RTK Check Shot Difference Logger
A free, browser-based tool. Runs entirely in your browser — no sign up, nothing stored.
Check shots
| ID | Known E | Known N | Known RL | Meas E | Meas N | Meas RL | |
|---|---|---|---|---|---|---|---|
Residuals
| ID | dE | dN | dRL | Horiz | H/V |
|---|---|---|---|---|---|
| CP1 | 0.020 | 0.000 | 0.010 | 0.020 | ✓ ✓ |
| CP2 | 0.010 | 0.030 | 0.015 | 0.032 | ✗ ✓ |
How to use this calculator
- Set your horizontal and vertical tolerances.
- Add a row per check shot — the known control coordinate and the measured RTK coordinate.
- Read each shot's residual and pass/fail, plus the max and RMS for the set.
How it works
For each shot, dE/dN/dRL are measured minus known. The horizontal residual is √(dE² + dN²); it passes if it's within the horizontal tolerance, and the height passes if |dRL| is within the vertical tolerance.
RMS is the root-mean-square of the residuals across all shots — a good single number for the set's quality.
Frequently asked questions
Why check into known control?
An independent check shot catches a bad base set-up, wrong datum/height, or a poor fix before you trust a whole job's RTK data.
Is this official course material?
No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.