We built a new GPS receiver engine
Mostly off-topic here, but it seems like the best place to get an answer: several years ago in my lab at Georgia Tech, a technician I worked with said he had a friend who invented a device for doing celestial navigation, but that it 1) worked in the daytime somehow and 2) used digital technology so that it was more precise than a sextant / traditional celestial navigation.The technician was prone to a bit of exaggeration, so I'm not 100% sure that this is real, but I'd love to find out more if so.