[time-nuts] GPS Interference Question
jimlux at earthlink.net
Sat Oct 1 14:46:27 UTC 2011
On 10/1/11 1:38 AM, Magnus Danielson wrote:
> On 30/09/11 18:06, Chris Albertson wrote:
>> One sure-fire "fix" to the problem is to open up the military frequencies
>> to everyone. GPS broadcasts on more than just the common L1 freq.
>> but also on 1.2Ghz.
>> Again, not really pratical because of the huge cost of conversion
> L2C is already being roled out, but relying only on that is to early as
> only 8 birds transmitt it.
> L5 is also an option in the future. Only one bird transmits it.
I think there's actually two, but not turned on all the time. Not sure
> In a distant future it would be possible to build devices with L2C & L5
> only. They are so close in frequency that a common RF chain would not be
> too hard.
But you lose the ability to measure ionospheric delays as well, when the
two frequencies are close.
L5 is all about safety of life applications, since the spectrum for L2
isn't protected as well as that for L5.
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