Initial Results from an In-Situ Environmental Monitoring Marine Mammal Tag

Gabriel Hugh Elkaim, Eric B. Decker, Guy Oliver and Brent Wright

Abstract:	Current understanding of the behavior of marine mammals (pinnipeds) is quite limited by the observation technology used. Surface tracking using geolocation or Argos satellite tags have shown that these mammals range much farther than previously thought. Relatively simple time/depth recorders (TDRs) have shown that they dive to depths of over 1000 meters for over one hour. In order to further the understanding of these aquatic creatures, a smaller, more capable tag is being developed that can be deployed for longer durations and with increased capability. The MAMMARK tag measures approximately 2.5 x 4 cm., uses a low-power microcontroller, and multiplexes a set of sensors through a high resolution analog-to-digital converter. The sensor suite consists of temperature, depth, speed, salinity, three axes of magnetic field, three axes of acceleration, and GPS. GPS measurements are, of course, only available at the surface. Quick measurements are enabled by keeping the GPS receiver in ""hotstart"" mode enabling satellite reacquisition in as little as one second upon return to the surface. The three-axis magnetometer and accelerometer are used to construct the attitude of the pinniped using a quaternion-based Whaba's problem solution. Fusing the attitude data with velocity measurements and GPS position data at the surface, a dead reckoning filter is used to generate the full pinneped trajectory. This work extends previous development efforts on the MAMMARK tag by creating a unified model for sensor errors based on the Allan Variance and autocorrelation methods. Bias drift is modeled as a first order Gauss-Markov process (exponentially correlated). Long term static (bench) accelerometer data is used to develop this unified model, showing short and long term stability. Data taken from the three axis accelerometers while tumbling the sensor in order to calibrate the null shift, scale factor, and cross-coupling errors using a two-step non-linear estimation algorithm. Lastly, bench tests of power consumption are performed and used to estimate probable MAMMARK tag longevity while attached to the tagged pinneped.
Published in:	Proceedings of IEEE/ION PLANS 2008 May 6 - 8, 2008 Hyatt Regency Hotel Monterey, CA
Pages:	912 - 922
Cite this article:	Elkaim, Gabriel Hugh, Decker, Eric B., Oliver, Guy, Wright, Brent, "Initial Results from an In-Situ Environmental Monitoring Marine Mammal Tag," Proceedings of IEEE/ION PLANS 2008, Monterey, CA, May 2008, pp. 912-922. https://doi.org/10.1109/PLANS.2008.4570033
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In