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Testing·April 18, 2025

Simulation vs. Reality: Validating Our Gazebo Environment

Comparing simulation predictions against real pool test data to calibrate our Gazebo environment for more accurate pre-competition testing.

Side-by-side comparison of Gazebo simulation and real pool test footage

Gazebo simulation (left) vs. real pool test (right)

Overview

Before committing to pool time, we test extensively in our Gazebo simulation environment. But how accurate is it? We ran the same maneuvers in simulation and in the pool to find out.

Graph comparing simulated vs actual thruster response curves

Thruster response: simulation vs. reality

Methodology

  • Ran identical mission scripts in Gazebo and in the pool
  • Recorded position, depth, and heading data from both
  • Compared thruster response, turn rates, and depth hold accuracy

Results

MetricSimulationReal WorldDifference
Forward speed (m/s)0.80.72-10%
Yaw rate (deg/s)4538-16%
Depth hold accuracy±2cm±5cmLarger
Gate nav success rate95%60%-35%

Calibration Changes

  • Added drag coefficients to match real-world forward speed
  • Increased sensor noise models (IMU drift was underestimated)
  • Added current simulation to model pool water movement

Key Takeaways

  • Simulation is optimistic — real-world success rates are lower
  • After calibration, forward speed and yaw rate match within 5%
  • Depth hold accuracy gap is mostly from sensor noise
  • Gate navigation gap is primarily from vision, not controls