A method, and an apparatus to perform the method, of tracking a mobile subject based on Global Navigation Satellite Systems (GNSS) data, the method including detecting motion of the mobile subject independently of the GNSS data with a motion detector, receiving the GNSS data and determining an actionable position and speed of the mobile subject, with an actionable position and speed unit, according to GNSS position and speed, detection results of the motion detector, and at least one of, or any combination of, GNSS solution metrics, GNSS signal metrics, or a prior actionable position and speed, and evaluating, with a boundary test unit, the actionable position and speed of the mobile subject relative to a predetermined boundary.
