RTK (Real-Time Kinematic) is an advanced GNSS positioning technology used in inertial navigation systems (INS) to achieve high-precision positioning. RTK works by using real-time corrections from a reference station to improve the accuracy of the GNSS signals received by a rover or mobile receiver. The corrections help to eliminate errors caused by atmospheric delays, satellite clock inaccuracies, and orbital errors, allowing for centimeter-level positioning accuracy.
How RTK Works in INS?
Reference Station – A base station (also known as the reference station) is set up at a known position. This station collects GNSS data from satellites and computes correction data based on the difference between its known position and the GNSS-derived position.
Correction Data – The reference station transmits the correction data in real-time to the rover (mobile GNSS receiver), which is usually integrated into the INS.
Real-Time Positioning – The rover applies the corrections to its own GNSS measurements, resulting in high-precision positioning.
Integration with INS – RTK-corrected GNSS data is combined with IMU data (accelerometer and gyroscope readings) to improve the accuracy and stability of the overall navigation solution. This is especially useful in GNSS-denied environments, where the INS can help correct errors when RTK data is available.
Applications of RTK in INS
✔ Surveying & Mapping – RTK is widely used in geodetic surveying and high-precision mapping, especially for land surveying and construction projects.
✔ Autonomous Vehicles – Self-driving cars and drones use RTK for high-precision positioning, ensuring accurate navigation in urban environments and GNSS-denied areas.
✔ Agriculture – RTK is used in precision farming for automated machinery, helping to guide tractors and harvesters with centimeter-level accuracy.
✔ Aerospace & Aviation – RTK provides accurate positioning for aircraft and spacecraft during flight and satellite operations.
Advantages of RTK in INS
✔ Centimeter-Level Accuracy – RTK improves the GNSS positioning accuracy to centimeter-level precision, significantly reducing errors in navigation.
✔ Real-Time Corrections – Provides real-time data corrections, ensuring up-to-date and accurate positioning at all times.
✔ Enhanced Navigation in Challenging Environments – RTK can be combined with INS to offer accurate navigation even in GNSS-challenged environments like tunnels, forests, or urban canyons.
Challenges of RTK in INS
✔ Dependence on Base Stations – RTK requires the availability of a base station or reference station, which may not be feasible in remote areas or mobile applications.
✔ Signal Blockage – RTK is susceptible to signal blockage or interference in environments with obstructions like tall buildings, dense foliage, or underground areas.
✔ Short Range of Corrections – The effective range of RTK corrections is generally limited to a few kilometers, and the base station must be within this range to provide accurate corrections.
