With the continuous development and improvement of satellite positioning technology, high-precision positioning technology has been applied to all walks of life in modern life, such as surveying and mapping, precision agriculture, uav, unmanned driving and other fields, high-precision positioning technology can be seen everywhere. In particular, with the completion of the network of the new generation of Beidou navigation satellite system and the advent of 5G era, the continuous development of Beidou +5G is expected to promote the application of high-precision positioning technology in the fields of airport scheduling, robot inspection, vehicle monitoring, logistics management and other fields. The realization of high precision positioning technology is inseparable from the support of high precision antenna, high precision algorithm and high precision board card. This paper mainly introduces the development and application of high precision antenna, technology status and so on.

1. Development and application of GNSS high-precision antenna

1.1 High-precision antenna

In the FIELD of GNSS, high-precision antenna is a kind of antenna which has special requirements for the stability of the antenna phase center. It is usually combined with high-precision board to realize the high-precision positioning of centimeter-level or millimeter-level. In the design of high-precision antenna, there are usually special requirements for the following indicators: antenna beam width, low elevation gain, non-roundness, roll drop coefficient, front and rear ratio, anti-multipath ability, etc. These indicators will directly or indirectly affect the phase center stability of the antenna, and then affect the positioning accuracy.

1.2 Application and classification of high-precision antenna

The high-precision GNSS antenna was initially used in the field of surveying and mapping to achieve static millimeter-level positioning accuracy in the process of engineering lofting, topographic mapping and various control surveys. With high precision positioning technology becoming more mature, the high accuracy antenna is gradually applied in more and more fields, including continuous operation reference station, deformation monitoring, earthquake monitoring, measurement of surveying and mapping, unmanned aerial vehicles (uavs), areas of precision agriculture, automatic driving, driving test driving training, engineering machinery and other industrial areas, in different applications to the index requirement of the antenna also has the obvious difference.

1.2.1 CORS system, deformation monitoring, seismic monitoring – reference station antenna

High accuracy antenna used continuous operation reference station, through long-term observation for accurate location information, and through the data communication system in real time observation data transmission to the control center, the error of the calculated control center area after correction parameters to enhance the system of soil, and star in waas enhance system, etc., to send error messages to rover (client), Finally, the user can get accurate coordinate information [1].

In the application of deformation monitoring, earthquake monitoring and so on, because of the need to accurately monitor the amount of deformation, the detection of small deformation, so as to predict the occurrence of natural disasters.

Therefore, in the design of high-precision antenna for applications such as continuous operation reference station, deformation monitoring and seismic monitoring, the first consideration must be its excellent phase center stability and anti-multipath interference ability, so as to provide real-time accurate position information for various enhanced systems. In addition, in order to provide as many satellite correction parameters as possible, the antenna must receive as many satellites as possible, four system full frequency band has become standard configuration. In this kind of application, reference station antenna (reference station antenna) covering the whole band of four systems is usually used as the observation antenna of the system.

1.2.2 Surveying and mapping – Built-in surveying antenna

In the field of surveying and mapping, it is necessary to design a built-in surveying antenna that is easy to integrate. The antenna is usually built into the top of the RTK receiver to achieve real-time and high precision positioning in the field of surveying and mapping.

Built-in measuring antenna coverage in the main consideration in the design of frequency stability, beam coverage, phase center, the antenna size, etc., especially with the application of network RTK, integrated with 4 g, bluetooth, WiFi all netcom built-in measuring antenna gradually occupy the main market share, since it launched in 2016 by the majority of RTK receiver manufacturers, It has been widely applied and promoted.

1.2.3 Driving test and driving training, unmanned driving – external measuring antenna

The traditional driving test system has many disadvantages, such as large input cost, high operation and maintenance cost, great environmental impact, low accuracy, etc. After the application of high-precision antenna in the driving test system, the system changes from manual evaluation to intelligent evaluation, and the evaluation accuracy is high, which greatly reduces the human and material costs of driving test.

In recent years, unmanned driving system has developed rapidly. In unmanned driving, the positioning technology of RTK high precision positioning and inertial navigation combined positioning is usually adopted, which can achieve high positioning accuracy in most environments.

In the driving test driving training, such as unmanned systems, often antenna are measured with the external form, the need to work frequency, multi-frequency antenna with multiple system can achieve high positioning accuracy, the multipath signal has certain inhibition, and good environmental adaptability, can be long-term use in outdoor environment without failure.

1.2.4 UAV — High-precision uav antenna

In recent years, the uav industry has developed rapidly. Uav has been widely used in agricultural plant protection, surveying and mapping, power line patrol and other scenarios. In such scenarios, only equipped with high-precision antenna can ensure the accuracy, efficiency and safety of various operations. Due to the characteristics of high speed, light load and short endurance of uav, the design of uav high-precision antenna mainly focuses on weight, size, power consumption and other factors, and realizes broadband design as far as possible on the premise of ensuring weight and size.

2, GNSS antenna technology status at home and abroad

2.1 Current status of foreign high-precision antenna technology

Foreign research on high-precision antenna started early, and a series of high-precision antenna products with good performance have been developed, such as GNSS 750 series choke antenna of NoVatel, Zepryr series antenna of Trimble, Leica AR25 antenna, etc., among which there are many antenna forms with great innovative significance. Therefore, in the past for a long period of time, China’s high-precision antenna market is out of the monopoly of foreign products. However, in recent ten years, with the rise of a large number of domestic manufacturers, foreign GNSS high-precision antenna performance has basically no advantage, but the domestic high-precision manufacturers began to expand the market to foreign countries.

In addition, some new GNSS antenna manufacturers have also developed in recent years, such as Maxtena, Tallysman, etc., whose products are mainly small GNSS antennas used for uav, vehicle and other systems. The antenna form is usually microstrip antenna with high dielectric constant or four-arm spiral antenna. In this kind of antenna design technology, foreign manufacturers have no advantage, domestic and foreign products are entering the period of homogeneous competition.

2.2 Current situation of domestic high-precision antenna technology

In the past decade, a number of domestic high-precision antenna manufacturers began to grow and develop, such as Huaxin Antenna, Zhonghaida, Dingyao, Jiali Electronics, etc., which developed a series of high-precision antenna products with independent intellectual property rights.

For example, in the field of reference station antenna and built-in measurement antenna, HUaxin’s 3D choke antenna and full-netcom combined antenna not only reach the international leading level of performance, but also meet the requirements of various environmental applications with high reliability, long service life and very low failure rate.

In the industry of vehicle, uav and other industries, the design technology of external measuring antenna and four-arm spiral antenna has been relatively mature, and has been widely used in the application of driving test system, unmanned driving, uav and other industries, and has achieved good economic and social benefits.

3. Current situation and prospect of GNSS antenna market

In 2018, the total output value of China’s satellite navigation and location service industry reached 301.6 billion YUAN, up 18.3% compared with 2017 [2], and will reach 400 billion yuan in 2020; In 2019, the total value of the global satellite navigation market was 150 billion euros, and the number of GNSS terminal users reached 6.4 billion. The GNSS industry is one of the few industries that has bucked the global economic downturn. The European GNSS Agency forecasts that the global satellite navigation market will double to more than 300 billion euros in the next decade, with the number of GNSS terminals increasing to 9.5 billion.

Global satellite navigation market, applied to road traffic, unmanned aerial vehicles in areas such as terminal equipment is in the next 10 years the fastest growing segment of the market: intelligence, unmanned vehicle is the main development direction, the future road vehicle automated driving ability of the vehicle must be equipped with GNSS antenna has high precision, so the huge market demand for GNSS antenna automatic driving. With the continuous development of China’s agricultural modernization, the use of uav equipped with high-precision positioning antenna, such as plant protection uav, will continue to increase.

4. Development trend of GNSS high-precision antenna

After years of development, various technologies of GNSS high-precision antenna have been relatively mature, but there are still many directions to be broken:

1. Miniaturization: The miniaturization of electronic equipment is an eternal development trend, especially in the applications such as uav and handheld, the demand for small-size antenna is more urgent. However, the performance of the antenna will be reduced after the miniaturization. How to reduce the antenna size while ensuring the comprehensive performance is an important research direction of the high-precision antenna.

2. Anti-multipath technology: The anti-multipath technology of GNSS antenna mainly includes choke coil technology [3], artificial electromagnetic material technology [4][5], etc. However, they all have disadvantages such as large size, narrow band width and high cost, and cannot achieve universal design. Therefore, it is necessary to study the anti-multipath technology with the characteristics of miniaturization and broadband to meet various application requirements.

3. Multi-function: Nowadays, in addition to GNSS antenna, more than one communication antenna is integrated in various devices. Different communication systems may cause various signal interference to GNSS antenna, affecting normal satellite reception. Therefore, the integrated design of GNSS antenna and communication antenna is realized through multi-function integration, and the interference effect between antennas is taken into account during the design, which can improve the integration degree, improve the electromagnetic compatibility characteristics and improve the performance of the whole machine.