Genesis and Design of the Tracking, Telemetry, and Command System for the Navstar Global Positioning System

International Telemetering Conference Proceedings / November 14-16, 1978 / Hyatt House Hotel, Los Angeles, CaliforniaThe genesis and design of a unique Tracking, Telemetry, and Command (TT&C) System for the Navstar Global Positioning System (GPS) is described from the perspective of the System Architect/Engineer. Working from the diverse and sometimes conflicting mission requirements, derivative performance requirements for the TT&C System were generated. System design tradeoffs were performed in an effort to compromise conflicting requirements which affected the frequency domain, link budgets, antenna sizing, and modulation schemes. The characteristics of the resulting TT&C System included the following: a. Primary uplinking to the satellite on a spread spectrum secure link at X-Band. b. Use of a closed-loop uplink which takes advantage of existing onboard functions as references to achieve precise ground-space synchronization. c. Incorporation of state-of-the-art error control techniques to achieve high net data throughputs with concurrently "zero error" data transfer from ground to space. d. Hybrid frequency ground antennas to accommodate both the primary and backup command links, with compatible telemetry downlinks. A common S-Band frequency input within the satellite to both the primary wideband Pseudo Random Noise (PRN) correlation receiver and the backup Space Ground Link System (SGLS) receiver.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection