General Electric Company

Lockheed Martin Corporation

Arthur J Heidrich

Kenneth B Donovan

Dominick S Zirpolo

Richard A Ferrell

A system and a method for retrieving geographic information stored in geodetic coordinates based on one or more input positions based on nongeodetic coordinates includes a programmable processor in combination with a previously loaded database defined in geodetic coordinates. The processor is coupled to a display device and converts the received query position or positions into geodetic coordinates which are then used to retrieve associated geographic or structural information from the database for display.

System and method for accurate and efficient geodetic database retrieval

A beam width integrator is provided for a radar simulation system in which a synthetic radar image is generated from echoes comprised of simulated echo contributions. The amount of special-purpose digital equipment required is significantly reduced, together with the overall cost and complexity of the equipment. Data signals which jointly represent an echo contribution are provided in logarithmic form in order to limit the required storage and other logic and to reduce the number of operations required to process the signals. The echo contributions are divided into successive groups, each group comprising a predetermined number of echo contributions lumped to constitute a single set of equivalent signals. A complete echo is represented in uncorrected form by a predetermined number of successive groups. By numeric addition, an average weighting signal is applied to each group of lumped echo contributions to correct for gain profile-originated echo intensity variations. The corrected signals are successively paired in an adder tree comprising a plurality of power adders, each performing a numeric addition of a pair of logarithmic input signals. The output of the adder tree comprises a plurality of beam width integrated data signals which are jointly representative of a true echo.

Horizontal beam width integrator

To simulate the radar return from terrain of particular generic type (e.g. desert, forest, cultivated land) it is a known suggestion to employ closed-loop shift register with feedback suitable to produce particular 'texture' of return from specified terrain. It is here disclosed to synchronize output of such register with azimuthal position of simulated search radar; but this alone gives 'grainy' effect because 'smeary' or slowly changing amplitude with range in PPI sweep is not matched by corresponding lateral, or azimuthal, 'smear'. This objectionable effect is overcome by providing three sets of output terminals on feedback register, giving outputs corresponding to shifts for azimuths N, N+1, and N+2. By buffing together the three outputs, an azimuthal variation at a slow rate, comparable with the variation with range, is obtained, giving a more deceptive (and thus better) simulation.

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South Daytona, FL, United States of America

Arthur J Heidrich