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Results for “deep space telemetry”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Effects of correlated noise on the full-spectrum combining and complex-symbol combining arraying techniques

The process of combining telemetry signals received at multiple antennas, commonly referred to as arraying, can be used to improve communication link performance in the Deep Space Network (DSN). By coherently adding telemetry from multiple receiving sites, arraying produces an enhancement in signal-to-noise ratio (SNR) over that achievable with any single antenna in the array. A number of different techniques for arraying have been proposed and their performances analyzed in past literature. These analyses have compared different arraying schemes under the assumption that the signals contain additive white Gaussian noise (AWGN) and that the noise observed at distinct antennas is independent. In situations where an unwanted background body is visible to multiple antennas in the array, however, the assumption of independent noises is no longer applicable. A planet with significant radiation emissions in the frequency band of interest can be one such source of correlated noise. For example, during much of Galileo's tour of Jupiter, the planet will contribute significantly to the total system noise at various ground stations. This article analyzes the effects of correlated noise on two arraying schemes currently being considered for DSN applications: full-spectrum combining (FSC) and complex-symbol combining (CSC). A framework is presented for characterizing the correlated noise based on physical parameters, and the impact of the noise correlation on the array performance is assessed for each scheme.

Vazirani, P.↗
NASA NTRS1993

Cryogenic, low-noise high electron mobility transistor amplifiers for the Deep Space Network

The rapid advances recently achieved by cryogenically cooled high electron mobility transistor (HEMT) low-noise amplifiers (LNA's) in the 1- to 10-GHz range are making them extremely competitive with maser amplifiers. In order to address future spacecraft navigation, telemetry, radar, and radio science needs, the Deep Space Network is investing both maser and HEMT amplifiers for its Ka-band (32-GHz) downlink capability. This article describes the current state cryogenic HEMT LNA development at Ka-band for the DSN. Noise performance results at S-band (2.3 GHz) and X-band (8.5 GHz) for HEMT's and masers are included for completeness.

Bautista, J. J.↗
NASA NTRS1995

Incorporating CCSDS telemetry standards and philosophy on Cassini

The Cassini project at the Jet Propulsion Laboratory (JPL) is implementing a spacecraft telemetry system based on the Consultative Committee for Space Data Systems (CCSDS) packet telemetry standards. Resolving the CCSDS concepts with a Ground Data System designed to handle time-division-multiplexed telemetry and also handling constraints unique to a deep-space planetary spacecraft (such as fixed downlink opportunities, small downlink rates and requirements for on-board data storage) have resulted in spacecraft and ground system design challenges. Solving these design challenges involved adapting and extending the CCSDS telemetry standards as well as changes to the spacecraft and ground system designs. The resulting spacecraft/ground system design is an example of how new ideas and philosophies can be incorporated into existing systems and design approaches without requiring significant rework. In addition, it shows that the CCSDS telemetry standards can be successfully applied to deep-space planetary spacecraft.

Day, John C.↗
NASA NTRS1973

Nonlinear analysis of phased-locked loops with rapidly varying phase

The performance of command and telemetry systems, useful in deep-space communications, is frequently affected by the radio-frequency phase error which is introduced at the point of reception by means of the carrier tracking loop. In low data rate communications, this phase error may vary rapidly over the duration of the signaling interval. In this paper such phase variation is characterized by a sinusoidal input phase, K sin (omega sub o t+, pi/6), which models a typical phase variation in communication over turbulent media. Conditions for synchronization stability and the acquisition behavior are examined by detailed computer study of the phase-plane trajectories for the second and third-order loops with perfect integrator. It is demonstrated that for the phase variation considered the third-order loop has no real advantage over the second-order loop. Finally, it is shown that nonzero initial conditions may result in large steady-state phase error.

Chen, C.↗
NASA NTRS1977

Baseband recording and playback

Analog recordings of spacecraft telemetry signals are made by Deep Space Network Deep Space Stations to provide backup for both spacecraft and ground station anomalies. The requirements that must be met to insure successful baseband recording and playback are given. Recording and playback procedures are developed to insure that these requirements are met and performance results from tests conducted at the Compatibility Test Area (JPL) are tabulated.

Kent, S. S.↗
NASA NTRS1982

Deep Space Telecommunications Systems Engineering

Descriptive and analytical information useful for the optimal design, specification, and performance evaluation of deep space telecommunications systems is presented. Telemetry, tracking, and command systems, receiver design, spacecraft antennas, frequency selection, interference, and modulation techniques are addressed.

Yuen, J. H.↗
NASA NTRS1983

Deep space telecommunication systems engineering

Descriptive and analytical information useful for the optimal design, specification, and performance evaluation of deep space telecommunications systems is presented. Telemetry, tracking, and command systems, receiver design, spacecraft antennas, frequency selection, interference, and modulation techniques are addressed. Previously announced in STAR as N83-22226

Yuen, J. H.↗
NASA NTRS1991

Broadcasting Satellite-3A and -3B (BS-3A and 3B)

The BS-3A and -3B will provide direct color TV broadcasting to the Japanese mainland and remote islands. The satellites will be launched from Tanegashima Space Center by a type H-1 launch vehicle. The coverage will consist of the 26-m antenna and the 34-m antenna as a backup support for the transfer and drift orbits. Maximum support will consist of one 8-hour track per station for a seven day period, plus 23 days of contingency support from all complexes. Information is given in tabular form for Deep Space Network support, frequency assignments, telemetry, command, and tracking support responsibility.

Horii, M.↗
NASA NTRS1991

Giotto Extended Mission (GEM)

The primary objectives of the Giotto Extended Mission (GEM), are to determine the composition and physical state of the Grigg Skjellerup Comet's nucleus; to determine the processes that govern the composition and distribution of neutral and ionized species in the cometary atmosphere. Giotto consists of a single European Space Agency (ESA) spacecraft that was launched in 1985 from Center Spatial Guyanis in French Guiana on an Ariane launch vehicle. After a successful launch into geostationary orbit and a heliocentric transfer trajectory, the spacecraft successfully encountered Halley's Comet in 1986. One month after encountering Halley's Comet, Mar. 1986, the spacecraft was placed in hibernation in a heliocentric orbit slightly less than 1 AU. Between Feb. and Jul. 1990 the spacecraft was successfully reactivated, checked out, and placed on a trajectory course to intercept comet Grigg Skjellerup. The spacecraft has been in hibernation since Jul. 1990. Information is presented in tabular form in the following areas: coverage goals, Deep Space Network Support, frequency assignments, telemetry, command, and tracking support responsibility.

Wilkins, D. E. B.↗
NASA NTRS1991

Goldstone Solar System Radar (GSSR)

The primary objective of the Goldstone Solar System Radar is the investigation of solar system bodies by means of Earth-based radar. Targets of primary interest include the Galilean moons, Saturn's rings and moons, and Earth-approaching asteroids and comets. Planets are also of interest, particularly Mercury and the planets to which NASA has not yet planned spacecraft visits. Based on a history of solid achievement, including the definition of the Astronomical Unit, imaging and topography of Mars, Venus, and Mercury, and contributions to the general theory of relativity, the program will continue to support flight project requirements and its primary objectives. The individual target objectives are presented, and information on the following topics are presented in tabular form: Deep Space Network support, compatibility tests, telemetry, command, and tracking support responsibility.

Renzetti, N. A.↗
NASA NTRS1991

Hubble Space Telescope (HST): Emergency support

The Hubble Space Telescope (HST) is a national facility that consists of a 2.4-m aperture Ritchey-Chretien cassegrain telescope weighing approximately 9525 kg with various energy detectors designed for the observation of IR, visible, and UV wavelengths (0.12 to 1000 microns). The HST was deployed into a 28.5-degree inclination, circular orbit, which permits a mission lifetime of 15 years. The orbit is decaying circular between 594 and 400 km x 28.5 deg; the period = 95 minutes. Information is presented in tabular form on the following areas: Deep Space Network support, frequency assignments, telemetry, command, and tracking support responsibility.

Repass, J.↗
NASA NTRS1991

International Cometary Explorer (ICE)

The primary mission objectives of the International Cometary Explorer (ICE) Comet Mission are to determine the composition and physical state of the Giacobini-Zinner Comet's nucleus; to determine the processes that governs the composition and distribution of neutral and ionized species in the cometary atmosphere; and to investigate the interaction between the solar wind and the cometary atmosphere. The spacecraft was in a halo orbit around the Sun-Earth libration point until it was moved 10 Jun. 1982 to the Earth's Geomagnetic Tail (GT). The spacecraft reached the GT in Jan. 1983 and remained there until Dec. 1983, at which time a lunar swing-by placed the spacecraft in a trajectory heliocentric orbit which encountered the comet Giacobini-Zinner in Sep. 1985. The spacecraft provided observations of solar wind upstream of Halley's Comet in 1986. Information is presented in tabular form and includes the following areas: Deep Space Network support, frequency assignments, telemetry, command, and tracking support responsibilities.

Wales, R.↗
NASA NTRS1991

International Solar Terrestrial Physics (ISTP) WIND Mission

The launch of the WIND spacecraft will place the satellite into a sunside apogee double-lunar swing-by orbit for a period of one year, after which WIND may be transferred to a Sun-Earth L1 Halo orbit. Information is presented in tabular form on the following topics: Deep Space Network support; frequency assignments, telemetry, command, and ranging.

Sanford, R.↗
NASA NTRS1991

International Solar Terrestrial Physics (ISTP) program polar mission

The polar spacecraft will be launched from Western Test Ranges (WTR) into a 2 earth radii by 9 earth radii polar orbit, with apogee near the North Pole. Information is presented on the following topics: Deep Space Network support, frequency assignments, telemetry, command, and ranging.

Sanford, R.↗
NASA NTRS1991

LANDSAT 4 and 5: Emergency

The primary purpose of LANDSAT is to study Earth resources. Each satellite contains a Thematic Mapper (TM) and a Multispectral Scanner (MSS) imaging device plus mission unique hardware. The flight profile is presented, and information is presented in tabular form on the following topics: Deep Space Network support, frequency assignments, telemetry, command, and tracking support responsibility.

Webb, W.↗