What is odometry?
Odometry estimates how far and in what direction a robot has moved by integrating readings from its own motion sensors. Wheel odometry counts wheel rotations, visual odometry tracks how the scene shifts between camera frames, and inertial odometry integrates acceleration and rotation from an IMU. Adding up these increments gives a running estimate of the robot's trajectory.
Its weakness is drift: small per-step errors accumulate, so odometry alone slowly diverges from the true path.
Key takeaways
- Odometry estimates motion by integrating sensor readings over time.
- It comes in wheel, visual, and inertial forms, often combined.
- It drifts over time, so it is usually corrected by other methods.
How it works
Each sensor provides an increment of motion between time steps, and those increments are summed to track pose. Because every measurement carries a little noise, the errors compound, which is why odometry is typically fused with other sensors and corrected by SLAM's loop closure or absolute references. Fusing complementary sensors reduces drift compared to any one alone.
Why it matters
Odometry is the fast, local motion estimate that higher-level navigation depends on, and it is a key input to SLAM. Understanding its drift explains why physical AI systems fuse many sensors rather than trusting a single stream.
Frequently asked questions
Why does odometry drift?
Each step's small measurement errors accumulate as they are summed, so the estimate gradually diverges from the true position.
How is odometry different from SLAM?
Odometry estimates incremental motion, while SLAM also builds a map and uses it to correct the accumulated drift in that motion estimate.
Related terms