This manual describes the operation of the Navstar XR4-G GPS Receiver. It relates to object ZBA9319 (above) and the Daventry collection as it is in the Navstar XR4 series, but this is a different model. Unlike the XR4, the XR4-G could operate in two modes which the manual describes in detail: the LAT/LONG mode and the UTM mode. Both sections cover the device’s initial programming, entry of navigational data, and display of navigational data in detail. The Appendix has a valuable overview of the GPS system at that time, GPS errors and the device’s installation and antenna. 70 pages. Paper and spiral bound.