System theoretic framework for active sensing in disaster management: modifying sensor guidance for life prolongation in hazardous fields

This work considers disaster management from a system theoretic framework. Assuming that disasters result in spatiotemporally varying fields, such as hazardous plumes that are harmful to humans and equipment, it proposes a three-step approach to disaster management: (i) detection of the presence of a disaster, (ii), reconstruction of the effects of the disaster and (iii) adaptive evacuation in terms of active path planning using information on the effects of the disaster. The second step is considered here and an integrated design for the reconstruction of the state of the spatiotemporally varying field, as described by advection-diffusion PDE, with a mobile sensor is proposed. The mobile sensor has tolerance limits on the measurements, beyond of which ceases to operate. A modification to the sensor guidance is proposed and which initially moves the sensor using a gradient ascent policy. The guidance policy switches to a gradient descent policy whenever the measurements are within a percentage of the tolerance limit ensuring the life prolongation of the sensor. Simulation studies for a 2D advection-diffusion PDE are included to demonstrate the effects of modified guidance on life extension of a sensor.