Sperry Rand Corporation

Northrop Grumman Systems Corporation

Sperry Corporation

Terry A Tucker

Jeffrey Clarus Rice

Eric J Isbister

Robert F Riggs

Robert J Klepach

Wilfred M Seay

Donald J Wigent

Albert L Coleman

Johnny A Cornett

Howard S Gentry

Performance of an inertial navigation system (INS) corrected with GPS position data is enhanced with the addition of a filter that smooths the GPS-INS position difference data and couples the smoothed data to the INS position data. Difference data provided to the filter is edited to eliminate GPS-INS position data that excceeds a predetermined level. Performance is further improved by applying position resets from the INS Kalman filter in a ramp like manner.

Method and apparatus for improving performance of an inertial navigation system having global positioning system corrections

A complete frame of radar data is stored in radar real time addressed in accordance with antenna azimuth. The PPI rotating display scan is generated by deflecting the beam along the azimuth sweeps thereof under control of X-rate and Y-rate signals provided for each sweep. The X-rate and Y-rate signals are applied sequentially to X and Y binary rate multipliers which generate clock signals at a frequency proportional to the rate signals. The clock signals are applied to X and Y position counters respectively for generating the X and Y deflection signals via digital-to-analog converters. Sequential application of the X and Y rate signals to the X and Y rate multipliers generates the rotating scan. The radar data stored in memory is accessed in accordance with the azimuth address in synchronism with the generation of the azimuth display sweeps. The stored data provides the video signal for the display tube so as to generate the radar display. The rotating scan is generated in non-real radar time at a rapid rate. X-rate and Y-rate signals are also applied to the binary rate multipliers for generating concatenated straight line strokes to display synthetic symbology. .DELTA.X and .DELTA.Y signals are utilized to control the lengths of the strokes.

PPI Display for radar and synthetic symbology

An electronic docking system utilizing a multiplicity of sensing subsystems to derive and display docking parameters during the docking operation is disclosed. The parameters displayed include bow and stern velocities ship's velocity perpendicular and parallel to the jetty and ship's orientation to the jetty during the docking maneuver. Parameters are derived from data gathered by sensors that include a receive only monopulse and a receive only doppler system which determine the angular position of a selected reference location aboard the ship and a signal with a frequency representative of the ship's velocity from a signal radiated from a beacon antenna aboard the ship. Range measurements are accomplished by utilizing baseband pulse radar systems capable of determining range to accuracies in the order of one foot. A telemetry link between the ship and the shore based system provides a means for simultaneously displaying data on board and on land and for relaying docking commands from the jetty master to the docking pilot.

Electronic docking system

Each output signal from a synchro device is applied to an individual voltage comparator through a step-down transformer. Each comparator is biased to a predetermined threshold level and produces an output signal whenever the magnitude of the associated synchro signal exceeds the threshold in the proper polarity. The comparator output voltages are applied to individual clocked flip-flops so as to produce binary output signals in a parallel format indicative of the rotor displacement of the synchro device.

Synchro-to-digital converter

A video detector wherein the ratio of the energy contained in a range cell of interest to the average energy contained in adjacent range cells is obtained. When the two ratios are both greater than a predetermined value, a hit is recorded. After a number of transmitted pulses, the hits obtained in the range cell of interest are summed and a target report is given when this sum is equal to or exceeds a specified value.

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Charlottesville, VA, United States of America

Terry A Tucker