Application of Intelligent Sensor in Space Transportation System

Summary:The application of smart sensors helps to improve the carrying capacity and safety performance of space transportation systems. Based on the introduction of intelligent sensors and their characteristics, this paper discusses the research and application of intelligent sensors on launch vehicles, and expounds the way to realize intelligent sensors, aiming to improve the measurement level of China's aerospace field and better adapt to the development of aerospace industry.

Key words:intelligent sensor; space transportation; measurement

0 Introduction

In the era of electronic information, electronic information has a guiding role in the development of all walks of life, as well as the space transportation system. At present, electronic information technology has become the main factor in the development of space transportation system. With the application of electronic information technology in the space transportation system, the carrying capacity and safety performance of the space transportation system have been effectively improved, and one of the representative core devices in improving the performance of these systems is the sensor. It should be noted that with the development of space flight technology, in order to ensure the safety and reliability of space transportation system, sensors are required not only to have high measurement accuracy, stable operation and rapid response, but also to have data analysis, processing and storage functions. at the same time, it can realize the functions of analysis and judgment, remote communication and so on. Therefore, the traditional sensor because of its detection function is relatively single, large size and other shortcomings, has gradually can not meet the application requirements, must use better performance of intelligent sensors to complete the measurement of different measurement and control projects.

1 Smart Sensors Overview

Smart sensor refers to a micro-electro-mechanical system (MEMS) that integrates sensors, microprocessors and actuators. Its main features:

(1)Its core is to combine the function of sensor information detection with the function of microprocessor information processing organically, which makes up for the deficiency of traditional sensor performance.

(2)It can design the original sensitive information through advanced software to realize information processing, information memory, logical thinking and judgment functions, so as to realize self-calibration, self-compensation, etc., and finally convert the original information into a standard digital format and send it to the user through a standard communication protocol.

(3)Because it contains a microprocessor, it can not only give full play to the functions of various software, but also complete the tasks difficult to complete by hardware, thus greatly reducing the difficulty of sensor manufacturing, improving sensor performance and reducing costs.

2 Smart Sensor Features

With the development of China's aerospace industry, higher requirements are put forward for the existing measurement and control system and data transmission mode, resulting in an increase in the demand for telemetry parameter monitoring, and an exponential increase in the demand for measurement of vibration, shock, temperature, noise, heat flow, pressure and other parameters. The use of traditional sensors is bound to bring greater pressure to the existing space transportation system, the functions and characteristics of smart sensors in some aspects can alleviate this contradiction. Key features:

(1)Easy to network, convenient networking. Intelligent sensors mostly use digital output, and it is easy to use some kind of wired or wireless communication protocol to connect into a sensor network, which reduces a series of problems caused by many types, wide distribution and difficult wiring. Among them, the wired network is typically a CAN bus, and only two wires can be connected to hundreds of measurement points. At the same time, in some local space, the use of wireless sensor networks can significantly reduce the number of traditional cable networks.

(2)Easy to achieve self-test. Due to the existence of the microprocessor, compared with the traditional sensor, the sensor can be self-checked without adding hardware, detect whether each part of the sensor is normal, and diagnose the faulty parts.

(3)Easy to improve the measurement accuracy. Also due to the existence of the microprocessor, the nonlinearity, temperature drift, time drift, response time of the sensor can be automatically compensated by software to improve the measurement accuracy.

(4)Easy to achieve miniaturization. In order to meet the complex measurement environment of space transportation system, the traditional sensor needs multiple filter circuits, which increases the volume and brings the problem of power consumption, while the intelligent sensor can realize digital filtering according to the internal program, and even carry out statistical processing to eliminate the measured values that do not meet the requirements.

(5)Easy to achieve integration. Due to the development of microelectronics and micromachining technology, MEMS sensors, which are suitable for mass production, easy to integrate and intelligent, have developed rapidly, promoting the development of sensors in the direction of miniaturization, high performance and low power consumption.

3 Application in Space Transportation System

The real-time wireless sensor network suitable for the complex field environment on the arrow has been applied in the launch process of the launch vehicle. One of the main components of the wireless sensor network is the intelligent wireless sensor/transducer. Among them, the intelligent wireless sensor is designed by one-piece or split-type to realize the measurement of environmental parameters such as temperature, humidity, pressure, heat flow, low-frequency vibration and high-frequency vibration during rocket flight. Specific performance:

(1)One-piece design. The so-called integrated intelligent sensor refers to that the sensitive core body and the microprocessor module at the back end are integrated in a housing, and the sensitive signal is directly sent to the microprocessor module AD for sampling, and is processed by the software and hardware inside the microprocessor module, linearized and normalized, and then delivered to the wireless communication module and sent to the data receiving terminal. Figure 1 shows the principle block diagram of the integrated intelligent wireless pressure sensor as an example.

(2)Split design. Due to the limitation of the on-site use environment, especially the temperature range, some measuring points adopt split sensors. The so-called split sensor means that the sensitive core body and the microprocessor module at the rear end are separated in two housings. The sensitive probe and the back-end microprocessor module are connected by wire, and the output signal of the sensitive probe is transmitted by wire to the microprocessor module AD for sampling, and then processed by the internal software and hardware of the microprocessor, linearized and normalized to the wireless communication module and then sent to the data receiving terminal. Taking a split temperature sensor as an example, its principle block diagram is shown in Figure 2.

It should be noted that with the rapid development of intelligent MEMS sensors, MEMS acceleration sensors and gyroscopes are also widely used in space transportation systems, mainly in attitude heading reference systems, flight control systems, guidance systems, etc. Especially in the process of rocket launch vibration state monitoring, MEMS vibration acceleration sensor because of its small size, high precision, low power consumption and become the direction of the two unified type.

4 Concluding remarks

Compared with traditional sensors, smart sensors have advantages in accuracy, reliability, and adaptability. It changes the design concept and application mode of the original traditional sensor, and represents the development trend of sensor technology in the future. It introduces micro-processing technology into the sensor, so that the sensor has a certain degree of intelligence. It will have a profound impact on the future of human life. As more and more microprocessors are localized, the application of smart sensors in space transportation systems will also shine.

References

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[2]Song Zhenlong, Sun Fengwei, Chen Feng et al. Networked intelligent sensor and its application in aerospace [J]. Electronic Testing [J],2009(9):10-13,53

[3]Lu Juan, Wang Ying, Liu Bingtai, Zhang Yuan. Research on wireless sensor network technology based on rocket measurement system [J]. Astronautical Survey Technology, 2015,35(4):44-47,53

[4]Gu Yan. Research on the development status of intelligent sensor [J]. Wireless Internet Technology, 2017(21):12-13

Introduction to the Author

Lan Zhikang,Graduated from Southeast University, majoring in MEMS Microelectronic Systems Engineering. From April 2008 to September 2017, he served as Project Manager and R & D Manager of Honeywell's Sensing and Internet of Things Division in the United States. From September 2017 to December 2017, he served as the manager of the inertial sensor and microsystem division of Gaohua Technology Co., Ltd., and since January 2018, he has been the deputy general manager and director of the technical center of Gaohua Technology Co., Ltd.