On 12/16/14, 4:29 PM, Magnus Danielson wrote:
Jim, Bob,
On 12/17/2014 01:06 AM, Bob Camp wrote:
Hi
On Dec 16, 2014, at 7:01 PM, Jim Lux <jim...@earthlink.net> wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull
off if
people want to do dual frequency without going full bandwidth.
Then again, if you are willing to pay good money, you can get it today.
what about one of the software receivers? I would think that making
L2 and L5 filters isn't that tough, so all you need is the back end.
….. and the back end is where all the work is.
There is a fair amount of work along the full path.
LNA with some L2 and L5 filters is pretty easy.
I think you still want to have a correlator baseband processing in say
an FPGA.
well, yes.. but I don't know if there's any handy open source free cores
out there for that.
I do know <grin> of an implementation that does the acq and track in a
pair of Xilinx 2-3000 parts and does the nav solution in a SPARC V8, but
it's not open source and it's definitely export controlled.
Seems that what's out there is mostly "record bits" and "postprocess in
C++ or Matlab" Several textbooks even include it.
There is naturally stuff to be done on the L2C and L5 modulated signals,
but it goes in a relatively slow paze so that even modest processors can
keep up with it.
Indeed.. we do 24 channels (where channel is one PRN at one frequency)
with a 3 frequency solution without making a 66 MHz LEON2 based SPARC
sweat too much.
That's why it would be intriguing if someone had the FPGA stuff out there.
It would still be an expensive project, I suspect. Either you'd have a
few $50-100 boards that would need interfacing and a lot of time, or a
$1000 board with less time.
One hopes that in a few years, multifrequency stuff will become available.
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