Japan yesterday launched a fourth satellite for a new high-precision global positioning system (GPS). The Michibiki satellite lifted off from the Tanegashima space port aboard an H-2A rocket, the Japan Aerospace Exploration Agency said.

Having four satellites that loop over Japan and Australia in a figure of eight orbit will allow for uninterrupted coverage and puts engineers on course to switch the system on in April. Japanese GPS can locate devices to within centimetres compared with the US system, which has an accuracy of about 10m.