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PATTERNS: Panoptic Aspect Time Triggered Ethernet Robust Network Scheduler, Version 1.0

Lyndon B. Johnson Space Center, Houston, Texas The PATTERNS scheduling tool was created to test the multi-plane concept of a Time Triggered Ethernet (TTE) network. The TTE network interface cards used in the Orion vehicle contain three physical network ports, referred to as planes. Each plane exists to serve as a redundant communication channel for each link in the network. The scheduler used prior to PATTERNS was the vendorprovided demonstration tool, TTE-demo-scheduler, which was unable to schedule Ethernet traffic in a manner that would allow the plane-specific and plane-independent tests required to be performed.

Posted in: Electronics & Computers, Articles, Briefs, TSP

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Electromagnetic Waves Transformed from a Coherent to a Quasi-Coherent Nature

NASA’s Jet Propulsion Laboratory, Pasadena, California The transformation of naturally occurring electromagnetic waves called “chorus” from a coherent nature to a quasi-coherent nature when propagating a distance from its source was demonstrated. The aim of the mission was to study the energizing of electrons by the waves and also the loss of these particles by interaction with the waves. Both of these processes will be affected by the quasi-coherent nature of chorus. This work indicates that if coherent waves are not propagated in enhanced ionization ducting, the waves will become only quasi-coherent, and their effect of scattering trapped particles will be substantially diminished.

Posted in: Electronics & Computers, Articles, Briefs

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An Earth-Observing, Frequency-Agile Radar Receiver for RFI Mitigation

Applications include automotive collision-avoidance radar, cellular phone networks, and radar surveillance sensors for unmanned vehicles. NASA’s Jet Propulsion Laboratory, Pasadena, California The Soil Moisture Active Passive (SMAP) mission will have the first L-band radar/radiometer sensor suite dedicated to global measurements of soil moisture. For the radar sensor, the requirements for achieving high backscatter measurement accuracy from low-Earth orbit present a unique design challenge in the presence of terrestrial radio frequency interference (RFI). The SMAP radar shares the same 1,215 to 1,300 MHz spectrum used by high-power ground-based transmitters like air-route and defense surveillance radars, which can generate strong interference in a conventional fixed-frequency spaceborne radar. The noisy ground environment motivated the development of a frequency-hopping (self-tuning) feature in the radar design. As the SMAP spacecraft orbits across various regions of the Earth, the radar continually adjusts its RF operating frequency to quieter areas of the spectrum for improved fidelity in soil-moisture science data observations.

Posted in: Electronics & Computers, Articles, Briefs, TSP

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Wireless Electrical Devices Using Floating Electrodes

Langley Research Center, Hampton, Virginia A wireless, connection-free, open circuit technology can be used for developing electrical devices like sensors that need no physical contact with the properties being measured. At the core of the technology is the SansEC (Sans Electrical Connections) circuit that is damage-resilient and environmentally friendly to manufacture and use.

Posted in: Electronics & Computers, Sensors, Articles, Briefs, TSP

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Web-Enabled and Automatic Ground Processing Infrastructure Servicing the UAVSAR Airborne Missions

NASA’s Jet Propulsion Laboratory, Pasadena, California The UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) ground data processing infrastructure facilitates a wide range of mission operational processes through a centralized database, Web-enabled interfaces, and background automation. By tracking flight request submissions and flight planning activities, the database provides the most up-to-date historical records on how and when flight missions took place, as well as what radar data were collected. As data-collection missions wrap up, post-mission reports are uploaded to the database via a Web interface, while raw data are scanned into the database enabling the operator to perform polarimetric/interferometric processing on the radar data.

Posted in: Electronics & Computers, Data Acquisition, Aviation, Articles, Briefs, Aeronautics

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Technology-Independent RHBD Library Through Gate Array Approach

All gates in the library are based on one common cell. Goddard Space Flight Center, Greenbelt, Maryland As semiconductor technology nodes scale down, the limitation on polysilicon pitch makes it almost impossible to shrink libraries built for previous technologies. To design a library for a new technology, all of the cells have to basically start from scratch. Starting over for each technology node shrink is time-consuming and expensive. Further, obtaining space qualification for a technology node will require significant time and money. If a RHBD (radiation-hardened-by-design) library gates invention shares the same transistor structured as the SASIC (Structured Application-Specific Integrated Circuit), it will benefit from the existing qualification effort and high-performance advanced technology of the SASIC design flow.

Posted in: Electronics & Computers, Briefs, TSP

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Advanced Pulse Compression System and Testbed

Industrial applications include 3D machine vision systems that rely on radar for target identification and obstacle avoidance. Goddard Space Flight Center, Greenbelt, Maryland Detection of low-level water clouds from space is one of the outstanding challenges in radar remote sensing. Spaceborne remote sensing is the only means of assessing the distribution and variability of cloud cover on a global basis. Uncertainties in models of the Earth’s heating budget will persist until CloudSat and follow-on missions such as ACE (Advanced Composition Explorer), with enhanced radar capabilities, complete their missions. Detecting weak scatters at lower altitudes presents significant challenges. Millimeter-wave radars offer the only chance to measure these scatters from space. Unfortunately, the peak power available at Ka and W-band — desirable wavelengths for cloud remote sensing — does not provide adequate sensitivity at the resolution required. For many spaceborne radars, pulse compression techniques are used to overcome the limitations in peak power and take advantage of the average power available. But the backscatter from clouds, even at W-band, can be 7 to 8 orders of magnitude weaker than the surface backscatter. In order to use pulse compression techniques, peak range sidelobes need to be suppressed by upwards of 80 dB.

Posted in: Electronics & Computers, Briefs, TSP

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