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Environment

April 1, 2020

Small Packages, Big Missions. Simulation Testing of CubeSats Before Launch is Critical

Hundreds, thousands of tiny satellites no bigger than a breadbox orbit the Earth, gathering a staggering amount of data and relaying petabytes of communication. These nanosatellites, commonly called cubesats, serve a variety of research and, increasingly, commercial roles. They work for science, exploration, technology development, education, telecommunications and other operations.

They are built to a standard dimension of 10 cm x 10 cm x 10 cm, or small multiples thereof. Typical weight is less than 1.33 kg (3 lbs) per U, or Unit, which equals on 10 cm cube.

Among other launch opportunities, the National Aeronautics and Space Administration’s (NASA’s) CubeSat Launch initiative (CSLI) can give a ride up to small satellites as auxiliary payloads on planned rocket missions.

To meet performance requirements, commercial cubesats must often report from a precisely known location. Faulty positioning can produce inaccurate data that will adversely affect commercial operations on Earth. Cubesats typically carry a commercial GPS L1 receiver to determine their orbit, as altitude and orbit determination and control form key parameters.

Cubesats often fly in formation and wil then use a GPS/GNSS receiver to co-ordinate and synchronize among themselves. Finally, they use GNSS for onboard synchronization of operations and for precise timestamping of Earth observation data

Though small is size, cubesats can carry a large price tag, up to hundreds of thousands of dollars per project. Pre-launch testing for quality assurance is critical, particular of the satellites’ PNT capabilities. Earth-bound testing cannot replicate the conditions of low-Earth orbit, where the satellites will be moving at several kilometers per second, and need to maintain awareness of the also moving GNSS satellites above them in mid-Earth orbit. Thus the key role of GNSS simulation in this burgeoning industry.

The content of this article is largely drawn from a blog post by Talini Pinto Jayawardena, a space science technologist with Spirent Communications, and also a research manager at the University of Bath. To read her full blog, which contains a detailed description of key performance criteria to test with a simulator, visit here.

Extensive discussion of Doppler shift handling, precise orbit determination, antenna performance, time synchronization, special events, onboard interference handling, and the impact of environmental test (vibration and thermal vacuum) is presented.

 

By Inside GNSS
February 5, 2020

European Space Agency Looks at 2020

European Space Agency (ESA) top brass welcomed journalists to the Agency’s headquarters in Paris for its annual New Year’s press launch. On hand was the Director General as well as ESA’s Galileo guru Paul Verhoef, who spoke one-on-one with Inside GNSS.

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By Peter Gutierrez
January 8, 2020

HxDR: New Vision of Digital Reality at CES 2020

A new cloud-based, digital reality visualization platform in the Hexagon AB booth captured the attention of CES 2020 visitors in Las Vegas this week. HxDR creates accurate digital representations of the real world through the seamless combination of reality-capture data from airborne, ground and mobile sensors.

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By Inside GNSS
December 18, 2019

New Ionospheric Model for Galileo Users

A version of the NeQuick G ionospheric model algorithm to help single-frequency receivers to estimate and correct for the ionospheric propagation delay  is now available for download from the Galileo Service Center (GSC) website). Using a new coding approach, this version is the result of intensive effort by engineers at the EU’s Joint Research Centre.

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By Inside GNSS
July 10, 2018

Harris Corp. Delivers Advanced Environmental Monitoring Sensor for Japanese Satellite

Harris Corporation has delivered an environmental monitoring sensor for the Greenhouse Gases Observing Satellite-2 (GOSAT-2), which will significantly enhance Japan’s ability to monitor greenhouse gases from space.

The Harris-built TANSO-FTS-2 (Thermal and Near Infrared Sensor for Carbon Observation-Fourier Transform Spectrometer-2) will measure greenhouse gases in the atmosphere. The newly built instrument will collect high-spectral resolution data of the Earth in five bands, which enables measurement during daylight and darkness. The instrument’s unique intelligent pointing system identifies, in real time, cloud-free areas of the atmosphere – greatly increasing the amount of useable data, according to the company.

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By Inside GNSS
May 25, 2018

EU’s Green Week Brings Focus to GNSS and Protecting Our Environment

In recent years there has been plenty of talk about Smart Cities, including numerous lectures on the topic at a variety of GNSS conferences including multiple Institute of Navigation meetings. The benefits delivered by these Smart Cities range from improved safety, efficiencies in transportation and deliveries, reduced traffic congestion and improved environmental effects.

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By Stan Goff
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