An apparatus and method are disclosed for cart navigation using a portable device that is conveyed by the cart, but may be tethered or untethered and wherein mobility of the portable device may be constrained or unconstrained within the cart. The cart may be any apparatus propelled by on foot motion of a user. The portable device may have an integrated sensor assembly integrated with at least one sensor outputting data representing motion of the portable device. From the motion sensor data, it may be determined if the portable device is in a cart motion mode, if the cart is moving and an effective motion frequency for the portable device. Further, the motion sensor data may be reconstructed, a heading misalignment angle calculated and steps taken by the user detected. From this information, dead reckoning for the cart may be performed so that a navigation solution may be provided.