MatrixLoc: Centimeter-Level Relative Vehicle Positioning with Matrix Headlight

Precise vehicle positioning is the fundamental technology in vehicle platooning, for sensing the driving environment, detecting hazards, and determining driving strategies. While radars offer robust performance in extreme weather, the positioning error of up to 1.8 m could be insufficient for platoons with vehicle spacings of a few meters. In contrast, LiDARs provide great accuracy, but its high cost hinders its penetration in the commercial market. To this end, this paper presents MatrixLoc, utilizing a projector as the headlight and a customized light sensor array as the receiver to achieve low-cost and centimeterlevel relative vehicle positioning in both longitudinal and lateral axes, along with bearing information. MatrixLoc leverages differential phase shift keying (DPSK) modulation to create a fringe pattern, enabling single-shot positioning. Accurate positioning is achieved by analyzing the observed space-varying frequency and demodulated phase information. Real-world driving results demonstrate that MatrixLoc achieves centimeter-level positioning accuracy, with a positioning error of 30 cm and a bearing error of 9 degrees at a distance of 20 m.