satellites/space segment Archives - Page 2 of 23 - Inside GNSS

satellites/space segment

September 7, 2015

GLONASS for Precise Navigation in Space

Figures and Tables

The current stage of GLONASS evolution is aimed at meeting future user requirements of which the most important is the improved accuracy of positioning.

During the implementation of the GLONASS Space Segment Modernization Program (2012–2015), the GLONASS team is facing the situation in which it is not feasible to launch new navigation satellites because the existing constellation is comprised of GLONASS-M satellites operating beyond their guaranteed design lifetime. Nine more GLONASS-M satellites are in ground storage.

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By Inside GNSS
May 20, 2015

Estimating the Short-Term Stability of In-Orbit GNSS Clocks

Global navigation satellite systems provide position, velocity, and time (PVT) solutions to users whose receivers calculate position based on one-way ranging from satellites. As is well-understood, a key step in the positioning process involves a determination of the difference between the time of signal transmission identified in the satellite’s broadcast navigation message and the time of its reception by user equipment.

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By Inside GNSS
November 17, 2014

Evaluating the Performance of Navigation Payloads

As a navigation satellite transmits multiple signals on single frequency (e.g., Open Service and Restricted Service over L5 Band), these are combined on a common carrier to comprise a composite signal. This composite signal passes through navigation payload subsystems such as an up-converter, traveling wave tube amplifier (TWTA), filters, and so on. These subsystems may introduce adverse effects on the signal, such as amplitude and phase distortion, nonlinear effects, gain imbalance, IQ imbalance, and phase noise.

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By Inside GNSS

Tracking IRNSS Satellites

Figure 2: Sky plot showing position of IRNSS and GPS satellites over Helsinki Finland on November 6, 2014 at 16:10 local time.

The Indian Regional Navigation Satellite System (IRNSS)] is designed as a stand-alone regional navigation system with a primary service area extending up to 1,500 kilometers from the Indian land mass. Finland lies north of 60°N latitude more than 5,000 kilometers away from India, as shown in Figure 1 (see photo at the top of this article).

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By Inside GNSS

Higher Aspirations for GNSS

GPS Space Service Volume (SSV) Requirements/Performance Parameters

New space missions such as the robotic repair and recovery of damaged or errant communication satellites may become possible with the aid of an emerging class of receivers that is able to use GPS signals for navigation in orbits thousands of kilometers above the middle Earth orbit (MEO) GPS constellation itself.

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By Dee Ann Divis

EU and Russia: Lost in Space?

Space business as usual — ESA Director-General Jean-Jaques Dordain addressing Munich Satellite Navigation Summit 2014 earlier this year.

Russia’s involvement in the Ukraine crisis has turned much of public opinion in the West against that country, in particular souring the relationship between the European Union (EU) and Russia. And, while the ceasefire signed in September technically is still in force, the EU-Russia rift is far from smoothed over.

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By Peter Gutierrez
July 21, 2014

GPS Receiver Performance On Board a LEO Satellite

Equation 1

The small satellite “Technologie-Erprobungs-Träger 1” (TET-1) is the first spacecraft developed for the German Aerospace Center (DLR) On-Orbit-Verification (OOV) program, which provides flight opportunities dedicated to testing and qualification of new technologies in space. The satellite was lifted into a low-Earth orbit (LEO) on July 22, 2012, from the launch site in Baikonur, Kazakhstan.

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By Inside GNSS
June 9, 2014

NavtechGPS Winter GNSS Training (Courses 123, 346 & 546)

NavtechGPS Winter GNSS Training 2014 will take place at the Bay Club Hotel and Marina in San Diego, California, December 8-11, 2014.

Register by October 15, 2014 and get a $100 Discount for 4-Day Courses.

Course 346: In-Depth GPS/GNSS Operation for Engineers & Technical Professionals: Principles, Technology, Applications and an Introduction to Basic DGPS Concepts. (4-day course)
Taught by Dr. Chris Hegarty, MITRE

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By Inside GNSS