Global Navigation Satellite Systems Engineering, Policy, and Design
It is not all about the satellites, of course.
And, despite the thrill of launches — the Fourth of July and every other national holiday celebration all grown up — it’s not about the rockets.
When evaluating the progress of GNSS programs, however, satellites and launches are a way to keep count — in fact, it is the way most of us do keep count.
By that measure, then, the numbers are adding up quickly.
By Inside GNSS
Tony Russo, Director, U.S. National Space-Based PNT Coordination OfficeReturn to main article: "NaviForum Shanghai 2010"
The United States brought a strong message that it is pursuing a new direction in GNSS relations with China in presentations at the recent 2010 NaviForum Shanghai.
By Inside GNSS
FIGURE 1: Screenshot of RF simulation software showing GPS + GLONASS + Galileo constellationsIn the first article in this series (Inside GNSS, July/August, 2010) we looked at the range of tasks that require GNSS signal simulation during design, manufacturing, certification, and maintenance of GNSS equipment. The second installment (Inside GNSS, September, 2010) described a range of simulation solutions.
In this final article, we try to find a simulation solution that best suits a particular task.
By Inside GNSS
GNSS utilization of the S-band portion of the radio spectrum provides some challenges to designers of both GNSS navigation signals as well as signals used by other services, in terms of interference avoidance and signal power.
An important existing user of S-band spectrum is the Globalstar communications satellite system. The voice and data services provided by Globalstar employ the 2483.5–2500 MHz band for its satellite downlink communications to user terminals. Additionally, these satellites use multi-beam antennas to enable frequency reuse.
By Inside GNSS
A completely GPS-based navigation solution is generally not feasible in GNSS signal–challenged environments such as urban canyons. However, even in these difficult environments a partial set of GPS signal measurements may still be available. For instance, one or two satellites are generally still visible even in dense urban canyons.
By Inside GNSS
A close brush by a passing typhoon on its opening day aside, NaviForum Shanghai 2010 mustered an impressive slate of senior executives from Chinese companies working in the navigation and telematics/location based services (LBS) field.
By Inside GNSS
Return to main article: A Search for Spectrum
By Inside GNSS
