XGRIDS Pro Guide™ / Module 4: Positioning

4.8 Positioning Visual

Interactive diagram showing how satellite signals, base stations, and correction methods combine to produce survey-grade scanner accuracy.

Section 1

How Corrections Reach the Scanner

Every GNSS correction method begins with the same source: satellites. The raw satellite signal alone is accurate to roughly 3 to 16 ft (1 to 5 m) because the signal is distorted by the ionosphere, troposphere, and satellite clock drift. A receiver at a known location measures those distortions and produces correction data that cancels most of the error, bringing the result to 1.2 in (3 cm) RMSE or better.

This page is a visual companion to 4.2 RTK Positioning and 4.3 PPK Positioning, which cover configuration steps, field requirements, and decision criteria in full. Read those pages first. Use this diagram to understand signal flow before going to site.

Section 2

GNSS Correction Signal Flow

Interactive GNSS correction signal flow diagram Live-rendered SVG component on the production page. Shows satellite signal paths to both the rover (scanner) and the base station / CORS network, the correction data path from the base or CORS back to the rover via NTRIP, the PPK path where raw RINEX from both rover and base is processed together after the scan, and the final output: a georeferenced point cloud at approximately 1.2 in (3 cm) RMSE accuracy.

Georeferenced Point Cloud (after processing). Verify valid data points exceed 100 before processing. Any gap in the RINEX file cannot be filled after the fact. Accuracy: approximately 1.2 in (3 cm) RMSE or better in ideal conditions.

Section 3

Method Comparison

RTK via CORS / NTRIP

WhyYou can connect to NTRIP. A CORS network covers the project area and you have cellular or Wi-Fi at the site.

Correction timingLive, during the scan.

What you needMobile data or Wi-Fi. NTRIP credentials from your CORS provider (host, port, mountpoint, username, password).

What you skipAny base station equipment. No post-processing.

Critical riskA dropped NTRIP connection stops corrections immediately. That portion of the trajectory is not recoverable.

Device supportL2 Pro (external Standard or Survey grade module) and K2 (built-in UM980). Same NTRIP workflow on both.

RTK via Your Own Base

WhyYou are out of range of a CORS/NTRIP network but have internet at the site. You deploy your own base station at a known point.

Correction timingLive, during the scan, delivered via NTRIP.

What you needA multi-band GNSS receiver (such as an Emlid Reach RS3) at a known control point within 3.1 mi (5 km). In LixelGO, select Custom RTK type and enter the base NTRIP host, port, and mountpoint.

What you skipDependence on a third-party CORS network.

Critical riskA wrong base coordinate shifts the entire scan by that exact amount. There is no warning and no way to correct afterward.

Device supportL2 Pro and K2. Same Custom NTRIP workflow on both.

PPK (Post-Processed)

WhyNo cellular or internet coverage at the site. You cannot receive NTRIP corrections in the field.

Correction timingAfter the scan, in LixelStudio v4.0.

What you needA base station (such as an Emlid Reach RS3) logging continuous RINEX data during the scan. The scanner raw GNSS log. LixelStudio v4.0 PPK workflow (RINEX 3.0+). Base within 3.1 mi (5 km), under 1.2 mi (2 km) optimal.

What you skipLive internet in the field. No real-time fix confirmation.

Critical riskA single gap in the RINEX file invalidates data for that period. Verify valid data points exceed 100 in LixelStudio before processing.

Device supportL2 Pro fully supported. K2 PPK workflow compatibility is pending XGRIDS confirmation as of May 2026.

K2 PPK status. The K2's built-in UM980 is a survey-grade GNSS receiver that supports RINEX logging at the hardware level, but the LixelStudio v4.0 K2 PPK ingestion pipeline is not yet explicitly documented in current K2 materials. For K2 projects in NTRIP-denied environments, plan around surveyed ground control points until XGRIDS confirms K2 PPK support. The L2 Pro PPK workflow shown above is fully documented and operational.

Section 4

Legend and Key Specifications

Base station shown: the Emlid Reach RS3 is shown as an example of a commonly used third-party GNSS receiver. Any multi-band GNSS receiver that supports NTRIP output and RINEX logging will work in this role. The XGRIDS system does not require a specific base station brand.

Signal Paths

The diagram color-codes the satellite-to-rover path (raw GNSS signal subject to atmospheric and clock error), the satellite-to-base path (the same raw signal observed at a known position), the correction data path (base or CORS to rover via NTRIP for RTK; rover to base RINEX file for PPK), and the processed output trajectory (corrected positions applied to the SLAM trajectory in LixelStudio).

Equipment

Scanner (L2 Pro with external RTK module or K2 with built-in UM980), optional base station (Emlid Reach RS3 or equivalent), CORS network reference station, mobile data connection (cellular or Wi-Fi at the site), and the processing computer running LixelStudio v4.0.

Outputs

Georeferenced point cloud at approximately 1.2 in (3 cm) RMSE in ideal conditions. Accuracy degrades with baseline distance, multipath, atmospheric conditions, and the time the trajectory spends in unfixed status.

Ready to configure? Read the full setup guides before going to site: 4.2 RTK Positioning and 4.3 PPK Positioning.

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