On 12/15/11 10:25 PM, Chris Albertson wrote:
For testing, I'd assume the gps simulator only needs to be good enough
that the receiver will detect the signal. There is some Doppler
shift so the receiver must have to look over a wider range of
frequencies so if the simulator was inside that range it could work.
Light travels at about one foot per nanosecond. so your simulator
should need to know the time to within a few tens of nanoseconds.
Receivers can deal with not-perfect signal. Multipath and refraction
are common.
Not just functional test, but to verify the "added noise" from the
receiver.
TO just see if it can acquire and track, pretty crummy would work,
because it's just like the horrible signals it's seeing "off the air"
You GPS simulator would likely have a GPS receiver inside of it and
sync to a real GPS.
Not necessarily. You might be testing in a screen room with no external
signals available.
Clearly, one can go out and spend 500k on a nice Spirent, but I'm
looking at what is the few hundred dollar solution. A reasonably quiet
oscillator driving an FPGA or playing back bits from RAM
On Thu, Dec 15, 2011 at 9:37 PM, Jim Lux<[email protected]> wrote:
Say you want a quik n easy n cheap GPS simulator to test a GPS timing
receiver. How good does the oscillator (presumably some nice multiple of
the chip rate) have to be?
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