For users relying on centimeter-level accuracy — such as surveyors, engineers and autonomous systems — ionospheric disturbances can mean system downtime and significant losses. Traditional network real-time kinematic (NRTK) positioning methods assume smooth ionospheric conditions and thus fail during active solar periods.
To meet these challenges, a research team from Wuhan University and Guangzhou Hi-Target Navigation Tech Co. Ltd. developed an NRTK positioning model capable of maintaining centimeter-level accuracy under intense ionospheric disturbances.
This approach could serve as the foundation for next-generation, self-correcting navigation systems that operate reliably under any atmospheric condition.
The study (DOI: 10.1186/s43020-025-00179-4), published in Satellite Navigation on Oct. 6, introduces a dual-optimization framework that integrates real-time ionospheric indices with adaptive functional and stochastic models. By learning from disturbance patterns and automatically recalibrating user-side algorithms, the system dramatically enhances GNSS reliability during the ongoing solar cycle peak — offering a key safeguard for positioning technologies in low-latitude regions most vulnerable to ionospheric turbulence.
The innovation centers on leveraging the rate of the total electron content index (ROTI), a key indicator of ionospheric activity, to dynamically adjust both ionospheric residual estimation and observation weighting. When the system detects disturbances, it automatically reduces the influence of affected satellites and refines error models in real time.
Using data from Hong Kong’s Continuously Operating Reference Station (CORS) network — one of Asia’s most active low-latitude regions — the researchers found that ROTI showed a strong positive correlation (0.91) with ionospheric interpolation errors and a negative correlation (–0.9) with signal-fixing rates.
Compared to conventional NRTK methods, their adaptive “Method B” improved horizontal and vertical positioning accuracy by 37.6% and 41.6%, respectively. Moreover, it achieved a stable 84% average fixing rate, even during equinoctial months when ionospheric scintillation is strongest. The results reveal not just a technical upgrade but a practical solution for real-time navigation across regions frequently affected by solar-induced ionospheric noise.
“Our method essentially teaches GNSS systems to think smarter under stress,” said Xiaodong Ren, senior researcher at Wuhan University and lead author of the study. “By allowing the model to ‘sense’ and adapt to space-weather disturbances in real time, we’ve moved beyond static correction systems toward intelligent positioning. This is crucial not only for maintaining accuracy but also for ensuring resilience as solar activity intensifies.”
He added that this approach could serve as the foundation for next-generation, self-correcting navigation systems that operate reliably under any atmospheric condition.
This adaptive NRTK framework marks a significant leap forward for industries that depend on precise, real-time location data — from autonomous driving and drone surveying to precision agriculture and infrastructure monitoring, Ren said. By integrating live ionospheric monitoring into everyday positioning workflows, it ensures continuous accuracy even when solar storms strike.
Future developments may combine the model with artificial intelligence and multi-constellation GNSS networks to further enhance forecasting and resilience. As Earth moves through one of its most active solar cycles, Ren said, such innovations will be essential to keeping navigation, communication and automation systems firmly on course.
Hi-Target, a Chinese high-precision positioning enterprise and manufacturer of high-end GNSS equipment, and GMV, a global technology group specializing in advanced navigation solutions, have established a strategic alliance to jointly develop integrated differential service solutions.
Through this partnership, Hi-Target and GMV support a wide range of automation-driven positioning applications — ADAS, robotics, UAVs, precision agriculture, smart infrastructure and intelligent mobility systems.
As industries progressively adopt automated technologies, precise and reliable positioning has become a foundational requirement across application domains. From today’s L2 and L2+ driver assistance systems (ADAS) in vehicles to autonomous UAV operations, robotic platforms, and the emerging needs of Level 3+ mobility solutions, the demand for scalable and high-accuracy positioning continues to grow.
The strategic alliance between the two companies leverages Hi-Target’s strengths in high-precision satellite navigation and user-grade GNSS systems, along with GMV’s extensive global expertise in precise navigation algorithms and satellite-based augmentation services. The result will be a high-availability, low-latency positioning service with global reach.
By combining their complementary technologies, including user-grade GNSS hardware, correction services, and augmentation infrastructure, Hi-Target and GMV will facilitate the adoption of high-precision positioning across various industries and geographic regions.
Their collaboration will support system integrators, OEMs, and solution providers in accelerating the development and deployment of automation in sectors with increasing levels of autonomy.
Hi-Target has launched a real-time-kinematic (RTK) GNSS receiver that has an eye for visual positioning.
The pocket-sized vRTK GNSS RTK System is equipped with professional dual cameras to enable non-contact image surveying. It also has an advanced inertial measurement unit (IMU).
vRTK is suitable for non-contact measurements in a variety of hazardous and complex environments. High-quality sensors ensure the stability of the receiver’s accuracy in working status. By combining imagery with high-precision positioning equipment, users benefit from the convenience of visual positioning technology, which allows them to obtain the location of the target with a touch of a finger from a distance.
The lightweight, innovative visual RTK receiver improves the speed of stakeout with its Live View Stakeout function. Non-contact measurement greatly improves the usable range of GNSS and efficient, safe operation, the company said, greatly improving the efficiency of surveyors and engineers.
vRTK Features
The vRTK receives 1,408 channels, including GPS, GLONASS, BeiDou, Galileo, QZSS, IRNSS and SBAS. A new generation of GNSS engine supports the new frequency points B1C, B2a and B2b RTK decoding of the Beidou-3 satellite. The introduction of multi-frequency anti-jamming technology and multi-step adaptive filtering technology features strong signal, high-quality data, fast fix and high accuracy.
The vRTK has a nine-axis IMU module with auto installation for tilt surveying. Users can easily pick it up and arrive at the target point to carry out the tilt survey with an error of less than 2.5 cm within a 60° inclination.
It is compatible with popular modeling software programs and can be used to collect point cloud and 3D modeling data in one step.
A case study describing development and use of the vRTK is available.
Hi-Target has introduced a new GNSS receiver, the V200. The V200 is a GNSS RTK receiver with an integrated nine-axis inertial measurement unit (IMU). The receiver is designed to provide superior performance and high-efficiency to support fieldwork with reliable solutions.
The advanced RTK engine and new-generation nine-axis IMU guarantees a 25% performance improvement over the company’s previous V100 model, even in demanding environments. It is designed to be easy to use and carry.
A smart Hi-Fix function supports the receiver to increase stability. Hi-Fix enables continuous connectivity and quality results even if the signal is lost while using an RTK base station or VRS network under extreme circumstances.
Advanced RTK Technology features
Full constellation support (receives GPS, GLONASS, Galileo, BDS, QZSS, SBAS, IRNSS)
800+ channels
9-axis IMU for better tilt survey performance
Increases productivity by 25%
Convenient Features
Lightweight at 820 grams
Can work continuously for more than 12 hours
Supported by the latest Hi-Survey Road software and smart Hi-Fix function
The V200 nine-axis IMU GNSS RTK receiver represents a step forward in the development of GNSS receivers towards miniaturization, according to maker Hi-Target.
A roundup of recent products in the GNSS and inertial positioning industry from the January 2020 issue of GPS World magazine.
OEM
Heavy-duty antenna
For challenging environments
AT311 antenna. (Photo: CHC Navigation)
The heavy-duty CHCNAV AT311T is designed for demanding applications subject to shocks and vibrations. With advanced filtering and robust signal tracking, it provides survey-grade GNSS signals to enhance position reliability for marine applications, machine control, precision agriculture and industrial automation. Features include multi-constellation GNSS tracking using GPS, GLONASS, BeiDou, Galileo, QZSS, IRNSS and SBAS. Its IP68 water-resistant design makes it safe to use in extreme conditions with a wide temperature range (–40° C to +85° C). Its internal stacked structure enhances performance in high-interference environments, and the 40-dB signal gains, advanced signal filtering and multipath rejection design provide superior and robust GNSS signal tracking in challenging surroundings.
The UAS1 GNSS receiver module has been designed for UAV/UAS applications requiring centimeter accuracy in a small package.(Photo: Trimble)
The UAS1 compact, high-precision GNSS board was designed for unmanned aerial systems (UAS). It allows UAS system integrators to add upgradeable GNSS-based positioning using rugged connectors and Trimble’s software interface. Its 336-channel GNSS engine is capable of tracking L1/L2 frequencies from GPS, GLONASS, Galileo and BeiDou for centimeter-level, real-time kinematic (RTK) positioning. The compact board provides capabilities from high-accuracy GPS-only to full GNSS features. The receiver supports fault detection and exclusion (FDE) and receiver autonomous integrity monitoring (RAIM). System integrators also have the ability to detect interference with an RF spectrum monitoring and analysis tool embedded in the receiver.
The Onyx multi-frequency GNSS OEM board offers integrated StarFire/real-time kinematic (RTK) GNSS capabilities. It features 255-channel tracking, including multi-constellation support for GPS, GLONASS, BeiDou and Galileo. It provides high performance in GNSS receiver sensitivity and signal tracking as well as patented multipath mitigation, interference rejection and anti-jamming capabilities. Through software options, the Onyx ,allows upgrades from free differential GPS signal sources such as WAAS, to increased accuracy services such as StarFire and RTK Extend. The software-enabled features are sold in bundles, but can also be purchased individually to suit changing application needs.
The OSA 5401 and OSA 5405 now enable power utility and broadcast networks to achieve sub-microsecond synchronization. (Photo: Business Wire)
The OSA 5401 and OSA 5405 upgraded PTP grandmaster clocks deliver precise, robust timing in a compact form factor. Oscilloquartz PTP timing technology enables power utility and broadcast networks to achieve sub-microsecond synchronization. The pluggable OSA 5401 is a small PTP grandmaster clock, and the OSA 5405 is an integrated PTP grandmaster with dual GNSS antenna and receiver. With spoofing and jamming detection capabilities, they also provide high availability. The OSA 5401 and 5405 provide new levels of accuracy and resilience for infrastructure and support emerging bandwidth-intensive, latency-sensitive applications. With sub-microsecond synchronization, smart grids can perform flexible, real-time decision making, as well as monitoring and automated maintenance. The OSA 5401 and OSA 5405 comply with the latest PTP profiles for time, frequency and phase synchronization in both power utility and broadcast networks. These include the IEC/IEEE 61850-9-3 Power Utility Profile for precise time distribution and clock synchronization in electrical grids with an accuracy of 1μs, and SMPTE 2059 for synchronizing video and audio equipment over packet networks.
The SBAS-capable CMA-5024 GPS has received U.S. Federal Aviation Administration (FAA) approval for installation on Boeing 737 Next-Generation aircraft. It enables B737NGs to comply with worldwide ADS-B Out mandates as well as SBAS/GPS navigation, enabling the first localizer performance with vertical guidance (LPV) approaches for B737NGs. The CMA-5024 GPS is a cost-effective alternative to replace a multi-mode receiver (MMR). The approved DO-260B ADS-B Out positioning source can be paired with any DO-260B compliant transponder, allowing operators to meet FAA and EASA ADS-B Out requirements, the UAE’s ADS-B Out and RNP requirements mandated by GCAA as well as India’s GAGAN requirements.
The U.S. Federal Aviation Administration (FAA) has approved the VTU-20 automatic dependent surveillance – broadcast (ADS-B) transmitter for airport surface management. Adhering to the performance and design assurance specifications of FAA-E-3032, the externally mounted VTU-20 ensures integration and interoperability with Airport Surface Detection Equipment, Model X (ASDE-X), Airport Surface Surveillance Capability (ASSC) and ADS-B receiver surveillance solutions for airport. The VTU-20 can be permanently or magnetically mounted to all airside vehicles, including utility, emergency, snow-removal and maintenance equipment. Each vehicle is clearly and uniquely identified, providing an essential addition to any surface movement guidance and control system.
Skyward’s Advanced Airspace Intelligence drone airspace maps provide airspace data combined with essential ground intelligence including 3D views of key structures, transmission lines, and more than a million vertical obstacles. The platform also provides access to LAANC, the Low Altitude Authorization and Notification Capability program provided by the U.S. Federal Aviation Administration. Data available for situational awareness includes vertical structure obstacles, power lines, airports, runways, national parks, stadiums, hospitals and schools.
Hi-Target PPK GO precision add-on enables Phantom 4 RTK drones to achieve the accurate and reliable camera positioning data in any coordinate system without measure targets or ground control points. With 2-centimeter accuracies on XYZ, the output text file with position information or geotagged images can be used directly in major photogrammetric mapping or 3D survey software. The add-on allows selection of GPS/GLONASS/Beidou/ Galileo L1+L2+L5 and further parameter adjustments for position calculation in the PPK process to ensure the most reliable and accurate camera positioning even in poor single satellite system signals.
The R620 GNSS receiver is a complete refresh of Hemisphere’s previous version, the R330. (Photo: Allison Barwacz)
The next-generation R620 receiver is designed for land and marine applications requiring high-precision positioning. It is a complete refresh of the previous version (R330) and has a new low-profile ruggedized enclosure. Customers can start with sub-meter positioning accuracy and upgrade the receiver through activations and subscriptions to add functionality and improve performance capability to centimeter-level accuracy. Powered by the Vega series, the R620 GNSS receiver processes and supports more than 1,100 channels. It simultaneously tracks GPS, GLONASS, BeiDou (including Phase 3), Galileo, QZSS, IRNSS, SBAS and Atlas L-band corrections. It has status LEDs , a powerful WebUI, UHF (400-MHz and 900-MHz) radio, cellular modem, Bluetooth, Wi-Fi, Ethernet (including power over Ethernet), CAN, serial and USB.
For land surveying and geospatial information systems (GIS)
Photo: Geneq
The rugged SXPad 1500 data collector features an alphanumeric keypad and long-range Bluetooth, and was designed to meet the rigorous IP67 standard for challenging field conditions. It has a 5-inch sunlight-readable touchscreen. The SXPad 1500 can be connected to any GNSS receiver or compatible robotic total station. Driven by a 1-GHz processor and the Windows Mobile 6.5 operating system, providing the power to work with maps and large data sets in the field. Its integrated cellular modem and Wi-Fi provides wireless connectivity for internet access and GIS data transfer — helpful for configuring a real-time kinematic (RTK)-compatible GNSS receiver. Equipped with an internal memory of 1 GB (memory can be expanded to 16 GB with an SD card), the SXPad 1500 provides enough storage space for data recording. Its high-performance lithium battery allows uninterrupted field operation for up to eight hours.
The LT700H RTK Android tablet is designed to increase efficiency and productivity of the mobile field workforce in applications requiring centimeter-to-decimeter positioning accuracy. Portable, rugged and versatile, the LT700H enables precision GIS data collection, forensic mapping, construction site layout, environmental surveys, landscaping and earthmoving jobs. Powered by 184-channel high-performance GPS, GLONASS, Galileo and BeiDou module and a superior tracking GNSS helical antenna, the LT700H provides position availability in demanding environments. Its integrated 4G modem ensures seamless communication from field-to-office and robust connectivity to RTK correction networks.
The Trimble Alloy GNSS reference receiver now supports BeiDou Generation III (BDS-3) signals. This will enable operators to meet the ongoing demand from surveyors, mapping professionals and precision farmers for accurate, reliable corrections derived from real-time networks. Released in 2018, the Alloy has the processing power needed for high-quality data from multiple constellations. Alloy version 5.42 firmware tracks all available and planned GPS Block IIIA L1C and BDS-3 signals.
Hexagon showcased the Leica DSX utility detection solution at Intergeo 2019. (Photo: Allison Barwacz)
The Leica DSX utility detection solution can be used together with Leica GPS/GNSS systems to generate highly accurate, georeferenced maps. The DSX uncovers utilities for repair and maintenance, civil engineering and surveying projects. The ground-penetrating radar system includes portable hardware and software that automates data analysis and creates a 3D utility map.
Stefan Wei of Hi-Target Surveying Instrument Co. Ltd. discusses the company’s new V90 Plus GNSS RTK at INTERGEO 2015, which was held Sept. 15-17 in Stuttgart, Germany.
The V90 Plus with Trimble BD970 OEM delivers centimeter accuracy and supports all constellations. The company’s self-developed antenna, based on air dielectric technology, is designed for multipath mitigation.
