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.

How to Quickly Check Control Points with RTK？

2025-10-22

How to Quickly Check Control Points with RTK

When working on a surveying project, it's very important to make sure the control points provided by the client are accurate and stable.
Today, let's look at a quick and simple way to check control points using an RTK.

🧭 Step 1: Input the control point coordinates

First, open your data collector.
On the Project page, click Points Database, then Add.
Enter the coordinates one by one — Northing, Easting, and Elevation.
Next, click Property Type, choose Input Point, and hit OK.

Repeat the same steps to add the second control point.

📍 Step 2: Measure the control points on site

Go to the Survey page and tap Point Survey.
Now, measure both control points in the field to get their actual (measured) coordinates.

⚙️ Step 3: Use coordinate inverse calculation

Go back to the Tools page and select Coordinate Inverse Calculation.
Click Point Coordinates, select the two control points you just entered, and tap Calculate.
Write down the plane distance between these two points.

Then, repeat the same process —
but this time, use the coordinates you just measured on site.
Click Calculate again.

📏 Step 4: Compare the distances

Now, compare the plane distance from the input coordinates with the distance from the measured coordinates.

✅ If the difference is within the project's allowed error range, the control points are fine.
⚠️ But if the error is too large, you should contact the client to redo the control points.

💡 Principle behind this method

This quick check works by comparing the relative positions of two sets of coordinates through inverse calculation.
If the difference is small, it means the control points haven't been moved or damaged.
If not, there might be a problem with one of them.

⚠️ Important reminder

This method is only for a quick preliminary check.
If you need precise and reliable data, you'll have to perform a traverse or a static survey instead.

🧩 Final thoughts

A simple inverse calculation can save you a lot of time during field work.
It's a quick way to ensure your control points are still valid before starting detailed measurement —
because no one wants to find out their base is off after collecting a whole day's data!