Improved Sliding Window Online AIS Track Data Compression Algorithm

Abstract

Analyzed the Time Series Characteristics of Ship AIS Data and Ship Handling Characteristics, Proposed Improved Sliding, Window and Online Compression Algorithm; Calculated 277 Total Ships 1 026 408 Coordinate Points, AIS and Track Data, Determined the appropriate compression threshold, Analyzed the sensitivity of distance threshold and angle threshold to the compression ratio of the algorithm; Recommended the distance threshold of high, medium, low 3 and 1 angle threshold, Contrast Douglas-Peucker Algorithm and Improvement Sliding Window Algorithm Compression Ratio and Compression Efficiency. Test results show that: as the compression rate increases, the number of points left after compression, the useful information retained by the data is also less and less; the compression rate is proportional to the distance threshold, the angle threshold; the high, medium, the low-range compression distance threshold after dimensional 1 normalization They are 43%, 38%, 33% Captain; Distance Threshold 130m Time, Angle Threshold Exceeds 9° Stable Post Compression Rate, So Recommended Angle Threshold is 9°, and Harbour Master Design Code (JTS XZ8 024--2013) Stroke Flow Pressure Difference Angle 8° Close; With Increase of Distance Threshold, Douglas-Peucker Algorithm and Improvement Sliding Window Algorithm Compression Rate Closer, When Distance Threshold is 120m, Douglas-peucker algorithm compression ratio is only higher than improved sliding window algorithm 1.74%; Under 5 Different Distance Thresholds, Douglas-Peucker The average time taken for the algorithm to run is improved Sliding, Window and 5 of the algorithm. 39 Times; With the Increase of Data Quantity, 2 The Difference in Compression Efficiency of Different Algorithms Is More Obvious. Visible, Improved Sliding Window algorithm can greatly improve compression efficiency while reducing compression risk, Can keep compression state in the state of continuous data update, Compared with normal compression mode, System occupies less resources, Processing efficiency is higher, Can be used for ship trajectory data processing, Electronic chart display and extraction of key behavior characteristics of ships.