Global Navigation Satellite Systems Engineering, Policy, and Design
The satellite-based NextGen program is in trouble — no question about it.
The Federal Aviation Administration (FAA) air traffic modernization effort will likely cost triple its original $40-billion program budget and need an extra decade — until 2035 or beyond — to reach completion, according to 2014 testimony by Department of Transportation (DoT) Inspector General Calvin Scovel.
By Dee Ann Divis
SBAS and RNSS: The Unsung Heroes of GNSS
Okay, if I had wanted to pander to GNSS fans, I might have called this, “Making Great Greater.”
But there are only so many superlatives that can be lathered on this remarkable technology before simple praise turns into hagiography.
So, it’s time once more to give a little love to those unsung heroes of GNSS: the augmentations and regional navigation satellite systems.
By Inside GNSS
Europe’s space community rang in the New Year with two of its brightest annual fixtures: the European Union (EU) Space Policy conference in Brussels and the European Space Agency (ESA) media briefing in Paris.
The events brought out all of the relevant voices and served to illustrate not only the disposition of materiel and troops but also their intent and even the level of morale.
By Peter Gutierrez
Working Papers explore the technical and scientific themes that underpin GNSS programs and applications. This regular column is coordinated by Prof. Dr.-Ing. Günter Hein, head of Europe’s Galileo Operations and Evolution.
With the support of the European Space Agency (ESA), a European team designed a frequency- and time-transfer process and validated its performance in a complex navigation test bed. This two-way time-transfer technology took advantage of the following:
By Günter W. Hein
Figure 1, 3, 4 & 5Q: What is Doppler collision and is it a problem in GNSS?
A: Doppler collision is a physical effect in code-division multiple access (CDMA) systems where code measurement errors are observed due to cross-correlation effects. Doppler collision may occur when the Doppler frequency between signals from two different transmitters is smaller than the code lock loop bandwidth.
By Inside GNSS
The GPS Aided Geo Augmented Navigation (GAGAN) system was developed by the Indian Space Research Organization (ISRO), together with Airports Authority of India (AAI), to deploy and certify an operational satellite-based augmentation system (SBAS). The system’s service area covers the Indian Flight Information Region (FIR), with the capability of expanding to neighboring FIRs.
By Inside GNSS
Figures and TablesIn satellite navigation, the user receiver finds its position by measuring its distance to satellites and knowledge of the satellite position. The distance is measured by ranging, i.e., finding the delay of the signal from the transmitter to the receiver. The delay will comprise of payload hardware delay and the geometric range delay. Hence, the payload delay of the signal from generation to radiation is very important and needs to be transmitted in navigation data.
By Inside GNSS
Small GPS jammers, particularly the “personal privacy devices” readily available on the Internet, pose one of the greatest risks to the nation’s critical infrastructure, according to a now-public Homeland Security assessment.
By Dee Ann DivisFor an organization with its name, the Federal Communications Commission (FCC) is a remarkably opaque public entity.
Such is the case with the agency’s inaction on requests by foreign GNSS services to waive the so-called FCC Part 25 rules that require licensing of non-Federal receive-only Earth stations (e.g., GNSS receivers) operating with non-U.S. licensed space stations (i.e., satellites).
Although at least one such request has reportedly been submitted, the FCC has not even acknowledged it, let alone moved to render a decision on the request.
By Inside GNSS
Riley and his son, Ben.Return to main article: Stuart Riley: Right Turn from the Wrong Path
COMPASS POINTS
Professional Path
Riley received a Ph.D. in electrical engineering at the University of Leeds (United Kingdom) where he then worked as a research fellow in 1994–5. After that, he joined Trimble Navigation Ltd. as a GNSS receiver designer. He is based in Sunnyvale, California, where since 2010 he has served as the company’s engineering director
By Inside GNSS
Equations 1 – 10The constant growth and evolution of the positioning, navigation, and timing (PNT) market generate demands for more and more added-value applications and services relying on GNSS signals, with expectations for improved accuracy and availability. Some services may also rely on added-value content other than navigation messages, for example, higher data volume with less latency, such as the data carried by satellite-based augmentation system (SBAS) services and the Galileo Commercial Service.
By Günter W. Hein
Q: How Important Is It to Synchronize the Code and Phase Measurements of a GNSS Receiver?
A: Precise timing lies at the heart of GNSS implementation and operation and is generally well understood in terms of synchronizing individual satellites and/or receivers. Recent results, however, have demonstrated that timing of code and phase measurements in a receiver can have significant implications for the timing community in particular.
By Inside GNSS
Speakers at the low-in-profile but high-in-content International Association of Institutes of Navigation (IAIN) conference in Prague this year threw into stark relief some of the big GNSS programs and even bigger GNSS questions.
By Peter Gutierrez
