5:15 PM - 6:45 PM
[SGD01-P11] Development and test observation of compact and small GNSS observation instrument
Keywords:GNSS, Crustal deformation
Geospatial Information Authority of Japan (GSI) operates more than 1,300 GNSS Continuously Operating Reference Stations (GNSS CORSs) nationwide, and the observation data are often used for monitoring crustal deformation. On the other hand, we need dense observation network to grasp mesoscale (tens of kilometers) deformation because the CORSs whose intervals are 20 km in average cannot detect such local deformation. Under the background, small-sized and high mobility GNSS observation instrument has become popular in recent years. If it is possible to observe with comparable accuracy to that of conventional instruments using the small and maneuverable system, we could monitor the mesoscale deformation with sufficient measurement accuracy.
GSI has developed methods to model both wide and local deformation with a dense GNSS observation network (Kokado, 2020). To realize the dense network by deploying numerous observation sites, we have developed small and compact GNSS instrument. The developed instrument is composed of compact and small GNSS antenna (Septentrio PolaNt-x MF) and receiver module (Mosaic), enabling high mobility. To validate the detectability of crustal deformation, we have installed the instruments to the Noto Peninsula, Ishikawa prefecture where seismic activity has been continuing since December 2020 and Chiba prefecture where mesoscale ground subsidence proceeds.
In the Noto Peninsula, GSI has installed the Removable GNSS Monitoring System (REGMOSS) on July, 2022. REGMOS is the observation system which has solar panel and observable with no supply from external power. We installed our device at the same site in July, 2022 and started observation to compare the measurement accuracy with that of REGMOS.
In this study, we evaluated the observation stability by changing the observation conditions step by step. First, to investigate the receiver performance, we installed our GNSS antenna on the body of REGMOS. Next, we started autonomous observation by setting the antenna to a tripod-shaped stand made of steel. At this stage, the power was supplied from REGMOS. The standard deviation before and after installation of the stand are 0.9 mm -> 1.1 mm, 1.3 mm -> 1.2 mm, and 3.8 mm -> 3.6 mm for east-west (E-W), north-south (N-S), and up-down (U-D) direction, respectively, meaning that there is no serious changes. Unfortunately, the power supplied from REGMOS stopped due to lack of sunlight in January, 2023, and the observation also stopped. We resumed the power supply by solar panels specified for our instrument since June, 2023. An earthquake (Mw 6.5) occurred on May 5th2023 while our instrument had stopped the observation. We calculated the coseismic displacements by taking the difference between the daily coordinate data before and after the earthquake; 11.5 mm in E-W, 1.8 mm in N-S, and 120.7 mm in U-D for our instrument, and 10.8 mm in E-W, 0.5 mm in N-S, and 122.9 mm in U-D for REGMOS respectively. The difference between the coseismic displacements obtained by our instrument and REGMOS is only 2mm for each component. The results show that our small and compact GNSS instrument has stable performance comparable to REGMOS.
We have also installed the instruments to the Boso peninsula, where 30 sites are deployed; 10 sites since 2021 and 20 sites in 2023. In this presentation, we will report the status of observation in this study area.
Reference:
Kokado (2020): Development of GNSS Observation System utilizing Low-Cost Antenna and Receiver, 134th Meeting of the Geodetic Society of Japan Abstracts, 135-136.
GSI has developed methods to model both wide and local deformation with a dense GNSS observation network (Kokado, 2020). To realize the dense network by deploying numerous observation sites, we have developed small and compact GNSS instrument. The developed instrument is composed of compact and small GNSS antenna (Septentrio PolaNt-x MF) and receiver module (Mosaic), enabling high mobility. To validate the detectability of crustal deformation, we have installed the instruments to the Noto Peninsula, Ishikawa prefecture where seismic activity has been continuing since December 2020 and Chiba prefecture where mesoscale ground subsidence proceeds.
In the Noto Peninsula, GSI has installed the Removable GNSS Monitoring System (REGMOSS) on July, 2022. REGMOS is the observation system which has solar panel and observable with no supply from external power. We installed our device at the same site in July, 2022 and started observation to compare the measurement accuracy with that of REGMOS.
In this study, we evaluated the observation stability by changing the observation conditions step by step. First, to investigate the receiver performance, we installed our GNSS antenna on the body of REGMOS. Next, we started autonomous observation by setting the antenna to a tripod-shaped stand made of steel. At this stage, the power was supplied from REGMOS. The standard deviation before and after installation of the stand are 0.9 mm -> 1.1 mm, 1.3 mm -> 1.2 mm, and 3.8 mm -> 3.6 mm for east-west (E-W), north-south (N-S), and up-down (U-D) direction, respectively, meaning that there is no serious changes. Unfortunately, the power supplied from REGMOS stopped due to lack of sunlight in January, 2023, and the observation also stopped. We resumed the power supply by solar panels specified for our instrument since June, 2023. An earthquake (Mw 6.5) occurred on May 5th2023 while our instrument had stopped the observation. We calculated the coseismic displacements by taking the difference between the daily coordinate data before and after the earthquake; 11.5 mm in E-W, 1.8 mm in N-S, and 120.7 mm in U-D for our instrument, and 10.8 mm in E-W, 0.5 mm in N-S, and 122.9 mm in U-D for REGMOS respectively. The difference between the coseismic displacements obtained by our instrument and REGMOS is only 2mm for each component. The results show that our small and compact GNSS instrument has stable performance comparable to REGMOS.
We have also installed the instruments to the Boso peninsula, where 30 sites are deployed; 10 sites since 2021 and 20 sites in 2023. In this presentation, we will report the status of observation in this study area.
Reference:
Kokado (2020): Development of GNSS Observation System utilizing Low-Cost Antenna and Receiver, 134th Meeting of the Geodetic Society of Japan Abstracts, 135-136.