Global Navigation Satellite Systems Engineering, Policy, and Design
Valérie Renaudin’s Compass Points
Geomatics engineer Valérie Renaudin now directs a major research laboratory in Nantes, France, working on the future of personal navigation and intelligent transportation systems (ITS).
By Inside GNSS
A few studies (by universities and industry) have shown the feasibility of simulation of real-time digital intermediate frequency (IF) signals based on a graphics processor unit (GPU). And a couple of articles have also demonstrated use of a universal software radio peripheral (USRP)–based software-defined radio (SDR) as a simulator (in playback mode) in real test environments.
By Inside GNSS
Figure 1The Indian Regional Navigation Satellite System (IRNSS) is an Indian Space Research Organisation (ISRO) initiative to build an independent satellite navigation system that provides precise position, velocity, and time (PVT) to users across the Indian region.
The primary objective of IRNSS is to achieve position accuracy of 20 meters (2σ) for dual-frequency users over India and the primary service area (a region extending to about 1,500 kilometers or 930 miles).
By Inside GNSS
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.
By Inside GNSS
The House Appropriations Committee voted May 13 to cut the White House request for civil GPS funding and a number of other GPS-related program at the Dept. of Transportation.
By Inside GNSS
GPS III satellites and their new ground system, both years behind schedule and hundreds of millions of dollars over budget, still may not be on track despite corrective actions, Air Force Secretary Deborah L. James told a U.S. Senate hearing recently.
By Inside GNSS
GPS Block IIF-5 on its way from Cape Canaveral on February 20, 2014. Photo by Ben Cooper, United Launch Alliance[Updated May 26, 2015] The U.S. Air Force released a draft request for proposal (RFP) yesterday (May 13, 2015) for GPS III Launch Services, including launch vehicle production, mission integration, and launch operations. The Space Exploration Technologies Corporation — better known as SpaceX and headed by Elon Musk — may well enter the competition.
By Inside GNSS
In April, Lockheed Martin fully integrated the U.S. Air Force’s first next-generation GPS III satellite at the company’s Denver, Colorado–area satellite manufacturing facility. The first in a design block of new, more powerful and accurate GPS satellites, GPS III Space Vehicle One is now preparing for system-level testing this summer. Lockheed Martin photoLockheed Martin has finally been able to announce victory in its effort to complete integration of the first GPS Block III satellite.
Integration took place last month at the company’s GPS III Processing Facility near Denver, Colorado, bringing together the system module — which includes the navigation payload that performs the primary positioning, navigation, and timing mission — the functional bus containing the electronics that manage all satellite operations, and the propulsion core that enables the satellite to maneuver for operations on orbit.
By Inside GNSS
The House Armed Services Committee (HASC) is considering legislation that would fully authorize the White House’s funding request for GPS and possibly add provisions aimed at evaluating the new, troubled GPS ground system and pushing the Pentagon to look at a global backup for GPS.
By Inside GNSS
The Federal Aviation Administration (FAA) has awarded a $103-million contract to the Raytheon Company to maintain the GPS Wide Area Augmentation System (WAAS).
The company will develop a payload to be incorporated into a new geostationary satellite and two associated ground uplink stations to support the WAAS system within U.S. airspace. WAAS improves real-time GPS accuracy from 10 meters to about two meters by transmitting differential corrections as well as integrity messages and an additional ranging signal.
By Inside GNSS
The Air Force has sharply recast the contest to build up to 22 additional satellites to fill out the GPS III constellation, slashing the maximum funding for the first phase of a “recompete” from $200 million per award to a scant $6 million.
By Inside GNSS
The incorporation of GNSS and inertial technologies is helping drive an explosion of systems development and applications of unmanned systems. On Tuesday, September 29, Inside GNSS and NovAtel presented a 90-minute web seminar showcasing some of these applications, including the use of remote sensing technologies to assess pest populations in commercial crops and to conduct infrastructure inspections, with the aid of air and ground vehicles.
By Inside GNSS
New delays and higher costs should be expected for both the GPS III satellite program and GPS-OCX, the new GPS ground system, federal watchdogs warned in a new report.
The Government Accountability Office (GAO) said both programs are in the process of rebaselining, that is, resetting their estimated schedules and costs. In the case of the Next Generation Operational Control System (GPS OCX), which is essential for full operation of the new GPS III satellites, the changes could be significant.
By Inside GNSS
