Techniques are provided which may be implemented using various methods and/or apparatuses in a mobile device to request a transport vehicle. Techniques are provided which may be implemented using various methods and/or apparatuses in a transport vehicle to respond to a request from a mobile device. Various embodiments include customer and transport authentication and security techniques. Various embodiments include location update techniques to enable a transport vehicle to navigate to a mobile device, even in areas of low position accuracy for traditional GNSS and terrestrial transceiver-based systems.