Theory of GNSS Reflectometry - GNSS Remote Sensing: Theory, Methods and Applications - page 207

Fig. 8.18 Real PIT
waveform obtained during the
experimental campaign
described in Rius et al.
( 2012 ), from an aircraft at
200 m altitude flying over
estuary calm waters. The PIT
waveform has contribution
from all the transmitted
codes, which for that
particular GPS satellite were
C/A, P(Y), and M codes.
Compare with the theoretical
PIT waveform in
Martín-Neira et al. ( 2011 ,
Fig. 6)

Fig. 8.19 Real PIT
waveform and C/A reflected
waveforms obtained during
the experimental campaign
described in Rius et al.
( 2012 ), using two different
receivers ( Rius et al. 2011 ;
Nogués-Correig et al. 2007 )
from an aircraft at 3 km
altitude flying over Ocean
waters. The floor-noise levels
have been subtracted for
better comparison. Coherence
integration time: 1 ms;
non-coherent averaging: 20 s

also seen. Another example of a PIT waveform under rougher surface conditions
is displayed in Fig. 8.19 . The plot shows both real PIT and C/A-code waveforms
taken simultaneously with two different receivers (PIR-A Rius et al. 2011 and
GOLD-RTR Nogués-Correig et al. 2007 ) from an aircraft flying at 3 km altitude
over the Ocean surface. Both suffer distortion due to the diffuse scattering, but the
PIT waveform still presents a steeper leading edge.

8.10 Observables

In the frame of these GNSS-R Chapters, we will define the observables as mea-
surable objects (scalar values, arrays,...) from which geo-physical information can
be derived. Different receiving instruments produce different types of observables,