Relative position refers to the position of an object or vehicle relative to a reference point rather than an absolute coordinate system (such as GNSS-based latitude and longitude). It is commonly used in formation flying, autonomous navigation, robotics, and military applications where the focus is on the relative movement between objects rather than global positioning.
How Relative Positioning Works in INS?
Initial Reference Point – The system defines a starting position (e.g., the position of a leader vehicle, a docking station, or another object).
INS Data Processing – The IMU (Inertial Measurement Unit) tracks motion using accelerometers and gyroscopes, continuously updating relative displacement from the reference point.
Sensor Fusion for Corrections – Additional sensors such as GNSS, LiDAR, radar, or vision systems help correct INS drift and maintain accurate relative positioning.
Continuous Update – The system continuously updates the relative position by integrating velocity and acceleration over time.
Applications of Relative Positioning in INS
✔ Autonomous Vehicles & Drones – Used for convoy navigation, drone swarming, and formation flying where vehicles must maintain a precise distance from each other.
✔ Aviation & Spacecraft Docking – Helps aircraft or spacecraft perform autonomous refueling, rendezvous, and docking maneuvers.
✔ Maritime & Underwater Navigation – Used in submarine formations and autonomous underwater vehicles (AUVs) for coordinated movement.
✔ Military & Defense – Critical for missile guidance, tactical formations, and target tracking in combat scenarios.
Advantages of Relative Positioning in INS
✔ No Need for GNSS – Works effectively in GNSS-denied environments such as underground, underwater, or combat zones.
✔ High Precision in Short Ranges – Provides centimeter-level accuracy when combined with sensor fusion techniques.
✔ Real-Time Tracking – Enables instantaneous updates for fast-moving objects like drones, missiles, or autonomous convoys.
