Obtaining real-time and reliable traffic information has always been a bottleneck in the development of intelligent transportation systems. Establishing an intelligent transportation vehicle-mounted information acquisition system can provide a good auxiliary testing and verification platform for research on driving behavior characteristics, traffic data collection, and field testing within intelligent transportation systems. It can also provide strong technical support for the construction and development of multi-functional experimental vehicles for intelligent transportation systems in my country. This paper introduces the design and research of an intelligent transportation vehicle-mounted information acquisition system based on virtual instrument technology. The intelligent transportation vehicle-mounted information acquisition platform mainly uses satellite positioning technology, sensor technology, and data acquisition technology to establish the necessary environment for the development, research, and experimentation of related technologies in intelligent transportation systems, providing a good auxiliary testing and verification platform for research on driving behavior characteristics, traffic data collection, and field testing within intelligent transportation systems. Its main functions are: real-time synchronous acquisition of various vehicle-mounted sensor data and saving these records in a certain format; offline processing of various sensor data using multiple multi-sensor information fusion algorithms to verify various multi-sensor information fusion algorithms and compare their advantages and disadvantages; the results processed by the multi-sensor information fusion algorithm can be used to improve the accuracy of the positioning system and enhance system reliability; and by collecting and processing information such as speed and acceleration, the driver's driving behavior can be analyzed to study its characteristics. The hardware of this intelligent transportation vehicle-mounted information acquisition platform mainly consists of three parts: various vehicle-mounted sensors, I/O interface devices, and an onboard computer. The platform software uses LabVIEW, a 32-bit virtual instrument software development platform developed by NI using virtual instrument technology for computer-based measurement and control, capable of running on multiple operating systems. The software design of the entire data acquisition platform adopts a modular and structured design philosophy, including many functional modules. The real-time control module includes an I/O interface device initialization module, a data acquisition module, a data display module, a data storage module, a motion detection module, a data reading module, and a multi-sensor information fusion module. System Hardware Design The system hardware consists of a GPS OEM board, a MicroGyro100 dual-axis gyroscope, an ADXL202EA dual-axis accelerometer, an SCC signal conditioning module, a DAQPad-6015 data acquisition card, and a computer. The GPS ITrax02 is directly connected to the PC's serial port. The ADXL202EA and MicroGyro100, after SCC signal conditioning, are used for data acquisition via the DAQPad-6015. The system structure diagram is shown in Figure 1. The GPS power supply voltage range is 3.4–6V, the ADXL202EA power supply voltage range is 3–5.25V, and the gyroscope power supply voltage range is 2.2–5.5V. Therefore, a 5V output power supply is uniformly selected as the power supply. The data output by the GPS ITrax02 is input to the computer via RS232 to extract time and location information. The accelerometer and gyroscope signals are amplified and isolated by the signal conditioning circuit SCC, and then converted by the DAQpad-6015 to input the data into the computer, thereby calculating the vehicle's acceleration, velocity, position, and attitude angles. The accelerometer is a key component in the inertial measurement unit, used to measure the motion of the vehicle relative to the inertial coordinate system. The acceleration component in the vehicle coordinate system is transformed to the component along the geographic coordinate system through a strapdown matrix, and then the velocity and position of the vehicle are obtained through one and two integrations, respectively. With the development of inertial technology, the accelerometer is also constantly being developed and improved. Analog Devices' ADXL202EA is a micromechanical accelerometer based on integrated circuit and microfabrication processes. It is small, lightweight, low-power, low-cost, easy to integrate, and has strong overload capacity. While medium- and low-precision gyroscopes cannot meet the requirements of inertial measurement systems, they can be combined with GPS to form low-cost miniature integrated navigation systems, which is a future development direction. In such integrated navigation systems, gyroscopes and GPS complement each other. The long-term accuracy of the integrated navigation system is guaranteed by GPS, whose errors do not accumulate over time. When GPS signals are lost for a short period, the micro-inertial element provides dynamic parameters and status information of the motion. When GPS is working normally, the micro-inertial element uses GPS information for correction to improve accuracy. Therefore, this system uses a micromechanical gyroscope as an onboard sensor. NI's SCC module is a highly modular, low-cost signal conditioning system for PC-based measurement and automation systems. SCC provides a compact, portable system for single/dual-channel signal conditioning and connectivity. The data acquisition card selected for this system, the DAQPad-6015, is a 16-bit precision NI USB multi-function DAQ product with a single-channel sampling rate of up to 200kS/s. This device also features built-in threaded terminals, eliminating the need for additional cables and connectors. System Software Design The software design of this system mainly includes the software design of the GPS information acquisition module and the inertial sensor data acquisition and processing module. Typically, a GPS positioning information receiving system consists of a GPS receiving antenna, frequency converter, signal channel, microprocessor, memory, and power supply. Since GPS positioning information is relatively limited, RS-232 serial ports are used to transmit the positioning information (NEMA0183 statement) from the GPS receiver to the computer for information extraction and processing. As long as the GPS receiver is operational, it continuously transmits the received and calculated GPS navigation and positioning information to the computer via the serial port, receiving data from the serial port and storing it in a buffer. Before further processing, the buffer contains a long stream of bytes. This information is unusable without being categorized and extracted. Therefore, the program must extract the information from each field of the buffered byte stream and transform it into meaningful location information data that can be used for high-level decision-making. Similar to other communication protocols, LabVIEW is used to extract GPS location information read from the RS232 serial port based on the frame structure. The flowchart of the serial port information reading program is shown in Figure 2. Serial port initialization completes the serial port parameter settings, including the serial port number, data bits, stop bits, parity bits, data flow control, and baud rate. The number of characters in the serial port buffer determines whether a signal has arrived at the serial port, i.e., whether the hardware circuit is normal. If normal, serial port data is read. Figure 3 shows the flowchart of the process by which the inertial measurement unit (IMU) inputs data collected by the data acquisition card into the computer. First, the IMU data is read from the data acquisition card, initial alignment is performed, and the initial value of the strapdown matrix is ​​calculated. Then, the strapdown matrix is ​​updated to obtain the rotation angle of the geographic coordinate system relative to the inertial coordinate system. Considering the angular velocity output of the gyroscope, the direction cosine matrix between the vehicle coordinate system and the geographic coordinate system can be calculated. Through the decomposition of this direction cosine matrix, the accelerometer output can be transformed into the acceleration components of the vehicle along the geographic coordinate system. Then, using the general expression for acceleration, harmful acceleration is compensated to obtain the vehicle's acceleration along the ground. Integrating this, the north-south and east-west ground velocity components Va and Ve are obtained. With the ground velocity components, after appropriate transformation, the rate of change of latitude and longitude is obtained. Integrating this again, the latitude and longitude of the vehicle's instantaneous position are finally obtained. Finally, the elements of the attitude matrix are used to extract attitude and orientation information. Conclusion The realization of intelligent transportation vehicle-mounted information collection systems has greatly accelerated the research and development of related technologies for intelligent transportation systems, improved traffic order, alleviated traffic congestion, and provided real-time and reliable traffic information. Applying virtual instrument technology to intelligent transportation vehicle-mounted information collection systems not only meets the current requirements for multi-sensor information collection and fusion in intelligent transportation, but more importantly, it allows for flexible functional expansion according to the needs of technological development. Therefore, for the rapidly developing intelligent transportation technology, this information collection system based on virtual instrument technology has significant practical implications. Editor: He Shiping