Design of a Grating Lobes-Free Architecture for Distributed Sensor System with Arbitrary Element Spacing

Two main difficulties for the accurate direction of arrival (DOA) estimation in a distributed sensor system are grating lobes and synchronization. Different from traditional phased array based on single carrier frequency, this paper designs novel architecture using dual frequency measurements. Both two frequencies combined transmitted simultaneously proposed architecture. Instead f1 method, separation f2−f1 is used algorithm to determine maximum unambiguous DOA estimate. Since much less than choice more flexible, method can provide an estimate whole field view (FOV) arbitrary element spacing looser requirement synchronization frequency. For case with f1=3 Ghz, f2−f1=150 Mhz 10 times spacing, there no lobe FOV [−π/2,π/2], whereas has many without only 5.73∘. To obtain same combining efficiency case, positioning error 0.4 m location must be smaller 0.02 m. Hence, greatly reduce hardware requirements. The performances cases perfect imperfect synchronizations evaluated terms average beampattern efficiency, respectively. Some characteristics derived also presented paper.