Hi On Jul 29, 2013, at 4:45 AM, David <t_list_1_o...@braw.co.uk> wrote:
> John, Omega did make it into the 'uP age' I briefly got involved in the 80's > and my first patent was for using DSPs and software radio for an Omega > development . The key thing was Omega was genuinely world wide from a small > chain of transmitters and one of the important users had to do their > navigation while staying underwater for weeks on end, even Loran had > limitations never mind satellite. Loran-C was always a poor bet for navigating in the southern hemisphere. > > It might be the answer "the mystery Collins Ru" posting here, I remember > similar items in airborne Omega receivers, the omega carrier frequencies were > low but the receiver bandwidths were measured in mHz and phase error was > critical hence the boxes I saw included similar references. > > Its rather painful to see all the warnings about GPS made 30 years ago having > to be re addressed. Indeed, all of this was gone over *many* times in the 80's. Those involved were *very* knowledgeable about all of these systems and their weaknesses. None of the decisions we are living with were made in a vacuum or without a lot of discussion. Bob > I suspect Loran will not get a big revival, the important development since > the '80s is probably cheap MEMS inertial measurement sensors that give a user > a secure cheap independent accessory to integrate with GPS etc. Its not an > alternative but a rather useful thing to merge into a system to help deal > with spoofing or other signal loss, this page from Analog Devices shows > prices and performance: > > http://www.analog.com/en/mems-sensors/mems-inertial-measurement-units/products/index.html#iSensor_MEMS_Inertial_Measurement_Units > > There are other opportunistic navigation systems that try (tried?) other > approaches such as Peter Duffett-Smith's Cursor system which I think is now > in the hands of CSR. > > Regards > David > > >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Sun, 28 Jul 2013 15:24:30 -0700 (PDT) >> From: "J. Forster" <j...@quikus.com> >> >> Subject: Re: [time-nuts] GPS Spoofing >> >> I'm not so convinced about this: >> >> "OMEGA was the primary means of radio navigation, world wide, from 1976 to >> 1997. ." >> >> There was LORAN-C, after all. >> >> And Omega was a CW, phase difference system, LORAN a pulse system. >> >> AFAIK, Omega never really made it into the uP age; LORAN certainly did. >> >> -John >> >> =========== >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.