This document specifies the functional requirements of nomadic devices for lane-level positioning and integrity monitoring with the network-based precise positioning infrastructure for land transportation (NETPPI-LT), a lane-level positioning system based on global navigation satellite systems (GNSS) described in ISO/TR 22086‑1. This document identifies the GNNS threats to monitor and the errors to remove or mitigate to achieve lane-level accuracy and integrity. It also specifies the data sets to be contained in messages between the nomadic device and the control station providing GNSS correction and integrity information. This specification enables the nomadic device to support lane-level positioning and integrity monitoring. Enabling techniques and methods, which can be different for each provider or vendor, are not addressed in this document.