Trimble announced that it has received a contract from the U.S. Coast Guard (USCG) to provide up to 400 reference station receivers over the next three years for its Maritime Differential GPS (DGPS) Service modernization program.
The USCG’s Maritime DGPS Service provides navigation information for coastal areas, harbors and waterways in the continental U.S., the Great Lakes, Puerto Rico, portions of Alaska, Hawaii, and a greater part of the Mississippi River Basin free-of-charge. As part of the DGPS system, the Trimble® NetRS® reference station receivers will provide accurate navigation correction messages that are broadcast to recreational boaters, commercial shipping and fishing fleets, workboats and cruise ships. In addition, surveyors, mapping and Geographic Information System (GIS) professionals, environmental consultants, police and emergency response vehicles, trucking fleets, aviators and in-car navigators with differential-ready GPS equipment are capable of receiving the USCG’s broadcast signal, if they are located in established coverage areas. With DGPS, the USCG’s beacon system meets the Federal Radionavigation Plan (FRP) accuracy requirements for Harbor/Harbor Approach (HHA) navigation and international Safety of Life at Sea (SOLAS) requirements.
The Coast Guard Maritime DGPS Service, operated by NAVCEN, consists of two control centers and over 85 remote broadcast sites. The service broadcasts correction signals on marine radiobeacon frequencies to improve the accuracy and integrity of GPS-derived positions. The Coast Guard DGPS Service is required to deliver 10 meter accuracy, but typically delivers accuracies of 1-3 meters in all established coverage areas. The modernized service is expected to provide even greater accuracies. Many foreign nations are implementing and modernizing standard DGPS services modeled after the U.S. Coast Guard’s system to significantly enhance maritime safety in their critical waterways.
As part of a multi-phased modernization project, the USCG also purchased 400 Trimble Zephyr Geodetic™ antennas in 2006 along with Trimble Charisma™ software, which provides the backbone of their new DGPS radiobeacon operating architecture.
Trimble NetRS Reference Station
The NetRS is a powerful field-proven GPS receiver designed for a range of high precision and monitoring applications. The receiver offers ease of use, low power consumption, R-track™ technology for L2C signal tracking, Ethernet connectivity, advanced data management capability, and a rugged design–making it an extremely flexible product for scalable infrastructure solutions.
With Internet Protocol as the primary communications mechanism, the NetRS GPS receiver can be accessed and fully controlled remotely using simple Internet browsers or Trimble infrastructure software. The NetRS uses the Linux framework, which allows for extension and customization that is simply not possible with proprietary operating systems. Network management features of the NetRS include the ability to store one receiver’s data configuration to a file and restore it to the same receiver at a later date or clone the information to other receivers within a network. Additionally, low power consumption allows for autonomous operation from a variety of site power schemes, even in remote areas.
Multiple levels of security are possible, guarding against unwarranted access to the receiver’s configuration and files. The system can function as a completely open system allowing complete access, but can also be programmed as a fully secure system requiring encrypted access.
Trimble Charisma Software
The Trimble Charisma software is a configurable, reference station/integrity monitor architecture for SOLAS DGPS beacon applications. Inspired by the U.S. Coast Guard’s standards for modern beacon navigation systems, the Charisma software architecture provides a flexible platform for hardware, network and communications protocols. It supports redundant configurations encompassing modern GPS receivers, modulators and demodulators, and the latest broadcasting transmitters. Trimble Charisma modulates correction messages on an MSK beacon signal using industry-standard RTCM and the new RSIM 1.2 messages for increased safety at sea.