RTK (Real-Time Kinematic)

RTK (Real-Time Kinematic) is a high-precision GNSS measurement method that provides centimeter-level coordinate precision in real-time. RTK has become one of the main methods in professional surveying.

How does RTK work?

1. Base station (with known coordinates) receives satellite signals
2. Base station calculates correction data
3. Corrections are transmitted to rover (mobile receiver)
4. Rover combines its measurements with corrections
5. Precise coordinates obtained in real-time

Types of RTK:

• Local RTK - own base station at site
• NRTK (Network RTK) - national base station network (LatPos)
• VRS - Virtual Reference Station
• MAC - Master-Auxiliary Corrections

RTK precision:

• Horizontally - 1-2 cm + 1ppm
• Vertically - 2-3 cm + 1ppm
• Precision depends on distance to base station
• Best precision within 10-15 km from base

LatPos system in Latvia:

• 27 permanent GNSS base stations
• Covers entire Latvian territory
• Provides RTK corrections via internet
• Subscription service for surveyors

RTK use in surveying:

• Boundary point measurement - cadastral surveying
• Topographic surveying - detail coordinate determination
• Construction stakeout - design point placement
• Control point measurement - for drone and LiDAR work
• Utility surveying - communication positioning

RTK advantages:

• Fast measurement (seconds per point)
• High precision in real-time
• No line of sight needed between points
• Efficient over large areas

RTK limitations:

• Sky visibility required
• Limited use in forests, cities
• Mobile internet connection needed
• Lower height precision compared to leveling