A Comparison of Power Management Techniques in Wireless RF Direction Finding Sensor Networks

In this paper, the unique nature of direction finding in an RF environment against an uncooperative emitter is presented. Specifically, the focus is on power management in a wireless antenna array. This paper will present two competing methods of power management. Both methods will use a Least Mean Squares (LMS) adaptive beamforming algorithm to compensate for grating lobes that are present in the arrays of this type. The first method creates a subset of sensors from a randomly distributed antenna array. This method uses data exclusively from these elements and increases the number of iterations until the desired beam is formed. The second method creates a new subset of sensors, from a randomly distributed array, for each iteration, until the desired beam is formed. The second method is observed to provide better power management across the sensor network. In addition it will be shown that the later technique also yields a substantially better defined beamwidth with reduced grating lobes for all of the frequencies simulated.