Geoceiver Satellite Surveyor MX 1502 manufactured by Magnavox circa 1979, measuring 17″ x 14″ x 13.5″ and weighing 46 pounds, with the front and back featuring carrying handles and spring-loaded locking clasps for the upper lid, which when removed reveals the main instrument panel with keypad, keyboard codes, switches, meters, digital window, and a tape cassette compartment. The underside of the lid also bears a detailed “Keyboard Codes” information plate. The parts label to the lower right reads: “Magnavox, Government & Industrial Electronics Co., Geoceiver / Satellite Surveyor, Model No. MX1502, Part No. 91028014-802, Serial No. 366, Power: 12VDC 60 Watts.” A few Magnavox labels affixed to the exterior are dated to 1982 and 1983. In fine condition, with scattered scuffs and marks.
The Magnavox Geoceiver is a satellite receiver that was used for surveying. The Geoceiver was interesting because it was one of the first receivers to use signals from the Transit satellites, which were placed into orbit initially for the US Navy, and were called NAVSAT or NNSS for ‘Navy Navigation Satellite System.’ The Navy wanted a satellite system so they could get precise position fixes for submarines (Polaris), which could be obtained by rising to periscope depth and using a sextant built into the periscope to get a celestial fix.
The Transit satellite system used the Doppler shift resulting from the motion of the satellites in orbit as the signal used to generate a fix. The Doppler shift varies with the motion of the satellite relative to the receiver, and by combining the Doppler shift signals, a location that satisfied the measured Doppler shifts could be computed.
The Transit system is no longer in operation. It, along with Omega and most recently LORAN, has been replaced by GPS. Like GPS, the satellites did need to be replaced. But with GPS availability, the Transit satellites were no longer replaced. The Navy continued to use them, but not for navigation; they had a system for monitoring the ionosphere that used the satellites.
