PTTI-Aided Ephemeris Calculation and Rapid Data Link Acquisition for Manned Space Flight

Abstract

Complexity of future manned space flight mission control can be significantly reduced by integrating GPS, the PTTI source, into telemetry, tracking and command (TT&C). Future telecommunications, space tracking electronic intelligence, metrology, navigation, and data acquisition will thereby be sewed, including: (1) On-board ephemeris determination, (2) Reduced synchronization time for time division muUiple access (TDMA) links, and (3) In-flight clock calibration, increasing on-board autonomy and reducing ground support costs. Manned space transportation through the first quarter of the 21st century will probably depend on a mix of vehicles, including the Advanced Manned Launch System (AMLS), the Personnel Launch System (PLS), and continued use of the Shuttle Fleet. Precise Ephemeris is important on-board for mission success, status monitoring, also for rendezvous and docking. Use of GPS can eliminate ground based tracking/processing, enhancing autonomy and reducing communications bandwidth. GPS time can simplify complicated functions used in bandwidth efficient time division multiple access (TDMA) communications, such as: (1) Precise and real-time synchronization of receive reference timing, (2) nansmit-timing and acquisition control, (3) Unique synchronization word (UW) detection, and (4) Elastic buffering. High clock accuracy provides increased signal-to-noise (S/N) ratio during acquisition, permitting narrower acquisition frequency and time windows. Spaceborne systems requirements to provide capabilities such as: (1) Refinement of the GEM-72 gravity model based on satellite tracking observations from ATS-6 to GEOS-3, (2) Relativistic clock experiments, (3) NASA crustal dynamics program for developing space geodetic techniques to study the earth's crust, its gravity field, and earthquake mechanisms, and (4) Multi-disciplinary space geodetic tracking for studying global climatic changes are also reviewed.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1992
Accession Number
ADA501962

Entities

People

  • Alfred Anderman

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Accuracy
  • Acquisition
  • Artificial Satellites
  • Clocks
  • Communication Systems
  • Data Links
  • Data Processing
  • Measurement
  • Multiple Access
  • Sea Level
  • Sea Level Rise
  • Space Flight
  • Space Systems
  • Space Transportation
  • Spacecraft
  • Time Division Multiple Access
  • Time Intervals

Readers

  • Aerospace Engineering.
  • Positioning, Navigation, and Timing (PNT) Technology.
  • Unmanned Aerial System (UAS) Autonomous Capabilities and Mission Reconnaissance.

Technology Areas

  • Microelectronics
  • Microelectronics - Microelectromechanical Systems
  • Space
  • Space - Satellites