Download SMOS L1 Processor Algorithm Theoretical Baseline Definition

SMOS L1 Processor
Algorithm
Theoretical Baseline
Code
:
SO-DS-DME-L1PP-0011
Date
:
29/10/10
Issue
:
2.10
Page
:
40 of 89
Using ϑ during measurement in NIR-A mode, the denormalisation factor due to noise leakage is
computed by
′′ ,v + TNA
′′ ,h ) ϑ
VUTnoise = η (TNA
Eq. 90
′′ is the antenna noise injection temperature and η is the NIR pulse length, both in
Where, this time, TNA
NIR-A while the instrument is in science measurements.
In conclusion, the correction functions f ii and f qi are computed during measurement by solving VUTblind ,
VUTnoise and VUL and then using
f ii = −2 Re {VUTblind + VUTnoise + VUL }
f qi = −2 Im {VUTblind + VUTnoise + VUL }
Eq. 91
3.1.10. Receiver Noise Temperature Monitoring
As of September 2006, a new step has been introduced in the PMS calibration sequences. In this step,
the instrument is in Uncorrelated Noise Injection configuration, with the NIR-LICEF also in LICEF-LU
configuration.
The purpose of this step is to measure the System Temperatures with the switch in U position, at the
same time (and temperature) as the rest of PMS calibration is performed, and use it to derive the
Receiver Noise Temperature. This way, the Receiver Noise Temperature can be characterised in the
same way as the PMS gain and offset are, and be computed during nominal science observations. The
objective is to have an independent source for the antenna temperature not related to the NIR
measurements.
The basic principle behind this formulation is presented in [RD.28], and is repeated here below.
The System temperature at LIP plane when the switch is in U position is given by the following
equation:
UL
Tsysk
= (TphUk + Trec )
Eq. 92
Where Trec is receiver temperature at LIP plane and T phUk is the physical temperature of the U-Load
(LICEF isolator). However, since the PMS is calibrated at CIP plane, we must write system temperature
at this plane:
UC
=
Tsysk
1
S LCk
2
(T
phUk
+ Trec )
Eq. 93
And now, taking into account that this system temperature can be retrieved by the PMS as per Eq. 65,
the receiver temperature at LIP plane can be recovered from PMS measurement as
2
UC
Trec = S LCk Tsysk
− TphUk
Eq. 94
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