Noise pair velocity and range echo location system

Patent · Fri Jan 01 00:00:00 EST 1999

OSTI ID:872157

Erskine, David J ^[1]

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1. Oakland, CA

An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 5872628
• OSTI ID: 872157
• Country of Publication: United States
• Language: English

Related Subjects

noise
pair
velocity
range
echo
location
echo-location
method
microwaves
sound
light
capable
incoherent
arbitrary
waveforms
wide
bandwidth
measure
target
size
simultaneously
resolution
interferometers
nearly
equal
delays
series
interposed
interferometer
imprints
partial
coherence
initially
source
allows
autocorrelation
performed
reflected
signal
determine
coherent
cross-correlation
subsequent
determines
discriminated
dithering
identifies
portions
belonging
apart
clutter
moving
discrimination
insensitive
slowly
varying
distortions
path
speckle
image
antenna
lobing
due
parasitic
reflections
minimal
varies
spectrum
dramatically
randomly
pulse
creates
radar
elusive
jamming
monochromatic
sources
jigger
frequency
combinations
simulate
benefits
broadband
symmetrical
self-cancel
wavelengths
apparent
motion
ground
surrounding
sidelooking
airborne
wide band
signal path
target size
reflected signal
nearly equal
measure velocity
wide bandwidth
incoherent source
coherent source
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