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International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, Nevada / As on-board satellite systems develop increased sophistication and autonomous capabilities, failures become fewer, but the diagnosis of the remaining failures becomes more complex. In addition, autonomy requirements for space vehicles are being issued along with requirements for reduced staffing of ground stations. Thus successful groundbased fault handling in the future will require greatly increased automation of fault detection and diagnosis. This paper investigates the use of an expert system as a ground system component for diagnosis. The diagnostic cycle of the system is presented, along with requirements for its knowledge base. The results of implementing the design to diagnose part of a satellite attitude control system are given. Knowledge acquisition for this problem centered on the generation and analysis of terminal displays of telemetry which look much like strip charts. Correct diagnosis by the expert system derived from the use of extensive telemetry analysis, operations and satellite status databases, and satellite modeling.

This dissertation proposes analytic tools for dynamics and control problems in the perspective of large-scale relative motion without perturbations. Specifically, we develop an exact and efficient analytic solution of satellite relative motion using a direct geometrical approach in spherical coordinates. The resulting solution is then transformed into general parametric equations of cycloids and trochoids. With this transformation, the dissertation presents new findings for design rules and classifications of closed and periodic parametric relative orbits. A new observation from the findings states that the orbit shape resulting from the relative motion dynamics of circular orbit cases in polar views are exactly the same as the parametric curves of cycloids and trochoids. The dynamics problem of satellite relative motion is expanded to include the design of satellite constellations for multiple satellite systems. A Parametric Constellation (PC) is developed to create an identical constellation pattern, or repeating space track, of target satellites with respect to a base satellite. In this PC theory, the number of target satellites is distributed using a real number system for node spacing. While using a base satellite orbit as the rotating reference frame, the PC theory consists of satellite phasing rules and closed form formulae for designing repeating space tracks. The evaluation of the PC theory is illustrated through it’s comparison to the existing Flower Constellation theory in terms of node spacing distribution and constellation design process. For the control problems, the efficient analytic solution is applied to the reference trajectory of satellite relative tracking control systems for inter-satellite links. Two types of relative tracking control systems are developed and each is evaluated to determine which is more appropriate for practical applications of inter-satellite links. All of the proposed analytic solutions and tools in this dissertation will be useful for the mission analysis and design of relative motions involving a two or more satellite system. / Ph. D.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Deutsche Telekom is operating various communication satellites since 1989. The SCC (spacecraft control center) is located near Frankfurt / Germany. The entire system is based on antenna/RF equipment, baseband and computer software packages running on a computer network of different machines. Due to increased maintenance effort the old baseband system needed to be replaced. This also had effects to the computer system, especially to the M&C. The aim was to design the entire system in a way that the operation effort in costs aspects and human intervention are minimized. This paper shows the successful real world project of reengineering a traditional spacecraft control center (SCC). It is shown how a fifteen year old hardware (baseband system) and software design was replaced by a modern concept during normal operations. The new software packages execute all necessary tasks for spacecraft- and ground station control. The Monitor and Control System (M&C) is a database driven design (FRAMTEC, from CAM Germany).

International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / ASW-II (Advanced Satellite Workstation, Version II) has been developed and delivered as an operational prototype in support of the Ultra High Frequency (UHF) Follow-On satellite. It provides unified and coordinated real time reception and storage of satellite telemetry, display of both real time and stored telemetry, expert-system analysis of spacecraft status, and an information navigator system that stores and presents information about the spacecraft. The architecture is modular and reconfigurable, and it provides support for multiple analyst workstations. There are several unusual aspects of the design. The entire telemetry history of the satellite is regarded as a continuum by the user, with ASW-II automatically tracking and displaying contact periods. A "streams" mechanism organizes the telemetry in such a way that the user can interactively define new derived parameters and have them presented graphically. Both real time and archived data can be displayed simultaneously. The user has very flexible controls for all display interfaces using mouse and window technologies.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A critical area for achieving interoperability between satellite control networks is the means chosen to interconnect Satellite Operations Centers and remote antenna systems. The CCSDS Space Link Extension (SLE) services are good candidates for this purpose, but national security space activities have demanding requirements for accuracy of data transfer, controlled delay, and security, which may not be fully achievable with the existing recommendations. The US Air Force developed a test bed to evaluate the SLE protocols during live satellite contacts, for both data transfer and management functions such as scheduling, configuring ground resources, and status reporting. Performance was generally satisfactory, but several extensions were found to be necessary. The SLE services provide a promising basis for use in ground stations to support both legacy Air Force interfaces and newer standards based satellite control services.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Deutsche Telekom has been operating different communication satellites for several years. The Satellite Control Center (SCC) of Deutsche Telekom is located near Usingen, about 50 km northwest of Frankfurt/Main. The system has been under operation since the launch of the first flight model DFS in June 1989. The entire computer system was based on Digital Equipment Corporation (DEC) VAX type computers. The maintenance costs of these old Complex Instruction Sets Computers (CISC) were increased significantly during the last years. Due to the high operational costs Deutsche Telekom decided to exchange the operational computer system. Present-day information technology world uses more and more powerful Reduced Instruction Set Computers (RISC). These new designs allow operational costs to be reduced appreciably. The VAX type computers will be replaced by DEC Alpha AXP Computers. This paper describes the transition process from CISC to RISC computers in an operational realtime environment.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / In a modern ground control network for space communications, secure peer-to-peer TCP/IP network socket connections are typically used to transfer real-time telemetry and command frames between satellite operations centers and remote ground stations. Reliable and timely reconfiguration of data paths for upcoming pass supports becomes rather complex when many spacecraft and ground stations are involved. This paper describes a routing software application that was developed to facilitate switching of telemetry and command data paths between multiple ground stations and spacecraft command and control systems, and to forward telemetry streams to multiple client applications in parallel. Fully automated configuration and monitoring of the data flows is accomplished via a remote control interface that is tied into a pass scheduling system. The software is part of the SatTrack Suite and currently supports multi-mission flight operations, including those of the recently launched THEMIS constellation mission at Space Sciences Laboratory, University of California at Berkeley.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / When hundreds of millions of dollars are invested in building, launching, and command/control of modern military space systems, the developers and operators need assurance that when their system achieves orbit, it will be able to "talk" with the ground network, exchanging commands, telemetry and ranging signals. Furthermore, prior to launch they need proof of compatibility with the ground data systems, showing that operational ground-based crypto keys, database parameters, and processing software are in-fact compatible with the spacecraft. This paper describes Air Force Materiel Command (AFMC), Space & Missile Center (SMC) Detachment 2's four classes of deployable test assets, emphasizing deployable's contribution to successful on-orbit performance. With not only the huge dollar investment, but even more important, the ability to execute a vital test or operational mission riding on compatibility, and launch vehicle and on-orbit test and evaluation operations the watchwords are "Don't leave the pad without it."