User manual RAYSTAR 112 GPS

[. . . ] Distributed by Any reference to Raytheon or RTN in this manual should be interpreted as Raymarine. The names Raytheon and RTN are owned by the Raytheon Company. GPS SENSOR OPERATION MANUAL RAYSTAR 112 Installation and Operation Handbook RAYSTAR 112 GPS SENSOR Owner/Installation Manual PURPOSE This manual contains very important information on the installation, operation, and maintenance of your new equipment. In order to get the best results in operation and performance, please take the time to read this manual thoroughly. IMPORTANT NOTICE This device is only an aid to navigation. Its accuracy can be affected by many factors, including equipment failure or defects, environmental conditions and improper handling or use. [. . . ] The C/A ID code permits the user to identify particular satellites and, in some cases, to determine and select the "best satellites" to use in position calculations. If it were possible to measure true satellite ranges directly, it would only be necessary to track data from any two satellites to obtain a vessel's latitude/longitude. In actual practice, for marine navigation, the receiver must lock onto and track a minimum of three satellites in order to resolve timing errors, including the receiver's own internal clock timing bias error which must be factored into the various range calculations. Chapter 1: Introduction 3 Normally the Raystar 112 tracks up to 12 satellites (if visible) and uses all tracked satellites for calculating position fixes. By using these satellites, the processor can determine the amount of clock errors in each range calculation. The receiver subtracts the error bias equally from each range solution until the lines of position (LOP's) intersect. Theoretically, this process can produce highly accurate latitutde/ longitude (L/L) position fixes for navigation within +/- 15m (rms). Continuous tracking of each satellite allows the receiver to perform this timing adjustment process and to calculate accurate measurements to the satellites. The Raystar 112 uses a 12 channel receiver. This sensor design method provides fast efficient acquisition and accurate position updating, even when satellites are obstructed from view. The US Department of Defense, for security reasons, has included a special mode in the GPS satellite system design which introduces variable timing errors into the satellite signals. This mode is known as "Selective Availability" (SA), and when it is enabled, is designed to provide less accurate fixes for all users (except military users). Accuracy in the order of +/- 100 Meters (rms) 95% of the time is obtained when SA is ON. This means that 95% of the time the actual ship's GPS Lat/ Long position will be within a radius of 100 meters (+/- one football field) and 5% of the time the actual position will be out of this 100 meter circle. Selective Availability has been enabled almost continuously since early 1991. The use of Differential GPS technology can remove most of these intentionally induced errors in the GPS satellite signals due to the "Selective Availiblity" mode including errors that can result due to environmental conditions as the satellite signals travel to earth. When you attach Raytheon's Differential Beacon Receiver to the Raystar 112 GPS sensor, the GPS differential corrections can improve the L/L 4 RAYSTAR 112 Installation and Operation Handbook position output accuracy of the Raystar 112 from +/- 100 meters down to 5 to 8 meters in most cases. The Raystar 112 provides NMEA 0183 formatted data at its output as follows: RMC GLL VTG GGA GSA GSV Combines position, course, and speed Vessel's Latitude/Longitude position Course over the ground, Speed over ground Ships L/L position & satellite status information Active satellites and DOP Satellites in view This data can be supplied to plotters, fishfinders, radars, integrated systems, etc. , which are set up to use these sentences from the NMEA 0183 format. The base of the sensor has a slot cut into it so that the prewired cable can be fed externally of the mount or extension mast if so desired. If the connector is removed, the cable can be fed down through the extension mast or mount, exiting through the mount assembly. The aluminium base of your Raystar 112 Sensor has received a chromation treatment which adds toughness, resistance to wear and tear, and resistance to corrosion of the assembly. Prior to attaching the GPS sensor to the mount, we do recommend that a light coating of the silicon grease be applied th the surface of the threads of the sensor and mount. Screw the antenna onto the mount fully by hand while paying attention to avoid curling, tight loops, and kinking of the cable. When the unit is fully threaded on the mount use a proper sized spanner wrench and protective cloth to grip the base and snug the sensor to the mount. If the cable is fed internally through an extension mast, it is recommended that the cable slot in the sensor base assembly be sealed with RTV silicon sealant as protection from the environment. If Chapter 2: Installation 7 the cable is fed externally through the slot, the cable should be tyrapped or clamped at the base. Then the slot in the base should be sealed with RTV silicon sealant. [. . . ] If operating this unit with other navigation equipment, refer to the equipment users manual for instructions on set-ups or programming to select and receive external data inputs into those equipments. Chapter 4: Maintenance 13 Chapter 4: Maintenance 4. 1 General Maintaining satisfactory operation of your Raystar 112 can depend on how well you care for the equipment. The simple maintenance tips that follow can save you time and money, as well as prevent unnecessary premature failures when the unit is most needed. Note: Periodically check system hardware. Inspect the sensor, mount, and cables, making sure all components are free of corrosion and are securely mounted. Examine the cable for evidence of chafing or abrasions. [. . . ]