Information Technology & Software

Presentation Extensions of the SOAP

A set of extensions of the Satellite Orbit Analysis Program (SOAP) enables simultaneous and/or sequential presentation of information from multiple sources. SOAP is used in the aerospace community as a means of collaborative visualization and analysis of data on planned spacecraft missions. The following definitions of terms also describe the display modalities of SOAP as now extended: In SOAP terminology,

Posted in: Briefs, Information Sciences, Trajectory control, Computer software / hardware, Computer software and hardware, Computer software / hardware, Computer software and hardware, Data management, Terminology, Satellites
Read More >>

Error-Rate Bounds for Coded PPM on a Poisson Channel

It is now possible to calculate tight bounds at high SNR.

Equations for computing tight bounds on error rates for coded pulse-position modulation (PPM) on a Poisson channel at high signal-to-noise ratio have been derived. These equations and elements of the underlying theory are expected to be especially useful in designing codes for PPM optical communication systems.

Posted in: Briefs, Information Sciences, Design processes, Mathematical analysis, Communication protocols, Wireless communication systems, Communication protocols, Wireless communication systems
Read More >>

Biomorphic Multi-Agent Architecture for Persistent Computing

Computing systems would reconfigure themselves to continue functioning despite failures of components.

A multi-agent software/hardware architecture, inspired by the multicellular nature of living organisms, has been proposed as the basis of design of a robust, reliable, persistent computing system. Just as a multicellular organism can adapt to changing environmental conditions and can survive despite the failure of individual cells, a multi-agent computing system, as envisioned, could adapt to changing hardware, software, and environmental conditions. In particular, the computing system could continue to function (perhaps at a reduced but still reasonable level of performance) if one or more component(s) of the system were to fail.

Posted in: Briefs, Information Sciences
Read More >>

Using Covariance Analysis To Assess Pointing Performance

A Pointing Covariance Analysis Tool (PCAT) has been developed for evaluating the expected performance of the pointing control system for NASA’s Space Interferometry Mission (SIM). The SIM pointing control system is very complex, consisting of multiple feedback and feedforward loops, and operating with multiple latencies and data rates. The SIM pointing problem is particularly challenging due to the effects of thermomechanical drifts in concert with the long camera exposures needed to image dim stars.

Posted in: Briefs, TSP, Information Sciences
Read More >>

Integrated System Health Management Development Toolkit

This software toolkit is designed to model complex systems for the implementation of embedded Integrated System Health Management (ISHM) capability, which focuses on determining the condition (health) of every element in a complex system (detect anomalies, diagnose causes, and predict future anomalies), and to provide data, information, and knowledge (DIaK) to control systems for safe and effective operation.

Posted in: Briefs, Information Sciences, Computer software / hardware, Computer software and hardware, On-board diagnostics, On-board diagnostics (OBD), Computer software / hardware, Computer software and hardware, On-board diagnostics, On-board diagnostics (OBD), Systems management
Read More >>

TCP/IP Interface for the Satellite Orbit Analysis Program (SOAP)

The Transmission Control Protocol/Internet protocol (TCP/IP) interface for the Satellite Orbit Analysis Program (SOAP) provides the means for the software to establish real-time interfaces with other software. Such interfaces can operate between two programs, either on the same computer or on different computers joined by a network. The SOAP TCP/IP module employs a client/server interface where SOAP is the server and other applications can be clients. Real-time interfaces between software offer a number of advantages over embedding all of the common functionality within a single program. One advantage is that they allow each program to divide the computation labor between processors or computers running the separate applications. Secondly, each program can be allowed to provide its own expertise domain with other programs able to use this expertise.

Posted in: Briefs, Information Sciences, Architecture, Communication protocols, Computer software / hardware, Computer software and hardware, Architecture, Communication protocols, Computer software / hardware, Computer software and hardware, Satellites
Read More >>

High-Performance Algorithm for Solving the Diagnosis Problem

Computation time is reduced substantially.

An improved method of model-based diagnosis of a complex engineering system is embodied in an algorithm that involves considerably less computation than do prior such algorithms. This method and algorithm are based largely on developments reported in several NASA Tech Briefs articles: “The Complexity of the Diagnosis Problem” (NPO-30315), Vol. 26, No. 4 (April 2002), page 20; “Fast Algorithms for Model-Based Diagnosis” (NPO-30582), Vol. 29, No. 3 (March 2005), page 69; “Two Methods of Efficient Solution of the Hitting-Set Problem” (NPO-30584), Vol. 29, No. 3 (March 2005), page 73; and “Efficient Model-Based Diagnosis Engine” (NPO-40544), on the following page.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Diagnosis, Prognostics
Read More >>

Efficient Method for Optimizing Placement of Sensors

This systematic method supplants ad hoc placement and exhaustive-search optimization methods.

A computationally efficient method has been developed to enable optimization of the placement of sensors for the purpose of diagnosis of a complex engineering system (e.g., an aircraft or spacecraft). The method can be used both in (1) designing a sensor system in which the number and positions of sensors are initially not known and must be determined and (2) adding sensors to a pre-existing system to increase the diagnostic capability.

Posted in: Briefs, TSP, Information Sciences, Optimization, Sensors and actuators, Sensors and actuators
Read More >>

Truncation Depth Rule-of-Thumb for Convolutional Codes

The new rule is more accurate and tight at high signal-to-noise ratios.

In this innovation, it is shown that a commonly used rule of thumb (that the truncation depth of a convolutional code should be five times the memory length, m, of the code) is accurate only for rate 1/2 codes. In fact, the truncation depth should be 2.5 m/(1 – r), where r is the code rate. The accuracy of this new rule is demonstrated by tabulating the distance properties of a large set of known codes. This new rule was derived by bounding the losses due to truncation as a function of the code rate.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Product development
Read More >>

Multibeam Altimeter Navigation Update Using Faceted Shape Model

The model is applicable to a body having almost any complex shape.

A method of incorporating information, acquired by a multibeam laser or radar altimeter system, pertaining to the distance and direction between the system and a nearby target body, into an estimate of the state of a vehicle upon which the system is mounted, involves the use of a faceted model to represent the shape of the target body. In the original intended application, the vehicle would be a spacecraft and the target body would be an asteroid, comet, or similar body that the spacecraft was required to approach. The method could also be used in navigating aircraft at low altitudes over terrain that is rough and/or occupied by objects of significant structure.

Posted in: Briefs, Information Sciences, Mathematical models, Altimeters, Flight guidance systems, Lasers, Radar, Altimeters, Flight guidance systems, Lasers, Radar
Read More >>

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.