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)): BTD 
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after applying ground measured antenna pattern 
correction. MSMR data product accuracy specification is 
given in Table 2. 
4) Geophysical Parameter Data of 3 Grids (GPD):GPD 
data product is grided data containing individual 
geophysical parameter file. Sensor corrected Brightness 
Temperature data are input in Radiative Transfer (RT) and 
hydrometerological modeling for retrieving geophysical 
variables like sea surface temperature (SST), wind speed, 
water vapor content and liquid water content. 
IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India,2002 
beam efficiency & polarization isolation given in Table 4 and 
Fig 5a, 5b. 
The antenna temperatures are input to the APC algorithm, 
which reformat data and compensate for antenna side-lobe and 
polarization coupling effects. The brightness temperature with 
grid locations in the latitude/longitude and time tags are then 
passed to the final stage of geophysical processing 
  
  
Freq Span | Inte | Beam Width | Beam | Isolati 
GHz (deg) | rval | at-3 dB(Deg) | Efficie | on at 
deg Azimuth ncy at | -10dB 
Elevation -10 
dB% 
  
  
  
  
  
Parameters Frequency (GHz) 
6.6 10:65 18:05 21.0 
Location Accuracy km 20 20 20 20 
Brightness Temp Accuracy 1.33 1.38] 2:007] 233 
°K) 
  
  
  
  
6.6 -14 to 
H +14 02 1382 3.77 88.4 -22.33 
V 3.73 3.76 88.1 -20.84 
  
Table 2 MSMR Data Products Accuracy Specification 
3.0 DATA QUALITY EVALUATION PARAMETERS 
3.1 Ground Measured Parameters 
3.1.1 Ground Calibration: The MSMR instrument is 
calibrated before launch in the Thermal Vacuum chamber to 
simulate the environment conditions to be experienced in space 
to derive accurate values for the constants in the calibrations. In 
order to relate the radiometer output voltage to the input 
antenna temperaments of the MSMR operating on the 
spacecraft, a calibration equation is used which makes use of 
data from the two calibration points. This calibration equation 
is obtained by applying radiative transfer to each of the lossy 
components between the antenna and calibration switch output. 
In ground calibration the cold source is provided by a 
blackbody whose temperature is maintained at 78?k by 
circulating liquid Nitrogen around it. The horns thus see this 
low temperature. The hot load is provided by the constant 
ambient temperature (10?c, 20?c & 30?c) inside the thermovac 
chamber. Using the two-point calibration source the linearity of 
the receiver is quantified as shown in Table 3 for each 
channel/polarization. These slope & offset of Table are look up 
tables for carrying out on-board data calibration depending on 
Hot/Cold calibration counts & systems junction temperature. 
  
  
  
Temp: 20deg 
Frequency (GHz) 
6.6 10.65 18.0 21.0 
Offset 
H 3648.08 3635.40 2792.78 3150.38 
V 3573.49 3673.44 3268.34 3028.49 
Slope 
H -8.95 -8.87 -5.88 -6.98 
V -8.70 -9.01 -7.12 -6.58 
  
  
  
  
  
  
  
Table 3 Ground Measured System Linearity 
3.1.2Antenna Pattern Measurement 
The characteristics of the onboard antenna pattern are measured 
on ground. These patterns are very important in the derivations 
of corrected Brightness temperature from the MSMR 
measurements. These patterns are obtained from field 
measurements for each frequency and polarization as co & 
cross polarization, main lobe, side-lobe & back-lobe energy. 
The antenna patterns were integrated numerically to provide the 
  
  
  
  
  
  
  
  
  
  
10.65 | -8to 
H +8 0.2 | 2.41 2.40 90.3 -29.82 
V 2.38 12:37 89.7 -23.77 
18.00 | -4to 
H +4 0.1 | 1.43 1,35 87.5 | -26.53 
V 1.44 1.50 87.6 -20.26 
21.00 
H -5 to 0.1:]:1.29 1.19 84.59 | -24.26 
V +5 1.23 1.30 87.10 | -21.00 
  
Table 4 Beam Efficiency of MSMR Antenna 
      
    
  
Bs ASA 
30 PLOT FOR FREQ : 21 GHz V PORT 
(a) 3D Plot For 21.0 GHz V Port 
  
an à . 1$ 50 PLOT FREQ: 5.6 GHz 1 PORT 
CounTONR FOR IRE ST CME H 
(b) 3D Plot For 6.6 GHz V Port 
Fig 5 Sample Plot Of Ground Measured Antenna Pattern 
3.2 Onboard Measured Parameters: 
Data Quality Evaluation Activity mainly monitors the specified 
Sensor Performance & Evaluate Radiometric, Geometric 
accuracy parameters from MSMR Data Products. The main 
parameters for each product are evaluated as per data type. 
3.2.1 Raw data (SDF) quantifies data reception quality & 
MSMR sensor performance. 
e Sensor Data reception quality is a function of the number 
of invalid scans due to bad sync status. Similarly quality of 
Calibration data is bad, if number of scans with Standard 
deviation more than 15 counts from 30 samples/scan of 
HOT & COLD counts (as it has been observed from 
ground data, 1deg Kelvin corresponds to 8 counts)