GPS Antenna; First Signal – Early GPS Horn Antenna
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front At 11:35 pm CDT on July 19, 1977, the first GPS satellite was turned on. At 11:41 pm, the Rockwell Collins team working in building 106 (in the area now used as the company’s auditorium) detected and tracked the satellite, decoding that special message, "AAAAAAAAAAAA". [each A=10101010 binary] The sophisticated Beam Steering Antenna being designed for the project wasn’t quite ready at the time, so the team located the little horn antenna pictured here in a junk box at our Richardson, TX facility. After adding calibrations for azimuth and declination, it was suitable for the project. A young engineer, David Van Dusseldorp, was assigned the post on the roof to manually reposition this antenna every five minutes based on vectors being computed in real time by another engineer down in the lab. David’s wife was expecting a child around this time and he wasn’t wild about missing the birth, so a special phone line was run to David’s post on the roof. But the baby waited until August 6th, and Rockwell Collins went on to become the dominant player in military GPS receivers.