# List of Abbreviations

This section contains a list of terms and abbreviations used in the NSR ECDIS NES-3000 documentation.

| Term / Abbreviation | Definition |
|---------------------|------------|
| **AIS** | Automatic Identification System |
| **ARPA** | Automatic Radar Plotting Aid |
| **AtoN** | Aids to Navigation |
| **BNWAS** | Bridge Navigational Watch Alarm System (see Section 21 "BNWAS") |
| **BRG** | Bearing |
| **CATZOC** | Category Zone of Confidence |
| **CCRP** | Consistent Common Reference Point |
| **COG** | Course Over Ground |
| **CPA** | Closest Point of Approach |
| **CWL** | Construction Water Line |
| **DDSC** | Digital Distress Communication System |
| **DIST** | Distance |
| **DPI** | Dots Per Inch |
| **DSC** | Digital Selective Call |
| **ECDIS** | Electronic Chart Display and Information System |
| **EFPS** | Electronic Fixing and Pilotage System |
| **ENC** | Electronic Navigational Chart |
| **EUT** | Equipment Under Test |
| **GC** | Great Circle — an arc of a great circle on the Earth's sphere, known in navigation as an orthodrome |
| **GNSS** | Global Navigation Satellite System |
| **HDG** | Heading |
| **HDOP** | Horizontal Dilution Of Precision — reduction in GNSS receiver accuracy in the horizontal plane |
| **IHO** | International Hydrographic Organization |
| **IMO** | International Maritime Organization |
| **ISM** | International Safety Management Code |
| **MMSI** | Maritime Mobile Service Identity |
| **NMEA 0183** | National Marine Electronics Association — a standard defining a text-based communication protocol between marine (typically navigational) equipment |
| **RADAR** | Radio Detection and Ranging |
| **RADAR IM** | Radar Image |
| **RL** | Rhumb Line — a loxodrome, a curve crossing meridians at a constant angle |
| **RM** | Relative Motion |
| **RMS** | Root Mean Square |
| **SENC** | System Electronic Navigational Chart |
| **SW** | Software |
| **TCPA** | Time to Closest Point of Approach |
| **TM** | True Motion |
| **TRIG** | Trigger — display trigger pulse |
| **WP** | Waypoint |
| **XTD** | Cross Track Distance — deviation from the course or the distance from the vessel to the laid course line |

[^1]: In accordance with IHO S-63 requirements.
