**1. Introduction**

Indoor positioning is an important area of development with wide applications in surveillance, human motion analysis, logistics, and entertainment [1–5]. As one of the most well-known indoor positioning approaches, infrared positioning is characterized by low energy consumption and high precision [6–8]. In an infrared positioning system, an infrared emitter is installed on a movable target that is required to be localized, and infrared receivers are fixed onto the ceiling. The infrared positioning result is accurate only when the number of valid infrared receivers is more than three. An infrared receiver becomes invalid if it does not receive the light originating from the infrared emitter due to indoor occlusions.

Automated guided vehicles (AGVs) are commonly used in warehouses for cargo delivery [9,10]. However, AGV positioning results easily become inaccurate when cargoes in a warehouse occlude the light beams originating from the emitter installed on an AGV. Instead of improving the positioning of the sensors, the current work considers the planning of occlusion-aware paths that would enable an AGV to drive in the occlusion-free part of the drivable area in a warehouse.

If the cargoes in a warehouse are permanently fixed, then the poor positioning regions may be estimated a priori and regarded as static obstacles in an AGV path planning scheme. In most cases, however, cargo placement is always changing, resulting in unfixed poor

**Citation:** Li, B.; Tang, S.; Zhang, Y.; Zhong, X. Occlusion-Aware Path Planning to Promote Infrared Positioning Accuracy for Autonomous Driving in a Warehouse. *Electronics* **2021**, *10*, 3093. https://doi.org/ 10.3390/electronics10243093

Academic Editor: Jose Eugenio Naranjo

Received: 8 November 2021 Accepted: 9 December 2021 Published: 13 December 2021

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positioning regions. Thus, the concerned occlusion-aware path planner must work fast while guaranteeing its outputs are collision-free and kinematically feasible [11].
