...is just a dvb-s grabber, see:
http://www.skygrabber.com/en/skygrabber.php
And all it does is intercept unencrypted IP packets from satellites which use IP over dvb-s for internet connections (most of them are one-way connections, uplink via pots modem/isdn).
So this is _definitly_ _NOT_ "spying on drones", I highly doubt that the drones themselves have an dvb-s transmitter in the same frequency range as "public" communication sats. It _might_ be that some of the drone data was/is routed through the internet and therefore could be intercepted with above software _IF_ some military dudes use any of the commercial ip-via-sat-providers (or even their _unencrypted_ own), but this isn't different from normal ethernet/wifi/whatever carrier ist used - sniffing.
Oh and btw., open source terrorists get their awsome drone sniffing software for FREE!!!!1111:
http://sites.google.com/site/skynetr32/skynet.%3Ar32_index_en
(in case you're to lazy to klick on the link: basically another dvb-s file sniffer, but open sauce).