It is possible to make a hologram that has a different 2-D picture encoded for each angle of incoming light, which can be white light. This allows a digital or analog clock-face sundial. It should be possible to do something similar in RF. The moon likely also reflects solar RF well enough to make an electronic moondial possible, maybe even with precise moon phase, size and tilt measurements. It would be easier optically, though.
Seems like any high-res astronomical timing synch would only be needed if GPS and other satnav services and the cell network and the internet are all down, though.
Not entirely related, but this make me think of an old Heinlein story where a guy develops artificial crystals that resonate at the frequencies of visible light. Which made for cheap and efficient lighting and solar power. Naturally people were out to kill him.
It is possible to make a hologram that has a different 2-D picture encoded for each angle of incoming light, which can be white light. This allows a digital or analog clock-face sundial. It should be possible to do something similar in RF. The moon likely also reflects solar RF well enough to make an electronic moondial possible, maybe even with precise moon phase, size and tilt measurements. It would be easier optically, though.
Seems like any high-res astronomical timing synch would only be needed if GPS and other satnav services and the cell network and the internet are all down, though.
Not entirely related, but this make me think of an old Heinlein story where a guy develops artificial crystals that resonate at the frequencies of visible light. Which made for cheap and efficient lighting and solar power. Naturally people were out to kill him.
Interesting paper, and easily read. If I understand and interpret correctly, it's not practical at the combination for a few reasons:
The antenna diameter is perhaps too close the the Airy distance for good resolution (navigation needs);
The sun is a bit large to represent as a good point source, so the usual math approximation on small angle doesn't quite work;
Sunspots create a distributed (spatial and temporal) energy source across a non-point aperture.
This becomes a stochastic answer set, making it hard to get a precise answer on large distances.
Coffee just finished brewing, so time to re-sketch the classical optics setup and find my own wrrors.