A Short-Range Ship Navigation System Based on Ladar Imaging and Target Tracking for Improved Safety and Efficiency

Abstract

A new maritime navigation system based on a laser rangefinder scanner for obstacle avoidance and precise maneuvering operations is described in this paper. The main novelty of this work is the adaptation and implementation of known technology for laser range finding and algorithms for target tracking into a system that operates in real time and has been tested in different natural sea and inland navigation scenarios. The principal components of this system, namely, 1) the laser range finder, 2) the scanning unit, and 3) the data processing and displaying unit, are described in detail. Ladar images are dense horizontally and sparse vertically as a compromise between capturing relevant features and quick frame formation. Images are processed for range outlier removal, and significant observable patterns are extracted. This multiple-target tracking problem is tackled using robust Kalman filtering techniques for continuous tracking of each detected observation. We minimize unreliable track initializations and preserve tracks from deletion during temporal misobservations. The evaluation in open-sea and inland waterways gave good results, making the system valid for precise maneuvering, fluent navigation, and accident mitigation. Objects of interest, from boats to ships, are detected and robustly tracked; pier and lock chamber sketches are reliable; bridge height estimation is precise; and narrow waterways (river banks and bridge columns) are correctly detected. The prototype developed can be considered to be a very valuable complementary device to traditional radar-based techniques that are not totally valid for accurate short-range exploration, improving efficiency and safety in ship operations.

Accuracy Improvement of Stereo-Based Distance Measurement for Close Range Vessel Positioning

“…The Global Positioning System (GPS) has been widely used to obtain the position data of a vessel in an ocean. However, it does not satisfy our conditions pertaining to 1,2) . While this has a high accuracy in distance measurement, it is not suitable for continuously tracking a target.…”

“…For example, for high accuracy on the measured distance, we have referred the distance accuracy of the sensor system to be within 100 mm for berthing 2) . To verify the distance accuracy, we measured a distance of 2-8 m to the target template shown in Fig.…”

Ship performance and navigation information under high-dimensional digital models

“…The same network connectivity within the maritime infrastructure, i.e. IoT, creates global internetworking facilities for the shipping industry to function as an information-based industry [6]. Hence, the same maritime infrastructure creates various opportunities, i.e.…”

Stereo vision–based navigation for autonomous surface vessels

“…Ruiz and Granja (2009) describe a system designed to assist human pilots in inland waterways. It adapts a commercial Riegl LIDAR, converting it to a two-axis scanner, and processes the resultant two-dimensional (2D) range image to detect discrete contacts.…”