3.1. Speed analysis
3.2. Deceleration & acceleration analysis
Vessels navigate with a constant speed in order to save fuel consumption in open seas. Acceleration and deceleration happen under the condition that ships are about to cross, overtake, meet, or turn, namely, scenarios with collision potentials. Accordingly, the degree of acceleration and deceleration can be considered as a collision risk index.
In order to calculate the degree, we will also firstly group the records based on the location and vessels’ MMSI numbers. In Step 2, we calculate the acceleration and deceleration for consecutive records vessel by vessel by