With the continuous development and improvement of satellite positioning technology, high-precision positioning technology has been applied in all walks of modern life, such as in the field of measurement and mapping, precision agriculture, drones, unmanned vehicles and other fields, high-precision positioning technology can be seen everywhere. Especially with the completion of the network of the new generation of satellite navigation system of BeiDou, as well as the arrival of the 5G era, the continuous development of BeiDou + 5G is expected to promote high-precision positioning technology in the field of airport scheduling, robotic inspection, vehicle monitoring, logistics management and other areas to usher in a more broad application. The realization of high-precision positioning technology is inseparable from the support of high-precision antenna, high-precision algorithm and high-precision board, this paper mainly introduces the development and application of high-precision antenna, the current state of the art and so on.
1、GNSS high precision antenna development and application
1.1 High-precision antenna introduction
In the field of GNSS, high-precision antenna is a kind of antenna which has special requirements for the stability of antenna phase center, and usually cooperates with high-precision board to realize centimeter-level or millimeter-level high-precision positioning. In the design of high-precision antenna, the following indexes of the antenna usually have special requirements: antenna beamwidth, low elevation gain, out-of-roundness, roll-off coefficient, front-to-back ratio, and anti-multipath capability. These indicators will directly or indirectly affect the phase center stability of the antenna, which in turn affects the positioning accuracy.
1.2 High-precision antenna application and classification
High-precision GNSS antenna was initially mainly used in the field of surveying and mapping, which was used to realize static millimeter-level positioning accuracy in the process of engineering sampling, topographic mapping, and various control measurements. With the increasing maturity of high-precision positioning technology, high-precision antennas are gradually applied in more and more fields, including continuous operation reference station, deformation monitoring, seismic monitoring, measurement and mapping, unmanned aerial vehicles, precision agriculture, automatic driving field, driving test and training, engineering machinery and other industrial fields, and there are obvious differences in the index requirements of antennas in different applications.
1.2.1 CORS system, deformation monitoring, seismic monitoring-reference station antenna
High-precision antenna is used in continuous operation reference station, through long-term observation to obtain accurate position information, and through the data communication system real-time observation data transmission to the control center, the control center to solve the error correction parameters in the region and then through the ground-based enhancement system, wide-area enhancement system, star-based enhancement system, etc., will be sent to the error information to the mobile station (the user), and ultimately the user to get the accurate coordinate information [1].
In applications such as deformation monitoring, earthquake monitoring, etc., it is necessary to accurately monitor the amount of deformation and detect small deformations in order to predict the occurrence of natural disasters, etc.
Therefore, in the design of high-precision antennas for applications such as continuously operating reference stations, deformation monitoring, and seismic monitoring, the first thing that must be considered is their excellent phase-center stability and resistance to multipath interference, so that they can provide accurate position information in real time for various enhancement systems. In addition, in order to provide as many satellite correction parameters as possible, the antenna must receive as many satellites as possible, and the four-system full-band has become the standard configuration. In such applications, a reference station antenna (base station antenna) covering the full four-system frequency band is usually used as the observation antenna of the system.
1.2.2 Measurement and Mapping - Built-in Measurement Antenna
In the field of surveying and mapping, it is necessary to design a built-in measurement antenna that is easy to integrate, and the antenna is usually built into the top of the RTK receiver to realize real-time high-precision positioning in the field of surveying and mapping.
The main considerations in the design of the built-in measurement antenna are frequency band coverage, beam coverage, phase center stability, antenna size, etc. Especially with the popularization of network RTK application, the all-network built-in measurement antenna integrated with 4G, Bluetooth, WiFi gradually occupies the main market share, and has been favored by the majority of RTK receiver manufacturers since its launch in 2016, and has been widely used to promote its application .
1.2.3 Driving test driving training, unmanned driving-external measurement antenna
The traditional driving test system has many drawbacks, such as large investment costs, high operation and maintenance costs, large impact by the environment, low accuracy, etc., high precision antenna applied to the driving test system, the driving test system from manual judging into intelligent judging, judging accuracy, greatly reducing the driving test manpower and material costs.
In recent years, the unmanned driving system has been developing rapidly, and in unmanned driving, the positioning technology of RTK high-precision positioning and inertial guidance combined positioning is usually adopted, which can realize high positioning accuracy in most environments.
In the driving test and driving training, unmanned and other systems, often used in the form of external measurement antenna, the antenna needs to have a multi-system multi-frequency working band, can realize high positioning accuracy, have a certain suppression ability to multipath signals, as well as better environmental adaptability, can be used in outdoor environments over a long period of time without failure.
1.2.4 UAV-High-precision UAV Antenna
In recent years, the UAV industry has been developing rapidly, and UAVs have been widely used in agricultural plant protection, surveying and mapping, electric power patrolling and other scenarios, and in such scenarios, the only way to ensure the accuracy, efficiency and safety of all kinds of operations is to be equipped with high-precision antennas. Due to the UAV has a fast speed, light load, short endurance and other characteristics, UAV high precision antenna in the design of the main focus on the weight, size, power consumption and other factors, and in order to ensure that the weight and size of the premise to achieve as wide as possible under the broadband design.
2, GNSS antenna technology status at home and abroad
2.1 Foreign high-precision antenna technology status
Foreign research on high-precision antenna started earlier, and also developed a series of high-precision antenna products with better performance, such as NoVatel's GNSS 750 series choke antenna, Trimble's Zepryr series antenna, Leica AR25 antenna, etc., which has a large innovative significance of the antenna form. Therefore, for a long time in the past, China's high-precision antenna market is monopolized by foreign products. But in the past ten years, with the rise of a large number of domestic manufacturers, foreign GNSS high-precision antenna has basically no advantage in performance, but the domestic high-precision manufacturers began to open up the market abroad.
In addition, in recent years, foreign countries have also developed some new GNSS antenna manufacturers, such as Maxtena, Tallysman, etc., its products are mainly used for unmanned aerial vehicles, vehicle-mounted systems such as small GNSS antennas, antenna form is usually a microstrip antenna with a high dielectric constant or four-armed helical antenna form, in this kind of antenna design technology, foreign manufacturers have no advantage, and domestic and foreign products are entering a period of homogeneous competition. Entering the homogenization competition period.
2.2 Domestic high-precision antenna technology status
Domestic high precision antenna productization started late, but the development is rapid, in the past ten years, there are a number of domestic high precision antenna manufacturers began to develop and grow, such as Huaxin antenna, ZhongHaiDa, DingYao, JiaLi electronic, etc., developed a series of high precision antenna products with independent intellectual property rights.
For example, in the field of base station antenna and built-in measurement antenna, Huaxin's 3D choke antenna, all-network combination antenna, etc., not only the performance reaches the international leading level, and the product reliability is high, the service life is long, and the failure rate is extremely low, and it can satisfy all kinds of environmental applications.
And in the vehicle, UAV and other industries, external measurement antenna and four-arm spiral antenna design technology has been relatively mature, and in the driving test system, unmanned, UAV and other industry applications have been used on a large scale, achieved good economic and social benefits.
3, GNSS antenna market status and prospects
In 2018, the total output value of China's satellite navigation and location services industry reached RMB 301.6 billion, an increase of 18.3% compared with 2017 [2], and will reach RMB 400 billion in 2020; the total output value of the global satellite navigation market in 2019 was 150 billion euros, and the number of GNSS terminal users reached 6.4 billion units; in the context of the global economic situation in the doldrums, the GNSS industry is one of the few industries that have risen against the trend. The European GNSS Bureau predicts that in the next ten years, the total value of the global satellite navigation market will double over 300 billion euros, and the number of GNSS terminals will increase to 9.5 billion.
Global satellite navigation market, applied to road traffic, unmanned aircraft and other areas of the terminal equipment is the fastest growing segment of the market in the next ten years: intelligent, unmanned vehicles is the main direction of development of the future road vehicles, with the ability of self-driving car must be equipped with GNSS high-precision antenna, so the self-driving market for GNSS antenna demand is huge. With the continuous development of China's agricultural modernization process, plant protection drones and other drones equipped with high-precision positioning antennas will continue to grow.
4, GNSS high precision antenna development trend
GNSS high-precision antenna after years of development, the technology has been relatively mature, but there are still many directions to be broken through:
1, miniaturization: the miniaturization of electronic equipment is the eternal development trend, especially in applications such as drones, handhelds, etc., the demand for small size antenna is more urgent. But the antenna performance will be reduced after miniaturization of antenna, how to reduce the antenna size under the premise of ensuring comprehensive performance is an important research direction of high precision antenna.
2, anti-multipath technology: GNSS antenna anti-multipath technology mainly has choke technology [3], artificial electromagnetic material technology [4] [5], etc., but all have the disadvantages of large size, narrow bandwidth, high cost and so on, and can't realize the universal design, so we need to research on the anti-multipath technology with the characteristics of miniaturization and broadband, to satisfy the needs of various applications.
3, multifunctionalization: nowadays, in addition to the GNSS antenna on a variety of equipment, but also integrated more than one kind of communication antenna, different communication systems on the GNSS antenna may produce a variety of signal interference, which affects the normal collection of stars. Therefore, through the multifunctional integration of GNSS antenna and communication antenna to realize the integrated design, in the design of the antenna on the consideration of the interference between the impact of the antenna, you can improve integration at the same time to improve the electromagnetic compatibility characteristics, improve the performance of the whole machine.
Ltd. specializes in high-precision GNSS modules and wireless communication products, technology development and application promotion service providers, relying on the wireless communication technology in the field of R & D and promotion of experience, JUNODA set up a team with a wealth of experience in hardware and software development technology, aimed at domestic and foreign OEM / ODM customers and system integrators to provide high-quality, high-performance wireless modules and applications! We aim to provide high-quality, high-performance wireless modules and application programs to OEM/ODM customers and system integrators at home and abroad, and create long-term value for customers!
The company mainly provides integrated antenna module, dual-frequency high-precision module, single-frequency high-precision module, thousand-seeking high-precision module, Zhongke micro-positioning module, U-BLOX positioning module, SICOM communication module, inertial navigation DR module, UWM GNSS module, RTK differential module, 4G communication module and high-precision antenna, etc., the products are sold well in Beijing, Shanghai, Shenzhen, Guangdong, Jiangsu, Zhejiang, Sichuan, Hunan and other parts of the country. Our GNSS modules are widely used in many application fields, such as drones, vehicle security monitoring and dispatching, automatic bus stop announcement, DVR, car DVD navigation, GPS electronic dog, synchronized timing, high-altitude balloon monitoring, engineering machinery, industrial automation, etc. In the field of wireless communication products, the company is closely involved in the field of wireless communication, such as RTK differential module, 4G communication module and high-precision antenna.
In the field of wireless communication products, the company follows the latest development of international communication technology, introduces and acts as an agent for wireless communication modules that meet the market demand, and the products have a comprehensive layout from 2G, 3G, 4G, and are widely used in financial electronic payment, vehicle remote control, remote advertising information, repeater monitoring, mobile Internet terminals, smart home, remote medical care, network testing, enterprise information management, anti-theft alarm, Remote video transmission, intelligent meter reading, mobile computing, network navigation, voice phone, wireless gateway and other fields. Focused areas include video surveillance, network optimization, routers, POS and other M2M industry applications.
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