The search was conducted twice, once with the SLAR set at high Pulse Repetition 

 Frequency (PRF) and a second time at low PRF. The reason two PRF settings were 

 used was to provide detection opportunities at ranges greater than 27 NM, a radar range 

 setting that requires the lower PRF. After completing the northernmost leg of the search 

 pattern (60 NM from original line) the track was reversed, the radar was set to low PRF 

 and the search pattern reversed. Gain and sea state adjustments were set at 35% and 

 9, respectively, and were not changed during the test. 



Figure 



3. Test pattern and iceberg distribution for the January 30, 2001 evaluation. 



Results . The following results are based on post-flight analysis of the film and MSS 

 5000 data. 



Comparisons between film and MSS 5000 display . Due to the poor quality of the film 

 recorder images when the radar was set to low PRF, direct comparison between the 

 MSS 5000 images and the film was possible for only one leg of the search. On this leg, 

 the icebergs ranged from 16 to 25 NM from the aircraft. The film clearly showed four of 

 the icebergs, three visible with the unaided eye, and one with the aid of a loupe 

 (magnifying glass). The smallest iceberg (#4) was not seen on the film. Locating the 

 icebergs on the MSS 5000 display depended on the range setting of the display. The 

 greater the data compression required to show the image on the MSS 5000 display 

 station, the less likely the targets could be seen. Although the four icebergs could be 

 seen using 2X2 data compression, full resolution (no data compression) provided a 

 superior image that was comparable and, perhaps, slightly better than the film. The 

 MSS 5000 display did not show iceberg #4 on the leg for which the comparisons were 

 made. 



59 



