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Notes and Reflections on Books and Media

by Hannah Leitheiser

Accurate GPS

Accessory to War: The Unspoken Alliance Between Astrophysics and the Military

Neil deGrasse Tyson

2018SEP

Link

2018-10-26

- Neil deGrasse Tyson, Accessory to War: The Unspoken Alliance Between Astrophysics and the Military (2018SEP)

When first implemented, accurate GPS tracking required military crypto. Without crypto, an added jitter made the location about 1/10 as accurate.

I had heard that people figured out the jitter didn't effect the differential between receivers and were able to use a stationary receiver to achieve military grade accuracy, so to make things simpler, the military eventually turned the jitter off. Neil deGrasse Tyson said the problem was a lack of cryptographic equipment. The military were largely buying civilian GPS units, so the inaccuracy was crippling their capacity, and the military cleared the crypto requirement. Tyson's account seems more reasonable.