5. 12 Wenchuan earthquake severely paralyzed the ground transportation and communication system in the earthquake area. The disaster relief headquarters urgently dispatched several teams to carry out search tasks in various designated areas to determine the exact location of people in need of assistance. Other occasions often have similar search tasks. In this emergency, an important problem to be solved is to make the travel route of the search team and conduct a quick and comprehensive search of the predetermined area. Usually, every Seeker is equipped with GPS locator, walkie-talkie, food and daily necessities. There are also a certain number of satellite phones in the team. Global positioning system can let searchers know their location. Walkie-talkies can communicate with each other. Satellite phones are used to report the search to the headquarters.

Here is a simplified search question. There is a flat rectangular target area with an area of 1 1200m× 7200m, which needs to be searched nationwide. Assumption: the starting point is in the regional center; After the search is completed, assembly is needed, and the assembly point (end point) is at the midpoint of the left short side; The detectable radius of each person during search is 20 meters, and the average traveling speed during search is 0.6 meters/second; Traveling without searching, the average speed is 1.2 m/s, and everyone has a GPS locator and walkie-talkie. The communication radius of interphone is1000 m. The search team consists of several people, one of whom has a satellite phone. Everyone who finds the target needs to report to the team leader in time by walkie-talkie, and the team leader reports the latest search results to the headquarters by satellite phone.