Data simulation methods for cartosat satellites

Data simulation methods for cartosat satellites

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B. Gopala Krishna, Medha Alurkar and P. K. Srivastava
Satellite Photogrammetry and Digital Cartography Division, Signal and Image Processing Group
Space Applications Centre (ISRO), Ahmedabad – 380 015

India’s future remote sensing satellites viz., CARTOSAT series are planned to provide high resolution images of Earth’s surface operationally, either in mono or in stereo modes. This data enables the user to enter into the cartographic applications, where the requirement is high radiometric and geometric accuracy products.To visualise the data sets and their applications potential before the satellite is launched, it is necessary to simulate data sets with the same geometric and radiometric characteristics of the planned satellite. This paper presents some of the techniques developed by data products team at Space Applications Center, Ahmedabad for data simulation for CARTOSAT. The basic objectives of the data simulation are:

  • To visualise and prove the applications potential of CARTOSAT
  • To study and analyse the behavior of various parameters related to platform, payload and orbit on the imagery
  • To evolve the specifications of the new hardware onboard, for example data compression
  • To validate the data processing software
  • To stimulate new application areas for the improved resolutions and
  • To prepare the users for CARTOSAT data utilisation in advance

The geometric and radiometric parameters to be simulated in the output images are generally depend on the input data set used. The basic requirements for the simulation are that the input data should have (a) minimum twice the geometric resolution; and (b) half or similar radiometric resolution than the ones to be simulated. The general parameters considered for the simulation studies are:

  • Geometric resolution
  • Radiometric resolution
  • Orbital parameters
  • Payload parameters
  • MTF and
  • Photo Response Non Uniformity (PRNU)

Other than these, many intermediate parameters are also to be considered depending on the input data. The techniques for data simulation are developed and tested for various parameters with (a) IRS-1C/1D PAN data; (b) scanned (at high resolutions) aerial images; and (c) aerial digital frame camera data sets to generate CARTOSAT sub-images.