Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!philabs!seismo!hao!hplabs!sri-unix!VLSI@DEC-MARLBORO From: VLSI%DEC-MARLBORO@sri-unix.UUCP Newsgroups: net.space Subject: re: G.K. O'Neill's satellite plan Message-ID: <16075@sri-arpa.UUCP> Date: Fri, 27-Jan-84 16:00:00 EST Article-I.D.: sri-arpa.16075 Posted: Fri Jan 27 16:00:00 1984 Date-Received: Tue, 31-Jan-84 01:55:59 EST Lines: 42 From: John RedfordSo Gerard O'Neill is going to put up his own communications/navigation satellite. I find this sort of idea really exciting. Information is the one commodity that we know can be produced in space. Advanced materials processing may or may not work, and solar power satellites may or may not be a economical, but space info is already a billion dollar industry. But if O'Neill's system can actually let you find your position to within meters, then the government may not let him build it. The DoD is already building an elegant navigation system, the Global Positioning System or Navstar, and wants to keep it to itself. They figure that if they can find their way around with it then so can the enemy. There's a good description of the system in the October '83 Proceedings of the IEEE. The original proposal for GPS had several classes of equipment. There were to be expensive receivers with accuracies of under ten meters and cheap backpack units with accuracies of a hundred meters. Then when they actually tested the equipment they found that the backpack guys were good to forty meters. There was rejoicing among the engineers, but the military became worried. The portable units can be built and used by anyone. There's less advantage to knowing where you are if your enemy also knows where he is. They decided to degrade the accuracy of the signals that the portable units used, and to encrypt the signals for the accurate receivers. Military receivers get the key to the encryption and civilian ones don't. The cheap receiver's accuracy dropped to 200 m, although it's still apparently possible to get it down to 100 m. A hundred meters isn't bad, but it isn't good either. Ships and airplanes could still use it, but it doesn't seem quite accurate enough to be useful for cars or hikers. There's also no guarantee that they won't degrade it again. The receivers could be produced for only a couple of hundred dollars and could be shrunk to handheld units, but only if they are built in volume. Without better accuracy the volume applications aren't there. It makes you sick at heart. With a system like this no one need ever be lost anywhere in the world. In rain or in snow, in Oklahoma or Antarctica, you could always find out where you were. But the people with the purse strings decided that it was more important to hurt the Russians than to help civilians. If O'Neill wants to build his own system, then more power to him. Anyone want to lay bets, though, that the FCC will be pressured not to permit it? John Redford DEC-Hudson --------