21. Common Reference System; Installation Of System; Reference Management - Furuno FCR-2107 Operator's Manual

21. Common Reference System

21.1

Installation of System

Note 1: Special attention of following topics is required to maintain "Common Reference System"
Note 2:: Origin of common reference system is the conning position on vessel.
• The values of center and conning positions depend on size and geometry of the ship. .
• Offsets from antenna position to conning position of position sensors depend on the location of position sensor
antennas.
Offsets from antenna position to conning position of radars depend on the location of radar antennas.
21.2

Reference Management

This radar is designed to comply with IEC 62388. The expected tolerance of the chart to radar picture is as shown
below.
Measuring conditions
Own ship position: North latitude, less than 70°, South latitude, less than 70°
Measuring range: 24 nm
Target range: 10-24 nm
Target bearing: ±5° bearing tolerance on 45°, 135°, 225° and 315°.
Maximum error range
Range error: Less than 0.25 nm
Bearing error: Less than 1.0°
Note however that the following items must be properly adjusted to meet above conditions.
• Timing (Tx timing of radar echo). The procedure for adjustment is shown in "Adjustment of Sweep Timing" in
the Installation Manual.
• Heading (Adjustment of radar echo heading). The procedure for adjustment is shown in s "Heading Alignment"
in the Installation Manual.
• Radar ANT position (Center of radar image is the radar antenna position). Radar antenna position is input in
the initial settings.
• Conning position
• The chart radar uses position data fed from a GPS navigator to calculate the latitude and longitude position
of the conning position.
• GPS antenna position and conning position are entered in the initial settings to calculate offset.
• The latitude and longitude position displayed at the upper right side of the screen is the latitude and
longitude position of the conning position.
• The latitude and longitude position shown on the SENSORS dialog box is raw position data fed from a GPS
navigator.
• The chart datum used by the chart radar is recorded in geodetic datum WGS-84; therefore, the geodetic
datum setting on the GPS navigator must be WGS-84.
• The center position of the range rings, EBL and VRM is the conning position; therefore their center position
is different from the center position of the radar image.
• The calculation reference for TT and AIS bearing and range, CPA, TCPA, etc. is the conning position.
21-1