Wireless Video Tele-operation using Internet Protocols

By definition, remotely piloted or tele-operated vehicles require a wireless link between the vehicle and the operator. The wireless link will carry control commands from the operator to the vehicle, telemetry data from the vehicle back to the operator and frequently also a real-time video stream from an onboard camera. In many cases these requirements are met by a number of radio subsystems; typically one for control and telemetry data and another, high-bandwidth radio subsystem, for analogue video. This paper proposes that for short-range applications the use of Wireless Local Area Network (WLAN) technology would enable these diverse communications requirements to be integrated into a single radio subsystem, with significant benefits to cost and performance. Wireless Local Area Network technology, developed primarily to extend wired networks to allow, for instance, roaming network nodes within a building, is now relatively mature. Typically a WLAN connection will employ spread spectrum modulation over a 2.4GHz RF carrier, with a raw data rate of 1-2Mbits/s. A number of manufacturers have adopted the recently agreed IEEE 802.11 standard for the physical and access layer protocols which, significantly, allow for straightforward integration with TCP/IP: the Internet Protocols. Thus a tele-operated vehicle employing WLAN technology becomes, from a systems design perspective, a node on a Local Area Network, which can with relative ease be bridged from the base-station to a Wide Area Network or even the Internet. Remarkably, therefore, this opens up the possibility that the tele-operated vehicle could be operated from anywhere with Internet access. One could envisage a scenario in which a robotic hazard inspection vehicle could be tele-operated by an expert via an international Internet connection. In the Intelligent Autonomous Systems laboratory at UWE, Bristol, we have already demonstrated the feasibility of these ideas on a number of mobile robotic platforms. This paper reports on current work to develop adaptive video compression tools in order to enable practical video tele-operation of robotic vehicles over any TCP/IP connection.