On 01/09/2011 1:08 PM, Nick Foster wrote:
On Thu, Sep 1, 2011 at 8:42 AM, Wolfarth, Ryan <wolfa...@muohio.edu
<mailto:wolfa...@muohio.edu>> wrote:
Hi all,
I am generating my masters thesis proposal and I have a few
questions about the capabilities of the E100 and the feasibility
of my project. I have read other posts to gather information, but
correct me if anything I've determined is wrong. My goal is to
implement an 8 channel GPS L2C receiver on an FPGA. I am
interested in doing this with the E100 since I may be able to take
advantage of the ARM processor as well. Can anyone with
experience in this area provide advice?
I would like to use the RFX1200 to receive the L2C signal since it
has better performance characteristics than the DBSRX. This would
prevent me from first acquiring L1 signals to aid in acquisition,
so I propose using preloaded almanac data to estimate SV
position/Doppler frequency. This would reduce the number
computations when acquiring L2 CM code. The end result only has
to go as far as to decode the navigation bits: I will not need a
position solution.
The root of my question is: does the FPGA on the E100 have enough
space to handle this project?
Does it sound like I'm on the right track?
Sounds like a very interesting project. I have two suggestions:
1. The SBX daughterboard has a better noise figure (5dB vs. 8dB typ.),
with better linearity, and would be better suited for GPS work,
especially if you aren't using front-end filters. SBX will also
receive both the L1 and L2 frequencies.
In the specific case of GPS, most active GPS antennas (which is what
most people use) have GPS-optimized LNAs with very low noise figure,
and easily enough gain to swamp the noise figure of whatever
receiving hardware is downstream, so the noise figure of the receiver
board is largely irrelevant in most cases with GPS active antennae.
In my radio astronomy work (where Tsys is absolutely critical), as long
as the downstream receiver has a noise figure below about 15dB or
so, I generally don't care what it is, since I use a tuned vLNA in
front of it. It's a very similar situation with GPS.
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