Real-Time QC Monitoring in HYPACK: Monitoring HDOP and Fixed RTK for Accurate Surveying

 Introduction: During a live hydrographic survey, watching the depth pings is not enough. You must monitor the quality of your positioning data in real-time. If your GNSS quality drops without you noticing, your entire day's work could be rejected during processing.

Figure 1: A real-time HYPACK survey interface showing active data logging with a perfect "Fixed RTK" status (Mode 4), ensuring centimeter-level vertical and horizontal accuracy.

Key QC Parameters to Monitor:

• Fixed RTK Status: Always ensure your survey software (like HYPACK) shows "Fixed" status. A "Float" or "DGPS" status means your vertical accuracy is compromised.

• HDOP & PDOP: Horizontal and Position Dilution of Precision. Ideally, these values should be below 2.0. High values indicate poor satellite geometry, which leads to positioning errors.

• Latency: Check the time delay between your GNSS and Echo Sounder data. High latency causes a "shift" in your data points during turns.

Expert Tips: Set up an alarm in your acquisition software to alert you if the RTK fix is lost. It's better to pause the survey and fix the link than to collect unusable data.