碩士 / 國立臺灣海洋大學 / 電機工程學系 / 97 / This thesis aims to study and analyze the application of integration of inertial navigation technology and Emergency Locator Transmitter (ELT), which will form an Active ELT with beacon containing position data.
Conventional rescue system involving the use of Triangulation method to estimate a target position suffers the problems of difficulty in accurately locating the target in time, which inevitably incurs increasing cost of search and rescue operation as well as risking the life of the rescued person. To overcome these problems, the Search and Rescue Satellite Aided Tracking (SARSAT) satellite system can provide coordinates of the distress location, but it has been reported that SARSAT coordinates are valid with 50% probability when ELT is within an elliptical area 14 miles in length and 7 miles in width. The development of integration GPS and ELT can actively provide position for search and rescue, but there is a risk of antenna to be mantled or electromagnetic wave to be cut off.
Inertial Navigation System (INS) is a technology for determining a vehicle’s attitude, velocity and position. INS is completely self-contained in the sense that it contains gyros, accelerometers and a computer. For example, a strapdown INS has 3 gyros and 3 accelerometers rigidly fixed on a base which is mounted to a vehicle. The kernel of an INS is an algorithm executed by the computer to (1) calculate the vehicle’s attitude, (2) transform coordinate from body frame to navigation frame, and (3) perform integration computation.
By integrating with INS, it is expected that ELT can transmit signals with more accurate location of distress target than any other kinds. Prior to implementation, it is necessary to study the concept of coordinate frames, related theories and error budget of INS. Experiments are performed to access the performance of INS, namely the variation of attitude, velocity and position with respect to time.
The INS we use for test is designed with ordinary specifications, like all other kinds of INS; it comes with a drawback in that parameters values diverge with time. Our results show that for static test (lasting 78 seconds); the maximum horizontal position error is 7M and 3.8M for X- and Y-axis, respectively. And for dynamic test (lasting 78 seconds too); the maximum horizontal position error is 30M and 28M for X- and Y-axis, respectively. These errors are small than those of SARSAT satellite system.
As aforementioned, navigation errors of INS are inherently increasing with time. After long-term operation the location error will be excessively large. In the future, this difficulty can be alleviated by integrating INS, GPS and Kalman Filter.
| Identifer | oai:union.ndltd.org:TW/097NTOU5442010 |
| Date | January 2009 |
| Creators | Sheng-Shih Wang, 王盛時 |
| Contributors | Jyh-Jier Ho, 何志傑 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 160 |
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