Best practice for GNSS data collection

Best practices for minimizing errors during GNSS data collection

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Best field practices for collecting geospatial data

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GNSS measurement campaign for estimating surface kinematics

Data collection principles

• All input data and coordinates should refer to the pillar reference point, which has to be uniquely defined for each point.

• At least three non-overlapping (preferably consecutive) days of 48h observation session with 30-second sampling rate and simultaneous measurement of all network points should be used.

• Multi-frequency (e.g., L1, L2, E1, E5a, C1A) multi-constellation (GPS, GLONASS, Galileo, Beidou) GNSS data should be collected and used for the data processing.

• All GNSS antennas have to be individually calibrated in order to know the exact phase centre position for all frequencies depending on the satellite position (azimuth and elevation).

• Whenever possible, choke-ring antennas or other multipath-mitigating antennas should be used.

• Elevation masks should be measured at each point and applied to remove data below the obstruction mask in pre-processing, in order to reduce the impact of signal diffraction and repeated signal interruptions.

Field-data collection tips

• Hold receiver to south of your body
• Present to sky with as unobstructed view as possible
• Hold away the antenna from body
• Don’t place the antenna on ground
• Don’t turn upside down (unless you have an external antenna)
• Use an external antenna positioned above your head and shoulders

Data processing

• The raw GNSS data should be post-processed using a scientific software (e.g. the Bernese GNSS software.

• The processing parameters (configuration) should follow the IGS recommendations.

• At least 10 stable reference stations within a few hundred kilometers of the new/interesting points should be used for providing the geodetic datum in the post-processing.

  • Information on the stability of the European CORS can be obtained from the web-page of EPN.

• The transformation between ITRFYY and ETRFYY should be performed according to EPN TN-1, e.g. using the online transformation tool.

Documentation

• The data processing and results should be documented comprehensively in a technical report which covers all relevant aspects from campaign preparation and realisation, to data processing, transformations and final coordinates.

• All reported coordinates should be accompanied by the respective standard deviations ($1\sigma$).

• The raw GNSS data (in RINEX format), site logs, auxiliary data (orbits, atmospheric models, antenna calibrations etc.), configuration files and output files are listed in the technical report and provided as supplement to it.

External sources

Queensland Government, Guidelines GNSS Control Surveys

• link1, link2

UNAVCO knowledge base

Author: UNAVCO, Expertise level: 🌟🌟🌟🌟☆, Our score: 🌟🌟🌟🌟🌟 Link

Eight common mistakes in GNSS surveying and how to fix them

Author: Emlid, Sam Pepple, Expertise level: 🌟🌟🌟🌟☆, Our score: 🌟🌟🌟🌟☆

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Best practices for GNSS data collection [podcast]

Author: Dan Colbert and Jeff Ryan, Expertise level: 🌟🌟🌟☆☆, Our score: 🌟🌟🌟🌟☆

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Best practices for GNSS surveying

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