| With the improvement of science, scope of people's activities is more and more wide, and the remote target positioning and monitoring technology is urgently required. The traditional remote positioning technology is mainly combined with inertial navigation technology, radio station or fixed wire network transmission technology, and electronic maps. It plays a significant role in practice, but also has follow deficiencies:positioning error will increase follow the time, longtime initial aiming, inertia devices are much expensive, do not have time information, the traditional radio station cost much and moving inconvenience, the fixed wire network has difficulties in constructing the network and convenience using, the electronic maps cost much and can only used to show in two-dimension in general. These deficiencies severely limit its widespread application in modern society. To resolve the above problems, a remote positioning technology which based on GPS technology, GSM technology and Google Earth software is put forward in this paper, it has the advantages of higher-accuracy, no restrict of using distance, cost less, show remote target's position and running track in three-dimension. The remote positioning technology can be simply implemented, and can be generally adopted in many remote positioning systems.In the system designed in this paper, remote target terminal consisted of GPS module and its peripheral interface circuit, GSM module and its peripheral interface circuit and the main control circuit with the processor of AT89S52 single chip microcomputer. The remote target terminal sends short message which contains GPS positioning information to monitoring center, and implements other system extend functions. The monitoring center consisted of GSM module and its peripheral interface circuit and PC. The monitoring software in the PC is designed with visual basic programming language, which has functions of sending, receiving, displaying message, and calling. At the same time, the messages successfully sent or received were stored in the ACCESS database. Besides, the monitoring software can achieve remote target's three-dimensional map displaying and running track drawing by the second development of Google Earth. From experiment results, it can be seen that the remote positioning technology researched in this paper has been successfully implemented, and the positioning error is about 12.8m. Besides, two problems which need to improve in the system are pointed out, and some improvement methods are researched. In the end, two effective improvement methods are put forward.The main innovation points in this paper are summarized as follows:(1) The traditional elctronic maps can only achieve the two-dimensional map display in general, so take the place of traditional electronic maps with Google Earth, and used in the remote positioning technology discussed in this paper, it has the advantages of high accuracy, three-dimensional map displaying and remote target running track drawing.(2) Proposed an improved GPS resolve algorithm which based on ILS and EKF algorithm, the simulation results show that the algorithm has both advantages of ILS and EKF algorithm, and can quickly and effectively improve the GPS positioning accuracy.(3) Proposed an improved bitmap-half-byte GPS positioning data compression algorithm which has simple theory, and is easy to implement in single chip microcomputer. By statistic the compression ratio of real GPS positioning data, it can be seen that the algorithm has high compression ratio.(4) Using virtual serial port communication technology to resolve the problem of the inadequate serial port of remote target terminal's master-chip (89S52 single chip microcomputer) simply and ingeniously. So the system functions are completed with fewer resources, and the costly and bulky shortcomings of using dual serial port controller or hardware expansion approach are overcame. |
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