Effect of Troposphere and Ionosphere on C-Band Radar Track Data and Correction of Tracking Parameters

Rayi Varaprasad; Vellanki SeshagiriRao; S Vijaya Bhaskara Rao

doi:10.14429/dsj.62.1160

Rayi Varaprasad ISRO
Vellanki SeshagiriRao Dy Director Range Operations SDSC SHAR ISRO
S Vijaya Bhaskara Rao Professor SV University Tirupathi A.P

DOI: https://doi.org/10.14429/dsj.62.1160

Keywords: Astronomical refraction, mapping function, refraction error, ionospheric refraction, single layer model, ionospheric pierce point

Abstract

At any launch base radar tracking is critical for assessing the state of the launch vehicle for range safety function as well as for trajectory monitoring. Tracking data corrected for refraction effects is essential for estimating the flight performance. This paper presents the refraction effects of troposphere and ionosphere on the radio waves of C-Band radars in terms of errors in the measured tracking parameters. Application of mapping functions for correcting refraction errors in C-Band radar track data is studied and a comparison of the performance of mapping functions is presented. The mapping functions not only show good convergence at low elevations but also correct around 90 per cent of the refraction error in elevation.

Defence Science Journal, 2012, 62(6), pp.420-426, DOI:http://dx.doi.org/10.14429/dsj.62.1160

Author Biographies

Rayi Varaprasad, ISRO

M
r V Seshagiri Rao obtained his MSc (Electronics) from Andhra University, Visakhapatnam. Currently working as Deputy Director for Range Operations and Vehicle Assembly and Static Testing Entities at SHAR launch base. He was awarded the Space gold medal of Astronautical Society of India, 2000. He worked extensively in the design and development of real time systems at Sriharikota range. He has developed various filtering algorithms for state estimation using radar data. He is instrumental in establishing various processing methodologies for radar calibration, wind profile estimation, and telemetry data processing.

Vellanki SeshagiriRao, Dy Director Range Operations SDSC SHAR ISRO

M
r R Varaprasad obtained his MSc (Physics) from Andhra University. Presently working as Dy. General Manager of SHAR Computer Facility, Indian Space Research Organization, at Sriharikota range. He was awarded the ISRO team excellence award-2009. He worked in different areas such as orbital data analysis, LAN-based vehicle telemetry real time monitoring systems and range safety real time systems. He has developed a number of digital filter algorithms for state estimation of launch vehicles for various tracking scenario. His fields of interest include advanced data processing techniques for trajectory estimation for upcoming space missions.

S Vijaya Bhaskara Rao, Professor SV University Tirupathi A.P

D
r Vijaya Bhaskara Rao S received PhD from Sri Venkateswara University, Tirupati. At present he is working as Professor of Physics at Sri Venkateswara University, Tirupati. He implemented many sponsored projects from UGC, AICTE, DST, ISRO, CSIR etc., and published 80 papers in journals of international repute and guided 15 students for PhD degree. He has been to many countries to attend conferences and also worked as a Visiting Fellow at NTU, Singapore. He is a fellow of Andhrapradesh akademi of Sciences and IETE, New Delhi. He is recipient of IETE-Prof. K. Sreenivasan Memorial award for the year 2012.