GNSS Techniques Research Articles

An Evaluation of the Accuracy of GNSS Receivers Integrated with MEMS-IMU Sensors for Optimal Angle Determination in Tilted Observation Scenarios Using the NRTK GNSS Technique in Thailand

An Evaluation of the Accuracy of GNSS Receivers Integrated with MEMS-IMU Sensors for Optimal Angle Determination in Tilted Observation Scenarios Using the NRTK GNSS Technique in Thailand

Mapping Longitudinal and Transverse Displacements of a Dam Crest Based on the Synergy of High-Precision Remote Sensing

Reservoirs are highly relevant infrastructure assets, and now, more than ever, they play an essential role in society’s welfare and national security. Their importance is related to regional socioeconomic development due to their capacity to store water for different uses, such as human consumption, agricultural irrigation, flood control, and hydroelectric energy production, among other important services. However, many reservoirs are reaching the end of their period of life, and others are showing undesired displacements and cracking. Four 3D surveys were conducted on a reservoir that serves the Metropolitan Area of Monterrey City in Mexico. These surveys were carried out over a period of 5 years using GNSS observation to assist in understanding the actual dam kinematics, i.e., the behavior of its longitudinal and transversal displacements and the possible correlation with the reservoir level. The high-precision leveling and close-range remote sensing data were assessed and then mapped. The high-precision geodetic and leveling techniques allowed us to locate and measure 84 established permanent control points with errors of about ± 0.003 m. The mapping of displacements was made possible by modeling the positive and negative translations. The highest uplifts (11 mm) occurred at the left riverbank, and the highest subsidences (−5 mm) occurred along the downstream piers from the middle of the dam crest to the right riverbank. A ground laser scanner (GLS) produced 3D digital models with geometrical and radiometric characteristics, detecting displacements among the dam crest elements. The synergy of GNSS and high-leveling techniques allows the possibility to measure displacements, while the use of geographical information system (GIS) and geomatic techniques allows a better visualization through 2D and 3D maps validated using traditional topographical methods.

The Importance of Ground Control Points In A Photogrammetric Workflow

Abstract This study investigates the optimal distribution and pattern of ground control points (GCPs) in aerial photogrammetric projects. Aerial triangulation (AT), also known as bundle adjustment, is the fundamental step in refining 3D reconstruction models and camera positions, thereby minimizing reprojection errors. The study utilizes data from a national project in Romania, employing high-resolution aerial images acquisition using photogrammetric sensors. The project has rigorous requirements of ground control points (GCP) placement and field measurements using GNSS and geometric leveling techniques. The study employs various scenarios, manipulating the number and distribution of GCPs, to assess their influence on planimetric and altimetric accuracy. Results indicate that the configuration and number of GCPs significantly affect the accuracy of photogrammetric products, such as dense image point clouds, digital surface models, and orthophotos. Moreover, the study underscores the importance of precise GCP determination methods, especially in regions lacking a precise gravimetric geoid model. In scenarios with inadequate GCP coverage the outcomes have inferior quality, emphasizing the critical role of GCPs in ensuring the quality of photogrammetric products. Overall, the research gives a clear view on the best placement patterns of GCPs and their influence on AT process evaluation performed in check points (CHKs).

Performance evaluation of real-time orbit determination for LUTAN-01B satellite using broadcast earth orientation parameters and multi-GNSS combination

Real-time orbit determination (RTOD) for spacecraft using the space-borne GNSS technique needs earth orientation parameters (EOPs) for the required coordinate transformation between earth-fixed and inertial reference frames. GPS and BDS transmit EOPs in modernized navigation messages, which enables GNSS-equipped spacecraft to update EOPs onboard and improves the RTOD automaticity. However, the impact of broadcast EOP errors on RTOD has not yet been evaluated. With the GPS and BDS-3 observations collected from a Chinese low-earth orbit (LEO) mission, the LUTAN-01B satellite, we analyze the LEO RTOD performance with broadcast EOPs and GPS/BDS-3 combination for the first time. In RTOD, we parameterize the ephemeris signal-in-space range error (SISRE) to account for its slow-varying signature and to compensate for the EOP errors. Without estimating SISRE, the RTOD precision using broadcast EOPs is 70.1 cm with only GPS observations and 42.4 cm with only BDS-3, revealing degradations of 5.1 cm (7.8%) and 3.3 cm (8.4%) compared to those using the precise C04 EOPs, respectively. With SISRE estimated, the impact of broadcast EOP error is compensated and the RTOD precisions with broadcast EOPs show identical results to those with C04, reaching 36.3 cm with GPS and 25.8 cm with BDS-3. Combining GPS and BDS-3 further improves the RTOD precision to 23.9 cm. Furthermore, we show that the RTOD precision can be further improved by using GPS and BDS broadcast EOPs’ differences to correct ephemeris rotation errors. With this correction, the precision improvement of BDS-3 independent and GPS/BDS-3 combined RTOD increases significantly when BDS-3 broadcast EOPs suffer large errors due to long update intervals. During the experiment period, their maximum orbital improvements reach 10.2 and 7.7 cm, respectively, while the average improvements are both around 1.5 cm.

Performance assessment of continuously operating reference stations using the deemed rover analysis approach with NRTK GNSS technique in Thailand

The study initiated an evaluation of the GNSS continuously operating reference stations (CORS) performance for Network-based Real-Time Kinematic (NRTK) positioning in Thailand, using the deemed rover analysis approach. Fifty CORS were selected as rovers with varying network geometries. Results indicated the highest performance, 79.9% of fixed solutions, for an average triangle side length of 54 km, while the lowest performance, 29.9%, was observed for a 93 km length with accuracies at a decimetre level. These initial explorations suggest that reducing side lengths enhances fixed solution efficiency and positioning accuracy at rovers. Occasional metre-level errors occurred, potentially linked to Internet instability.

Global Digital Elevation Model Comparison Criteria: An Evident Need to Consider Their Application

From an extensive search of papers related to the comparison of Global Digital Elevation Models (hereinafter GDEMs), an analysis is carried out that aims to answer several questions such as: Which GDEMs have been compared? Where have the comparisons been made? How many comparisons have been made? How have the assessments been carried out? Which is the GDEM option with the lowest RMSE? Analysis shows that SRTM and ASTER are the most popular GDEMs, that the countries where more comparisons have been made are Brazil, India, and China, and that the main type of reference data for evaluations is the use of points surveyed by GNSS techniques. A variety of criteria have been found for the comparison of GDEMs, but the most used are the RMSE and the standard deviation of the elevation error. There are numerous criteria with a more user-centric character in thematic areas, such as morphometry, geomorphology, erosion, etc. However, in none of the thematic areas does there exist a standard method of comparison. This limits the possibilities of establishing a ranking of GDEMs based on their user-focused quality. In addition, the methods and reference data set are not adequately explained or shared, which limits the interoperability of the studies carried out and the ability to make robust comparisons between them.

A new technical pathway for extracting high accuracy surface deformation information in coal mining areas using UAV LiDAR data: An example from the Yushen mining area in western China

Western China is the world’s major coal-producing area, accounting for 1/3 of global coal production. Large-scale underground coal mining has led to serious ground deformation that has unique spatial and temporal characteristics. However, there are obvious engineering limitations to using GNSS, InSAR, and other common measurement techniques for monitoring mining subsidence. In recent years, researchers have attempted to use UAV LiDAR to monitor subsidence in mining areas. Point clouds are obtained through periodic ground scanning. Surface subsidence information is extracted through the filtering, modeling, and superposition processes. Conventional point cloud processing usually produces subsidence models that are too noisy and only provide information on surface subsidence. This means that it is unable to capture the horizontal ground displacement accompanying subsidence in mining areas, which hinders the practical application of this technology. A local flat point extraction (LFPE) algorithm based on geomorphic features is proposed. The algorithm extracts flat surface point clouds from the scan data and calculates the precise subsidence value of the ground by superposition to facilitate deformation monitoring. The obtained subsidence volume is spatially interpolated based on the unique spatial distribution characteristics of the mining subsidence basin to generate the initial surface subsidence model. By denoising this model, we can obtain a fine surface subsidence model that avoids significant noise caused by non-ground point clouds participating in modeling and superposition in common processing methods. On this basis, we successfully extracted the horizontal displacement information accompanying subsidence by employing sub-pixel correlation using the surface feature images before and after subsidence. The proposed technical pathway was validated by applying it to a coal mining subsidence area in the Yushen mining area in western China. Results demonstrate that, compared to conventional treatments, the proposed subsidence modeling method using laser scanning point clouds improves monitoring accuracy by over 50% while also obtaining the necessary horizontal displacement information for engineering requirements. These findings confirm the efficiency and accuracy of the proposed method for acquiring 3D surface deformation in mining areas.

Nonlinear Regression-Based GNSS Multipath Dynamic Map Construction and Its Application in Deep Urban Areas

GNSS signals are easily blocked or degraded because of the dense presence of high-rise buildings in urban areas, and positioning errors arising from reflected signals amount to as much as hundreds of meters. Various conventional GNSS techniques have been utilized to resolve this problem, but applying them to urban environments has been difficult owing to the complexity of the reflected signals and their unpredictable and nonlinear variation to the signal receiving environments. In this study, multipath maps were generated for dynamic users at multiple positions on a road and a residual-based map selection algorithm was implemented to solve the problem of user position uncertainty in deep urban environments. GNSS data collected over a period of 327 min were used to train the multipath maps corresponding to 247 points near the 2.5 km stretch of the Teheran-ro road in Seoul, South Korea. The proposed system performed efficiently—it was verified to be capable of constructing a multipath map with a radius of 25 m using only 4 min of data. Moreover, it improved positioning accuracy by 45 % horizontally and by 80 % vertically, enabling the determination of the positional information of an urban vehicle with a horizontal accuracy of 18 m during 99% of the duration of a one-hour-long dynamic test. Due to the nonreliance of the proposed method on prior information or implementation of additional sensors, it is expected to be widely used for constructing map-based multipath mitigation models as part of intelligent transportation infrastructure in all cities in future.

EDM-GNSS distance comparison at the EURO5000 calibration baseline: preliminary results

Abstract At the Pieniny Klippen Belt in Poland, the novel primary reference baseline EURO5000 is required as part of the European Research project GeoMetre to both validate refractivity-compensated EDM prototypes and investigate the metrological traceability of GNSS-based distances. Since the aimed uncertainty is 1 mm at 5 km (k = 2), the design, construction, and validation must be carefully prepared to fulfil the high standards of the GeoMetre field campaigns which are planned to be carried out in May 2022. This contribution describes the main features of the EURO5000 and presents the results of the preliminary validation which includes a first comparison between the results obtained by using precise currently available EDMs as well as GNSS techniques following the standard GNSS geodetic processing algorithms, on the one hand, and the improved GNSS-Based Distance Meter (GBDM+) approach developed at UPV, on the other hand. The preliminary validation presented in this contribution also permits (1) to detect potential problems in the use of the baseline such as potential geodynamic problems, atmospheric refraction or multipath limitations, (2) to produce a set of reliable results, and (3) to pave the way for the final field comparisons between the novel EDMs and the GBDM+ approach. The result of this metrological experiment may significantly contribute to overcome the limitations of current high-precision deformation monitoring applications that require their scale to be consistent with the SI-metre within 0.1 ppm in several km.

Fixed-Wing UAV Flight Operation under Harsh Weather Conditions: A Case Study in Livingston Island Glaciers, Antarctica

How do the weather conditions typical of the polar maritime glaciers in the western Antarctic Peninsula region affect flight operations of fixed-wing drones and how should these be adapted for a successful flight? We tried to answer this research question through a case study for Johnsons and Hurd glaciers, Livingston Island, using a fixed-wing RPAS, in particular, a Trimble UX5 UAV with electric pusher propeller by brushless 700 W motor, chosen for its ability to fly long distances and reach inaccessible areas. We also evaluated the accuracy of the point clouds and digital surface models (DSM) generated by aerial photogrammetry in our case study. The results were validated against ground control points taken by differential GNSS techniques, showing an accuracy of 0.16 ± 0.12 m in the vertical coordinate. Various hypotheses were proposed and flight-tested, based on variables affecting the flight operation and the data collection, namely, gusty winds, low temperatures, battery life, camera configuration, and snow reflectivity. We aim to provide some practical guidelines that can help other researchers using fixed-wing drones under climatic conditions similar to those of the South Shetland Islands. Performance of the drone under harsh weather conditions, the logistical considerations, and the amount of snow at the time of data collection are factors driving the necessary modifications from those of conventional flight operations. We make suggestions concerning wind speed and temperature limitations, and avoidance of sudden fog banks, aimed to improve the planning of flight operations. Finally, we make some suggestions for further research.

Assessment of Shoreline Change Along The Sandy Beach of Ellembelle District of Ghana

Sandy beaches are most popular tourists and fish landing sites, and serve as habitat for several endangered species. However, sandy beaches more vulnerable to coastal erosion, particularly those along open oceans. Assessment of shoreline change using reliable dataset aid in understanding the morphology of coastal landforms, the processes associated with their occurrence and support decision making. This paper analysed available multi-temporal spatial dataset and field observations using GNSS techniques to assess the shoreline change along the study area. The shoreline features were extracted from 1974 topographic map and 2005 orthophotographs using the High Water Line (HWL) in conjunction with 2020 spatial data. Shoreline change statistics were computed using DSAS. A geodatabase was created, transects were cast and the shoreline change rates computed using EPR, LRR and WLR methods. Both accretion and erosion were recorded with mean erosion rate of 0.97 m/year. It was observed that sections of the shoreline nourished by Ankobra and Amunzuri rivers were experiencing some accretion, particularly the mouth of the Amuzuri river. The estuary of Amunzuri river was found to be drifting eastwards at a rate of 5.4m/year possibly due to tides, waves and currents. The study concludes that in spite of the littoral drift eastwards, fluvial sediment supplied by coastal rivers accounts for the relative stability of shoreline in the area. Policy formulation regarding possible damming of coastal rivers by government under the ‘one district one dam’ agenda must be carefully considered to avert high levels of erosion along the western coast of Ghana.

Comparative analysis among Asia–Pacific geoid models stored at the ISG repository

Geoid models have important applications in geosciences as well as engineering, for example, for the conversion from ellipsoidal heights observed by GNSS techniques to orthometric heights. To meet the user’s demands, the International Service for the Geoid (ISG, https://www.isgeoid.polimi.it/) provides access to a repository of local, regional, and continental geoid models through its website. Among hundreds of worldwide models, there are many covering countries in the Asia–Pacific area. The focus of this study is about this region, performing a series of analyses to assess the geoid models stored in the ISG repository through some relative comparisons. In particular, three kinds of analyses are performed with the purpose of: (a) investigating the evolution in time of a geoid series referring to the same country, (b) comparing the information provided by local and regional geoid models on overlapped areas, and (c) assessing the agreement between local and global models. These analyses are firstly performed on sample models, providing a detailed description, and then applied to all Asia–Pacific geoid models currently stored in the ISG repository, providing summary statistics.

GNSS Tekniği ile Düşey Yöndeki Deformasyonların Araştırılması

Monitoring and analysis of deformations in the earth's crust and engineering structures are among the important issues of geodesy. In order to monitor the deformations, a geodetic network consisting of reference and object points is created in general. Deformation research is carried out by analyzing the movements at the network points. Measurements for the determination of these movements can be made with classical techniques as well as with GNSS techniques. The static relative positioning is a widely used method in such precise geodetic applications. In this study; the capacity of the GNSS technique to detect vertical deformations was investigated. For this purpose, a micro geodetic network was designed in the Selcuk University Campus area. A mechanism to create virtual deformations was placed on the object point in the designed network and periodic measurements were carried out by creating virtual deformations in the vertical direction. Measurements were processed with the Bernese v5.2 scientific GNSS software, analyzed by Iterative Weighted Similarity Transformation Method using the software developed to perform deformation analysis in GNSS networks, and the determined deformations were compared with the real deformation value, considering the ionospheric activities on the measurement days. As a result of the analyses, vectorial deformation amounts compatible with the real deformation value were obtained and it was seen that the motion amounts in the direction of the coordinate components were also compatible with the virtual deformation amount given on the mechanism.

Investigation of the effects of different flight parameters on the accuracy of DEM generated using UAV systems

Unmanned Aerial Vehicles (UAVs), can be controlled automatically or with the help of a remote control system, provide high spatial and temporal resolution images in addition to its advantages in terms of cost and time. Due to these features, UAV’s have been widely used in studies such as map production, 3D modeling and volume calculation in recent years. In this study, it is aimed to investigate the effects of different flight parameters on the accuracy of Orthomosaic and DEM produced with UAV Systems. In addition, the rolling shutter effect and the use of pre-calibrated and automatic camera calibration parameters were also tested. For this purpose, a total of seven UAV flights were carried out at different heights, overlap ratios, angles and grids at a mining area located within the borders of Aksaray province. Agisoft MetaShape and Pix4D Mapper, which are widely used commercial software, were used to process the UAV images. In this study, 27 points were established and 3D coordinates of these points were measured using GNSS technique. 15 of these points were used as reference points and the remaining 12 points were used as check points. Accuracy analysis was performed by comparing the produced Orthomosaics and DEMs with the check points in the study area. CloudCompare and ArcGIS software were used in the comparison of the products as a result of the evaluation of the images. It is concluded that the Orthomosaics produced using 450 angle and DEMs with 600 angle has higher accuracy than the others. Point clouds and DEMs’ produced using automatic and pre-calibrated camera calibration parameters show that the pre-calibrated images provide higher accuracy. Also, it is seen that when the rolling shutter effect is modeled, the horizontal and vertical accuracy is increased in all three flights with different flight parameters in this study.

Kültürel mirasın belgelemesinde lazer tarayıcıların kullanılması

Cultural heritage is all tangible or intangible assets that carry traces of the past of the society, as well as transferring knowledge in terms of social, political, cultural accumulation and technical equipment used. Once the tangible or intangible cultural heritage is destroyed, it cannot be replaced, so it must be made sustainable, protected and documented. Different techniques have been applied for the documentation of cultural heritages in the past and today. These techniques can be divided into traditional and technological. Although traditional techniques are insufficient for damaged or sensitive detail measurements, they have begun to be abandoned due to their low sensitivity and slowness. Today, traditional documentation techniques have been replaced by technological documentation techniques with fast, optimal cost, high accuracy and precision. Some of the technological documentation techniques; documenting with total station, GNSS, lidar, photogrammetry and laser scanning technique. In this study, the definition and importance of cultural heritage is explained and the comparison of traditional and technological methods; the subtleties of the laser scanning technique, which is one of the technological methods, and its comparison with other techniques; Classification of laser scanners, working principles of laser scanners and technical features of terrestrial laser scanners of some commercial companies are explained. As a result, this study will answer the question of why I should / should not use laser scanning technique in the documentation of a cultural heritage and can be used as a base for future studies.

INTEGRATION OF UAV-LIDAR AND UAV-PHOTOGRAMMETRY FOR INFRASTRUCTURE MONITORING AND BRIDGE ASSESSMENT

Abstract. The health assessment of strategic infrastructures and bridges represents a critical variable for planning appropriate maintenance operations. The high costs and complexity of traditional periodical monitoring with elevating platforms have driven the search for more efficient and flexible methods. Indeed, recent years have seen the growing diffusion and adoption of non-invasive approaches consisting in the use of Unmanned Aerial Vehicles (UAVs) for applications that range from visual inspection with optical sensors to LiDAR technologies for rapid mapping of the territory. This study defines two different methodologies for bridge inspection. A first approach involving the integration of traditional topographic and GNSS techniques with TLS and photogrammetry with cameras mounted on UAV was compared with a UAV-LiDAR method based on the use of a DJI Matrice 300 equipped with a LiDAR DJI Zenmuse L1 sensor for a manual flight and an automatic one. While the first workflow resulted in a centimetric accurate but time-consuming model, the UAV-LiDAR resulting point cloud’s georeferencing accuracy resulted to be less accurate in the case of the manual flight under the bridge for GNSS signal obstruction. However, a photogrammetric model reconstruction phase made with Ground Control Points and photos taken by the L1-embedded camera improved the overall accuracy of the workflow, that could be employed for flexible low-cost mapping of bridges when medium level accuracy (5–10 cm) is accepted. In conclusion, a solution for integrating interactively final 3D products in a Bridge Management System environment is presented.

COMBINING UNMANNED AERIAL SYSTEMS AND STRUCTURE FROM MOTION PHOTOGRAMMETRY TO RECONSTRUCT THE GEOMETRY OF GROINS

Abstract. In the context of coastal environment, the combined use of Unmanned Aerial Systems (UAS) with Structure-from-Motion (SfM) photogrammetry has been demonstrated to be a suitable tool to collect accurate geoinformation. This work aims at investigating the effectiveness of UAS survey to accurately map the geometry of rouble mound groins for monitoring the structural integrity. A set of nadiral images was processed through SfM photogrammetry to obtain the Digital Surface Model (DSM) of the groin. The DSM accuracy was evaluated through the comparison of five profiles measured by the traditional GNSS technique. Overall, vertical accuracy returned a root mean square error of 2.6 cm. The results suggest that UAS combined with SfM photogrammetry can improve the current monitoring of coastal engineering structures by providing high accurate geospatial products.

Construction of nominal ionospheric gradient using satellite pair based on GNSS CORS observation in Indonesia

Ground-Based Augmentation System (GBAS) is a GNSS augmentation system that meets International Civil Aviation Organization (ICAO) requirements to support precision approach and landing. GBAS is based on local differential GNSS technique with reference stations located around an airport to provide necessary integrity and accuracy. The performance of the GBAS system can be affected by gradient in the ionospheric delay between aircraft and reference stations. A nominal ionospheric gradient, which is bounded by a conservative error bound, is represented by a parameter σvig. The parameter σvig is commonly determined using station pair to GNSS Continuous Operating Reference Station (CORS) data. The station-pair method is susceptible to doubling of the estimation error of receiver inter-frequency bias (IFB) and is not suitable with the CORS conditions in Indonesia. We propose a satellite-pair method that is found to be more suitable for the CORS network over Indonesia which is centered in Java and Sumatra islands. An overall value of σvig (5.21 mm/km) was obtained using this method along with preliminary results of a comparison of σvig from Java and Sumatra islands.Graphical

GPS Results from Long Time Monitoring of Geodynamic Processes in South-Western Bulgaria

Monitoring of geodynamic processes by modern GNSS techniques in the area of Sofia and South-Western Bulgaria has continued for 25 years. To study the modern crustal movements in the area, Global Positioning System (GPS) data acquired between 1996 and 2021 are analyzed to obtain the velocity field for South-Western Bulgaria. For a time period of almost 25 years, the monitoring has covered 28 stations. They have been measured in different years and in a number of campaigns. Despite the difference in the measurements, the obtained results are quite homogeneous in the different localities of the studied area and show clear uniform tendencies. All velocities are in the southern direction. They are in the range of 1.5 mm/year to slightly over 3 mm/year, almost reaching 4 mm/year. The velocities of the stations tend to increase from north (stations around Sofia), passing through an intermediate locality (between Sofia and Kyustendil–Pazardhik), clearly increasing in the southernmost part of the country (around Gotse Delchev). This velocity field motivates N–S expressed extension with increasing rates from North to South. The difference in the velocity rates tends to change along geologically suggested active fault zones. The obtained results generally confirm previously data, but with much better accuracy and details at the local level. This way, both the repeated measurements and extension of the geodynamic network prove to be a powerful tool for a better understanding of present-day geodynamics.

Detection of Particulate Matter Changes Caused by 2020 California Wildfires Based on GNSS and Radiosonde Station

From August to October 2020, a serious wildfire occurred in California, USA, which produced a large number of particulate matter and harmful gases, resulting in huge economic losses and environmental pollution. Particulate matter delays the GNSS signal, which affects the like precipitable water vapor (LPWV) derived by the GNSS non-hydrostatic delay. Most of the information of GNSS-derived LPWV is caused by water vapor, and a small part of the information is caused by particulate matter. A new method based on the difference (ΔPWV) between the PWV of virtual radiosonde stations network and GNSS-derived LPWV is proposed to detect the changes of particulate matter in the atmosphere during the 2020 California wildfires. There are few radiosonde stations in the experimental area and they are far away from the GNSS station. In order to solve this problem, we propose to use the multilayer perceptron (MLP) neural network method to establish the virtual radiosonde network in the experimental area. The PWV derived by the fifth-generation European center for medium-range weather forecasts reanalysis model (PWVERA5) is used as the input data of machine learning. The PWV derived by radiosonde data (PWVRAD) is used as the training target data of machine learning. The ΔPWV is obtained based on PWV derived by the virtual radiosonde station network and GNSS in the experimental area. In order to further reduce the influence of noise and other factors on ΔPWV, this paper attempts to decompose ΔPWV time series by using the singular spectrum analysis method, and obtain its principal components, subsequently, analyzing the relationship between the principal components of ΔPWV with particulate matter. The results indicate that the accuracy of PWV predicted by the virtual radiosonde network is significantly better than the fifth-generation European center for the medium-range weather forecast reanalysis model, and the change trend of ΔPWV is basically consistent with the change law of particulate matter in which the value of ΔPWV in the case of fire is significantly higher than that before and after the fire. The mean of correlation coefficients between ΔPWV and PM10 at each GNSS station before, during and after wildfires are 0.068, 0.397 and 0.065, respectively, which show the evident enhancement of the correlation between ΔPWV and particulate matter during wildfires. It is concluded that because of the high sensitiveness of ΔPWV to the change of particulate matter, the GNSS technique can be used as an effective new approach to detect the change of particulate matter and, then, to detect wildfires effectively.