# US 7,411,662 B1 · Systems and methods for performing active LADAR and passive high resolution imagery

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- Number: US 7,411,662 B1
- Document ID: US7411662B1
- Status: Granted
- Kind: B1
- Application number: 11/256,278
- Filed: 2005-10-20
- Granted: 2008-08-12
- Earliest claimed: 2005-10-20
- Assignees: The United States of America as represented by the Secretary of the Army
- Inventors: William C. Ruff; Barry L. Stann; Paul H. Shen; Brian C. Redman; Keith M. Aliberti
- Web page: https://patentgrep.com/patent/US7411662B1

## CPC

- G01S 17/89: for mapping or imaging
- G01S 17/26: wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals
- G01S 17/86: Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
- H04N 25/00: Circuitry of solid-state image sensors [SSIS]; Control thereof
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A system and method for performing high-resolution imagery of a target are provided. One embodiment is a method of performing high-resolution imagery of a target comprising: generating a chirped waveform that modulates a light signal transmitted toward a target for performing active LADAR of the target; generating a low-frequency local oscillator waveform for performing active imaging; and simultaneously performing passive imaging and active LADAR.

## Claims

### Claim 1

An imaging system comprising:
a chirp generator for generating a chirped waveform that modulates a light signal transmitted toward a target;
a passive waveform generator for generating a low-frequency local oscillator waveform; and
a self-mixing detector array that receives the low-frequency local oscillator and the chirped waveforms, where the low-frequency local oscillator waveform is configured to be used by the self-mixing detector to perform passive imaging and the chirped waveform is configured to be used by the self-mixing detector to perform active LADAR to determine the range to the target; further comprising a multiplexer configured to multiplex the low-frequency local controller signal with the chirped waveform and further configured to provide the multiplexed signal to the self-mixing detector.

### Claim 2

An imaging system comprising:
means for generating a chirped waveform that modulates a light signal transmitted toward a target;
means for generating a low-frequency local oscillator waveform; and means for detecting and self-mixing a light signal, the detecting means receiving the low-frequency local oscillator and the chirped waveforms, the low-frequency local oscillator waveform being used by the detecting means to perform passive imaging and the chirped waveform being used by the detecting means to perform active LADAR for measuring the range to the target; further comprising means for multiplexing the low-frequency local controller signal with the chirped waveform and providing the multiplexed signal to the detecting means.

### Claim 3

A method for performing active LADAR imaging and passive high-resolution imaging of a target, the method comprising:
generating a chirped waveform that modulates a light signal transmitted toward a target for performing active LADAR of the target;
generating a low-frequency local oscillator waveform for performing passive imaging; and simultaneously performing passive imaging and active LADAR and wherein the simultaneously performing passive imaging and active LADAR imaging comprises multiplexing the chirped waveform and the low-frequency local oscillator waveform; further comprising modulating the responsivity of a self-mixing detector with the multiplexed signal.