Localization or navigation of AUVs using only onboard local sensors, such as a Doppler Velocity Logger (DVL) or Inertial Measurement Unit (IMU), are certain to experience accumulated positioning error. One can, of course, utilize more precise sensors to reduce the rate of accumulated error but uncertainty will eventually grow. We have instead considered two alternative approaches:

AUV and CNA Cooperation

We aim to bound AUV uncertainty using measurements from a Cooperative Navigation Aid (CNA) operating on the surface. The CNA is an MIT autonomous kayak equipped with a WHOI acoustic modem as well as a basic GPS and compass sensor suite. Receiving position measurements from the CNA and estimating the inter-vehicle range allows the AUV to correct its own position estimate and to continue operating longer and more accurately than without this information.

  • Related Publications: IJRR 2008, FSR 2009, IJRR 2009, ICRA 2011 (Best Paper Nomination, 20 from 2000).

Combined AUV, CNA and Sonar Navigation

Inter AUV Cooperation

Consider an operation in which several AUVs with significantly different performance are operating in the same region – such as a fleet of AUVs doing harbour security or carrying out survey work. If only a single vehicle could surface, aquire GPS position and share this information (using acoustic ranging modems) with the other vehicles their missions could continue without interuption. Alternatively if a single vehicle has a high quality INS it would remain accurately localised for a longer period of time than a low quality vehicle. By sharing this information with the other vehicles in the fleet all vehicles can benefit from the high performance of the expensive vehicle.

  • Related Publication: ICRA 2010

Dead Reckoning only on left, cooperative navigation on right: