Overzicht van de ontwikkeling van uiterst nauwkeurige GNSS-antennes

introductie

With the continuous development and improvement of satellite positioning technology, high-precision positioning technology has been used in all walks of life in modern life. For example, in fields such as surveying and mapping, precision agriculture, drones, and unmanned driving, high-precision positioning technology can be seen everywhere. Especially with the completion of the networking of Beidou's new generation satellite navigation system and the arrival of the 5G era, the continuous development of Beidou + 5G is expected to promote the application of high-precision positioning technology in airport dispatching, robot inspection, vehicle monitoring, logistics management and other fields. The realization of high-precision positioning technology is inseparable from the support of high-precision antennas, high-precision algorithms and high-precision boards. This article mainly introduces the development and application of high-precision antennas and the current status of technology.

1. Development and application of GNSS high-precision antennas

1.1 Inleiding tot uiterst nauwkeurige antennes
In de GNSS-wereld zijn precisieantennes een type antenne dat speciale eisen stelt aan de stabiliteit van het fasecentrum. Ze worden doorgaans gebruikt in combinatie met precisieprintplaten om positionering met een nauwkeurigheid van centimeters of millimeters te bereiken. Bij het ontwerp van precisieantennes gelden doorgaans speciale eisen voor de volgende antenne-indicatoren: antennebundelbreedte, lage elevatieversterking, rondheidsafwijking, afvalcoëfficiënt, voor-achterverhouding, meerpadweerstand, enzovoort. Deze indicatoren beïnvloeden direct of indirect de stabiliteit van het fasecentrum van de antenne en daarmee de positioneringsnauwkeurigheid.

1.2 Application and classification of high-precision antennas
Hoogprecisie GNSS-antennes werden aanvankelijk vooral gebruikt in de landmeetkunde en cartografie om statische positioneringsnauwkeurigheid op millimeterniveau te bereiken bij het uitzetten van technische locaties, topografische kartering en diverse controlemetingen. Naarmate de technologie voor hoogprecisiepositionering zich verder ontwikkelt, worden hoogprecisieantennes steeds vaker ingezet in diverse sectoren, waaronder continu werkende referentiestations, vervormingsmonitoring, aardbevingsmonitoring, landmeting en cartografie, drones, precisielandbouw, autonoom rijden, rijtesten en rijtrainingen, machinebouw en andere industriële toepassingen. De eisen die aan antennes worden gesteld, verschillen aanzienlijk per toepassing.

1.2.1 CORS system, deformation monitoring, earthquake monitoring-reference station antenna
Wanneer in continu werkende referentiestations uiterst nauwkeurige antennes worden gebruikt, wordt nauwkeurige positie-informatie verkregen door middel van langdurige observaties. De observatiegegevens worden in realtime via het datacommunicatiesysteem naar het controlecentrum verzonden. Het controlecentrum berekent de foutcorrectieparameters in het gebied en stuurt vervolgens de foutinformatie naar de rover (gebruikerszijde) via het grondgebaseerde verbeteringssysteem, het systeem voor gebiedsverbetering, het satellietgebaseerde verbeteringssysteem, enzovoort, waardoor de gebruiker uiteindelijk nauwkeurige coördinateninformatie verkrijgt [1].In applications such as deformation monitoring and earthquake monitoring, it is necessary to accurately monitor the amount of deformation and detect tiny deformations to predict the occurrence of natural disasters.Therefore, in the design of high-precision antennas in applications such as continuously operating reference stations, deformation monitoring, and earthquake monitoring, the first thing that must be considered is its excellent phase center stability and anti-multipath interference capabilities, so that accurate position information can be provided 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 configuration has become a standard configuration. In such applications, a reference station antenna (base station antenna) covering the full frequency band of the four systems is usually used as the observation antenna of the system.

1.2.2 Measurement and mapping-built-in measurement antenna
In de meet- en karteringssector is het noodzakelijk om een ​​ingebouwde meetantenne te ontwerpen die eenvoudig te integreren is. De antenne wordt doorgaans bovenop de RTK-ontvanger geplaatst om realtime, zeer nauwkeurige positionering mogelijk te maken in de meet- en karteringssector.The main considerations in the design of built-in measurement antennas include frequency band coverage, beam coverage, phase center stability, antenna size, etc. Especially with the popularization of network RTK applications, full-network built-in measurement antennas that integrate 4G, Bluetooth, and WiFi have gradually occupied a major share of the market. Since their launch in 2016, they have been favored by the majority of RTK receiver manufacturers and have been widely used and promoted.
1.2.3 Rijexamen en rijopleiding, autonoom rijden - externe meetantenne
The traditional driving test system has many disadvantages, such as high investment cost, high operation and maintenance costs, large environmental impact, low accuracy, etc. After high-precision antennas are applied to the driving test system, the driving test system changes from manual judgment to intelligent judgment, with high judgment accuracy, which greatly reduces the human and material costs of the driving test.De afgelopen jaren hebben onbemande rijsystemen zich snel ontwikkeld. Bij onbemand rijden wordt doorgaans positioneringstechnologie gebruikt die RTK-precisiepositionering combineert met inertiële navigatie, waarmee in de meeste omgevingen een hoge positioneringsnauwkeurigheid kan worden bereikt.Bij rijvaardigheidstrainingen, zelfrijdende auto's en andere systemen wordt vaak gebruikgemaakt van een externe meetantenne. Deze antenne moet geschikt zijn voor meerdere systemen en frequentiebanden, een hoge positioneringsnauwkeurigheid bieden, meerpadsignalen kunnen onderdrukken, goed bestand zijn tegen omgevingsinvloeden en langdurig in de buitenlucht kunnen functioneren.

1.2.4 Drone-high-precision drone antenna
The UAV industry has developed rapidly in recent years. UAVs have been widely used in agricultural plant protection, surveying and mapping, power line inspection and other scenarios. In such scenarios, only high-precision antennas can ensure the accuracy, efficiency and safety of various operations. Since drones have the characteristics of fast speed, light load, and short endurance, the design of high-precision drone antennas mainly focuses on factors such as weight, size, and power consumption, and achieves as wideband a design as possible while ensuring weight and size.

2. Huidige stand van de GNSS-antennetechnologie in binnen- en buitenland

2.1 Current status of foreign high-precision antenna technology
Foreign research on high-precision antennas began earlier, and a series of high-precision antenna products with better performance have been developed, such as NoVatel's GNSS 750 series choke coil antennas, Trimble's Zepryr series antennas, Leica AR25 antennas, etc., among which there are many innovative antenna forms. Therefore, for a long time in the past, my country's high-precision antenna market was dominated by foreign products. However, in the past ten years, with the rise of a large number of domestic manufacturers, foreign high-precision GNSS antennas have basically no advantages in performance. Instead, domestic high-precision manufacturers have begun to expand markets abroad.In addition, some new GNSS antenna manufacturers have developed abroad in recent years, such as Maxtena, Tallysman, etc. Their products are mainly small GNSS antennas used in drones, vehicles and other systems. The antenna form is usually a high dielectric constant microstrip antenna or a four-arm helical antenna form. Foreign manufacturers no longer have an advantage in the design technology of this type of antenna, and domestic and foreign products are entering a period of homogeneous competition.