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Design and Construction of Protograph-Based LDPC Codes

This innovation can be used in magnetic tape recording and other channels with finite-state representation. NASA’s Jet Propulsion Laboratory, Pasadena, California Writing (recording) to a storage device and reading from it can be considered as a noisy channel. A storage device such as magnetic recoding and optical recording can be modeled as a partial response channel. Partial-response techniques are a special case of precoding technique where the intersymbol interference is forced to some known pattern. Thus, read-back data from storage devices may have intersymbol interference.

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Spitzer Integrated Resource Planning and Scheduling System (SIRPASS)

NASA’s Jet Propulsion Laboratory, Pasadena, California This decision support system provides an integrated platform for assessing the quality of Spitzer scheduling options. The application aids in scheduling instrument selection, assigns schedule times to specific observation requests, and generates stored sequence products destined for execution on the Spitzer Space Telescope.

Posted in: Briefs, TSP, Electronics & Computers

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Tracking a Scene on Earth from Space Using the Adaptive Cross-Correlation Algorithm

NASA’s Jet Propulsion Laboratory, Pasadena, California A software program enables a user to track a scene or a spot on Earth from space (such as from the ISS) using an innovative algorithm. This robust and highly accurate software allows a scene to be tracked that can be not only the shifted version of a previous scene, but can also be a distorted one.

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Automated Scheduling of Personnel to Staff Operations for the Mars Science Laboratory

NASA’s Jet Propulsion Laboratory, Pasadena, California The task of producing Mars Science Laboratory (MSL) personnel schedules is daunting. Through automation, the labor and number of mistakes made are reduced when compared to the manual process. This software not only allows for common constraints to be expressed, but also for these to be gracefully descoped in case a solution cannot be found, thus making this unique in the personnel scheduling arena.

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Area Coverage Path Planning Using Divided Grid-Graphs

NASA’s Jet Propulsion Laboratory, Pasadena, California Planning area coverage observations is a challenge in an architecture with a framing imager affixed to a bus that can be moved, and a mirror or other device that allows for small, but fast, observation of adjacent areas along the boresight of a telescope. The telescope boresight can slew slowly while the mirror system maintains pointing on a specific field of view. This allows the continuous gathering of data (much like push - broom instruments) without the need to slew or settle. Since the telescope field of view is much larger than the imager field of view, the areas to be imaged can be divided into quarters.

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Shape Sensing Using Multicore Fiber Optic Cable and Parametric Curve Solutions

Langley Research Center, Hampton, Virginia Apaper reports a method of converting distributed curvature measurements into a three-dimensional shape by combining elastic rod theory and differential geometry to arrive at a three-dimensional solution of the Frenet-Serret formulas. A new method of calculating the shape of a multicore fiber optic cable is presented. The method utilizes discrete strain measurements obtained in each core to create a continuous representation of fiber curvature and torsion. The Frenet-Serret equations are then solved using these representations to obtain fiber shape. Shape measurements were found to have, at most, 7.2% error. The primary source of error is most likely externally induced twisting in the fiber.

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Encoders and Decoders for the AR4JA LDPC Codes

NASA’s Jet Propulsion Laboratory, Pasadena, California Low-Density Parity-Check (LDPC) codes are the best error-correcting codes known for a wide variety of communications applications. The AR4JA code family encompasses encoders and decoders for nine error-correcting codes. These include Accumulate, Repeat-by-4, and Jagged Accumulate (AR4JA) codes developed at JPL.

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