Leica ERR-002 Error: What It Means and How to Fix It

Applies to: Leica GS18, GS10, GS15 GNSS rovers

What Does ERR-002 Mean?

ERR-002 RTK Float indicates the Leica GNSS rover is receiving RTK corrections from the base station or VRS network, but the carrier-phase ambiguity resolution process has not yet completed. The receiver produces positions in float mode — which are valid GNSS positions but with significantly lower accuracy than a fixed solution.

A fixed RTK solution achieves 10-20mm accuracy. A float solution is typically 0.3-1.0 meter accurate. ERR-002 is a quality warning, not an error that prevents positioning. However, float-level positions should not be used for construction layout or survey work requiring centimeter accuracy.

Float is the normal intermediate state during initialization. ERR-002 becomes a problem when the receiver remains in float for more than 3-5 minutes under good sky conditions.

Common Causes of ERR-002

• Short baseline — receiver is still initializing and needs more time (normal for first 1-3 minutes)
• Long baseline over 20-30km — carrier-phase ambiguity resolution becomes unreliable at long ranges
• Multipath interference from buildings, vehicles, or metal structures near the antenna
• Poor satellite geometry (high PDOP) — weak geometry slows or prevents ambiguity resolution
• Ionospheric disturbance — space weather causing differential ionospheric delay errors
• Outdated base station coordinates — base occupying an incorrect position biases corrections

How to Fix Leica ERR-002 — Step by Step

1. Wait 2-3 minutes. Float is normal during initialization. If the receiver fixes within 3 minutes in a clear-sky location, the system is functioning normally.
2. Move away from metal structures, parked vehicles, and building faces. Multipath from nearby reflectors is the most common cause of prolonged float in construction environments.
3. Check baseline length in Leica Captivate. For reliable fixed RTK, keep the rover within 20km of the base station. Use a VRS/CORS network for longer baselines.
4. Enable all GNSS constellations. Additional satellites improve geometry and accelerate ambiguity resolution.
5. Verify the base station coordinate. An incorrectly entered base coordinate causes systematic errors that prevent integer ambiguity resolution.
6. Power cycle the rover to restart the ambiguity resolution engine with a fresh start.

When to Send It In for Service

Persistent float is almost always a site or baseline issue rather than a hardware fault. If float persists across multiple clear-sky locations with short baselines, contact Leica support for receiver diagnostics.

Frequently Asked Questions

How do I know if I have a float or fixed RTK solution on a Leica receiver?

Leica Captivate clearly displays the solution type: Fixed (green), Float (yellow), or Autonomous (no corrections). Always verify you have a Fixed solution before recording survey measurements.

Can I survey in float mode?

Float mode (0.3-1.0m accuracy) is not suitable for construction layout or survey measurements requiring centimeter accuracy. Float positions may be suitable for rough reconnaissance or GIS mapping where meter accuracy is acceptable.

How does ionospheric activity affect float RTK?

During geomagnetic storms (Kp index above 4-5), differential ionospheric delay errors increase, making carrier-phase ambiguity resolution slower or impossible. Monitor spaceweather.gov and plan critical survey work during quiet ionospheric periods.

Related Leica Error Codes

Leica GNSS ERR-001 No Satellites | Leica GNSS ERR-003 Age of Corrections