The Autonomous Redundant Navigation System of an AUV for Mine ...

Recommendations

Info

MARPOSII further includes an accurate time system. Drift is < 0.1s per 24 hours of submerged operation and proven
Recent applications of NAVBOX include: • Extremely high performance navigation in support of Synthetic Aperture Sonar (SAS) detection of buried mines. German MJ2000 project [9], see also Figure 4. • NATO Naval Undersea Research Centre (NURC) MX3 AUV MCM trials, Nov. 2005, La Spezia, Italy. • NATO harbour protection trials, 2006, La Spezia. Figure 4 MJ2000: Synthetic Aperture Sonar (SAS) for buried mine detection - the first real-time navigation application derived from NAVBOX. Some of the NAVBOX supported AUV sensors and aiding techniques are: • IMU • GPS (or GNSS) • DVL • Pressure depth • USBL • Fluxgate compass • ZUPT (Zero velocity update) • Combined Synthetic LBL and SLAM. NAVBOX sensor models, simulation and Kalman filter designs are validated and refined through processing of large amounts of experimental data. Additional sensors and navigation techniques are easily integrated. 2.1 NAVBOX AINS core NAVBOX includes an accurate implementation of the AINS algorithms: • Inertial navigation equations. • Kalman filter (modular). • Optimal smoother. The algorithms are organized as shown in Figure 5. Each module is explained hereafter. Figure 5: Aided Inertial Navigation System Block- Diagram Inertial navigation is performed by (correct) integration of measurements from an Inertial Measurement Unit (IMU). The Kalman filter integrates information from aiding sensor measurements and applies estimated navigation error (corrections) to the inertial navigation. 2.1.1 Inertial Measurement Unit (IMU) The inertial measurement unit (IMU) consists of orthogonal triads of gyros and accelerometers. Modern IMUs generally make use of a strap-down configuration where the IMU sensors are strapped rigidly onto the vehicle body - no gimbals. An IMU outputs change in velocity and change in attitude, often referred as delta v's (ΔV's) and delta θ's (Δθ's). IMU data output frequency is typically 100-3000Hz. IMU's range in performance from low cost MEMS devices to state-of-the-art Ring Laser Gyro (RLG) or Fibre Optic Gyro (FOG) based systems. 2.1.2 Inertial Navigation Equations (INE) The inertial navigation block implements the strap-down inertial navigation equations: Position, orientation and velocity are computed by dead reckoning from initial conditions using Δθ's and ΔV's output by the IMU. Pure inertial navigation degrades with time. To maintain accuracy the inertial navigation block receives corrections computed by the Kalman filter. This configuration is referred to as
Page 1: The Autonomous Redundant Navigation
Page 5 and 6: 3 NAVBOX processing of real AUV dat
Page 7 and 8: general provide approximately the s
Page 9: 7 Literature [1] Mikael Bliksted La

The Autonomous Redundant Navigation System of an AUV for Mine ...

Create successful ePaper yourself

Delete template?

Save as template?