Satellite Systems

TDMA REFERENCE TERMINAL — The TDMA Reference Terminal is a satellite network timing subsystem whose purpose is to synchronize ground station traffic terminals. This project involved the analysis, design, development and testing of embedded software that controls the RTE (Reference Terminal Equipment), satellite network control software, and data channel control software. The software, developed in C++, runs on an Intel Strong Arm SA110 processor running the VxWorks Operating System. The architecture utilizes the VxWorks TCP/IP stack and the TFTP protocol product.

BANDWIDTH ON DEMAND — The Bandwidth on Demand product is a network management system that configures and controls groups of satellite modems. Its main use is in satellite-based video teleconferencing applications. The satellite modems provide the means by which the participants in a conference can transmit and receive video and audio streams. The product includes functions that allow an operator at the control center of the satellite network to schedule conferences, ensure that the necessary bandwidth is available for the conference, and monitor the transmission facilities for failures and outages. The product runs on a Windows NT platform, uses HP Openview, and has a browser-based user interface.

MOBILE TELEPHONY SATELLITE SYSTEM — Design of the Mobile Telephony Satellite System (MTSS), which provides telephony and data services to hand-held user terminals on a global basis. Features include the use of a constellation of intermediate earth orbit satellites and a ground segment of interconnected earth stations supporting voice and data communications to the hand-held mobiles.

MULTIMEDIA SET-TOP BOX — This project is for the development of a Multimedia Set-top Box that integrates the Navio Netscape Browser, a GUI-based front-end, Satellite DirecTV, Satellite Internet, Phoenix Bios, and AC97 audio capability. The set-top box uses a Pentium-based processor with the VxWorks operating system, as well as a MIPS processor using the Cexec OS.

SATELLITE NETWORK PERFORMANCE ANALYSIS TOOL — The Performance Analysis Tool is an application that incorporates a model of a satellite network system used in providing communications between stationary users and mobile users for the purpose of assessing traffic patterns and loads on various segments of the network. The application models all components of the network which includes mobile transceivers, the Land Earth Station and its resident applications, the stationary host users, and the various message data formats and sizes propagating through the network. The application’s determination of traffic loads for specific segments of the network incorporates the overhead associated with the various protocols such as X.25, Kermit, and Standard-C. The data throughput rates for all segments, disk I/O, and processor capacity are used in determining traffic load. The final output of the application provides information for the user to develop a plan for resolving potential traffic load problems.