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At least 19 records

Experience with the EURECA Packet Telemetry and Packet Telecommand system

The European Retrieval Carrier (EURECA) was launched on its first flight on the 31st of July 1992 and retrieved on the 29th of June 1993. EURECA is characterized by several new on-board features, most notably Packet telemetry, and a partial implementation of packet telecommanding, the first ESA packetised spacecraft. Today more than one year after the retrieval the data from the EURECA mission has to a large extent been analysed and we can present some of the interesting results. This paper concentrates on the implementation and operational experience with the EURECA Packet Telemetry and Packet Telecommanding. We already discovered during the design of the ground system that the use of packet telemetry has major impact on the overall design and that processing of packet telemetry may have significant effect on the computer loading and sizing. During the mission a number of problems were identified with the on-board implementation resulting in very strange anomalous behaviors. Many of these problems directly violated basic assumptions for the design of the ground segment adding to the strange behavior. The paper shows that the design of a telemetry packet system should be flexible enough to allow a rapid configuration of the telemetry processing in order to adapt it to the new situation in case of an on-board failure. The experience gained with the EURECA mission control should be used to improve ground systems for future missions.

Sorensen, Erik Mose

Packet telemetry and packet telecommand - The new generation of spacecraft data handling techniques

Because of rising costs and reduced reliability of spacecraft and ground network hardware and software customization, standardization Packet Telemetry and Packet Telecommand concepts are emerging as viable alternatives. Autonomous packets of data, within each concept, which are created within ground and space application processes through the use of formatting techniques, are switched end-to-end through the space data network to their destination application processes through the use of standard transfer protocols. This process may result in facilitating a high degree of automation and interoperability because of completely mission-independent-designed intermediate data networks. The adoption of an international guideline for future space telemetry formatting of the Packet Telemetry concept, and the advancement of the NASA-ESA Working Group's Packet Telecommand concept to a level of maturity parallel to the of Packet Telemetry are the goals of the Consultative Committee for Space Data Systems. Both the Packet Telemetry and Packet Telecommand concepts are reviewed.

Hooke, A. J.

Packet Telemetry and Packet Telecommand

Two communication protocols for telemetry and telecommand reduce amount of required hardware and software and facilitate bidirectional information exchange.

Hooke, A. J.

A packet telemetry system employing ARQ error control

A proposed packet telemetry system employing automatic retransmission request (ARQ) mode of error control is characterized. Limitations of the present multiplexing/demultiplexing approach are considered, and the use of the proposed system in near-earth satellites in the 1980s is suggested. Onboard processing and an adaptive multiplexing technique are described, as is an elastic buffer, required because the instantaneous data rate will be different from the telemetry transmission rate. The telemetry packets would be encoded into a powerful error-detection block code. A mechanism involving temporary buffering in a long shift register will permit retransmission request from the ground station for packets received in error. The ARQ mode of operation should ensure essentially error-free transmission at lower signal-to-noise ratios and at considerably higher transmission rates than are usually used.

Greene, E. P.

Application of CCSDS packet telemetry recommendations by JPL

The Consultative Committee for Space Data Systems (CCSDS) has adopted three Recommendations dealing with telemetry for conventional missions: Packet Telemetry, Telemetry Channel Coding and Time Code Formats. The currently flying JPL spacecraft were designed prior to the adoption of these Recommendations. Future JPL missions will be compatible, as will the Deep Space Network and Space Flight Operations Center. This paper discusses ways in which application of the Recommendations causes or allows functions to be done differently from previous JPL projects, including the impact on timing and on telemetry adaptability.

Moyd, K. I.

Ground equipment for the support of packet telemetry and telecommand

This paper describes ground equipment for packet telemetry and telecommand which has been recently developed by industry for the European Space Agency. The architectural concept for this type of equipment is outlined and the actual implementation is presented. Focus is put on issues related to cross support and telescience as far as they affect the design of the interfaces to the users of the services provided by the equipment and to the management entities in charge of equipment control and monitoring.

Hell, Wolfgang

Flight and ground packet telemetry systems activities at NASA's Goddard Space Flight Center

NASA's Goddard Space Flight Center (GSFC) has the responsibility for the telemetry ground data processing for two current spacecraft which use packet telemetry. These spacecraft are the Hubble Space Telescope (HST) and the Gamma Ray Observatory (GRO). GSFC has designed and built two ground systems to meet this responsibility. The first is the HST DATA Capture Facility (DCF), which has now completed its integration and test phase and is supporting spacecraft and data flow tests. The second is the Packet Processor System (Pacor). This system became operational in July 1987. These systems are known generally as Level Zero Processors. Level Zero Processors ingest telemetry composite bit streams, output selected user specific data in real time, and in a batch mode perform all necessary processing to produce individual user data files which are, within the limits of the quality of the received data, contiguous, complete, ordered and nonredundant.

Carper, Richard D.

The experiment of CCSDS packet telemetry using a highly elliptical orbit satellite 'Hiten'

This paper describes the outline of the telemetry scheme proposed by the Consultative Committee of Space Data Systems (CCSDS), and the on-orbit experiment which was carried out to show the applicability of the CCSDS packet telemetry scheme using the Japan's satellite Hiten in a highly elliptical orbit. The telemetry data which are generated by the instruments are packetized in Hiten and reformed to the original data in earth stations successfully. The experimental results showed that the standardized scheme is helpful in allowing for tracking cross support between organizations, and the concatenated code is quite effective to transmit data in a low C/N condition.

Takano, Tadashi

Packet telemetry - A possible standard protocol for spacecraft data handling

Packetized telemetry-handling offers an opportunity to standardize major portions of the spacecraft-to-ground interface for future NASA missions. An end-to-end packet transport protocol is proposed which enables delivery of telemetry data from a remote space sensor to a ground-based user with virtually no project-unique intermediate processing. This paper reviews the possibility of creating a single telemetry format standard for both deep-space and near-earth missions. The proposed standard addresses the greatest NASA problem of the coming decade - cost - by allowing telemetry streams from many inflight spacecraft to be handled on the ground by common, simple, multimission processing elements.

Greenberg, E.

Telemetry packetization for improved mission operations

The requirements for mission-operations data management will accelerate sharply when the Space Transportation System (i.e., Space Shuttle) becomes the primary vehicle for research from space. These demands can be satisfied most effectively by providing a higher-level source encoding function within the spaceborne vehicle. An Instrument Telemetry Packet (ITP) concept is described which represents an alternative to the conventional multiplexed telemetry frame approach for acquiring spaceborne instrument data. By providing excellent data-integrity protection at the source and a variable instrument bandwidth capability, this ITP concept represents a significant improvement over present data acquisition procedures. Realignments in the ground telemetry processing functions are described which are intended to take advantage of the ITP concept and to make the data management system more responsive to the scientific investigators.

Greene, E. P.

Standard services for the capture, processing, and distribution of packetized telemetry data

Standard functional services for the capture, processing, and distribution of packetized data are discussed with particular reference to the future implementation of packet processing systems, such as those for the Space Station Freedom. The major functions are listed under the following major categories: input processing, packet processing, and output processing. A functional block diagram of a packet data processing facility is presented, showing the distribution of the various processing functions as well as the primary data flow through the facility.

Stallings, William H.

The ESA standard for telemetry and telecommand packet utilisation: PUS

ESA has developed standards for packet telemetry and telecommand, which are derived from the recommendations of the Inter-Agency Consultative Committee for Space Data Systems (CCSDS). These standards are now mandatory for future ESA programs as well as for many programs currently under development. However, while these packet standards address the end-to-end transfer of telemetry and telecommand data between applications on the ground and Application Processes on-board, they leave open the internal structure or content of the packets. This paper presents the ESA Packet Utilization Standard (PUS) which addresses this very subject and, as such, serves to extend and complement the ESA packet standards. The goal of the PUS is to be applicable to future ESA missions in all application areas (Telecommunications, Science, Earth Resources, microgravity, etc.). The production of the PUS falls under the responsibility of the ESA Committee for Operations and EGSE Standards (COES).

Kaufeler, Jean-Francois

Data transport concepts for future NASA spacecraft

The anticipated increase in data quantity from NASA spacecraft over the next decade is expected to far exceed the capability of the present NASA data/information system to effectively manage and process that data. Conceptual designs aimed at providing more responsive and cost-effective methods for transporting and interpreting space-generated data are presented. Details of the Modular Data Transport System (MDTS) and Ancillary Data and Support Computing (ADSC) efforts done under the NASA End-to-End Data System (NEEDS) program are discussed. The common 'thread' throughout the data transport process involves the use of packet telemetry. Characteristics and benefits of packet telemetry are presented along with a discussion of techniques for generating and advantages of including ancillary data in each packet.

Lord, D. D.

Impact of advanced onboard processing concepts on end-to-end data system

An investigation is conducted of the impact of advanced onboard data handling concepts on the total system in general and on ground processing operations, such as those being performed in the central data processing facility of the NASA Goddard Space Flight Center. In one of these concepts, known as the instrument telemetry packet (ITP) system, telemetry data from a single instrument is encoded into a packet, along with other ancillary data, and transmitted in this form to the ground. Another concept deals with onboard temporal registration of image data from such sensors as the thematic mapper, to be carried onboard the Landsat-D spacecraft in 1981. It is found that the implementation of the considered concepts will result in substantial simplification of the ground processing element of the system. With the projected tenfold increase in the data volume expected in the next decade, the introduction of ITP should keep the cost of the ground data processing function within reasonable bounds and significantly contribute to a more timely delivery of data/information to the end user.

Sos, J. Y.

Process and methodology of developing Cassini G and C Telemetry Dictionary

While the Cassini spacecraft telemetry design had taken on the new approach of 'packetized telemetry', the AACS (Attitude and Articulation Subsystem) had further extended into the design of 'mini-packets' in its telemetry system. Such telemetry packet and mini-packet design produced the AACS Telemetry Dictionary; iterations of the latter in turn provided changes to the former. The ultimate goals were to achieve maximum telemetry packing density, optimize the 'freshness' of more time-critical data, and to effect flexibility, i.e., multiple AACS data collection schemes, without needing to change the overall spacecraft telemetry mode. This paper describes such a systematic process and methodology, evidenced by various design products related to, or as part of, the AACS Telemetry Dictionary.

Kan, Edwin P.

TDA Assessment of Recommendations for Space Data System Standards

NASA is participating in the development of international standards for space data systems. Recommendations for standards thus far developed are assessed. The proposed standards for telemetry coding and packet telemetry provide worthwhile benefit to the DSN; their cost impact to the DSN should be small. Because of their advantage to the NASA space exploration program, their adoption should be supported by TDA, JPL, and OSTDS.

Posner, E. C.

The CCSDS return all frames Space Link Extension service

Existing Consultative Committee for Space Data Systems (CCSDS) Recommendations for Telemetry Channel Coding, Packet Telemetry, Advanced Orbiting Systems, and Telecommand have facilitated cross-support between Agencies by standardizing the link between spacecraft and ground terminal. CCSDS is currently defining a set of Space Link Extension (SLE) services that will enable remote science and mission operations facilities to access the ground termination of the Space Link services in a standard manner. The first SLE service to be defined is the Return All Frames (RAF) service. The RAF service delivers all CCSDS link-layer frames received on a single space link physical channel. The service provides both on-line and off-line data transfer modes to accommodate the variety of access methods typical of space mission operations. This paper describes the RAF service as of the Summer of 1994. It characterizes the behavior of the service as seen across the interface between the user and the service and gives an overview of the interactions involved in setting up and operating the service in a cross-support environment.

Uhrig, Hans

Phoenix Telemetry Processor

Phxtelemproc is a C/C++ based telemetry processing program that processes SFDU telemetry packets from the Telemetry Data System (TDS). It generates Experiment Data Records (EDRs) for several instruments including surface stereo imager (SSI); robotic arm camera (RAC); robotic arm (RA); microscopy, electrochemistry, and conductivity analyzer (MECA); and the optical microscope (OM). It processes both uncompressed and compressed telemetry, and incorporates unique subroutines for the following compression algorithms: JPEG Arithmetic, JPEG Huffman, Rice, LUT3, RA, and SX4. This program was in the critical path for the daily command cycle of the Phoenix mission. The products generated by this program were part of the RA commanding process, as well as the SSI, RAC, OM, and MECA image and science analysis process. Its output products were used to advance science of the near polar regions of Mars, and were used to prove that water is found in abundance there. Phxtelemproc is part of the MIPL (Multi-mission Image Processing Laboratory) system. This software produced Level 1 products used to analyze images returned by in situ spacecraft. It ultimately assisted in operations, planning, commanding, science, and outreach.

Stanboli, Alice