A software package for use in a ground receiving station detects a beacon-monitor tone transmitted by a spacecraft. To recapitulate from previous NASA Tech Briefs articles on beacon monitoring: An onboard computer processes data from onboard sensors to summarize the condition of the spacecraft in terms of one of four standard statuses, then a message is transmitted on a radio-frequency carrier as phase modulation at one of four subcarrier frequencies that correspond to the four statuses. The present software implements a weak-signal-detection algorithm. The received signal is heterodyned at nine frequencies and recorded into nine corresponding frequency bands. Nominally, there is a center carrier and four pairs of symmetrical status bands. After recording, each frequency band is subdivided into subbands with a fixed temporal duration. Within each frequency subband, there is a bank of time-sequenced subband processors. The optimal linear path in the corresponding time-frequency band space is obtained by maximizing the summed squared signal amplitudes. The maximum summed subband-processor output is selected and compared to a predetermined threshold to determine whether the corresponding status message should be deemed to have been transmitted. The frequency drift of the status tone signal must be small enough to allow the search algorithm to detect the signal over a time long enough to provide a low signal-detection threshold.
Contributors to the development of this software package were Sue Finley, Gabor Lanyi, Robert Sherwood, Miles K. Sue, John Szijjarto, and E. J. Wyatt of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Software category.
This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393-3425. Refer to NPO-21023.
This Brief includes a Technical Support Package (TSP).
Software for Detecting Tones in Beacon Monitoring
(reference NPO-21023) is currently available for download from the TSP library.
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Overview
The document discusses advancements in spacecraft monitoring technology, specifically focusing on the Beacon system, which enhances mission operations by utilizing onboard autonomy and data summarization techniques. The Beacon system aims to reduce operational costs and risks associated with space missions by shifting from traditional telemetry downlink methods to more efficient onboard health determination and autonomous data summarization.
Key components of the Beacon system include the Monitor Message Component (MMC), which operates within existing subsystems, and the use of beacon tones to communicate spacecraft health information. The system's effectiveness largely depends on the level of autonomy achieved onboard, allowing for robust recovery from anomalies and flexible data management. Onboard engineering data summarization and monitor message selection are critical technologies that enable concise summaries of spacecraft health, prioritizing data for downlink during tracking periods.
The document outlines various types of telemetry packets, including episode packets, snapshot packets, and summary statistic packets, which provide different levels of detail about spacecraft conditions. These packets are designed to optimize data transfer and ensure that critical information is communicated effectively to mission operators.
The Beacon system also addresses challenges such as false episode alarms caused by mission activities, emphasizing the importance of clearly defining mission activities and their relationship to engineering data. The document highlights the need for careful calibration of summary content during early mission phases to fine-tune data prioritization.
Additionally, the document discusses the development of web-based tools for accessing summary data, aiming to improve accessibility for flight teams and enhance operational effectiveness. It notes that while the Beacon technology was not fully operational during the primary mission of the Deep Space 1 (DS1) spacecraft, lessons learned from the mission have informed future improvements.
Overall, the document emphasizes the potential of the Beacon system to transform spacecraft operations by enabling more frequent and smaller missions, ultimately contributing to NASA's goals for the next millennium. The integration of advanced monitoring technologies is positioned as a key factor in achieving cost-effective and reliable space exploration.
