Keyword: Calibration

Books & Reports: Electronics & Computers
Phase Calibration of Antenna Arrays Aimed at Spacecraft

A document describes a method of calibrating phase differences among ground antennas in an array so that the maximumintensity direction of the far-field interference pattern of the array coincides with the direction for aiming the antennas to enable radio communication with a distant...

Application Briefs: Sensors/Data Acquisition
Remote Voltage Sensor
Quasar Federal Systems
San Diego, CA
858-228-3386
www.quasarusa.com

Electrostatic charges impact the...

Briefs: Physical Sciences

An experimental nuclear-spin gyroscope is based on an alkali-metal/noblegas co-magnetometer, which automatically cancels the effects of magnetic fields. Whereas the performances of...

Books & Reports: Physical Sciences
Estimating Mixing Heights Using Microwave Temperature Profiler

A paper describes the Microwave Temperature Profiler (MTP) for making measurements of the planetary boundary layer thermal structure — data necessary for air quality forecasting as the Mixing Layer (ML) height determines the volume in which daytime pollution is primarily...

Briefs: Electronics & Computers
Waveguide Calibrator for Multi-Element Probe Calibration

A calibrator, referred to as the "spider" design, can be used to calibrate probes incorporating multiple acoustic sensing elements. The application is an acoustic energy density probe, although the calibrator can be used for other types of acoustic probes. The calibrator relies on the use...

Briefs: Information Technology
Fusing Image Data for Calculating Position of an Object

A computer program has been written for use in maintaining the calibration, with respect to the positions of imaged objects, of a stereoscopic pair of cameras on each of the Mars Explorer Rovers Spirit and Opportunity. The program identifies and locates a known object in the images. The...

Briefs: Information Technology
Improved Tracking of Targets by Cameras on a Mars Rover

A paper describes a method devised to increase the robustness and accuracy of tracking of targets by means of three stereoscopic pairs of video cameras on a Mars-rover-type exploratory robotic vehicle. Two of the camera pairs are mounted on a mast that can be adjusted in pan and tilt; the...

Briefs: Physical Sciences

Solid-state electrochemical sensors for measuring the degrees of acidity or alkalinity (in terms of pH values) of liquid solutions are being developed. These sensors are intended to...

Briefs: Physical Sciences

A laboratory blackbody cavity has been designed and built for calibrating infrared radiometers used to measure radiant temperatures in the range from about 200 to about 273 K. In this...

Briefs: Physical Sciences
Photometric Calibration of Consumer Video Cameras

Equipment and techniques have been developed to implement a method of photometric calibration of consumer video cameras for imaging of objects that are sufficiently narrow or sufficiently distant to be optically equivalent to point or line sources. Heretofore, it has been difficult to calibrate...

Briefs: Software
Program Merges SAR Data on Terrain and Vegetation Heights

X/P Merge is a computer program that estimates ground-surface elevations and vegetation heights from multiple sets of data acquired by the GeoSAR instrument [a terrain-mapping synthetic-aperture radar (SAR) system that operates in the X and P bands]. X/P Merge software combines data from...

Briefs: Electronics & Computers
Miniature Intelligent Sensor Module

An electronic unit denoted the Miniature Intelligent Sensor Module performs sensor signal conditioning functions and local processing of sensor data. The unit includes four channels of analog input/output circuitry, a processor, volatile and nonvolatile memory, and two Ethernet communication ports, all housed...

Briefs: Electronics & Computers

A generic design and a corresponding operating sequence have been developed for increasing the linear-response dynamic range of a complementary metal oxide/semiconductor (CMOS) image...

Articles: Photonics/Optics

For the last forty years, manufacturing technology for diffraction gratings has not changed significantly. Mechanical ruling and interferometric...

Briefs: Physical Sciences

In an alternative hardware design for an apparatus used in image-based wavefront sensing, defocus diversity is introduced by means of fixed lenses that are mounted in a filter wheel (see...

Briefs: Electronics & Computers
Processing Raw HST Data With Up-to-Date Calibration Data

On-the-Fly Reprocessing (OTFR) is a collection of data-processing routines that work within the context of the Hubble Space Telescope (HST) pipeline data-flow system. The purpose served by OTFR is to generate, on demand, scientifically useful data products from raw HST data stored in an...

Briefs: Information Technology
Estimating Dust and Water Ice Content of the Martian Atmosphere From THEMIS Data

Researchers at JPL and Arizona State University conducted a comparative study of three candidate algorithms for estimating components of the Martian atmosphere, using raw (uncalibrated) data collected by the Thermal Emission Imaging System (THEMIS). THEMIS is an...

Briefs: Mechanical & Fluid Systems
Estimation Filter for Alignment of the Spitzer Space Telescope

A document presents a summary of an onboard estimation algorithm now being used to calibrate the alignment of the Spitzer Space Telescope (formerly known as the Space Infrared Telescope Facility). The algorithm, denoted the S2P calibration filter, recursively generates estimates of...

Briefs: Electronics & Computers

An apparatus that generates four signals at a frequency of 7.1 GHz having precisely controlled relative phases and equal amplitudes has been designed and built. This apparatus is...

Briefs: Physical Sciences
Optimal Calibration of the Spitzer Space Telescope

A document discusses the focal-plane calibration of the Spitzer Space Telescope by use of the instrument pointing frame (IPF) Kalman filter, which was described in "Kalman Filter for Calibrating a Telescope Focal Plane" (NPO-40798), NASA Tech Briefs, Vol. 30, No. 9 (September 2006), page 62. To...

Briefs: Electronics & Computers

A correlated-noise source has been developed for use in calibrating an airborne or spaceborne Earth-observing correlation microwave polarimeter that operates in a pass band that includes a nominal...

Briefs: Photonics/Optics

An enhanced alignment cube has been invented for use in a confined setting (e.g., a cryogenic chamber) in which optical access may be limited to a single line of sight. Whereas traditional...

Briefs: Physical Sciences
Phase Sensor for Aligning a Segmented Telescope Mirror

A phase sensor has been developed for use in aligning a segmented telescope mirror to within a fraction of a wavelength in piston. (As used here, "piston" signifies displacement of a mirror segment along the optical axis of the telescope.) Such precise alignment is necessary in order to...

Briefs: Physical Sciences

The instrument-pointing frame (IPF) Kalman filter, and an algorithm that implements this filter, have been devised for calibrating the focal plane of a telescope. As used here,...

Briefs: Software
SOFTC: A Software Correlator for VLBI

SOFTC is an advanced software implementation of a signal correlator for verylong- baseline interferometry (VLBI) for measuring positions of natural celestial objects and distant spacecraft. Because of increases in processing speeds of general- purpose computers, software VLBI correlators have become viable...

Briefs: Software
Automated Camera Calibration

Automated Camera Calibration (ACAL) is a computer program that automates the generation of calibration data for camera models used in machine vision systems. Machine vision camera models describe the mapping between points in threedimensional (3D) space in front of the camera and the corresponding points in...

Briefs: Software
Processing TES Level-1B Data

TES L1B Subsystem is a computer program that performs several functions for the Tropospheric Emission Spectrometer (TES). The term "L1B" (an abbreviation of "level 1B"), refers to data, specific to the TES, on radiometric calibrated spectral radiances and their corresponding noise equivalent spectral radiances...

Briefs: Software

MarsLS is a software tool for analyzing statistical dispersion of spacecraft-landing sites and displaying the results of its analyses. Originally intended for the Mars Explorer Rover...

Briefs: Software

Researchers at NASA’s Jet Propulsion Laboratory have developed a method for automatically tracking the polar caps on Mars as they advance and recede each year (see figure). The...