Originally Posted by
ion_berkley
Orac,
Just for the record since you keep quoting from this magazine article which is not exactly "neutral" in what it's selling....
Free Space Path Loss = -10 * log10((4*pi*distance/wavelength)^2)
Distance from GPS orbit to 0 degree elevation on Earth (assuming average earth diameter of 12,734,000m) = square root (20200000*(20200000+12734000)) = ~25792766m
Distance form Iridium Orbit to 0 degree elevation on Earth (assuming average earth diameter of 12,734,000m) = square root (781000*(20200000+781000)) = ~3248879m
L1 GPS frequency of 1575MHz
That gives path loss of -184.6dB for GPS and -166.6dB for Iridium, so a difference of ~18dB... or 63x in pprune layman terms.
And that's assuming all other things are equal....a "cubesat" and a Block III GPS satellite are most definitely *not* equal on more points than I'd care to enumerate on pprune.
I'll stop now before this becomes a rant about skewed math to support agenda's...wait, there's a perfect segue back to Brexit....
I would love to see how they would squeeze the antennae in there for a start. One with a semi decent SNR. How you are supposed to fit a decent atomic clock, transponder, processor and the rest of the gubbins in something smaller than a packet of rice crispies, only the gubnermint can explain.