Made circa 1985 by Navstar Systems, the ‘Navstar 422’ is a satellite navigation receiver that worked with the Transit satellite system to determine a user’s latitude and longitude.

The Transit satellite system was developed by the United States Navy during the Cold War to provide accurate location information to Polaris ballistic missile submarines. Transit satellite system became operational in 1964 and the technology was later made available to civilians and the commercial market. By the 1980s, navigators working on thousands of warships, freighters and private watercraft used the Transit system. This was partly due to changes in how consumer electronics were manufactured and advances in chip technology.

The Navstar 422 was developed by a research and development team based in Daventry, UK. The unit was designed as a cost reduced version of the Polytechnic Marine 602S Transit SatNav (see ZBA9311), and introduced digital signal processing to the market. It was aimed at marine markets including leisure, fishing and commercial. Prior to this unit, there would have been 402 and 412 variants manufactured from about 1982.