Prof.  Tao  YU
Chinese Aeronautical Radio Electronics Research Institute,  China

Title: Single-Baseline Passive Precision Approach Guidance Technology Based on Differential Mapping

Abstract:

Traditional two-dimensional passive localization techniques are constrained by the fundamental principle that "the number of independent observations must match the spatial dimension," rendering a two-station system unable to solve for a target's 2D position using only a single range difference (one-way difference) measurement, as the resulting equations are underdetermined. This paper proposes and rigorously demonstrates a novel two-dimensional localization method based on differential mapping using a single range-difference measurement, aiming to fundamentally break through this dimensional constraint.

The core innovations are threefold. First, a "virtual midpoint angle-measurement model" is employed to provide a robust initial angle estimate for long baselines, shifting the observation reference point from the traditional baseline endpoint to the geometric midpoint of the baseline, thereby effectively suppressing the inherent nonlinear distortion of the endpoint model. Second, a "range-difference differential mapping principle" is proposed: by constructing a differential variable δ, a globally monotonic mapping relationship between δ and the target distance R is rigorously proven, decoupling the coupled distance-angle ambiguity at the physical level. Third, a "offline database construction – online table lookup" dual-mapping computation framework is designed, transforming complex nonlinear equation solving into efficient grid indexing and interpolation operations, achieving real-time computation with O(1) complexity.

Theoretical analysis proves the global injectivity and information orthogonality of the mapping. Monte Carlo simulations for a 3D precision approach guidance system demonstrate that, under conditions of a 50 m baseline and 20 mm standard deviation observation noise, the proposed method effectively suppresses observation noise across a wide detection range (50 m to 1000 m), maintaining centimeter-level localization accuracy even in the far field. This study provides a completely new theoretical pathway and engineering methodology for achieving 2D localization using only a single observation, featuring disruptive advantages of minimal hardware (only two stations and relative time synchronization required), robust computation (100% convergence), and low cost (time-synchronization cost reduced by 2–3 orders of magnitude), with broad application prospects in low-cost autonomous aircraft landing, passive aircraft surveillance, deep-space navigation, satellite formation flying, passive border monitoring, and wide-area passive surveillance.

Keywords: two-station localization; one-way difference localization; differential mapping; passive localization; information decoupling; virtual midpoint

Biography:

Professor Yu Tao, a leading academic figure in the field of passive detection and localization technology in China, was honored with the "Asia Lifetime Achievement Award" byAsian Figuresin 2025. With decades of dedicated research in this domain, he pioneered several core theories, including the two-dimensional planar bistatic localization model, the ambiguity-free phase difference localization method, and the Doppler-based ranging fusion algorithm. These innovations have effectively broken through key bottlenecks in passive localization technology and have laid the foundation for a critical technical system supporting national strategic security. Professor Yu has published over 200 research papers, authored two academic monographs, and filed more than 20 invention patents. In 2024, he was awarded five gold medals at international invention exhibitions for four core research achievements. Consistently committed to aligning scientific advancements with national needs, he is a key contributor to the development of Asia’s core scientific and technological competitiveness.