To avoid the added time and expense of a 

 FLAR-only aircraft, Ice Patrol has combined 

 the FLAR and SLAB in our operations. 



Figure 1 shows a typical Ice Patrol 

 search pattern. The same track spacing as 

 SLAR-only operations is used to continue to 

 take maximum advantage of SLAR detection 

 capabilities. Essentially, Ice Patrol relies on 

 the SLAR (and the FLAR search mode to a 

 lesser extent) for wide-area searching and 

 tries to identify as many targets as possible 

 with the FLAR imaging mode. 



Currently, the two radars are operated 

 independently. The FLAR and SLAR radar 

 repeaters are located next to each other in the 

 cargo compartment of the HC-130, allowing 

 for easy cross comparison once the SLAR 

 image is processed. 



Figure 1 



Schematic showing typical IIP parallel 



search pattern. Dashed lines indicate 



FLAR/SLAR search areas. 



This combination has been very suc- 

 cessful. Table 1 shows the significant de- 

 crease in unidentified targets after the FLAR 

 was integrated into IIP operations at the begin- 

 ning of the 1993 ice season. (Ice Patrol flies 

 approximately 65 reconnaissance flights dur- 

 ing a typical ice season.) An unidentified 

 target is one not positively identified as either 

 an iceberg or a ship. This 50% reduction in 

 unknown targets directly translates into a higher 

 quality Ice Patrol product, as Ice Patrol defines 

 the ice limits around positively identified ice- 

 bergs. 



CONCLUSION 



The AN/APS-137 FLAR has proven to 

 be a valuable addition to the combined AN/ 

 APS-135 SLAR/ "visual" sensor suite. This 

 radar does not replace the SLAR for iceberg 

 detection, but its identification ability has sig- 

 nificantly improved Ice Patrol's ability to iden- 

 tify targets and has made Ice Patrol's iceberg 

 danger warnings more accurate. 



The two radars are not fully integrated 

 as no radar data logging system is installed in 

 the aircraft. The SLAR data time delay makes 

 real time intercom pari son difficult. The Coast 

 Guard is planning to upgrade SLAR to make it 

 a digital real-time system. This is expected to 

 improve the range resolution and significantly 

 improve the georegistration. There are no 



Table 1 

 Average Number of Unidentified Targets 

 per Reconnaissance Flight 



Ice Season 



1991 

 1992 

 1993 

 1994 



Unidentified Targets/Flight 



3.5 

 3.6 

 1.8 

 1.0 



> 



65 



