Title:
AZIMUTH-DETECTING DEVICE AND DISTANCE CALCULATION METHOD
Document Type and Number:
Japanese Patent JP3237706
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To drastically reduce the search range of a sunken ship and to quickly discover the sunken ship by calculating relative distance to a transmission source based on current azimuth, last azimuth, and distance moving in an arbitrary direction.
SOLUTION: An azimuth θr1 at time T1 is obtained from the ratio of an ideal amount of Doppler shift obtained by a velocity V of a search ship 24 at time T1 to a received amount of Doppler shift, and the azimuth θr1 at the time t1 is stored at a data storage part 19. When a signal being transmitted from a sunken ship 1 arrives at the search ship 24 again, the azimuth θr1 being stored at the data storage part 19 is transmitted to a data storage part 20 for storage. An azimuth calculator 16 detects an azimuth of θr2, and the azimuth θr2 is stored at the data storage part 19. On the other hand, a traveling distance calculator 18 obtains a traveling distance Vt of the search ship 24 by an interval (t) between the time T1 and the time T2. Then, it obtains a relative distance rr2 by an expression rr2=Vt×SINθr1SIN(θr2-θr1).
Inventors:
Tatsuhiro Matsuura
Application Number:
JP15184599A
Publication Date:
December 10, 2001
Filing Date:
May 31, 1999
Export Citation:
Assignee:
NEC
International Classes:
G01S3/802; G01S5/18; (IPC1-7): G01S3/802; G01S5/18
Domestic Patent References:
| JP11166967A | ||||
| JP10282214A | ||||
| JP10104337A | ||||
| JP7264661A | ||||
| JP61226900A | ||||
| JP609225A | ||||
| JP559104A |
Attorney, Agent or Firm:
Nobuyuki Kaneda (2 others)
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