Einfache Worte habe ich leider nicht zu bieten.Kurt hat geschrieben: ...
kann mir jemand mit einfachen Worten sagen was damit gemeint ist. dBHz.
Es muss mit der Bandbreite zusammenhängen.
Ein Link wäre ganz recht.
Aber unter http://gauss.gge.unb.ca/papers.pdf/SNR.memo.pdf ist es ganz annehmbar erläutert:
A more technically precise and common measurement of GPS signal strength
is known as C/N0 (C-to-N-zero). Some recent Trimble receivers have the
ability to display or output values in these units. However, these
values are not measured directly, but are calculated from the directly
measured SNC count values.
C/N0 is the SNR (usually in dB) in a 1Hz bandwidth. That bandwidth is
1000 times less than our "standard" which implies a 30db change in
db-power units:
C/N0 = SNR[db]@1KHz + 30db.
So... C/N0 = 30 + 10*Log10(SNC^2/2)
= 30 + 10*Log10(SNC^2) - 3
= 27 + 20*Log10(SNC)
For example,
SNC SNR(db:1khz) C/N0(db:1Hz)
3 6.5 36.5 Very weak signal
5 11 41
10 17 47
20 23 53
30 26.5 56.5
40 29 59 Very strong signal
Notice that the SNR values are all positive here, which is somewhat
counter-intuitive. The GPS signal is below the noise level when looked
at over it's entire bandwidth of several Megahertz. This is why you
can't just hook up an oscilloscope to an antenna and see the signals.
Talking about 1KHz or 1Hz bandwidths is an engineering abstraction.
These formulae are all incredibly approximate. A dB or three of
variation is possible, especially at the extremes where things tend to
go a little non-linear.
Alternativer Beitrag: http://www.insidegnss.com/auto/novdec10-Solutions.pdf
Viele Grüße,
Hagen