to a display which may be controlled as a function of the square root of range.