SmartLOC: Indoor Localization with Smartphone Anchors for On-Demand Delivery

On-demand delivery is a rapidly developing business worldwide, where meals and groceries are delivered door to door from merchants to customers by the couriers. Couriers' real-time localization plays a key role in on-demand delivery for all parties like the platform's order dispatching, merchants' order preparing, couriers' navigation, and customers' shopping experience. Although GPS has well solved outdoor localization, indoor localization is still challenging due to the lack of large-coverage, low-cost anchors. Given the high penetration of smartphones in merchants and frequent rendezvous between merchants and couriers, we employ merchants' smartphones as indoor anchors for a new sensing opportunity. In this paper, we design, implement and evaluate SmartLOC, a map-free localization system that employs merchants' smartphones as anchors to obtain couriers' real-time locations. Specifically, we design a rendezvous detection module based on Bluetooth Low Energy (BLE), build indoor shop graphs for each mall, and adopt graph embedding to extract indoor shops' topology. To guarantee anchors' accuracy and privacy, we build a mutual localization module to iteratively infer merchants' state (in-shop or not) and couriers' locations with transformer models. We implement SmartLOC in a large on-demand delivery platform and deploy the system in 566 malls in Shanghai, China. We evaluate SmartLOC in two multi-floor malls in Shanghai and show that it can improve the accuracy of couriers' travel time estimation by 24%, 43%, 70%, and 76% compared with a straightforward graph solution, GPS, Wi-Fi, and TransLoc.