radar navigation chart

Radio AtoN, Radar, Gyro compass, Global Navigation Satellite System ( GNSS), Electronic Chart Display and Information System ( ECDIS), Automatic Identification System ( AIS), etc. have been applied to a large extent to ensure safety of navigation.

无线电航标、雷达、电罗经、全球导航卫星系统（GNSS）、电子海图显示与信息系统（ECDIS）、船舶自动识别系统（AIS）等的相继应用，在很大程度上保证了航海安全。

Most of the electronic sea chart navigation systems available measure the geographic coordinates of a ship by the GPS ( i.e. global position system), so that it is necessary for the electronic sea chart system to test timely the precision of the GPS by radar signals.

现有的电子海图导航系统主要靠全球定位系统（GPS）来测量舰船的地理坐标，用雷达信号适时检验GPS的定位精度就成为电子海图系统不可少的功能。