Executive Summary : | The Direction of Arrival(DoA) is a method to determine the direction of the incident EM waves. To estimate the DoA an array of EM sensors are required. For any DoA methods following conditions should be satisfied - (1) narrowband, and (2) Incident wave should be a plane wave. The DoA estimation makes use of antenna array techniques like MUSIC, root-MUSIC, ESPRIT, Beamforming method, time difference of arrival(TDOA), and Matrix Pencil(MP) method. All the aforementioned techniques utilize either the phase difference or the time delay between the antenna array elements. Among the aforementioned method, the MP method has a relatively very low computational cost with high accuracy in a noisy environment finding the delay or the phase between the array elements but, in a noiseless environment, TDOA is the simplest and most accurate. At present we are developing an algorithm for DoA for Space Electric and Magnetic Sensor (SEAMS) space mission to estimate the directions of the ultra-low frequency(100kHz-30MHz) signal using a tripole(3 orthogonal co-located antenna) configuration and a modified MP method. The current development is for only tripole antenna but, if there is a constellation of synchronous satellites or any antenna array the currently developed method will fail. Thus, here we propose for development of a methodology and an algorithm utilizing the MP method to determine the phase difference between the different elements in the satellite constellation along with the time difference of the arrival method to estimate the DoA with high accuracy and low computational cost. This proposed work will be a development over the existing algorithms in order to accommodate generalized antenna array system configuration and space-based operations. |