A vehicle-based positioning system (VBPS) for a vehicle traversing a guideway, the VBPS includes an inertial navigation system (INS) on-board the vehicle, wherein the INS is configured to detect inertial parameters of the vehicle while the vehicle traverses the guideway, the detected inertial parameters including roll, pitch and yaw of the vehicle. The VBPS includes a guideway database, wherein the guideway database is configured to store inertial parameters of the guideway at a plurality of locations along the guideway, the stored inertial parameters include roll, pitch and yaw of the guideway. The VBPS further includes a vital on-board controller (VOBC), the VOBC is configured to determine a position of the vehicle based on a comparison of the detected inertial parameters with the stored inertial parameters. The VOBC is configured to limit comparison of the inertial parameters with the stored inertial parameters based on a latest checkpoint passed by the vehicle.