Abstract: In one implementation, a computer-implemented method includes receiving, at a mobile computing device and after transmitting an order, information that identifies a delivery worker who is handling delivery of the order; continuously updating an interface presented by the mobile computing device until the order has been delivered, the interface identifying a current location of the delivery worker relative to a current location of the mobile computing device as both of the current locations change over time, the continuously updating including: determining, by the mobile computing device, the current location of the mobile computing device; receiving, at the mobile computing device, the current location of the delivery worker; and presenting, by the mobile computing device, the interface depicting the current location of the delivery worker relative to the current location of the mobile computing device.

Abstract: A system comprises a mobile vehicle, a global positioning system (GPS) based vehicle position and heading system, at least one two-dimensional (2D) velocity sensor, a yaw rate system, and a vehicle position and heading estimator. The GPS based vehicle position and heading system is supported on the vehicle and measures global easting and global northing (measured position) of the vehicle, and determines a heading (measured heading) of the vehicle. The 2D velocity sensor measures the velocity of the vehicle with respect to the ground, over which the vehicle travels, in two orthogonal directions (measured velocity). The yaw rate system is supported on the vehicle and measures a yaw rate of the vehicle (yaw rate measurement). The vehicle position and heading estimator comprises at least one processor that computes a position of the vehicle (estimated position) and a heading of the vehicle (estimated heading) based on the measured position, the measured heading, the measured velocity and the yaw rate measurement.