4.2 RTK Positioning

Hardware Setup

The L2 Pro and K2 both provide RTK, but the hardware differs. The L2 Pro uses an external RTK module that attaches to the top of the scanner. The K2 has a built-in UM980 RTK module, so there is no module to attach.

L2 Pro RTK Modules

The L2 Pro offers two RTK modules. The difference is how reliably the antenna holds a fix in poor conditions. Both use the same satellite constellations (GPS, GLONASS, BDS, Galileo) and publish the same accuracy: 0.8 cm + 1 ppm horizontal, 1.5 cm + 1 ppm vertical.

The Standard module (2.8 dBi maximum gain) acquires and holds Fixed status in open sky with minimal obstructions. The Survey-Grade module (5.5 dBi maximum gain) reaches Fixed faster and holds it longer in degraded conditions: partial tree canopy, urban sites, loading docks with overhead cover, and anywhere reflected signals compete with direct ones. Its tighter design rejects multipath, the signals that bounce off metal, glass, and concrete before reaching the antenna.

Select the correct RTK type on the LixelGO startup screen before scanning. The wrong type can degrade position quality even when the module is working.

K2 Built-In RTK

The K2's built-in UM980 is a survey-grade multi-band receiver. There is no module to attach and no module type to select; it powers up with the scanner. The K2 uses the same NTRIP correction workflow as the L2 Pro.

Before Any RTK Session

• Confirm the scanner is running current firmware; older firmware does not support RTK
• For the L2 Pro, attach the RTK module and confirm the connection is secure
• Give the antenna a clear view of the sky, unobstructed by buildings, vehicles, or overhangs
• Keep antenna tilt within 20 degrees of vertical during scanning
• Confirm the status reaches blue (connected, not yet fixed) before entering NTRIP credentials

NTRIP Configuration

RTK corrections arrive over the internet via an NTRIP service (Networked Transport of RTCM via Internet Protocol). Your provider supplies a host, port, mountpoint, username, and password. Enter these in the RTK settings screen in LixelGO before scanning.

Status Indicators

The L2 Pro module has three hardware light states with a matching software status in LixelGO. The K2 has no external module light; its RTK status appears in LixelGO only. The app status applies to both devices.

Minimum Validity Requirements

RTK data below these thresholds may still attempt conversion, but with compromised accuracy. Meet all of them for reliable georeferencing.

Maintaining RTK Fix During Scanning

A fix is not guaranteed to persist. Buildings, trees, canyon walls, and overhead structures attenuate satellite signals. When the fix drops, the scanner keeps recording, but that part of the trajectory is not anchored to absolute coordinates.

After the fix is confirmed, walk an L-shaped route of at least 10 m (33 ft) per leg before the primary scan. This gives the system confirmed geometry to anchor the coordinate frame.

• For the L2 Pro, any continuous unfixed section must be shorter than 100 m (330 ft) for RTK to stay valid across the dataset
• For the K2, any continuous unfixed section must be shorter than 50 m (165 ft)
• Sections longer than these limits break trajectory continuity and may cause processing failure or degraded georeferencing in the affected area
• Monitor RTK status in LixelGO; satellite count and status display continuously
• When entering an area that will block signal (covered parking, covered dock), note your position first and plan to exit the same way to restore the fix

RTK Indoors: What It Can and Cannot Do

RTK cannot reach a Fixed solution indoors; the structure blocks the satellite signals needed to establish a fix. A fix established outdoors before entering, however, carries across the threshold, and the scanner assigns absolute coordinates to the indoor path for the device carry-in distance: about 100 m (330 ft) for the L2 Pro and about 50 m (165 ft) for the K2. Beyond that distance, RTK no longer anchors the trajectory.

Reaching Interior Areas Beyond Carry-In Range

For facilities larger than a single entry's carry-in distance, plan multiple RTK-initialized entry segments and connect them with Map Fusion, then use surveyed GCPs for any interior beyond RTK reach. See 4.7 for the full method, including overlap planning and GCP placement.