Appendix D 



The Intergration of Forward-Looking Airborne Radar into tiie International Ice 



Patrol's Sensor Suite 



by Geoffrey A. Trivers and Donald L. Murptiy 



ABSTRACT 



International Ice Patrol (IIP) monitors 

 and broadcasts the southeastern, southern, 

 and southwestern limits of icebergs in the 

 vicinity of the Grand Banks of Newfoundland. 

 Because of the chronically foggy conditions 

 overthe Grand Banks, IIP relies almost exclu- 

 sively on radar aboard USCG HC-130H air- 

 craft for iceberg reconnaissance. Since 1 983, 

 MP's primary detection radar has been the AN/ 

 APS-135, Side-Looking Airborne Radar 

 (SLAR). In 1 993, IIP added the AN/APS-1 37, 

 Forward-Looking Airborne Radar (FLAR) as 

 an additional sensor. Our operational experi- 

 ence and two tests (1991 and 1993) have 

 shown that the strength of the FLAR is its 

 ability to distinguish between icebergs and 

 ships. However, the field tests showed that in 

 some cases the FLAR failed to detect small 

 and medium icebergs (50 m and 100 m long, 

 respectively) at ranges at which the SLAR 

 routinely detects targets. Therefore, to avoid 

 the smaller geographic coverage of a FLAR- 

 only equipped aircraft, the two radars are used 

 in combination, providing IIP with an greatly 

 improved sensor suite for iceberg reconnais- 

 sance. 



INTRODUCTION 



- InternationaMce-Patfol's-primary-mis- 

 sion is to determine and guard the southern, 

 southeastern, and southwestern limits of all 

 known ice in the vicinity of the Grand Banks of 

 Newfoundland. This service is provided to 

 transatlantic shipping by the U.S. Coast Guard, 

 as required by International Safety of Life At 

 Sea (SOLAS) Convention and 46 USC 738, in 



response to the tragic sinking of the RMS 

 TITANIC on 15 April 1912. 



Ice Patrol seeks to track all icebergs 

 reported in the western North Atlantic Ocean 

 and warns mariners of the extent of the threat 

 icebergs pose to safe navigation. This task is 

 a large scale problem, both spatially and tem- 

 porally. The Ice Patrol operating area extends 

 from 40°N to 52°N and 39°W to 57°W. During 

 a typical iceberg season, which extends from 

 March through July, approximately 300-600 

 icebergs pass south of 48°N, below which 

 icebergs are considered to be threats to trans- 

 oceanic shipping. 



Ice Patrol receives iceberg reports from 

 a variety of sources, including commercial 

 shipping and aerial reconnaissance supported 

 by several Canadian government agencies 

 and private industry. Ice Patrol's own aerial 

 reconnaissance accounts for about one-third 

 of the icebergs detected during a season. 

 However, the importance of Ice Patrol's aerial 

 reconnaissance exceeds that suggested by 

 these simple statistics. Because Ice Patrol's 

 intent is to define the limits as accurately as 

 possible, neither underestimating nor overes- 

 timating the extent of the threat, its reconnais- 

 sance effort focuses on icebergs that define 

 the boundaries. Thus, the Ice Patrol aircraft 

 usually operates in areas of low iceberg den- 

 sity. The ability of the Ice Patrol aircraft to 

 detect and identify icebergs is critical to the 

 success of the mission. 



Near the Grand Banks, the extraordi- 

 narily poor visibility caused by the conver- 

 gence of the cold Labrador Current and the 



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