Joint detection of carrier frequency and direction of arrival of wide-band signals using sub-nyquist sampling and interferometric direction finding

The main task of a reconnaissance receiver is to acquire wide-band radio signals of the environment and extract their important parameters/information. Direction of arrival (DOA) and carrier frequency are the two most important parameters that a reconnaissance receiver should extract. To extract internal information of the signals such as signal modulation and coded information, complete reception of the signals is necessary. Sub-Nyquist sampling is used in this study for signal conversion from analog to digital with a much reduced sampling rate compared to the carrier frequency and, phase interfemmetery is used for direction finding. In jointly designing of sub-Nyquist sampling and phase interferometry, several antennas are used and the signal of each antenna is sampled with a different rate. After sampling, the resulting signals are then processed and their internal information are estimated. The proposed receiver with the simple implementation has a good performance in terms of channel detection, ability to receive simultaneous narrow-band and or wide-band signals and extracting internal information, compared to the existing methods. Also, two new criteria are proposed for selecting the sampling rates to support the maximum instantaneous signal bandwidth, while at the same time avoid aliasing.