联合TDOA-SA的扫描辐射源半正定松弛定位算法OA

Scanning emitters are characterized by high main-lobe signal-to-noise ratios,narrow beams,and stable scan periods,and have been widely deployed in both military and civilian applications.To address the limited information offered by a single measurement modality in passive localization of scanning emitters,this paper proposes a semidefinite-re-laxation localization algorithm that jointly exploits time difference of arrival(TDOA)and scanning angle(SA)measure-ments.We first formulate a maximum-likelihood localization model under the combined TDOA-SA measurement scheme.To overcome the strong nonconvexity of the resulting cost function-manifested by sensitivity to initialization and suscepti-bility to local minima-we introduce auxiliary variables to relax the original nonconvex observation model and recast the problem into an efficiently solvable convex optimization program,yielding a stable globally optimal solution to the relaxed formulation.On this basis,feasible-set analysis is conducted by incorporating second-order cone constraints on range and bounded constraints on scanning angle,which effectively suppresses the feasible-set expansion induced by relaxation and enables accurate emitter localization.Furthermore,the Cramér-Rao lower bound(CRLB)under the joint measurement scheme is derived,and the minimum number of required receiving stations is analyzed.Simulation studies are conducted to evaluate the localization performance of the proposed algorithm.Simulation results demonstrate that,under scenarios with relatively large measurement errors,the proposed joint TDOA-SA scheme achieves higher localization accuracy than the scheme relying solely on SA measurements.When the root-mean-square error(RMSE)of SA measurement is below 1° and the RMSE of TDOA is below 50 μs,localization performance of the proposed algorithm approaches the CRLB.