Multi-GNSS High Precision Antenna System Integration

　　Multi-GNSS high-precision antenna system integration

　　Today, with the rapid development of global satellite navigation system (GNSS) technology, multi-GNSS high-precision antenna system integration has become the core key to achieve accurate positioning, efficient navigation and reliable communication. With the continuous increase in the demand for high-precision positioning in the fields of autonomous driving, intelligent transportation, surveying and mapping geographic information, precision agriculture, etc., single-function antennas can no longer meet the application requirements of complex scenarios, and the importance of multi-GNSS high-precision antenna system integration has become increasingly prominent.

　　I. Integration requirements and challenges

　　The demand for multi-GNSS high-precision antenna system integration comes from many aspects. From a market perspective, users expect devices to achieve seamless and accurate positioning in different environments, such as in complex terrains such as "canyon" environments with high-rise buildings in cities, underground parking lots, and mountainous areas, and can quickly obtain accurate location information. From the perspective of technological development trends, the coordinated application of multiple satellite navigation systems such as GPS, Beidou, Galileo, and GLONASS requires antenna systems to have multi-band and multi-system compatibility capabilities to fully utilize the advantages of each system and improve the reliability and accuracy of positioning.

　　However, system integration faces many challenges. In terms of electromagnetic compatibility, the coexistence of multi-band signals is prone to mutual interference, affecting the antenna's reception performance and positioning accuracy. For example, harmonics and stray signals of signals in different frequency bands may interfere with the normal reception of signals in other frequency bands. Multi-system signal processing is difficult, and the signal coding, modulation method, frequency, etc. of each satellite navigation system are different. Efficient signal processing algorithms and hardware architectures are required to achieve rapid capture, tracking and resolution of multi-system signals. In addition, the contradiction between miniaturization and high performance is also a major problem. While meeting the requirements of miniaturization and lightweight design of equipment, it is necessary to ensure that the antenna system has high gain, low noise, stable phase center and other high performance indicators, which puts forward extremely high requirements on material selection, structural design and manufacturing process.

　　II. Technical path of system integration

　　2.1 Hardware integration technology

　　Hardware integration is the basis for the integration of multi-GNSS high-precision antenna systems. In antenna design, multi-layer patches, four-arm spirals, inverted F antennas and other structures are used to achieve compatible reception of multi-band signals. For example, Zhejiang Spacetime's dual-frequency low-orbit occultation antenna can not only receive low-orbit satellite signals, but also be compatible with multiple traditional GNSS frequency band signals through innovative antenna structure design. In terms of RF front-end integration, RF devices such as low-noise amplifiers (LNA), filters, and mixers are highly integrated to reduce signal transmission loss and interference, and improve signal reception sensitivity and anti-interference capabilities. At the same time, a modular design concept is adopted to standardize the design of functional modules such as antennas, RF front-ends, and signal processors, which facilitates system assembly, debugging, and maintenance, and reduces development costs and cycles.

　　2.2 Software and algorithm integration

　　Software and algorithm integration is the key to improving the performance of multi-GNSS high-precision antenna systems. The multi-system signal fusion algorithm combines the signals of different systems such as GPS and Beidou to fully utilize the advantages of each system to improve positioning accuracy and reliability. For example, algorithms such as Kalman filtering and particle filtering are used to fuse observation data from multiple systems to effectively reduce positioning errors. The integration of anti-interference algorithms is also crucial. The adaptive zeroing algorithm can dynamically adjust the antenna's radiation pattern according to the direction and strength of the interference signal to form a null to suppress interference; the machine learning-driven interference detection algorithm can realize intelligent identification and suppression of interference signals by learning a large number of interference signal samples. In addition, through software-defined radio (SDR) technology, flexible configuration and functional upgrade of the antenna system can be achieved to improve the adaptability and scalability of the system.

　　2.3 Integration with other systems

　　Multi-GNSS high-precision antenna systems often need to be integrated with other systems to meet more complex application requirements. Integration with the inertial navigation system (INS) can maintain the continuity and accuracy of positioning by using the position, speed and attitude information provided by inertial navigation when the satellite signal is lost or interfered. For example, the CXP-FUSION micro high-precision positioning intelligent terminal launched by Chengxin Zhilian and Shuobei De integrates the satellite-inertial combined navigation system with the vehicle antenna function. In an environment with poor satellite signals, it relies on inertial navigation technology to continuously provide reliable positioning for the vehicle. Integration with visual sensors, lidar and other sensors can achieve multi-source information fusion, provide richer and more accurate environmental perception information for applications such as autonomous driving and robot navigation, and improve the decision-making ability and safety of the system.

　　III. Typical application scenarios

　　3.1 Intelligent transportation field

　　In the field of intelligent transportation, multi-GNSS high-precision antenna system integration plays a core role. Autonomous driving vehicles integrate multi-GNSS high-precision antenna systems, combined with inertial navigation, lidar, cameras and other sensors, to achieve centimeter-level precise positioning and environmental perception, and provide accurate location information for vehicle path planning, obstacle avoidance, and autonomous driving decisions. For example, Huawei's multi-GNSS high-precision antenna patented technology is applied to vehicle navigation, which dynamically adjusts antenna performance to adapt to different driving scenarios and improves positioning accuracy and response speed. In the intelligent motorcycle operation and maintenance system, based on Beidou single-frequency RTK and navigation maps, by installing a single-frequency RTK chip and a high-precision GNSS antenna in the vehicle's central control, combined with the Beidou ground-based augmentation system and the Internet of Things equipment, positioning information can be reported in seconds, effectively identifying vehicle parking and illegal behaviors, and improving the intelligent level of urban traffic management.

　　3.2 Surveying and mapping and geographic information fields

　　Surveying and mapping and geographic information fields have strict requirements for high-precision positioning. Multi-GNSS high-precision antenna system integration can provide stable and accurate positioning data for surveying and mapping equipment. Trimble's high-precision measurement antenna in the surveying and mapping field effectively suppresses multipath effects through technical integration such as optimized choke design, and occupies an important position in the professional surveying and mapping market. my country's first sub-meter resolution optical stereo mapping satellite, Gaofen-7, uses high-precision GNSS antenna system integration technology to obtain high-resolution stereo mapping remote sensing data and high-precision laser height measurement data, achieving 1:10,000 stereo mapping, which greatly improves the accuracy and efficiency of my country's geographic information collection. In addition, the relevant specifications drafted by the Guangzhou Institute of Metrology provide strong guarantees for the standardization and high-quality development of high-precision antenna system integration in the field of surveying and mapping and geographic information.

　　3.3 Precision agriculture

　　Precision agriculture relies on high-precision positioning to achieve refined management of farmland operations. Multi-GNSS high-precision antenna systems are integrated into agricultural machinery and drones to support farmland automation, intelligent sowing, irrigation, area calculation, nutrient determination, variety analysis, pest and disease monitoring, growth analysis and other operations.

　　IV. Future development trends

　　In the future, multi-GNSS high-precision antenna system integration will develop towards higher integration, intelligence and greening. Higher integration is reflected in chip-level integration, which highly integrates functional modules such as antennas, RF front-ends, and signal processors on the chip, further reducing the size of the equipment, reducing power consumption and costs, and improving the overall performance and reliability of the system. In terms of intelligence, with the help of artificial intelligence technology, the antenna system can realize autonomous perception, autonomous decision-making and autonomous optimization. For example, through machine learning algorithms, the antenna system can perceive environmental changes in real time and automatically adjust parameters to adapt to different signal propagation environments and user needs.