Using RAW GNSS Data Recorded on the CEESCOPE™ for Post Processed Precise Positioning in HYPACK®

A CEESCOPE™ with a NovAtel L1/L2 receiver (and the RTK CEESCOPE™ generally) can record raw GNSS data to internal memory or a USB drive. Post-processed against a fixed base station, it gives much more accurate position and elevation. This is useful when the deliverable needs accurate position and elevation but you can’t run an RTK base with a real-time radio link. Lower grade real-time GNSS is used for navigation during the survey, then replaced in software that supports it, such as HYPACK®.

How do I make the PPK file?

1. Export the raw GNSS data from the CEESCOPE™.
2. Convert it to RINEX (Receiver Independent Exchange) format.
3. Process it with third-party software or a service, adding reference station corrections, to get a PPK file, usually a CSV or similar text file.

The file needs at least time, position and height (if you also want level corrections). Time is critical: without it, the improved positions can’t be matched to the survey data.

A sample PPK file is shown below:

What should I check first?

• The PPK file must start before and finish after the survey.
• The antenna height may already be applied in the PPK file. Don’t apply it twice: set the HYPACK® antenna height to 0.00 if needed.
• Check the GNSS quality filter. In PPK, quality 1 is good; in NMEA output, 1 means uncorrected.

How do I apply it in HYPACK®?

1. Load the HYPACK® RAW file in the SBMax editor, tick Use Post Processed GPS and press Configure.
2. Set the parsing so HYPACK® reads the right columns. Add a time offset to convert GNSS time to local project time. Heights may already be corrected, or may need shifting from ellipsoid height to the project geodesy.
3. Load the data and process as normal.

For real-time options, see which GNSS corrections to use.