Software Design Of Large-Range Ship Model Indoor Positioning System Based On Ultrasonic Distance Measurement And Its Realization

As the much more research on the deep ocean, deep ocean technology keeps on developing, as well as the requirement of marine positioning. In order to make a better study of the modern marine Dynamic Positioning System(DPS), an indoor pool which is llm by 6m is built as a test platform of indoor model ship DPS. To achieve a high-precision control of indoor model ship DPS, one of the important conditions is that its position detection system can provide a real-time and accurate position signal. In order to provide the position signal for the system, this paper designs a set of indoor ultrasonic positioning system based on Atmegal6 and MAXQ7667 single chip.In this paper, the positioning system gets the required distance signals based on ultrasonic separate distance measurement, then calculates the real position of the model ship according to the relationship between the distance signals and the fixed nodes. The equipment consists of two main components---ultrasonic transmitting terminal and ultrasonic receiving terminal. The main task of the transmitting terminal is launching ultrasonic, receiving ultrasonic flight time signals, calculating position of the model ship and sending the coordinates to the upper computer. Meanwhile,the main task of the receiving terminal is dealing with the received ultrasonic signal, and transmitting the ultrasonic flight time signals to the transmitting terminal.The system consists of hardware and software parts. For the hardware, the design of real-time temperature compensation measurement circuit gathers the environment temperature to modify sound velocity, the design of ultrasonic driving circuit, ultrasonic receiving processing circuit and RF communications circuit measures the ultrasonic flight time, the design of serial interface communications circuit makes the SCM send the results to the upper computer in real-time. For the software, there is a reasonable arrangement for each node to complete the test in different time in a test cycle. Through the huge amount of test data, weighted least squares method is adopted to establish the algorithm mathematical model of the positioning system, the solving processes of the algorithm is given, as well as the specific implementation steps.This paper gives some problems and their solutions in the system making and debugging process, and analyzes the final test data. The experiment results show that, the test cycle of ultrasonic indoor positioning system is 100ms, which indicates the real-time works well. The measurement error is less than 2.2cm in the pool, measured value match the actual position, the positioning precision is relatively high, the system has a good engineering practicability. At present, the system has been applied preliminarily, it also provides a favorable condition for the research of model ship DPS, and provides reference value to the further research of ultrasonic testing technology.