IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India,2002 
  
MULTI FREQUENCY SCANNING MICROWAVE RADIOMETER (MSMR) SENSOR 
PERFORMANCE 
Shashikala Palsule, Anjali Garg, Hetal Pandya, Anuja Sharma 
Data Quality Evaluation Division, SIIPA, Space Applications Center, ISRO, Ahmedabad-15, India 
shashi@ipdpg.gov.in,anjali @ipdpg.gov.in,hetal @ipdpg.gov.in,anuja@ipdpg.gov.in - 
KEYWORDS: Calibration, Antenna & Brightness Temperature Data, Geophysical Parameter, Geo-location, Grid Resolution, 
Sensitivity 
ABSTRACT: 
The Multi frequency Scanning Microwave Radiometer (MSMR) is four frequencies (6.6 Ghz, 10.65 Ghz, 18.0 Ghz, 21.0 GHz), Dual 
polarized (H & V) microwave Sensor. This microwave radiometer is flown on IRS-P4 satellite which was launched by PSLV on 
26th May 1999 from ShriHari Kota (Shar), India. This radiometer measures the dual polarized microwave radiance from the earth 
Ocean surface and atmosphere. It has the revisit capability of two days. This paper highlight MSMR sensor performance results 
obtained by Data Quality Evaluation (DQE) system for data product generated routinely at Balanagar, Hyderabad. DQE system has 
developed operational Software Package to monitor & quantify various parameters like Sensor Data Reception Quality, System 
Calibration Performance, Stability of Antenna Scanning mechanism & Receiver Junction Temperature. Laboratory measured 
Antenna Pattern as Half Power Beam Width, Beam Efficiency, Side lobes are also estimated. Radiometric performance on uniform 
pre-defined targets (Ocean, Desert) is evaluated for Relative Channel Sensitivity Performance. Relative Global Geolocation 
Performance evaluation procedure was adopted by selecting land-sea-land transition tips from Greenland, Australia, India & South 
Africa. The. detailed statistical Performance analysis on RAW/ATD/BTD Product shows that receiver-engineering performance is 
stable from Hot/Cold Calibration data and antenna-scanning stability is within 0.5%. Radiometric Performance is within 1°k. and 
Geolocation of Product is within +/- 1.2 grid resolution. 
1.0 INTRODUCTION 
The Multi frequency Scanning Microwave Radiometer 
(MSMR) onboard IRS-P4 satellite was launched on 26^ May 
1999, Specifications of MSMR Payload are given in Table 1 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Frequencies(GHz) 6.6,10.65,18.0,21 H&V Polarization 
Angle of incidence 50°C 
Swath 1360 Km 
Scanning Conical Circular Scanning 
Repetivity 2 Days 
Scan Time Period 5.37 seconds 
Angular Scan Speed | 11.16 RPM 
Dynamic Range 10°k to 330°k 
Temperature Ideg K 
Sensitivity t 
Frequency (GHz) 6.6 10.65 18.0 
21.0 
Beam Footprint | 105 66 40 
(Km) Scan 34 
Beam Footprint | 67 43 26 
(Km) Pixel 22 
  
  
  
Table 1 Sensor Specifications 
Two point internal calibration approach has been utilized by 
using dedicated horn antenna viewing the cold space (2?7k) and 
a black body at a high temperature (receiver ambient 
temperature) is used for the hot reference. The fore half period 
of circular conical scan is utilized for data collection and the aft 
period is effectively used for cold and hot calibration 
sequences. Two sets of internal calibration data is acquired just 
before and after data collection cycle. Analog & Digital 
Telemetry subsystem (ADTMS) measures  51-junction 
temperature precisely. The radiometric sensitivity of MSMR 
system depends upon receiver pre-detection bandwidth, 
Integration time, Type of receiver, Antenna and receiver 
temperature, Gain measurement accuracy. 
2.0 MSMR DATA PRODUCTS 
The application of this payload is for estimation of 
oceanographic / meteorological parameters. The 6.6 GHz to 
10.65 GHz channels are used for estimating sea surface 
temperature and wind speed. The 18.0 GHz and 21.0 GHz 
channels are useful for estimating climatic and atmospheric 
humidity measurement. 
The MSMR data product gets generated routinely 24 hr data as 
a unit product. Each product is starting from 00.00 hrs to 
23.59.59.999hrs. This data product corresponds to Play Back 
mode, which is operational mode of mission. Real Time data is 
available for duration of 10 minutes & area coverage 
corresponds to visibility of Shadnagar Earth Station. 
Each product consists of 
1) Raw Data Set: This data set consists of orbit, attitude data 
(OAT) related to satellite position & platform. The other 
important data set recorded by MSMR sensor is the raw 
counts of 300 sample per scan (SDF) along with various 
51 receiver junction temperatures and additional 60 
samples of Calibration counts (Hot/cold) per scan to 
quantify sensor performance per Calibration channels. 
2) Antenna Temperature Data (ATD): This data product 
consists actual temperature values seen by antenna 
receiver using ground calibration coefficients and onboard 
Hot/Cold calibration counts. 
3) Brightness Temperature Data of 3 Grids (BTD): BTD 
data product is grided data available in three resolutions