[time-nuts] GPS Spoofing

[Bob Camp]

Hi

On Jul 29, 2013, at 4:45 AM, David <t_list_1_only at 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" <jfor at 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 at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.