What is the accuracy difference between Fixed and Float RTK?

Fixed RTK typically delivers ±8 mm horizontal and ±15 mm vertical accuracy. Float RTK carries ±300–1000 mm of positioning error depending on baseline length and atmospheric conditions.

Why does my RTK show Fixed but coordinates are still wrong?

Common causes are a datum mismatch (wrong coordinate system), an incorrect geoid model applied to elevation, or an antenna height entry error.

How do I know if multipath is affecting my survey?

Multipath typically shows as unstable repeated measurements — the same physical point measured three times gives results differing by 20–50 mm rather than the expected ±8 mm.

Can I survey during ionospheric storms?

RTK accuracy degrades during geomagnetic storms (Kp index above 5). For precision engineering or cadastral surveys, postpone sessions until the Kp index drops below 3.

What is the maximum reliable CORS baseline for centimetre accuracy?

Most CORS networks guarantee ±10–20 mm horizontal accuracy within 50 km of the nearest reference station. Beyond 70 km, deploy a self‑deployed base station within 15 km of the survey area.

APEKS FAQ | How to Correct CAD Map Coordinates for Stakeout in ApekSurv

2025-08-11

How to Correct CAD Map Coordinates for Stakeout in ApekSurv

When working on CAD stakeout, you may sometimes find that the CAD map coordinates don't match the actual location on the ground. This mismatch can lead to errors, wasted time, and frustration.
Luckily, there's a simple solution — CAD Calibration in ApekSurv.

In this guide, we'll walk you through the step-by-step process to quickly fix your CAD map so you can continue your stakeout work with confidence.

Why CAD Calibration Is Important

When your CAD drawing is not aligned with the real-world coordinates, every measurement and point location will be off. CAD Calibration allows you to match points on your CAD map with actual control points in the field, ensuring accuracy for all future stakeout operations.

Step-by-Step: How to Perform CAD Calibration

1.Launch ApekSurv

On your data collector, open the ApekSurv application.

2. Go to CAD Stakeout

From the Survey menu, select CAD Stakeout.

3. Enable CAD Calibration

Go to Settings
Tap Tool bar
In Options, select CAD Calibration
Tap OK

4. Add Calibration Points

Tap the CAD Calibration icon on your stakeout screen
Tap Add
In the top-right corner, tap the icon to pick points from your base map

5. Select Your First Control Point

Tap the Snap icon
Choose one control point on the map
Under Known Point, either collect the point in real time or manually enter its coordinates
Tap OK

6. Select the Second Control Point

Repeat the same steps to choose your second control point.

7. Apply the Calibration

Tap Next
Check the residual values to ensure they are within limits
If everything is fine, tap Apply

Your CAD map is now calibrated and ready for accurate stakeout.

Tips for Better Results

Use well-surveyed control points for maximum accuracy
Make sure your Snap settings are enabled for precise point selection
Always check residuals before applying the calibration

Final Thoughts

By following these steps, you can quickly align your CAD map with the real-world coordinates, saving time and avoiding costly mistakes. CAD Calibration is a must-know tool for surveyors and engineers who work with stakeout operations.

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