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Ground-Based Localization of Mars Rovers

The document discusses a procedure for localizing the Mars rovers in site frame, a locally defined reference frame on the Martian surface. MER onboard position within a site frame is estimated onboard and is based on wheel odometry. Odometry estimation of rover position is only reliable over relatively short distances assuming no wheel slip, sinkage, etc. As the rover traverses, its onboard estimate of position in the current site frame accumulates errors and will need to be corrected on occasions via relocalization on the ground (mission operations). The procedure provides a systematic process for ground operators to localize the rover. The method focuses on analysis of acquired images used to declare a site frame and images acquired post-drive. Target selection is performed using two main steps. In the first step, the user identifies features of interest from the images used to declare the current site. Each of the selected target’s position in site frame is recorded. In the second step, post-traverse measurements of the selected features’ positions are recorded again, this time in rover frame, using images acquired post-traverse. In the third step, we transform the post-traverse target’s positions to local level frame. In the fourth step, we compute the delta differences in the pre- and post-traverse target’s position. In the fifth step, we analyze the delta differences with techniques that compute their statistics to determine the rover’s position in the site frame.

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Real-Time Diagnosis of Faults Using a Bank of Kalman Filters

Gradual changes associated with aging are taken into account in the diagnostic process. A new robust method of automated real-time diagnosis of faults in an aircraft engine or a similar complex system involves the use of a bank of Kalman filters. In order to be highly reliable, a diagnostic system must be designed to account for the numerous failure conditions that an aircraft engine may encounter in operation. The method achieves this objective though the utilization of multiple Kalman filters, each of which is uniquely designed based on a specific failure hypothesis. A fault-detection- and-isolation (FDI) system, developed based on this method, is able to isolate faults in sensors and actuators while detecting component faults (abrupt degradation in engine component performance). By affording a capability for real-time identification of minor faults before they grow into major ones, the method promises to enhance safety and reduce operating costs.

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Conflict-Aware Scheduling Algorithm

An algorithm is being developed to automate NASA’s Deep Space Network antenna allocation. A conflict-aware scheduling algorithm is being developed to help automate the allocation of NASA’s Deep Space Network (DSN) antennas and equipment that are used to communicate with interplanetary scientific spacecraft. The current approach for scheduling DSN ground resources seeks to provide an equitable distribution of tracking services among the multiple scientific missions and is very labor intensive. Due to the large (and increasing) number of mission requests for DSN services, combined with technical and geometric constraints, the DSN is highly oversubscribed. To help automate the process, and reduce the DSN and spaceflight project labor effort required for initiating, maintaining, and negotiating schedules, a new scheduling algorithm is being developed.

Posted in: Briefs, TSP

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Predicting Numbers of Problems in Development of Software

A method has been formulated to enable prediction of the amount of work that remains to be performed in developing flight software for a spacecraft. The basic concept embodied in the method is that of using an idealized curve (specifically, the Weibull function) to interpolate from (1) the numbers of problems discovered thus far to (2) a goal of discovering no new problems after launch (or six months into the future for software already in use in orbit). The steps of the method can be summarized as follows:

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Improved Compression of Wavelet-Transformed Images

Code parameters are selected adaptively to achieve high compression performance. A recently developed data-compression method is an adaptive technique for coding quantized wavelet-transformed data, nominally as part of a complete image-data compressor. Unlike some other approaches, this method admits a simple implementation and does not rely on the use of large code tables.

Posted in: Briefs, TSP

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Generating Solid Models From

Topographical Data Topographical data are converted into forms useable by rapid-prototyping machines.A method of generating solid models of terrain involves the conversion of topographical data into a form useable by a rapid-prototyping (RP) machine. The method was developed to enable the use of the RP machine to make solid models of Martian terrain from Mars Orbiter laser-altimeter topographical data. The method is equally applicable to the generation of models of the terrains of other astronomical bodies, including other planets, asteroids, and Earth.

Posted in: Briefs, TSP

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Computationally Lightweight Air-Traffic-Control Simulation

This algorithm simulates ATC functions for a busy airport.An algorithm for computationally lightweight simulation of automated airtraffic control (ATC) at a busy airport has been derived. The algorithm is expected to serve as the basis for development of software that would be incorporated into flight-simulator software, the ATC component of which is not yet capable of handling realistic airport loads. Software based on this algorithm could also be incorporated into other computer programs that simulate a variety of scenarios for purposes of training or amusement.

Posted in: Briefs, TSP

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