United States of America As Represented by the Administrator of Nasa

The United States of America As Represented by the Administrator of the

Psionic, LLC

Diego Fernando Pierrottet

Farzin Amzajerdian

Glenn D Hines

Bruce W Barnes

George E Lockard

Larry B Petway

Stephen Parker Sandford

George E Busch

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

Aspects of the present disclosure are directed to imaging an environment and providing velocity characteristics of one or more objects in the imaged environment. As may be implemented in accordance with one or more embodiments, objects in a local environment are scanned with laser light, and reflections of the scanned laser light from the objects are received and processed to generate a 3D image of the local environment. Distance and velocity of each object is provided or detected based on a frequency delay and frequency shift of one or more reflections of the scanned laser light from the object. For instance, the 3D image may provide relative position of an object and indicate velocity of the object, which may be ascertained based on a frequency shift.

Lidar imaging with velocity acquisition

Methods and apparatus for providing self-contained guidance, navigation, and control (GN&C) functions for a vehicle moving through an environment on or near the ground, in the air or in space without externally provided information are disclosed. More particularly, one embodiment of the present invention includes a Heading Sensor (), an Absolute Location Sensor (), a timer (), a Range Doppler Processor (), a Navigation Reference Sensor (), an Area Range and a Velocity Sensor () which provide enhanced navigation information about a universal reference frame () and one or more targets ().

Navigation system for GPS denied environments

A hybrid fiber rod includes a fiber core and inner and outer cladding layers. The core is doped with an active element. The inner cladding layer surrounds the core, and has a refractive index substantially equal to that of the core. The outer cladding layer surrounds the inner cladding layer, and has a refractive index less than that of the core and inner cladding layer. The core length is about 30 to 2000 times the core diameter. A hybrid fiber rod laser system includes an oscillator laser, modulating device, the rod, and pump laser diode(s) energizing the rod from opposite ends. The rod acts as a waveguide for pump radiation but allows for free-space propagation of laser radiation. The rod may be used in a laser resonator. The core length is less than about twice the Rayleigh range. Degradation from single-mode to multi-mode beam propagation is thus avoided.

Compact hybrid laser rod and laser 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.

System and method for generating a frequency modulated linear laser waveform

A Doppler lidar sensor system includes a laser generator that produces a highly pure single frequency laser beam, and a frequency modulator that modulates the laser beam with a highly linear frequency waveform. A first portion of the frequency modulated laser beam is amplified, and parts thereof are transmitted through at least three separate transmit/receive lenses. A second portion of the laser beam is used as a local oscillator beam for optical heterodyne detection. Radiation from the parts of the laser beam transmitted via the transmit/receive lenses is received by the respective transmit/receive lenses that transmitted the respective part of the laser beam. The received reflected radiation is compared with the local oscillator beam to calculate the frequency difference therebetween to determine various navigational data.

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Poquoson, VA, United States of America

Diego Fernando Pierrottet