The　Unmanned　Surface　Vehicle　(USV)　cannot　rely　on　GPS　signals　for　positioning　when　they　pass　through　areas　with　weak　or　disappearing　GPS　signals　such　as　culverts　and　bridges　in　a　complex　outdoor　environment.　An　USV　system　based　on　lidar　is　designed　to　realize　the　positioning　and　autonomous　navigation　without　GPS.　Two-dimensional　lidar　combined　with　IMU　is　used　to　perceive　the　surrounding　environment,　Google　Cartographer　Simultaneous　Location　and　Mapping　(SLAM)　method　is　adopted　to　perform　2D　mapping　of　the　surrounding　environment,　and　the　Extended　Kalman　Filter　(EKF)　algorithm　is　used　for　the　fusion　of　map　matching　data　and　IMU　pre-integration　data.　Results　of　experiments　show　that　the　system　can　achieve　stable　and　high-precision　positioning　and　navigation　in　narrow　inland　rivers.　©　2022,　The　Author(s),　under　exclusive　license　to　Springer　Nature　Singapore　Pte　Ltd.