TULIP AIG with water exclusion

Introduction

Water Exclusion is a new optional feature of AIG algorithm added to TULIP. This removes the water area from the intersection region of AIG to give a more accurate representation of target's location. This reduces the size of the intersection region, the centroid --which is used as a location estimate for the target-- however, may not be closer to the actual target. This is illustrated in the examples below.

Examples

www.princeton.edu

In this case the centroid is in water and 134km away from target. The green marker shows the actual target's location	With water exclusion the AIG centroid (red) is closer to the target with an error of 78km

www.jhu.edu

Error: 223km	Error: 134km

www.columbia.edu

Error: 57km	Error: 45km

www.yale.edu

Error: 114km	Error: 92km

www.drexel.edu

Error: 53km	Error: 36km

The preceding examples showed cases where using water exclusion did not only reduce the size of intersection region but also improved the accuracy of the centroid. The following examples will show how is some cases the centroid moves further away from the target instead.

www.montclair.edu

Error: 80km	Error: 101km As you can see the error actually increased in this case. However, the intersection region is still better with water exclusion.

www.uri.edu

Error: 96km	Error: 172km The error in this case has almost doubled. The example shows a few points of the intersection region are still in water, this is because compromises were made in the algorithm to reduce computation time (from >60sec to <10sec). This feature is still in beta stage and it might improve in future.

www.ecu.edu

Error: 81km	Error: 241km