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Kibler, J. F.

Publications and source records attributed to Kibler, J. F..

14 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Design and development of the ERBE data management system

The Earth radiation budget experiment (ERBE) software development approach is described. An iterative development approach was adopted which provides for three releases or versions of the processing system, each of increasing levels of complexity and solidity. The final release of the system will be used to process the flight data. The major phases for each iterative release consist of specifications developed in concert with the science team, preliminary design, subsystem reviews, coding, subsystem code walkthroughs, system testing, system documentation, and project status review.

Kibler, J. F.↗
NASA NTRS1979

Earth radiation budget experiment and smart sensors

This paper presents the data analysis requirements for the Earth Radiation Budget Experiment and potential needs for a follow-on radiation budget system. The present requirements for determining the earth's radiation budget on scales from 250 by 250-km regions to global require two broadband measurements on each of three satellites. The instrument system is composed of wide- and medium-field-of-view radiometers and a narrow-field-of-view scanning radiometer. Modeled directional functions are required to interpret the data in terms of earth radiation fluxes. Meeting more stringent science requirements for a follow-on mission will require nine broadband channels with increased spatial and temporal sampling, resulting in six satellites and a fourfold increase in data transmission rates and ground-based data storage. Smart sensors can reduce the data and ground storage requirements by orders of magnitude with onboard processing, calibration, and attitude and ephemeris determination.

Young, G. R.↗
NASA NTRS1977

Contouring randomly spaced data

Computer program using triangulation contouring technique contours data points too numerous to fit into rectangular grid. Using random access procedures, program can handle up to 56,000 data points and provides up to 20 contour intervals for multiple number of parameters.

Kibler, J. F.↗
NASA NTRS1977

A simulation of air pollution model parameter estimation using data from a ground-based LIDAR remote sensor

One way to obtain estimates of the unknown parameters in a pollution dispersion model is to compare the model predictions with remotely sensed air quality data. A ground-based LIDAR sensor provides relative pollution concentration measurements as a function of space and time. The measured sensor data are compared with the dispersion model output through a numerical estimation procedure to yield parameter estimates which best fit the data. This overall process is tested in a computer simulation to study the effects of various measurement strategies. Such a simulation is useful prior to a field measurement exercise to maximize the information content in the collected data. Parametric studies of simulated data matched to a Gaussian plume dispersion model indicate the trade offs available between estimation accuracy and data acquisition strategy.

Kibler, J. F.↗
NASA NTRS1976

A simulation study of earth radiation budget data interpretation

The paper describes a simulation of a filtering analysis which yields radiation distributions, measured by a wide-field-of-view radiometer on board an earth satellite, on a scale smaller than the field of view of the instrument. Mathematical models are developed to represent an orbiting wide-field-of-view radiometer to provide simulated measurement data. The simulated measurements are analyzed by a data inversion technique to obtain estimates of the radiation heat fluxes at the top of the atmosphere. By comparing the estimated field to a real radiation field, the effects of directional model errors and sampling strategies are revealed.

Smith, G. L.↗
NASA NTRS1976

A simulation of water pollution model parameter estimation

A parameter estimation procedure for a water pollution transport model is elaborated. A two-dimensional instantaneous-release shear-diffusion model serves as representative of a simple transport process. Pollution concentration levels are arrived at via modeling of a remote-sensing system. The remote-sensed data are simulated by adding Gaussian noise to the concentration level values generated via the transport model. Model parameters are estimated from the simulated data using a least-squares batch processor. Resolution, sensor array size, and number and location of sensor readings can be found from the accuracies of the parameter estimates.

Kibler, J. F.↗
NASA NTRS1975

A program for contouring randomly spaced data

A description is given of a digital computer program which prepares contour plots of three dimensional data. The contouring technique uses a triangulation procedure. As presently configured, the program can accept up to 56,000 randomly spaced data points, although the required computer resources may be prohibitive. However, with relatively minor internal modifications, the program can handle essentially unlimited amounts of data. Up to 20 contouring intervals can be selected and contoured with either polygonal lines or smooth curves. Sample cases are illustrated. A general description of the main program and primary level subroutines is included to permit simple modifications of the program.

Hamm, R. W.↗
NASA NTRS1974

Time-fixed rendezvous by impulse factoring with an intermediate timing constraint

A method is presented for factoring a two-impulse orbital transfer into a three- or four-impulse transfer which solves the rendezvous problem and satisfies an intermediate timing constraint. Both the time of rendezvous and the intermediate time of a alinement are formulated as any element of a finite sequence of times. These times are integer multiples of a constant plus an additive constant. The rendezvous condition is an equality constraint, whereas the intermediate alinement is an inequality constraint. The two timing constraints are satisfied by factoring the impulses into collinear parts that vectorially sum to the original impulse and by varying the resultant period differences and the number of revolutions in each orbit. Five different types of solutions arise by considering factoring either or both of the two impulses into two or three parts with a limit for four total impulses. The impulse-factoring technique may be applied to any two-impulse transfer which has distinct orbital periods.

Green, R. N.↗
NASA NTRS1974

Modification of an impulse-factoring orbital transfer technique to account for orbit determination and maneuver execution errors

A method has previously been developed to satisfy terminal rendezvous and intermediate timing constraints for planetary missions involving orbital operations. The method uses impulse factoring in which a two-impulse transfer is divided into three or four impulses which add one or two intermediate orbits. The periods of the intermediate orbits and the number of revolutions in each orbit are varied to satisfy timing constraints. Techniques are developed to retarget the orbital transfer in the presence of orbit-determination and maneuver-execution errors. Sample results indicate that the nominal transfer can be retargeted with little change in either the magnitude (Delta V) or location of the individual impulses. Additonally, the total Delta V required for the retargeted transfer is little different from that required for the nominal transfer. A digital computer program developed to implement the techniques is described.

Kibler, J. F.↗
NASA NTRS1973

Round trip Mars missions using looping trajectories in the 1980-2000 time period

Round trip Mars missions combining a standard trajectory leg and a looping trajectory leg are suggested as an alternative to the more conventional trajectories. Looping trajectories are shown to make it possible to trade a slight increase in total mission time for a significant reduction in Mars stay time, with the possible added benefit of a decrease in energy requirements.

Kibler, J. F.↗
NASA NTRS1972

An approximation to midcourse correction direction errors.

A new approximation to the components of midcourse correction direction errors is described that is more accurate than a previously used approximation. The calculation effort involved is much less than that for numerical integration. A comparison of numerical integration results with those of the new approximation is presented in a diagram.

Kibler, J. F.↗
NASA NTRS1972

A multiple-impulse function for orbital transfer and its derivatives

A multiple-impulse function is represented as a sequence of single-impulse functions. The single-impulse transfer which yields the velocity change required to transfer from a specified initial orbit to a partially specified final orbit is developed. Analytic derivatives of the function are obtained for use in optimization techniques. A four-impulse transfer is outlined. The analytic derivatives may allow more efficient optimization than numerical derivatives do.

Kibler, J. F.↗
NASA NTRS1972

Orbital trim by velocity factoring with applications to the Viking mission.

An orbital trim technique has been developed to satisfy terminal rendezvous and intermediate timing constraints for planetary missions involving orbital operations. The technique utilizes a time-open two-impulse transfer from a specified initial orbit to a final orbit which satisfies all geometrical constraints. Each of the two impulses may then be factored, or split, into two or more vectorially equivalent impulses. The periods of the resulting intermediate orbits may be varied along with the number of revolutions in each orbit to satisfy the intermediate and final timing constraints. Factors in the range 0 to 1 result in rendezvous at the same cost as that of the two-impulse transfer. The technique is applied to the Viking mission to Mars although a similar procedure could be utilized for rendezvous operations about any planet.

Kibler, J. F.↗