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RTK monitoring under high
ionospheric activity
Author: Bence Takács
Budapest University of Technology and Economics
Faculty of Civil Engineering
Budapest, Hungary
PLAN
1. 11-year period of sunspot number
2. Quality monitoring of active GNSS networks
3. Developed quality monitoring methods:
1. with RTKLIB
2. with u-blox
4. Results
1. with RTKLIB
2. with u-blox
5. Conclusions
Approaching to the 25 solar sunspot maximum
30 March 202330 March 2018
Quality monitoring in gnssnet.hu
Geo++ GNSMART
Quality monitoring page:
•Number of active stations
•Number of available streams
•Number of satellites
•State of the ionosphere
2nd motivation: lack of monitor stations
Ionosphere modelling in gnssnet.hu
One week in April 2023 One week in September 2023Recent year
IPI=Irreguraltiy Parameter of Ionosphere
As a rule of thumb: IPI>5cm →initialization might be difficult
3rd motivation: measure the correlation between IPI and initialization performance
Quality monitoring with RTKLIB
•Monitoring stations with Septentrio AsteRx4 receivers (GPS+GLO+GAL+BDS, L1+L2+L5)
in the Hungarian E-GNSS network, in cooperation with PildoLabs and Hungarocontrol
•Hourly files with raw observations, one-hour latency
•Automated data post-processing in RTK mode with different scenarios using RTKLIB
demo5:
•With different satellite constellations
•From different RTK service providers
•With different network RTK concepts / streams / mountpoints
•Statistical parameters in a database
•RTKLIB is less efficient than professional RTK GNSS receivers
Quality monitoring with u-blox f9p
•Low-cost GNSS receiver (~300eur), (GPS+GLO+GAL+BDS, L1+L2), with RTK engine
•RTKLIB (str2str) to get RTK corrections and log NMEA data, Raspberry Pi
•Restart the GNSS unit every 2.5 minutes, initialization time and accuracy are monitored
U-blox
R-pi
12V→15V
battery
wifi
Results with RTKLIB - Budapest
•corrections from BUTE station, vector length: ~ 13 km
•10 days results in April 2023
•Far from physical stations
Corrections from corrigo.hu:
Corrections from gnssnet.hu:
Results with RTKLIB – Győr-Pér GPS GPS+GAL
Results with u-blox f9p
•10 days results in September 2023
•corrections from gnssnet.hu VRS, vector length: ~3 km
CONCLUSIONS
3 motivations:
•Outliers at Hungarian station in EUPOS quality monitoring
•Lack of monitor stations
•Measure the correlation between IPI and initialization performance
Two methods have been developed for RTK accuracy and efficiency monitoring:
1. RTKLIB: automated near real-time post-processing in RTK mode
2. u-blox: act as a rover receiver, reinitialize on a regular basis
Well promising results over the recent tests
Real test is expected during the sunspot number maximum