Hi Magnus, > Would not an antenna with a deep zero focus on the earth center help to reduce earth-noise (ground temperature noise as well as man-made noise)?
It might, although you'd need a large antenna to generate the angular resolution needed to reject Earth noise while listening to a GPS bird near the Earth's limb. If you make the tradeoff of using GPS satellites further from the limb (say at their max separation of ~5 degrees looking from lunar distance), hoping for less Earth noise, then you're working with a fainter sidelobe. I'm sure the proper tradeoff is known. The whole problem sounds much easier if you're merely at GEO. I wonder if there's any advantage in combining far-away GPS with X-ray pulsar navigation (XNAV), which is said to be good to a few kilometers, though long integration times are needed. For example, the rough system time from XNAV could enable very long (arbitrarily long?) coherent integration for very faint GPS signals obtained with a gain antenna pointed at the Earth. Cheers, Peter _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
