Engineering Papers⌕ Search

Engineering topics

Katzberg, S. J.

Publications and source records attributed to Katzberg, S. J..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Towards GPS Surface Reflection Remote Sensing of Sea Ice Conditions

This paper describes the research to extend the application of Global Positioning System (GPS) signal reflections, received by airborne instruments, to cryospheric remote sensing. The characteristics of the GPS signals and equipment afford the possibility of new measurements not possible with existing radar and passive microwave systems. In particular, the GPS receiving systems are small and light-weight, and as such are particularly well suited to be deployed on small aircraft or satellite platforms with minimal impact. Our preliminary models and experimental results indicate that reflected GPS signals have potential to provide information on the presence and condition of sea and fresh-water ice as well as the freeze/thaw state of frozen ground. In this paper we show results from aircraft experiments over the ice pack near Barrow, Alaska suggesting correlation between forward scattered GPS returns and RADARSAT backscattered signals.

Komjathy, A.↗
NASA NTRS1989

NASA in-house Commercially Developed Space Facility (CDSF) study report. Volume 1: Concept configuration definition

The results of a NASA in-house team effort to develop a concept definition for a Commercially Developed Space Facility (CDSF) are presented. Science mission utilization definition scenarios are documented, the conceptual configuration definition system performance parameters qualified, benchmark operational scenarios developed, space shuttle interface descriptions provided, and development schedule activity was assessed with respect to the establishment of a proposed launch date.

Deryder, L. J.↗
NASA NTRS1985

Potential space station evolution and growth modes

User requirements for the first ten years of space station operation are assessed, and space station system capabilities to meet those needs are delineated. A module length of about 11.5 m with external interconnects best meets growth needs, and a power unit which provides 42 KW is desirable. Four growth scenarios for the manned element of the space station program are studied, and typical growth configurations are described. The full dual keel configuration is attractive at this point due to its increased flexibility.

Pritchard, E. B.↗
NASA NTRS1983

Measuring Excess Noise in SDL's

New instrument gives quantitive information on "excess noise" in semiconductor-diode laser (SDL's). By proper selection of detector, instrument tests any SDL from visible wavelengths through thermal infrared. Lasers determine excess noise in SKL source by measuring photocurrent generated in photodetector exposed first to reference laser then to SKL under test.

Katzberg, S. J.↗
NASA NTRS1983

Tunable laser heterodyne spectrometer measurements of atmospheric species

It is pointed out that spectroscopic measurements conducted with the aid of tunable laser heterodyne spectrometers in the 3-30 micron range of the electromagnetic spectrum have the potential to measure the vertical profiles of tenuous gas molecules in the atmosphere with ultra high spectral resolution and great sensitivity. Programs related to the realization of this potential have been conducted for some time, and a Laser Heterodyne Spectrometer (LHS) experiment was developed. The present investigation has the objective to provide an overview of the LHS concept for measuring the vertical profiles of tenuous gas molecules in the upper atmosphere from space and airborne platforms, and to discuss the sensitivity ranges for this technique.

Allario, F.↗
NASA NTRS1982

Test-Bed Aircraft Scanner

Test-bed aircraft multispectral scanner (TBAMS) is line-scanning multispectral imaging system with eight visible/near-infrared channels and one thermal-infrared channel. Key design features of TBAMS are its large size and modular subsystem mounted on horizontal baseplate. This unique layout allows easy access to and replacement of subsystems and their subcomponents. System designed around existing inexpensive parts, sacrifices compactness for ease of modification.

Jobson, D. J.↗
NASA NTRS1982

Laser/Heterodyne Measurement of Temperature and Salinity

Proposed visible-light laser/heterodyne receiver would remotely measure temperature and salinity of subsurface water. Operation is based on acoustic/optical scattering of light by sound waves. Application of this concept is foreseen in current research on energy conversion from ocean currents produced by thermal gradients and on future marine remote-sensing program.

Jobson, D. J.↗
NASA NTRS1981

Noise effects in an optical heterodyne spectrometer using tunable diode lasers

A comparison of measured and predicted signal-to-noise ratio is made in an optical heterodyne spectrometer utilizing a tunable diode laser which exhibited excess noise. It is shown that good agreement between predicted and measured signal-to-noise ratios results if excess noise effects due to tunable diode lasers are included in the predictions. The methods used to quantify excess noise and to incorporate their effects into predictions of signal-to-noise ratio are discussed.

Katzberg, S. J.↗
NASA NTRS1981

Radiometric performance of the test-bed aircraft multispectral scanner /TBAMS/ system

Laboratory and flight radiometric performance testing of an experimental multispectral scanner system is described. High sensitivity performance is confirmed by test results using noise equivalent spectral radiance as the primary figure of merit. A performance comparison between the test-bed aircraft multispectral scanner (TBAMS) and the Bendix modular multispectral scanner (M2S) is presented. Methods for achieving high sensitivity operation are discussed as well as some of the practical implications of such operation for flight remote sensing experiments.

Jobson, D. J.↗
NASA NTRS1980

An experiment concept to measure stratospheric trace constituents by Laser Heterodyne Spectroscopy

The concept and techniques of a Laser Heterodyne Spectrometer experiment for measuring the vertical profiles of several stratospheric trace gases are discussed. The goal of the experiment is to develop a laser heterodyne receiver capable of measuring 2-4 gases simultaneously from Spacelab and, ultimately, from free-flying platforms. Sensitivity analyses are currently being performed for tenuous molecules such as ClO, ClONO2, NOCl, HO2, H2O2, and N2O5, although the capability exists for measuring more abundant gases, such as O3, HNO3, N2O, NO2, and CH4. Results indicate that O3 and ClO vertical profiles can be measured with an accuracy equal to or better than 95% and 80%, respectively, over the total profile. Laboratory measurements of the performance characteristics of the local oscillator and heterodyne detector are discussed with reference to 'excess-noise' and Doppler-shift effects.

Allario, F.↗
NASA NTRS1980

Sensitivity studies and laboratory measurements for the laser heterodyne spectrometer experiment

Several experiments involving spectral scanning interferometers and gas filter correlation radiometers (ref. 2) using limb scanning solar occultation techniques under development for measurements of stratospheric trace gases from Spacelab and satellite platforms are described. An experiment to measure stratospheric trace constituents by Laser Heterodyne Spectroscopy, a summary of sensitivity analyses, and supporting laboratory measurements are presented for O3, ClO, and H2O2 in which the instrument transfer function is modeled using a detailed optical receiver design.

Allario, F.↗
NASA NTRS1980

Remote sensing of benthic microalgal biomass with a tower-mounted multispectral scanner

A remote sensing instrument was mounted on a 50-ft tower overlooking North Inlet Estuary, South Carolina in order to conduct a remote sensing study of benthic microalgae. The instrument was programmed to take multispectral imagery data along a 90 deg horizontal frame in six spectral bands ranging from 400-1050 nm and had a ground resolution of about 3 cm. Imagery measurements were encoded in digital form on magnetic tape and were stored, decoded, and manipulated by computer. Correlation coefficients were calculated on imagery data and chlorophyll a concentrations derived from ground truth data. The most significant correlation occurred in the blue spectral band with numerical values ranging from -0.81 to -0.88 for three separate sampling periods. Mean values of chlorophyll a for a larger section of mudflat were estimated using regression equations. The scanner has provided encouraging results and promises to be a useful tool in sampling the biomass of intertidal benthic microalgae.

Jobson, D. J.↗
NASA NTRS1980

An experiment concept to measure stratospheric trace constituents by laser heterodyne spectroscopy

Laser heterodyne spectroscopy (LHS) techniques were used to measure radical gases from Spacelab. Major emphasis was placed on the measurement of ClO, ClOnO2, HO2, H2O2, N2O5, and HOCl in solar occultation with vertical resolution less than or equal to 2-km and vertical range from 1O to 70-km. Sensitivity analyses were performed on ClO and O3 to determine design criteria for the LHS instrument. Results indicate that O3 and ClO vertical profiles can be measured with an accuracy more than or equal to 95% and more than or equal to 80%, respectively, over the total profile.

Allario, F.↗
NASA NTRS1980

Smart sensors for the 80's - The status of smart sensors

The paper discusses the definition of smart sensor as perceived by three different groups of authors. The agreement and disagreement between the three separate definitions are briefly treated. Recent conferences held by the AIAA and SPIE have addressed smart sensors for a range of applications. The status of smart sensors is discussed in light of the papers presented at the three conferences. Also, the emerging technologies which will facilitate the development of smart sensors are discussed.

Breckenridge, R. A.↗
NASA NTRS1980

The laser heterodyne spectrometer - New sensor for the 80's

The paper deals with the basic concepts in optical heterodyne receivers with tunable diode lasers, operating in the thermal infrared. Simulation retrievals of vertical profiles of trace atmospheric gas species are carried out on the basis of heterodyne receiver performance parameters. Operational tests show a high signal-to-noise ratio in measuring gas absorption features. The results demonstrate the potential power of optical heterodyne receivers, and it is concluded that during the eighties they will become the major tool for measuring the earth's atmosphere and other planetary atmospheres.

Katzberg, S. J.↗
NASA NTRS1978

Device for measuring the contour of a surface

Light from a source is imaged by a lens onto a surface so that the energy from the source is concentrated into a spot. As the spot across the surface is scanned, the surface moves relative to the point of perfect focus. When the surface moves away from perfect focus the spot increases in size, while the total energy in the spot remains virtually constant. The lens then reimages the light reflected by the surface onto two detectors through two different sized apertures. The light energy going to the two detectors is separated by a beam splitter. This second path of the light energy through the lens further defocuses the spot, but as a result of the different sizes of the apertures in each light detector path, the amount of defocus for each is different. The ratio of the outputs of the two detectors which are indicative of the contour of the surface is obtained by a divider.

Burcher, E. E.↗
NASA NTRS1977

Signal-to-noise ratio analysis and evaluation of the Hadamard imaging technique

The signal-to-noise ratio performance of the Hadamard imaging technique is analyzed and an experimental evaluation of a laboratory Hadamard imager is presented. A comparison between the performances of Hadamard and conventional imaging techniques shows that the Hadamard technique is superior only when the imaging objective lens is required to have an effective F (focus) number of about 2 or slower.

Jobson, D. J.↗