This manual accompanies ZBA9319. Made by Navstar Systems in 1990, the XR4 GPS Marine Navigator receiver was aimed for use on ocean-going leisure, fishing and commercial vessels. It won a Design Centre award for its mechanical outline and user interface, and was considered the most cost effective and technically refined civilian GPS navigation receiver available at the time. For example, in the 1990s, the crew of the Royal Yacht Britannia utilised an XR4 GPS Receiver as part of the ship’s navigational system. The manual includes sections on the instrument’s specification, basic principles, initial programming, entry of navigational data, display of navigational data (including position, waypoint, cross track error, elapsed time, use of routes, velocity, alarms, satellites in use, GPS status), and installation of XR4 on a computer. 50 pages. Paper and spiral bound.