An AIS position report carries dynamic data such as position, position accuracy, time, course, speed and navigational status. The position and timestamp originate from the target's connected electronic position-fixing receiver. A target's AIS position is derived from its electronic position-fixing receiver and may not coincide exactly with the target detected by radar.
Poorly configured or faulty sensors can transmit incorrect position information, and the AIS built-in integrity test does not validate the truth of the sensor data. An AIS position report is not a guaranteed position; it is based on the transmitting station's data. Operators may compare the reported position with the target detected by radar to check the information.
Position reporting intervals vary by equipment class, speed, movement and reporting mode. Position reports normally arrive more often than static and voyage-related information.
