And even that seems "easy" to circumvent by having redundant satellites, such that during the equinoxes (equinoxen?) only a fraction of said satellites are shad

And even that seems "easy" to circumvent by having redundant satellites, such that during the equinoxes (equinoxen?) only a fraction of said satellites are shadowed out at once. Alternately, a massive battery or capacitor bank could give the receiver enough buffer to hold out through an equinox-induced shadowing.