by Laura Johnson for Aerospace News
Los Angeles CA (SPX) Aug 04, 2017
The U.S. and Brazil are teaming up to study scintillation in the ionosphere, a phenomena that affects radio signals, disrupting communications and GPS navigation. Aerospace is providing a sensor for this international CubeSat mission, dubbed SPORT, that will be deployed off the International Space Station. The ionosphere is a portion of Earth's atmosphere where radiation from the sun creates a lot of electrically charged particles called plasma. The density of the plasma varies depending on the season, time of day, and other factors.
Sometimes there are density depletions near the equator known as equatorial plasma bubbles, and rapid changes in the density at the edges of the bubbles are known as scintillation. Radio signals transmitting from satellites to the ground must pass through the ionosphere and may be affected by the scintillation.
According to the National Oceanic and Atmospheric Administration, "Severe scintillation conditions can prevent a GPS receiver from locking on to the signal and can make it impossible to calculate a position. Less severe scintillation conditions can reduce the accuracy and the confidence of positioning results."
Since scintillation can adversely impact everything from GPS signals to communication to over-the-horizon radar, there has been a large amount of research trying to understand what causes scintillation, how to predict its occurrence, and how to mitigate its effects. However, the ability to predict scintillation remains elusive.
SPORT, which stands for Scintillation Prediction Observations Research Task, is an effort to study the formation and evolution of equatorial plasma bubbles which may, in turn, cause scintillation. "We want to know what are the background conditions pre-scintillation, and can we use that to determine when scintillation will occur?" said Dr. Rebecca Bishop, Aerospace's lead on this project. "That's kind of the holy grail of our whole field."
Brazil will build and operate the 6U CubeSat as well as maintain the ground observation network of radars, imagers, and scintillation monitors. On the U.S. side, NASA is coordinating the launch and the instruments that will go on the CubeSat, including Aerospace's sensor and five other instruments provided by NASA and university partners. Both Brazil and the U.S. will analyze the data and collaborate on individual studies.
"Brazil is very, very interested in scintillation," Bishop said. Due to a large part of Brazil being located near the magnetic equator, and a feature known as the South Atlantic Anomaly, Brazil experiences more scintillation than a lot of other countries.
Aerospace's contribution to SPORT is the Compact Total Electron Content Sensor (CTECS), which is a GPS radio occultation (RO) sensor. It receives the GPS signals and measures how they change as they pass through the ionosphere. From these measurements, the plasma density and a scintillation index can be extracted.
"Historically, GPS RO sensors are on the order of 5 kg and 20 watts, which is basically the same size and twice the power of a 3U CubeSat," Bishop said. "We were developing this as a low-cost, low-mass, low-power GPS RO sensor for a CubeSat."
Aerospace adapted a commercial receiver by adding special software and a custom antenna to create CTECS.
The 0.153 kg sensor will fit nicely on the SPORT CubeSat, and together with the other five instruments, contribute to the valuable data this mission will collect.
Greenbelt MD (SPX) Jul 26, 2017
A new NASA study shows that updrafts are more important than previously understood in determining what makes clouds produce drizzle instead of full-sized raindrops, overturning a common assumption. The study offers a pathway for improving accuracy in weather and climate models' treatments of rainfall - recognized as one of the greater challenges in improving short term weather forecasts an ... read more
Earth Observation News - Suppiliers, Technology and Application
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|