eeh said:
I want to buy a GPS receiver to analyse the base band signal for
University course learning purpose. Could anyone introduce me one?
You could use GNURadio and a USRP to do this (although the near-baseband IF
might end up in slightly odd locations based on which transverter you use,
although hopefully this won't matter to you). Most GPS receivers today use a
highly integrated IC where you don't have any access to various intermediate
RF signals.
Since GPS signals are below the noise level of a typical (couple dBi) antenna,
just synchronizing to the chipping code involves a fair amount of effort if
you've never done this sort of thing before. I've seen people "cheat" in the
past (especially for university research projects where the research doesn't
involve anything having to do with those low signal levels) by aiming a high
gain dish up at a particular satellite such that their SNR is positive prior
to the process gain provided by despreading. You're be in hog heaven if your
university happens to have a radio telescope lying around!
You may want to re-post your question to a newsgroup such as
sci.geo.sattellite-nav or alt.sattellite.gps if they're available to you...
some of the folks who hang out there would know off the top of their heads
what kind of radios let you access various internal signals that could be of
value to your research.
---Joel Kolstad
