Grumman Aerospace Corporation

Other

Philip G Grieve

Robert W Brandstetter

Nils J Fonneland

Joseph R Guerci

Herman Kaplan

Stephen S Hsiao

Radar signal processor for the detection of fast moving targets having small radar cross-sections. A method and apparatus is used to analyze a target that may travel through many range cells during coherent integration time. By transforming the pulse return data into the spatial frequency domain, range bin migration problems have been solved. The signal to noise ratio is also improved thereby permitting the detection of small targets. The processing consists of three major steps: performing an FFT for each pulse to yield spatial frequency components for each return; performing a special DFT for each spatial frequency yielding constant velocity output for each spatial frequency; and finally performing an inverse FFT to obtain target velocity and position.

Moving target detection through range cell migration radar

The signal-to-noise ratio of a received radar echo is maximized by maximizing the received energy E of the echo. The energy E is maximized when the transmitted waveform s(t) is chosen so that ##EQU1## is maximized, where y(t) is the echo signal echoing from the target.

Optimum matched illumination-reception radar

A method and apparatus for facilitating communication among circuit components mounted on a board, in which the components transmit radiation to a 'lambertian' (optically rough) surface located in opposition thereto for detection by the other components. If component identification information is included with each transmission, the present invention allows establishment of dynamically changing interconnections among any of the components on a board. The invention requires a relatively small spatial volume for implementation, and affords large data-transfer rates and freedom from electrical or other interactions.

Lambertian mirror optical

An optimized theoretical approach to the design of a waveform for a matched illumination-reception radar system incorporates radar cross section codes along with detailed target geometry and system constrains to maximize the signal energy of a received echo. An Eigensystem is used to generate a family of solutions, one of which is chosen based upon system constraints to optimize the waveform.

Optimum matched illumination waveform design process

An optical notching filter is disclosed in which an optical spatial filter therein is formed by a spatial light modulator which is written into by light. The optical notching filter system of the present invention provides a linear phase and amplitude response with applications for high speed adaptive filtering to filter out noise and signals of no interest. In one particular disclosed embodiment, the write with light optical notching filter system of the present invention is designed to adaptively excise interference from Radio Frequency (RF) signals, such as are utilized in communications or radar systems. The technical approach of the present invention provides a more compact system design than similar electronically addressed optical notching filtering systems, and also significantly reduces the complexity and attendant power requirements of the system. Different embodiments of a write with light optical notching filter system can operate with either nonochromatic or polychromatic light sources. Moreover, the write light source can be independent of the read light source, such that any suitable write or read light source can be utilized therein, either with single pass or recursive optical arrangements.

Write with light optical notching filter

The invention features an optical spread spectrum decoder wherein linear, non-linear, and discontinuous broadband RF signals can be optically decoded. The system introduces a weighting function into a local oscillator beam, which is then combined with a laser beam which has been modulated with the RF signal, processed to remove unwanted spectral components and then compressed. The combined beams are then down-converted to recover the RF signal.

Optical spread spectrum decoder

The invention features an optical system for removing electromagnetic interference components from a radio frequency signal. The radio frequency signal is electrically cascaded through a series of multiple channels each having a common pathway. The final RF output of the system produces a notched signal whose notch depth is the cumulative depth of each channel notch depth.

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New York, NY, United States of America

Philip G Grieve