US20030076485A1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ladar system for detecting objects
Assignee: United States Department of the Army
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Filing: 2002-06-28
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Granted: —
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Expires: 2022-06-28
Abstract
Abstract A high range resolution ladar includes a chirp generator for producing a chirp signal waveform that is used by a laser diode to propagate a divergent laser light waveform. The reflected light signals from the target are directed to a self mixing detector that is coupled to the chirp generator where the responsivity of the detector varies in accordance with the chirp waveform for converting reflected light signals from the target to electrical signals and for mixing the converted electrical signal with the chirp waveform to produce an output electrical signal whose frequency is proportional to the range to the target. The self-mixing detector includes at least one detector having a semiconductor substrate and first and second electrodes deposited on the substrate and spaced from each other, wherein the first set of electrodes is connected to the chirp generator and the second set of electrodes is connected to a memory for storing a plurality of frames of image data.
Inventors
- 👤 William Ruff
- 👤 Barry Stann
- 👤 Paul Shen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:30
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/48; G01S7/491; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/32; G01S17/34; G01S17/88; G01S17/89; G01S17/894
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
154 words
1 . A high range-resolution ladar, comprising: a chirp generator for generating a chirp waveform; a bias tee coupled to the chirp generator, a DC current source, and a semiconductor laser diode, the bias tee summing the chirp waveform with the DC current source to provide a current drive for the semiconductor laser diode with a bandwidth at least equal to the chirp waveform; the semiconductor laser diode coupled to the bias tee, for receiving the current drive and for outputting a light signal toward a target; and a self-mixing detector coupled to and driven by the chirp generator, where the responsivity of the detector is varied in accordance with the chirp waveform for converting the reflected light signal received from the target to an electrical signal and for mixing the converted electrical signal with the chirp waveform to produce an output electrical signal whose frequency is proportional to the range to the target.
Claim 2
Dependent Claim
154 words
1 . A high range-resolution ladar, comprising: a chirp generator for generating a chirp waveform; a bias tee coupled to the chirp generator, a DC current source, and a semiconductor laser diode, the bias tee summing the chirp waveform with the DC current source to provide a current drive for the semiconductor laser diode with a bandwidth at least equal to the chirp waveform; the semiconductor laser diode coupled to the bias tee, for receiving the current drive and for outputting a light signal toward a target; and a self-mixing detector coupled to and driven by the chirp generator, where the responsivity of the detector is varied in accordance with the chirp waveform for converting the reflected light signal received from the target to an electrical signal and for mixing the converted electrical signal with the chirp waveform to produce an output electrical signal whose frequency is proportional to the range to the target.
Claim 3
Dependent Claim
83 words
2 . The high range resolution ladar of claim 2 , wherein the self-mixing detector comprises at least one detector having a substrate, a first set of electrodes deposited on the substrate, and a second set of electrodes deposited on the substrate and spaced from the first set of electrodes, wherein the first set of electrodes is connected to the chirp generator and the second set of electrodes is connected to the a memory for storing a plurality of frames of image data.
Claim 4
Dependent Claim
26 words
3 . The high range resolution ladar of claim 2 , wherein the self-mixing detector comprises a plurality of detectors arranged in a two dimensional array.
Claim 5
Dependent Claim
132 words
4 . A high range-resolution ladar comprising: a chirp generator for generating a chirp waveform; a bias tee coupled to the chirp generator, a DC current source, and a semiconductor laser diode, the bias tee summing the chirp waveform with the DC current source to generate a current drive for the semiconductor laser diode; the semiconductor laser diode coupled to the bias tee for receiving the current drive and for producing an output light signal toward a target; and a self-mixing detector coupled to and driven by the chirp generator, where the responsivity of the detector varies in accordance with the chirp waveform for receiving and mixing a reflected signal from the target with the chirp waveform to output an electrical signal whose frequency is proportional to the range to the target.
Claim 6
Dependent Claim
132 words
4 . A high range-resolution ladar comprising: a chirp generator for generating a chirp waveform; a bias tee coupled to the chirp generator, a DC current source, and a semiconductor laser diode, the bias tee summing the chirp waveform with the DC current source to generate a current drive for the semiconductor laser diode; the semiconductor laser diode coupled to the bias tee for receiving the current drive and for producing an output light signal toward a target; and a self-mixing detector coupled to and driven by the chirp generator, where the responsivity of the detector varies in accordance with the chirp waveform for receiving and mixing a reflected signal from the target with the chirp waveform to output an electrical signal whose frequency is proportional to the range to the target.
Claim 7
Dependent Claim
48 words
5 . The high range-resolution ladar of claim 4 , wherein the modulated electrical signal comprises a product of the reflected light signal from the target and the chirp waveform, the modulated electrical signal having a difference frequency signal whose frequency is proportional to range to the target.
Claim 8
Dependent Claim
41 words
6 . The high range-resolution ladar of claim 5 , further comprising: a wideband RF power amplifier, coupled to the chirp generator, for receiving and modulating the chirp waveform and outputting an amplified chirp waveform for summing in the bias tee.
Claim 9
Dependent Claim
78 words
7 . The high range-resolution ladar of claim 6 , further comprising: an impedance matching circuit, coupled to the wideband RF amplifier, for matching the driving impedance of the wideband RF power amplifier to the semiconductor laser diode over a range of the amplified chirp signal frequency such that light beam intensity from the semiconductor laser diode is highly amplitude modulated (AM) and the peak intensity of the light signal is constant as a function of chirp frequency.
Claim 10
Dependent Claim
23 words
8 . The high range-resolution ladar of claim 4 , wherein the self-mixing detector comprises a plurality of detectors arranged in an array.
Claim 11
Dependent Claim
43 words
9 . The high range ladar of claim 8 , wherein each detector comprises a substrate, a first set of electrodes deposited on the substrate, and a second set of electrodes deposited on the substrate and spaced from the first set of electrodes.
Claim 12
Dependent Claim
29 words
10 . The high range ladar of claim 9 , wherein the substrate is formed of a semiconductor material and the first and second sets of electrodes are metal.
Claim 13
Dependent Claim
18 words
11 . The high range ladar of claim 10 , wherein the semiconductor substrate material includes gallium arsenide.
Claim 14
Dependent Claim
72 words
12 . The high range-resolution ladar of claim 4 , wherein the self-mixing detector comprises at least one detector, wherein each detector comprises a substrate, a first set of electrodes deposited on the substrate, and a second set of electrodes deposited on the substrate and spaced from the first set of electrodes, and wherein the substrate is formed of a semiconductor material and the first and second sets of electrodes are metal.
Claim 15
Dependent Claim
31 words
13 . The high range-resolution ladar of claim 4 , further comprising: a trigger circuit for generating a trigger signal that triggers and synchronizes the chirp generator and the self-mixing detector.
Claim 16
Dependent Claim
28 words
14 . The high range-resolution ladar of claim 4 , further comprising: a memory, coupled to the self-mixing detector, for storing a plurality of frames of image data.
Claim 17
Dependent Claim
47 words
15 . The high range-resolution ladar of claim 14 , further comprising: computing means, coupled to the memory, for performing a discrete fourier transform on the plurality of frames of image data and outputting results of the discrete fourier transform as a b 3 -D image file.
Claim 18
Dependent Claim
78 words
16 . The high range resolution ladar of claim 4 , wherein the self-mixing detector comprises a substrate, a first set of electrodes deposited on the substrate, and a second set of electrodes deposited on the substrate and spaced from the first set of electrodes, wherein the first set of electrodes is connected to the chirp generator and the second set of electrodes is connected to the a memory for storing a plurality of frames of image data.
Claim 19
Dependent Claim
79 words
17 . A method for generating a high range-resolution using ladar comprising the steps of: generating a chirp waveform and summing the chirp waveform with a DC current source to provide a current drive for a laser diode, using the current drive to produce a light signal output from the laser diode that is directed toward a target, and modulating a reflected light signal from the target in accordance with the chirp signal to output a modulated electrical signal.
Claim 20
Dependent Claim
79 words
17 . A method for generating a high range-resolution using ladar comprising the steps of: generating a chirp waveform and summing the chirp waveform with a DC current source to provide a current drive for a laser diode, using the current drive to produce a light signal output from the laser diode that is directed toward a target, and modulating a reflected light signal from the target in accordance with the chirp signal to output a modulated electrical signal.
Claim 21
Dependent Claim
44 words
18 . The method of claim 17 , wherein the modulated electrical signal comprises a product of the reflected light signal from the target and the chirp waveform, the product comprising a difference frequency signal whose frequency is proportional to range to the target.
Claim 22
Dependent Claim
30 words
19 . The method of claim 17 , further comprising the step of: modulating the chirp waveform and outputting an amplified chirp signal for summing with the DC current source.
Claim 23
Dependent Claim
66 words
20 . The method of claim 17 , further comprising the step of: matching driving impedance of the amplified chirp signal to a semiconductor laser diode over a range of the amplified chirp signal frequency such that light beam intensity from the semiconductor laser diode is highly amplitude modulated (AM) and the peak intensity of the light signal is constant as a function of chirp frequency.
Claim 24
Dependent Claim
31 words
21 . The method of claim 17 , further comprising the step of: storing, in a memory coupled to the focal plane detector array, a plurality of frames of image data.
Claim 25
Dependent Claim
39 words
22 . The method of claim 17 , further comprising the steps of: performing a discrete fourier transform on the plurality of frames of image data, and outputting results of the discrete fourier transform as a 3-D image file.
Claim 26
Dependent Claim
66 words
23 . The method of claim 17 , wherein the responsivity of the modulated reflected light signal is varied in accordance with the chirp waveform for converting the reflected light signal received from the target to an electrical signal and for mixing the converted electrical signal with the chirp waveform to produce an output electrical signal whose frequency is proportional to the range to the target.
Claim 27
Dependent Claim
129 words
24 . A self mixing detector for use with a ladar system comprising a chirp generator for generating a chirp waveform, a DC current source, a semiconductor laser diode, means coupled to the chirp generator and the DC current source and the laser diode to provide a current drive for the laser diode to produce an output light signal directed toward a target, comprising: a self-mixing detector coupled to and driven by the chirp generator, where the responsivity of the detector is varied in accordance with the chirp waveform for converting reflected light signals received from the target to an electrical signal and for mixing the converted electrical signal with the chirp waveform to produce an output electrical signal whose frequency is proportional to the range to the target.
Claim 28
Dependent Claim
129 words
24 . A self mixing detector for use with a ladar system comprising a chirp generator for generating a chirp waveform, a DC current source, a semiconductor laser diode, means coupled to the chirp generator and the DC current source and the laser diode to provide a current drive for the laser diode to produce an output light signal directed toward a target, comprising: a self-mixing detector coupled to and driven by the chirp generator, where the responsivity of the detector is varied in accordance with the chirp waveform for converting reflected light signals received from the target to an electrical signal and for mixing the converted electrical signal with the chirp waveform to produce an output electrical signal whose frequency is proportional to the range to the target.
References Cited (Backward Citations)
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