SRC-462

Automatic Phase Control in Solar Power Satellite Systems, Final Report, contract NAS 9-15237, 15 February 1978

Commissioned by NASA Johnson Space Center, contract NAS9-15237; technical monitor named on the title page. Who paid for a study is recorded because it bears on how its conclusions should be read, not because it makes them wrong.

Published claims resting on this source

• CLM-0979 The three designs disagreed about what the guide signal from the ground should look like. One used a pair of tones either side of the target frequency; one used exactly the transmitter's own frequency and worried about telling the two apart; and by 1979 the reference design had moved to a coded, spread-out signal, the same family of technique that satellite navigation uses.
• CLM-0980 The company that designed the timing system in 1978 handled the bending of the transmitter by dividing it into groups of patches, each with its own small computer working out the correction from where the guide beam appeared to come from and where that group's elements actually were. How big a group could be depended on how much the structure bent. The report also shows how much cable length matters: two centimetres of mismatch between levels is about 58 degrees of error at 2.48 GHz but under two degrees at 70 MHz, and its remedy is to keep the cable lengths matched.

Cite this