Hughes Aircraft Company

Bill H Otoide

John K Keigharn

Robert R Hayes

Irwin L Newberg

Adrian E Popa

Harry T Wang

A radar target simulator for generating simulated targets used in testing a radar system. Simulated targets are generated out of the radar system noise. The radar system includes a radar receiver coupled to a receive antenna. The simulator has an input for sampling a transmitted output signal from the radar system. A first reference oscillator is provided for generating a first reference signal, and a first mixer is coupled to the first reference oscillator for mixing the first reference signal with the sampled signal from the radar system to provide a simulated target signal. A laser is coupled to the first mixer for generating a light output signal that corresponds to the simulated target signal. A plurality of selectable delay paths that each have a different predetermined delay length are coupled to the laser. A photodetector is coupled to the plurality of delay paths for convening the light output signal derived from a selected one of the delay paths into a radio frequency (RF) simulated target signal. The photodetector is coupled to an output circuit for transmitting the RF simulated target signal to the radar system. A variable attenuator may be coupled between the photodetector and the output circuit for variably controlling the power of the RF simulated target signal. The simulator may further include Doppler signal generator that comprises a second reference oscillator for generating second and third reference signals. A third mixer is coupled to the first and second reference oscillators for mixing the first and second reference signals to produce a difference signal. A direct digital synthesizer is coupled to the second reference oscillator for receiving a command signal and the third reference signal, and for generating a Doppler output signal in response thereto. A fourth mixer is coupled to the second reference oscillator for receiving the third reference signal and to the direct digital synthesizer for receiving the Doppler signal, and for generating an intermediate Doppler signal in response thereto. A fifth mixer is coupled to the third and fourth mixers and to the output means for mixing the difference signal and the intermediate Doppler signal to produce a simulated target Doppler signal in response thereto that is the RF simulated target signal.

Portable radar target simulator

A programmable fiber optic delay system employs multiple programmable fiber optic delay lines, and switches among the delay lines for inclusion in an overall delay path. Switching among the delay lines is coordinated with the programming of those lines so that only a delay line with a settled delay program is included in the overall delay path. Each delay line consists of a plurality of fiber optic segments of varying length. The line's delay is programmed by switching in particular segments whose aggregate lengths correspond to a desired delay period. The multiple delay lines are used to simulate target speed and distance for use in testing a radar system. The programming of each individual delay line and the switching between lines is preferably controlled by a computer resident in the target simulator.

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Manhattan Beach, CA, United States of America

Bill H Otoide