Real-Time Kinematic (RTK) Positioning

Real-Time Kinematic (RTK) positioning is an indispensable, revolutionary technology in modern automotive high-precision positioning and autonomous driving systems. Conventional Global Navigation Satellite Systems (GNSS) are constrained by physical factors such as atmospheric ionospheric refraction and satellite orbit errors, typically offering only metre-level absolute positioning accuracy (usually between 5 and 10 metres). RTK technology bridges the gap from "metre-level" to "centimetre-level" accuracy by introducing a network of ground reference base stations.

Core Working Principle and Technical Characteristics

At the heart of the RTK system lies the "carrier-phase differential and error cancellation mechanism": 

Base station and rover collaboration: Ground reference base stations are established at fixed locations with precisely known coordinates. These base stations continuously receive satellite signals and compute real-time positioning errors (correction parameters).

Real-time differential data broadcast: The base station transmits differential correction data in real time to the moving vehicle (the rover) via radio or cellular mobile networks (such as 4G, 5G, or V2X communication). The on-board positioning module integrates its own satellite observation data with these correction parameters, eliminating the vast majority of systematic errors via advanced algorithms to achieve high-precision 3D spatial coordinates.

Application Scenarios and Market Value

RTK is widely utilised in advanced driver assistance systems (ADAS) for intelligent connected vehicles, commercial vehicle platooning, automated port logistics vehicles, and precision agricultural machinery.

In high-level autonomous driving scenarios, vehicles demand pinpoint positional accuracy to align with high-definition (HD) maps, enabling complex manoeuvres such as lane-level navigation, automated lane changes at complex junctions, and automated parking. Conventional metre-level positioning cannot distinguish which specific lane a vehicle is travelling in, whereas centimetre-level RTK positioning equips the vehicle with precise environmental spatial awareness.

Safety Specifications and Physical Limitations

Autonomous driving systems must never rely solely on a single RTK signal for decision-making under elevated flyovers, inside long tunnels, or in dense primary forests where satellite signals are heavily obstructed and cellular blind spots exist. In such environments, the system must rely on Inertial Measurement Units (IMUs) or vision and radar sensors for continuous dead reckoning handover. 

Setting up or connecting to non-standard base station networks not authorised by official radio regulatory authorities is strictly prohibited. Doing so compromises the integrity and security of the vehicle's differential data feed, posing severe safety hazards such as positioning system crashes and vehicle control failure.