United States of America As Represented by the Administrator of Nasa

Glenn D Hines

Farzin Amzajerdian

Diego Fernando Pierrottet

Bruce W Barnes

George E Lockard

Larry B Petway

An FMCW Doppler lidar system and method for use in a host vehicle includes a laser system, lenses, a homodyne receiver, and a signal processing unit (SPU). The laser beam is modulated to generate a frequency waveform with three segments, i.e., Doppler, up-ramp, and down-ramp. The lenses transmit laser beams toward a target-of-interest, and receive return beams reflected from the target-of-interest. The homodyne receiver has photoreceptors configured to mix the return beams with a respective local oscillator beam to generate a three-section return waveform. The SPU is coupled to the photoreceptors and calculates a respective magnitude and frequency of an up-ramp, down-ramp, and/or Doppler IF section of the return waveform, estimates a sign of the IF sections, and calculates a range and/or velocity relative to the target-of-interest using the estimated sign, and controls the host vehicle using the range and/or velocity.

Ambiguity mitigation for FMCW lidar system

A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

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Yorktown, VA, United States of America

Glenn D Hines