Looks an awful lot like an Anti-Aircraft Surface-to-Air Missile battery to me.....
Ain't a joke and the pentagram is either a grading contractor goldplating a job or just coincidental.
Okay fatima, you've got both Navy and Marine confirmation on the SAM site. Close up on that picture really pulls out the berming, there are at least two really, really missile-on-a-launcher looking objects complete with berms for exhaust deflection out there and one bit of the stuff in the center of the site looks for all the world like a radar antenna.
I'd almost call it a Soviet-bloc SAM 3 battery, if Grimmy hadn't already exposed me as Old School. (And what's this OLD stuff, Marine?)
Considering that China Lake has been kind of multi-service spook deal ever since I first heard of it, it's no shock at all to see all kinds of funky gear scattered around the place.