Satellite Image Based Cross-view Localization for Autonomous Vehicle

Existing spatial localization techniques for autonomous vehicles mostly use a pre-built 3D-HD map, often constructed using a survey-grade 3D mapping vehicle, which is not only expensive but also laborious. This paper shows that by using an off-the-shelf high-definition satellite image as a ready-to-use map, we are able to achieve cross-view vehicle localization up to a satisfactory accuracy, providing a cheaper and more practical way for localization. Although the idea of using satellite images for cross-view localization is not new, previous methods almost exclusively treat the task as image retrieval, namely matching a vehicle-captured ground-view image with the satellite image. This paper presents a novel cross-view localization method, which departs from the common wisdom of image retrieval. Specifically, our method develops (1) a Geometric-align Feature Extractor (GaFE) that leverages measured 3D points to bridge the geometric gap between ground view and overhead view, (2) a Pose Aware Branch (PAB) adopting a triplet loss to encourage pose-aware feature extracting, and (3) a Recursive Pose Refine Branch (RPRB) using the Levenberg-Marquardt (LM) algorithm to align the initial pose towards the true vehicle pose iteratively. Our method is validated on KITTI and Ford Multi-AV Seasonal datasets as ground view and Google Maps as the satellite view. The results demonstrate the superiority of our method in cross-view localization with spatial and angular errors within 1 meter and $2^\circ$, respectively. The code will be made publicly available.