Communications

This week's Question: The U.S. military’s Defense Advanced Research Project Agency (DARPA) unveiled plans last week to develop a "brain modem." The implantable neural interface allows wearers to transmit data from their brains to external digital devices. DARPA's goal is to achieve this communications link in...

The bit error rate (BER) is a wellunderstood metric for measuring communications system performance. When a system is not amenable to analytical performance analysis, a Monte Carlo simulation is often used to determine the performance. In such simulations, it is necessary...

Secure communication over long distances requires robust encryption. While current encryption algorithms exist using classical methods, there are no unconditionally secure methods of distributing encryption keys classically. However, by exploiting...

This software provides a portable, flexible memory testing application meeting the NASA Space Telecommunications Radio System (STRS) specification. As an STRS-compliant application, the tester application is portable to any STRS-compliant hardware/software platform. Thanks to...

Dynamic frame sizing was added to the existing AOS Packet Service FPGA implementation. This capability provides in-flight system calibration functionality, allowing the spacecraft and ground station the means to optimize a communication link by...

In high-latency, low-bandwidth networks such as those employed when communicating with an extraterrestrial object via wireless communication over hundreds or thousands of miles, it may be difficult or expensive to communicate large quantities of information in a reliable...

Secure, efficient, and effective communication is critical for the multinational Cassini mission to Saturn. Cassini teams share information through the use of internal Web pages. The challenge was to develop dynamic Web pages that did not require special understanding of HTML complexities and the...

In response to the requirements of the Space-Based Relay Study (SBRS) undertaken by NASA in 2013, as well as the Integrated Radio and Optical Communications (iROC) project being conducted by NASA Glenn Research Center (GRC) beginning in 2012, a calculation procedure was required to rapidly assess the operation of...

A new computerized tool guides stakeholders in preparing for, and recovering from, natural and man-made disasters such as the cyclones in India that knocked out swaths of the Indian Railways Network. The method, developed by Northeastern University researchers, guides stake­holders in the...

Low-Density Parity-Check (LDPC) codes are a class of forward error correction (FEC) linear block codes that provide near-capacity performance for power-efficient communications. Optimum decoding requires accurate combining ratio estimation to scale the...

GPS signals are sparse and weak at high altitudes above the GPS constellation; this includes GEO and HEO orbit regimes. Spacecraft operating here need a high-sensitivity receiver capable of acquiring and tracking these weak signals throughout their orbits. Most space GPS receivers are...

Mars rovers and other landers typically use UHF relay to return their science and engineering data to Earth. Direct-To-Earth (DTE) communications are typically used for commanding. If future UHF relay capability becomes diminished, Mars landers may be forced...

In an effort to alleviate the environmental burden of electronic devices, a team of University of Wisconsin-Madison researchers has collaborated with the Madison-based U.S. Department of Agriculture Forest Products Laboratory (FPL) to develop a semiconductor chip made almost entirely of wood.

Optical communications in terrestrial and space environments require transmitted signals on the order of 40 GHz and higher, because of the uncertain and changing transmission environments. A robust communications system is needed that will provide these frequencies and substantial discrimination between...

The TRMM (Tropical Rainfall Measuring Mission) and Terra ESMO (Earth Science Mission Operations) Ground Systems needed a method of passing scheduling data through the Goddard Mission Services Evolution Center (GMSEC) bus to other subsystems without modifying the Planning and...

An aircraft pilot would prefer to receive information on weather patterns, obstructions, and other conditions that may interfere with a flight plan, formal or informal, as the pilot’s flight proceeds, with a latency of no more than a few minutes. Learning of, and reacting to, a changing environment...

The Integrated Trending and Plotting System (ITPS) is a comprehensive tool for storage, extraction, analysis, and plots of spacecraft housekeeping telemetry data (GMSEC R3.0 — Goddard Mission Services Evolution Center). ITPS reports information to...

Silicon avalanche photodiodes (Si APDs) have low dark current and low excess noise factor, and are currently used in many of NASA’s missions. Noise equivalent power (NEP) of 40 to 50 fW/(Hz)1/2 over 140-MHz bandwidth has been demonstrated for Si APDs. Si APDs have very...

The conventional methods of improving wireless system coverage performance are to increase the transmitter power and/or antenna gain. The high transmit power could lead to more power consumption and RF exposure issues. The use of a high-gain antenna could lead...

In communications systems, there must be a method to identify the beginning of a message at the receiving end, to know when the data stream of a specified structure begins. This is conventionally done by inserting attached sync markers (ASMs) between codewords, and looking for these ASMs in the...

For effective range safety, global positioning system (GPS) metric tracking must be robust to interference with, and jamming of, GPS signals. The conventional approach to mitigating interference and jamming is to use a Controlled Reception Pattern Antenna (CRPA)....

An integrated communications and control system for unmanned aircraft systems (UAS) utilizes automatic dependent surveillance broadcast (ADS-B) technology. The prime objective of this system is to address safety concerns related to UAS sharing airspace with...