[time-nuts] GPS Spoofing
Bob Camp
lists at rtty.us
Mon Jul 29 11:11:16 UTC 2013
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
>>
>> ===========
>>
>
>
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