ANALYSIS OF VISUAL DETECTION PERFORMANCE FOR 16-FOOT BOAT AND LIFE RAFT TARGETS

Since September 1978 the USCG R&D Center has conducted four visual detection experiments to improve the probability of detection in SAR. These are the first in a series of experiments designed to develop visual detection performance models which will be incorporated into the Coast Guard's computer-assisted search planning (CASP) system and the National Search and Rescue Manual. These were controlled experiments involving 82.95-foot cutters, 41/44-foot boats, helicopters, and fixed wing aircraft searching for 16-foot boat and life raft targets anchored at predetermined locations within the search area. Through a microwave ranging system, searcher and target positions could be accurately reconstructed to determine the lateral range of targets that were detected, as well as not detected. Thus, probability of detection versus lateral range curves could be developed and, by integrating these curves, sweep width could also be determined. A total of 2,234 detection opportunities was generated. A sophisticated binary multivariate logistic regression computer program was used to develop sweep width estimates for the environmental conditions experienced. Of the 11 visual detection parameters investigated, visibility, wind speed, swell height, cloud cover, search unit type, targe type and color, sun's elevation, and time on task were determined to have a significant effect on sweep width. A more rapid degradation of sweep width was found for deteriorating environmental conditions than is now predicted by the National Search and Rescue Manual.

• Supplemental Notes:
  • This report is the second in a series which documents the Visual Search Effectiveness Task of the Probability of Detection in the search and rescue project (SAR).
• Corporate Authors:

  United States Coast Guard

  Research and Development Center, 1082 Shennecossett Road
  Groton, CT  United States  06340-6096

  Analysis and Technology, Incorporated

  P.O. Box 220
  North Stonington, CT  United States  06259
• Authors:
  • Edwards Jr, N C
  • Mazour, T J
  • Hoever, G L
  • Osmer, S R
• Publication Date: 1980-2

Media Info

• Features: References;
• Pagination: v.p.

Subject/Index Terms

• TRT Terms: Life rafts; Lifeboats; Mathematical models; Radar tracking; Search and rescue operations; Tracking systems
• Old TRIS Terms: Search techniques
• Subject Areas: Marine Transportation; Safety and Human Factors;

Filing Info

• Accession Number: 00312223
• Record Type: Publication
• Report/Paper Numbers: CG-D-24-80 Intrm Rpt., CGR-D-24-80
• Contract Numbers: DOT-CG-81-79-2038
• Files: TRIS
• Created Date: Jun 26 1980 12:00AM