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Results for “OPTICAL RANGEFINDER”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

A geodetic laser radar rangefinder with 10(exp -7) resolution

A novel geodetic laser radar rangefinder (GLRR) unit utilizing a pair of synchronized 10-psec streak camera systems was developed for displacement measurements of the earth's plates. In order to achieve minimum computing error and assure extremely high spatial resolution, an optical pulse registration clock was developed and used to register a fiducial mark on the time scale of the system. Conventional optical rangefinders have been limited to a relative resolution of 10(exp -6) even for short distances. The system to be reported on today has the capability of measuring a 50km range with an accuracy of 4mm corresponding to a relative resolution of 10(exp -7). With a gain of greater than 3 x 10(exp 3), the system has the capability of detecting extremely weak signals on the order of photon counting. This combined with temporal gating makes daytime measurements comparable in signal-to-noise ratio to nighttime viewing. This is useful for measuring faint signals returning over a range of several tens of kilometers. The present ranging system was designed to observe the mutual displacement of geodetic plates and was employed to measure the boundary between the Philippine and Asian geodetic plates that pass beneath the Suruga Bay near Hamamatsu City, Japan. The system has been in operation for over 3 years. In addition, the system has the ability of producing and detecting optical ranging pulses of several wavelengths simultaneously, making this a complete multicolor system. The basic GLRR system consists of a frequency stabilizing crystal, optical clock, YAG laser, KDP doubling crystal, DK*P tripling crystal, two matched streak cameras (A and B), a control computer, and an output/input periscope system.

Mizushima, Y.↗
NASA NTRS1978

The 1.06 optical receiver

High performance 1.06 micron m avalanche photodetectors (APDs), fabricated in the GaAlSb system, have high quantum efficiency (90 percent), high speed (risetime less than 60 ps) and low leakage currents (less than 50 na). The dark current represents more than an order of magnitude reduction compared to previously reported results. The high speed avalanche gain of these devices is between 20 and 50. The area uniformity is better than + or - 10 percent. GaAlAs APDs at 0.53 micron m have even faster speed, lower dark currents, and high speed gains of 100 to 200. Optical rangefinders based on measured APD performance parameters have far superior performance when compared to even ideal photomultiplier tubes in either a one color or two color rangefinder system. For a one color system, f factor of two lower time jitter can be achieved with identical transmitted power. The superiority of the APD based two color receiver is significant and exists in the entire range of desired time jitters (less than 100 ps) and received power levels.

Tomasetta, L. R.↗
NASA NTRS2007

NASA Tech Briefs, January 2007

Topics covered include: Flexible Skins Containing Integrated Sensors and Circuitry; Artificial Hair Cells for Sensing Flows; Video Guidance Sensor and Time-of-Flight Rangefinder; Optical Beam-Shear Sensors; Multiple-Agent Air/Ground Autonomous Exploration Systems; A 640 512-Pixel Portable Long-Wavelength Infrared Camera; An Array of Optical Receivers for Deep-Space Communications; Microstrip Antenna Arrays on Multilayer LCP Substrates; Applications for Subvocal Speech; Multiloop Rapid-Rise/Rapid Fall High-Voltage Power Supply; The PICWidget; Fusing Symbolic and Numerical Diagnostic Computations; Probabilistic Reasoning for Robustness in Automated Planning; Short-Term Forecasting of Radiation Belt and Ring Current; JMS Proxy and C/C++ Client SDK; XML Flight/Ground Data Dictionary Management; Cross-Compiler for Modeling Space-Flight Systems; Composite Elastic Skins for Shape-Changing Structures; Glass/Ceramic Composites for Sealing Solid Oxide Fuel Cells; Aligning Optical Fibers by Means of Actuated MEMS Wedges; Manufacturing Large Membrane Mirrors at Low Cost; Double-Vacuum-Bag Process for Making Resin- Matrix Composites; Surface Bacterial-Spore Assay Using Tb3+/DPA Luminescence; Simplified Microarray Technique for Identifying mRNA in Rare Samples; High-Resolution, Wide-Field-of-View Scanning Telescope; Multispectral Imager With Improved Filter Wheel and Optics; Integral Radiator and Storage Tank; Compensation for Phase Anisotropy of a Metal Reflector; Optical Characterization of Molecular Contaminant Films; Integrated Hardware and Software for No-Loss Computing; Decision-Tree Formulation With Order-1 Lateral Execution; GIS Methodology for Planning Planetary-Rover Operations; Optimal Calibration of the Spitzer Space Telescope; Automated Detection of Events of Scientific Interest; Representation-Independent Iteration of Sparse Data Arrays; Mission Operations of the Mars Exploration Rovers; and More About Software for No-Loss Computing.

Source record↗
NASA NTRS2010

Alignment of optical system components using an ADM beam through a null assembly

A system for testing an optical surface includes a rangefinder configured to emit a light beam and a null assembly located between the rangefinder and the optical surface. The null assembly is configured to receive and to reflect the emitted light beam toward the optical surface. The light beam reflected from the null assembly is further reflected back from the optical surface toward the null assembly as a return light beam. The rangefinder is configured to measure a distance to the optical surface using the return light beam.

Hayden, Joseph E.↗
NASA NTRS1963

Pulsed-laser ranging

Pulsed rubidium laser range measurements with delayed sweep oscilloscope, and with digital readout system

RUBY LASER↗
NASA NTRS1974

Precision laser range finder system design for Advanced Technology Laboratory applications

Preliminary system design of a pulsed precision ruby laser rangefinder system is presented which has a potential range resolution of 0.4 cm when atmospheric effects are negligible. The system being proposed for flight testing on the advanced technology laboratory (ATL) consists of a modelocked ruby laser transmitter, course and vernier rangefinder receivers, optical beacon retroreflector tracking system, and a network of ATL tracking retroreflectors. Performance calculations indicate that spacecraft to ground ranging accuracies of 1 to 2 cm are possible.

Golden, K. E.↗
NASA NTRS1977

Fast, accurate rangefinder

Computer-controlled optical ranging system detects objects as close as 1m and as distant as 30m. Originally developed for robot planetary-surface exploration, system is applicable to vehicular obstacle avoidance, surveying, remote manipulator operation, and other applications.

Johnston, A. R.↗
NASA NTRS1973

Design of a laser rangefinder for Martian terrain measurements

Three methods for using a laser for rangefinding are discussed: optical focusing, the phase difference method, and timed pulse. For application on a Mars Rover, the timed pulse method proves to be the better choice in view of the requirements set down. This is made possible by pulse expansion techniques described in detail. Initial steps taken toward building the range finder are given, followed by a conclusion.

Palumbo, D. L.↗
NASA NTRS1985

Laser Rangefinder and Remote Profilometer

Proposed laser rangefinder and profilometer operates with precision of about 1mm at ranges of up to 100m. With scanning optics, device could track objects or accurately measure shapes of objects in field of view. New microprocessor-controlled design uses variable-length fiber-optic delay line as distance reference. New rangefinding method used in vision systems for industrial robots.

Mclauchlan, J. M.↗
NASA NTRS1977

High sensitivity 1.06 micron optical receiver for precision laser range finding

Aluminum gallium antimonide avalanche photodiodes with average gain of 10, internal quantum efficiency of greater than 60%, capacitance less than 0.2pf, and dark current of less than 1 micron were designed and fabricated for use in a low noise optical receiver suitable for 2 cm accuracy rangefinding. Topics covered include: (1) design of suitable photodetector structures; (2) epitaxial growth of AlGaSb devices; (3) fabrication of photodetectors; and (4) electro-optics characterization.

Scholl, F. W.↗
NASA NTRS1973

Design of a laser rangefinder for Martian terrain measurements

Methods for using a laser for rangefinding are discussed. These are: (1) Optical Focusing, (2) the Phase Difference Method, and (3) Timed Pulse. For application on a Mars Rover, the Timed Pulse Method proves to be the better choice in view of the requirements set down. This is made possible by pulse expansion techniques described in detail. Initial steps taken toward building the range finder are given, followed by a conclusion which is actually a proposal for future steps.

Palumbo, D. L.↗
NASA NTRS1982

Rangefinder Corrects for Air Density and Moisture

Proposed distance-measuring instrument compensates for variations in both dry atmospheric density and water-vapor content. Instrument would be expected to be more accurate than previous laser-ranging instruments. New rangefinder sends three signal trains to target: Two trains are at optical frequencies, and one is at a microwave frequency. All three signals are phase-locked.

Abshire, J. B.↗
NASA NTRS1985

Angle-Measurement and Ranging System

Optical system automatically supplies information on angular position and range of object. Stereo rangefinder video signals from cameras processed to determine center of brightness for images of beacon on target vehicle. Range updated by onboard computer. Originally developed for spacecraft rendezvous and guidance, features of system adapted to angle-measurement and ranging problems on Earth. Technique also used for tool alinement inspections and color recognition.

Tietz, J. C.↗
NASA NTRS1992

Effect of atmospheric extinction on laser rangefinder performance at 1.54 and 0.6 microns

Extinction of laser rangefinder (LRF) pulses by the atmosphere depends on the wavelength, weather conditions, and aerosol concentration along the optical path. In the IR, extinction is due to absorption by molecular constituents and scattering and absorption by aerosols. The total atmospheric extinction alpha(lambda) is the sum of the molecular and aerosol contributions, alpha(sub m)(lambda)and Alpha(sub a)(lambda). We present simple expressions for alpha(sub m)(lambda) and alpha(sub a)(lambda) for two LRF sources: Er:glass and CO2 which operate at 1.54 and 10.6 microns, respectively. The expressions are based on accepted models of atmospheric aerosols and molecular extinction and give an estimate of alpha(lambda) as a function of standard meteorological parameters, assuming horizontal beam propagation. Signal-to-noise ratios of LRF returns, measured from a reference target under different weather conditions are compared to predictions based on the estimate of alpha(lambda).

Hutt, D. L.↗
NASA NTRS2008

Video sensor with range measurement capability

A video sensor device is provided which incorporates a rangefinder function. The device includes a single video camera and a fixed laser spaced a predetermined distance from the camera for, when activated, producing a laser beam. A diffractive optic element divides the beam so that multiple light spots are produced on a target object. A processor calculates the range to the object based on the known spacing and angles determined from the light spots on the video images produced by the camera.

Briscoe, Jeri M.↗