1.
ORAN- ORBITAL AND GEODETIC PARAMETER ESTIMATION ERROR ANALYSIS
Document ID: 19940002592
Author: Putney, B.
Abstract: The Orbital and Geodetic Parameter Estimation Error Analysis program, ORAN, was developed as a
Bayesian least squares simulation program for orbital trajectories. ORAN does not process data, but is intended to compute the accuracy of the results of a data reduction, if measurements of a given accuracy are available and are processed by a minimum variance data reduction program. Actual data may be used to provide the time when a given measurement was available and the estimated noise on that measurement. ORAN is designed to consider a data reduction process in which a number of satellite data periods are reduced simultaneously. If there is more than one satellite in a data period, satellite-to-satellite tracking may be analyzed. The least squares estimator in most orbital determination programs assumes that measurements can be modeled by a nonlinear regression equation containing a function of parameters to be estimated and parameters which are assumed to be constant. The partitioning of parameters into those to be estimated (adjusted) and those assumed to be known (unadjusted) is somewhat arbitrary. For any particular problem, the data will be insufficient to adjust all parameters subject to uncertainty, and some reasonable subset of these parameters is selected for estimation. The final errors in the adjusted parameters may be decomposed into a component due to measurement noise and a component due to errors in the assumed values of the unadjusted parameters. Error statistics associated with the first component are generally evaluated in an orbital determination program. ORAN is used to simulate the orbital determination processing and to compute error statistics associated with the second component. Satellite observations may be simulated with desired noise levels given in many forms including range and range rate, altimeter height, right ascension and declination, direction cosines, X and Y angles, azimuth and elevation, and satellite-to-satellite range and range rate. The observation errors considered are bias, timing, transit time, tracking station location, polar motion, solid earth tidal displacement, ocean loading displacement, tropospheric and ionospheric refraction, and space plasma. The force model elements considered are the earth's potential, the gravitational constant, solid earth tides, polar radiation pressure, earth reflected radiation, atmospheric drag, and thrust errors. The errors are propagated along the satellite orbital path. The ORAN program is written in FORTRAN IV and ASSEMBLER for batch execution and has been implemented on an IBM 360 series computer with a central memory requirement of approximately 570K of 8-bit bytes. The ORAN program was developed in 1973 and was last updated in 1980.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: GSC-12766
Date Acquired: Dec 28, 1995
2.
PAFAC- PLASTIC AND FAILURE ANALYSIS OF COMPOSITES
Document ID: 19940002741
Author: Bigelow, C. A.
Abstract: The increasing number of applications of fiber-reinforced composites in industry demands a detailed
understanding of their material properties and behavior. A three-dimensional finite-element computer program called PAFAC (Plastic and Failure Analysis of Composites) has been developed for the elastic-plastic analysis of fiber-reinforced composite materials and structures. The evaluation of stresses and deformations at edges, cut-outs, and joints is essential in understanding the strength and failure for metal-matrix composites since the onset of plastic yielding starts very early in the loading process as compared to the composite's ultimate strength. Such comprehensive analysis can only be achieved by a finite-element program like PAFAC. PAFAC is particularly suited for the analysis of laminated metal-matrix composites. It can model the elastic-plastic behavior of the matrix phase while the fibers remain elastic. Since the PAFAC program uses a three-dimensional element, the program can also model the individual layers of the laminate to account for thickness effects. In PAFAC, the composite is modeled as a continuum reinforced by cylindrical fibers of vanishingly small diameter which occupy a finite volume fraction of the composite. In this way, the essential axial constraint of the phases is retained. Furthermore, the local stress and strain fields are uniform. The PAFAC finite-element solution is obtained using the displacement method. Solution of the nonlinear equilibrium equations is obtained with a Newton-Raphson iteration technique. The elastic-plastic behavior of composites consisting of aligned, continuous elastic filaments and an elastic-plastic matrix is described in terms of the constituent properties, their volume fractions, and mutual constraints between phases indicated by the geometry of the microstructure. The program uses an iterative procedure to determine the overall response of the laminate, then from the overall response determines the stress state in each phase of the composite material. Failure of the fibers or matrix within an element can also be modeled by PAFAC. PAFAC is written in FORTRAN IV for batch execution and has been implemented on a CDC CYBER 170 series computer with a segmented memory requirement of approximately 66K (octal) of 60 bit words. PAFAC was developed in 1982.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: LAR-13183
Date Acquired: Dec 28, 1995
3.
SIVA/DIVA- INITIAL VALUE ORDINARY DIFFERENTIAL EQUATION SOLUTION VIA A VARIABLE ORDER ADAMS METHOD
Document ID: 19940003135
Author: Krogh, F. T.
Abstract: The SIVA/DIVA package is a collection of subroutines for the solution of ordinary differential
equations. There are versions for single precision and double precision arithmetic. These solutions are applicable to stiff or nonstiff differential equations of first or second order. SIVA/DIVA requires fewer evaluations of derivatives than other variable order Adams predictor-corrector methods. There is an option for the direct integration of second order equations which can make integration of trajectory problems significantly more efficient. Other capabilities of SIVA/DIVA include: monitoring a user supplied function which can be separate from the derivative; dynamically controlling the step size; displaying or not displaying output at initial, final, and step size change points; saving the estimated local error; and reverse communication where subroutines return to the user for output or computation of derivatives instead of automatically performing calculations. The user must supply SIVA/DIVA with: 1) the number of equations; 2) initial values for the dependent and independent variables, integration stepsize, error tolerance, etc.; and 3) the driver program and operational parameters necessary for subroutine execution. SIVA/DIVA contains an extensive diagnostic message library should errors occur during execution. SIVA/DIVA is written in FORTRAN 77 for batch execution and is machine independent. It has a central memory requirement of approximately 120K of 8 bit bytes. This program was developed in 1983 and last updated in 1987.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: NPO-16699
Date Acquired: Dec 28, 1995
4.
PROCSCAN- MONITORING THE EXECUTION OF A VAX IMAGE
Document ID: 19940003163
Author: Scott, P. J.
Abstract: The program PROCSCAN was developed to monitor the profile of an executable image during execution.
The purpose is to identify the routines where a program is spending most of its time. Thus PROCSCAN can be a very useful first step in program optimization. PROCSCAN samples the program counter of the executing image and compares its value to a table of entry point addresses in order to determine which subroutine is executing. The table of subroutines in the image is generated by the program SCANEXE (NPO-17298), which is included with this program, but is also available from COSMIC as a separate package. The output from PROCSCAN is a sorted histogram of subroutines versus time spent in each subroutine. Because of the amount of data collected, it is not possible to sample the program counter every time it changes, so the data represents a proportionate sampling of where the program is spending its time. Over a period of a few CPU minutes, a fairly accurate picture can be formed. If a program has been linked with the /NOTRACEBACK qualifier, or it calls routines contained within a shareable library, then PROCSCAN will not function. This program is written in C, Assembler, and FORTRAN 77 for execution on a VAX 11/780 computer operating under VMS 4.X with a central memory requirement of 33,280 bytes. This program was developed in 1987.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: NPO-17297
Date Acquired: Dec 28, 1995
5.
RATIO_TOOL - SOFTWARE FOR COMPUTING IMAGE RATIOS
Document ID: 19940003220
Author: Yates, G. L.
Abstract: Geological studies analyze spectral data in order to gain information on surface materials.
RATIO_TOOL is an interactive program for viewing and analyzing large multispectral image data sets that have been created by an imaging spectrometer. While the standard approach to classification of multispectral data is to match the spectrum for each input pixel against a library of known mineral spectra, RATIO_TOOL uses ratios of spectral bands in order to spot significant areas of interest within a multispectral image. Each image band can be viewed iteratively, or a selected image band of the data set can be requested and displayed. When the image ratios are computed, the result is displayed as a gray scale image. At this point a histogram option helps in viewing the distribution of values. A thresholding option can then be used to segment the ratio image result into two to four classes. The segmented image is then color coded to indicate threshold classes and displayed alongside the gray scale image. RATIO_TOOL is written in C language for Sun series computers running SunOS 4.0 and later. It requires the XView toolkit and the OpenWindows window manager (version 2.0 or 3.0). The XView toolkit is distributed with Open Windows. A color monitor is also required. The standard distribution medium for RATIO_TOOL is a .25 inch streaming magnetic tape cartridge in UNIX tar format. An electronic copy of the documentation is included on the program media. RATIO_TOOL was developed in 1992 and is a copyrighted work with all copyright vested in NASA. Sun, SunOS, and OpenWindows are trademarks of Sun Microsystems, Inc. UNIX is a registered trademark of AT&T Bell Laboratories.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: NPO-18770
Date Acquired: Dec 28, 1995
6.
DESIGN OF SUPERSONIC INLETS
Document ID: 19940002862
Author: Anderson, B. H.
Abstract: This FORTRAN IV computer program which incorporates the method of characteristics was written to
assist in the design of supersonic inlets. There were two objectives: (1) to study a greater variety of supersonic inlet configurations and (2) to reduce the time required for trial-and-error procedures to arrive at optimum inlet design. The computer program was written with the intention of being able to construct a variety of inlet configurations by interchanging specific subroutines. In this manner, greater flexibility of choice was attained, and the time required to program a specific inlet configuration was greatly reduced. The second objective was accomplished by a reformulation of the boundary value problem for hyperbolic equations. By this reformulation of the boundary data, the engineering design quantities, throat Mach number and flow angle, were introduced as direct input quantities to the computer program. As a consequence of introducing the engineering parameters as input, the computer program will calculate the surface contours required to satisfy the specific throat conditions. Inviscid flow is assumed and the method used to calculate the inlet contour results in minimum distortion to the flow in the throat. This program was developed on an IBM 7094.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: LEW-10868
Date Acquired: Dec 28, 1995
7.
DISCOS- DYNAMIC INTERACTION SIMULATION OF CONTROLS AND STRUCTURES (DEC VAX VERSION)
Document ID: 19940002594
Author: Frisch, H. P.
Abstract: The Dynamic Interaction Simulation of Controls and Structure (DISCOS) program was developed for the
dynamic simulation and stability analysis of passive and actively controlled spacecraft. In the use of DISCOS, the physical system undergoing analysis may be generally described as a cluster of contiguous flexible structures (bodies) that comprise a mechanical system, such as a spacecraft. The entire system (spacecraft) or portions thereof may be either spinning or nonspinning. Member bodies of the system may undergo large relative excursions, such as those of appendage deployment or rotor/ stator motion. The general system of bodies is, by its inherent nature, a feedback system in which inertial forces (such as those due to centrifugal and Coriolis acceleration) and the restoring and damping forces are motion-dependent. The system may possess a control system in which certain position and rate errors are actively controlled through the use of reaction control jets, servomotors, or momentum wheels. Bodies of the system may be interconnected by linear or nonlinear springs and dampers, by a gimbal and slider block mechanism, or by any combination of these. The DISCOS program can be used to obtain nonlinear and linearized time response of the system, interaction constant forces in the system, total system resonance properties, and frequency domain response and stability information for the system. DISCOS is probably the most powerful computational tool to date for the computer simulation of actively controlled coupled multi-flexible-body systems. The program is not easy to understand and effectively apply, but is not intended for simple problems. The DISCOS user is expected to have extensive working knowledge of rigid-body and flexible-body dynamics, finite-element techniques, numerical methods, and frequency-domain analysis. Various applications of DISCOS include simulation of the Shuttle payload deployment/retrieval mechanism, solar panel array deployment, antenna deployment, analysis of multispin satellites, and analysis of large, highly flexible satellites, including the design of attitude-control systems. The overall approach of DISCOS is unique in that any member body of the system may be flexible, and the system is not restricted to a topological tree configuration. The equations of motion are developed using the most general form of Lagrange's equations, including auxiliary nonholonomic rehenomic conditions of constraint. Lagrange multipliers are used as interaction forces/ torques to maintain prescribed constraints. Nonlinear flexible/rigid dynamic coupling effects are accounted for in unabridged fashion for individual bodies and for the total system. Elastic deformation can be represented by normal vibration modes or by any adequate series of Rayleigh functions, including 'quasi-static' displacement functions. To 'solve' Lagrange's equations of motion, the explicit form of the kinetic and potential energy functions, the dissipation function, and the form of the transformation relating ordinary Cartesian position coordinates to the generalized coordinates must be defined. The potential energy and dissipation functions for a structure are determined with standard finite-element techniques by the NASTRAN program. In order to use the computed functions, the Lagrange's equations and the system kinematic constraint equations are expressed in matrix format. These differential matrix equations are solved numerically by the DISCOS program. Provisions are included for environmental loading of the structure (spacecraft), including solar pressure, gravity gradient, and aerodynamic drag. Input to DISCOS includes topological and geometrical descriptions of the structure under analysis, initial conditions, control system descriptions, and NASTRAN-derived structural matrices. Specialized routines are supplied that read the input data and redimension the DISCOS programs to minimize core requirements. Output includes an extensive list of calculated parameters for each body of the structure, system state vector and its time derivatives, euler angles and position coordinates and their time derivatives, control system variables and their time derivatives, and various system parameters at a given simulation time. For linearized system analysis, output includes the various transfer matrices, eigenvectors, and calculated eigenvalues. The DISCOS program is available by license for a period of ten (10) years to approved licensees. The licensed program product delivered includes the source code and supporting documentation. Additional documentation may be purchased separately at any time. The IBM version of DISCOS is written in FORTRAN IV for batch execution and has been implemented on an IBM 360 series computer under OS with a central memory requirement of approximately 1,100K of 8 bit bytes. The DEC VAX version of DISCOS is written in FORTRAN for batch execution and has been implemented on a DEC VAX series computer under VMS. For plotted output a SC4020 plotting system is required. DISCOS was developed on the IBM in 1978 and was adapted (with enhancements) to the DEC VAX in 1982.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: GSC-12810
Date Acquired: Dec 28, 1995
8.
WAVDRAG- ZERO-LIFT WAVE DRAG OF COMPLEX AIRCRAFT CONFIGURATIONS
Document ID: 19940002742
Author: Craidon, C. B.
Abstract: WAVDRAG calculates the supersonic zero-lift wave drag of complex aircraft configurations. The
numerical model of an aircraft is used throughout the design process from concept to manufacturing. WAVDRAG incorporates extended geometric input capabilities to permit use of a more accurate mathematical model. With WAVDRAG, the engineer can define aircraft components as fusiform or nonfusiform in terms of non-intersecting contours in any direction or more traditional parallel contours. In addition, laterally asymmetric configurations can be simulated. The calculations in WAVDRAG are based on Whitcomb's area-rule computation of equivalent-bodies, with modifications for supersonic speed. Instead of using a single equivalent-body, WAVDRAG calculates a series of equivalent-bodies, one for each roll angle. The total aircraft configuration wave drag is the integrated average of the equivalent-body wave drags through the full roll range of 360 degrees. WAVDRAG currently accepts up to 30 user-defined components containing a maximum of 50 contours as geometric input. Each contour contains a maximum of 50 points. The Mach number, angle-of-attack, and coordinates of angle-of-attack rotation are also input. The program warns of any fusiform-body line segments having a slope larger than the Mach angle. WAVDRAG calculates total drag and the wave-drag coefficient of the specified aircraft configuration. WAVDRAG is written in FORTRAN 77 for batch execution and has been implemented on a CDC CYBER 170 series computer with a central memory requirement of approximately 63K (octal) of 60 bit words. This program was developed in 1983.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: LAR-13223
Date Acquired: Dec 28, 1995
9.
VIRTUAL FRAME BUFFER INTERFACE
Document ID: 19940003136
Author: Wolfe, T. L.
Abstract: Large image processing systems use multiple frame buffers with differing architectures and vendor
supplied user interfaces. This variety of architectures and interfaces creates software development, maintenance, and portability problems for application programs. The Virtual Frame Buffer Interface program makes all frame buffers appear as a generic frame buffer with a specified set of characteristics, allowing programmers to write code which will run unmodified on all supported hardware. The Virtual Frame Buffer Interface converts generic commands to actual device commands. The virtual frame buffer consists of a definition of capabilities and FORTRAN subroutines that are called by application programs. The virtual frame buffer routines may be treated as subroutines, logical functions, or integer functions by the application program. Routines are included that allocate and manage hardware resources such as frame buffers, monitors, video switches, trackballs, tablets and joysticks; access image memory planes; and perform alphanumeric font or text generation. The subroutines for the various "real" frame buffers are in separate VAX/VMS shared libraries allowing modification, correction or enhancement of the virtual interface without affecting application programs. The Virtual Frame Buffer Interface program was developed in FORTRAN 77 for a DEC VAX 11/780 or a DEC VAX 11/750 under VMS 4.X. It supports ADAGE IK3000, DEANZA IP8500, Low Resolution RAMTEK 9460, and High Resolution RAMTEK 9460 Frame Buffers. It has a central memory requirement of approximately 150K. This program was developed in 1985.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: NPO-16713
Date Acquired: Dec 28, 1995
10.
SCANEXE- EXAMINING THE SUBROUTINE STRUCTURE OF A VAX IMAGE
Document ID: 19940003164
Author: Scott, P. J.
Abstract: SCANEXE is a command for the DEC VAX used to scan a VMS executable image and print information about
the routines it uses. Optionally, SCANEXE lists each routine, with its entry point, and how many times it is called, if at all. Information on the progress of the program will be optionally printed as it analyzes the various executable components. SCANEXE relies on debug records that are included by default in .EXE files. However, if an image is linked with the /NOTRACEBACK option (as are all system programs), then it cannot provide the necessary information. SCANEXE will only count the number of times it finds a statement calling each routine, which is not necessarily the same as the number of times that the routine would be called if the program were run. SCANEXE is written in C, FORTRAN 77, and Assembler for batch execution on the DEC VAX under VMS 4.X. It has a central memory requirement of 61952 bytes. This program was released in 1988.
Publication Year: 1994
Document Type: Computer Program
Report/Patent Number: NPO-17298
Date Acquired: Dec 28, 1995