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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

Control and Non-Payload Communications Generation 7 Prototype Radio Flight Test Report

This report presents a description and test results of a seventh-generation prototype radio developed for Control and Non-Payload Communications (CNPC) between a ground-based pilot and an unmanned aircraft. Radios were prepared under a cooperative agreement between the NASA Glenn Research Center and Collins Aerospace (formerly Rockwell Collins, Inc.) and were used to support the development and validation of air-to-ground CNPC radio system standards. The CNPC radios operated in the 5,030- to 5,091-MHz frequency range. This report describes radio waveforms, laboratory testing, flight test systems, and flight test results.

Control and Non-Payload Communications↗
NASA NTRS2016

Beaconless Pointing for Deep-Space Optical Communication

Free space optical communication is of interest to NASA as a complement to existing radio frequency communication methods. The potential for an increase in science data return capability over current radio-frequency communications is the primary objective. Deep space optical communication requires laser beam pointing accuracy on the order of a few microradians. The laser beam pointing approach discussed here operates without the aid of a terrestrial uplink beacon. Precision pointing is obtained from an on-board star tracker in combination with inertial rate sensors and an outgoing beam reference vector. The beaconless optical pointing system presented in this work is the current approach for the Integrated Radio and Optical Communication (iROC) project.

free-space optical communication↗
NASA NTRS1988

Experimental radio frequency link for Ka-band communications applications

An experimental radio frequency link has been demonstrated to provide two-way communication between a remote user ground terminal and a ground-based Ka-band transponder. Bit-error-rate performance and radio frequency characteristics of the communication link were investigated.

Fujikawa, Gene↗
NASA NTRS2019

Radio Frequency and Optical Communication Link Trade Studies Between Earth, Deep Space Gateway and Lunar Surface

Efficient and accurate communication are two of the most important aspects in a communications system. Hence, it was pertinent that radio frequency (RF) and optical link budget analyses were understood inside and out by the two young careerists when performing this study. This report covers RF and optical trade studies performed between Earth, Deep Space Gateway (DSG), Orion, and the Moon’s lunar surface. Using criteria provided by NASA Headquarters, the links were statically driven allowing review of the systems without bandwidth limitations, spectrum allocations, and hardware implementations. This provided the chance to review the efficiency of the links as technology improves throughout the decades. A few select RF links were analyzed using repeaters while select optical links were compared with coded and uncoded modulation schemes. The results from these analyses again prove the tradeoff theories in communications systems.

Booth, Stephanie L.↗
NASA NTRS1963

Millimeter waves

Millimeter waves for radio tracking and space communications

SPACE COMMUNICATION↗
NASA NTRS1965

Communicating with microwaves.

Microwave communications, discussing radio relay techniques, carrier telephony, satellite microwave communications, television, laser light wave communication, etc

MICROWAVE TRANSMISSION↗
NASA NTRS2011

Software-Defined Radio for Space-to-Space Communications

A paper describes the Space- to-Space Communications System (SSCS) Software- Defined Radio (SDR) research project to determine the most appropriate method for creating flexible and reconfigurable radios to implement wireless communications channels for space vehicles so that fewer radios are required, and commonality in hardware and software architecture can be leveraged for future missions. The ability to reconfigure the SDR through software enables one radio platform to be reconfigured to interoperate with many different waveforms. This means a reduction in the number of physical radio platforms necessary to support a space mission s communication requirements, thus decreasing the total size, weight, and power needed for a mission.

Fisher, Ken↗
NASA NTRS2006

Applications of Microwave Photonics in Radio Astronomy and Space Communication

An overview of narrow band vs wide band signals is given. Topics discussed included signal transmission, reference distribution and photonic antenna metrology. Examples of VLA, ALMA, ATA and DSN arrays are given. . Arrays of small antennas have become more cost-effective than large antennas for achieving large total aperture or gain, both for astronomy and for communication. It is concluded that emerging applications involving arrays of many antennas require low-cost optical communication of both wide bandwidth and narrow bandwidth; development of round-trip correction schemes enables timing precision; and free-space laser beams with microwave modulation allow structural metrology with approx 100 micrometer precision over distances of 200 meters.

microwave↗
NASA NTRS1982

Differentially coherent detection of QASK for frequency-hopping systems. I - Performance in the presence of a Gaussian noise environment

Bandwidth-conserving modulation techniques, which trade average power for bandwidth in a favorable exchange, have recently found widespread application in digital radio and satellite communication systems. Quadrature amplitude-shift-keying (QASK) is a particular type of the considered techniques. QASK makes use of multilevel signals to amplitude modulate the in-phase and quadrature components of a carrier. Frequency hopping (FH) is used to protect a conventional communication system from radio frequency interference (RFI) or jamming. Differentially coherent detection provides a possible solution to the effect of phase discontinuities introduced by FH. The application of such a detection technique to QASK signals is discussed. A receiver structure is proposed and its symbol error probability performance for an additive white Gaussian noise (AWGN) background is investigated.

Simon, M. K.↗
NASA NTRS2014

General Dynamic (GD) Launch Waveform On-Orbit Performance Report

The purpose of this report is to present the results from the GD SDR on-orbit performance testing using the launch waveform over TDRSS. The tests include the evaluation of well-tested waveform modes, the operation of RF links that are expected to have high margins, the verification of forward return link operation (including full duplex), the verification of non-coherent operational models, and the verification of radio at-launch operational frequencies. This report also outlines the launch waveform tests conducted and comparisons to the results obtained from ground testing.

radio communication↗