STUDY OF ROBUST TOA DISCRIMINATORS FOR SPACE-BASED RADAR ALTIMETER

• Published in: Izvestiâ vysših učebnyh zavedenij Rossii. Radioèlektronika no. 4; pp. 13 - 23
• Main Authors: Borovitsky, D. S., Zhesterev, A. E., Ipatov, V. P., Mamchur, R. M.
• Format: Journal Article
• Language: English; Russian
• Published: Saint Petersburg Electrotechnical University "LETI" 13.10.2018
• Subjects: временной дискриминатор; дискриминатор центра тяжести; пороговый дискриминатор; робастность; спутниковый высотомер; среднеквадратическая ошибка измерения запаздывания; эхосигнал
• ISSN: 1993-8985; 2658-4794
• DOI: 10.32603/1993-8985-2018-21-4-13-23

This paper  provides  a study  of robust  TOA discriminators used  in ground-based retracking  of a space-based altimeter da-ta. Requirements to an on-board TOA tracking loop are limited  to reliable locking of received echo-signal  within the tracking  window,  while fine measuring of altimetry parameters (orbit height,  SWH, etc.) is a task  of the Earth-based retracking.  In the  robust  algorithms TOA-measuring  is performed without  using  any  echo  physical  model.  It can  improve space-based altimeter operation near the coastline  where  terrain areas falling into the illuminated spot distort  the received signal  significantly  versus  the  one  from  the  “pure” water  surface.  Analytic  calculation of  noise  errors  is fulfilled  for  the OCOG. Besides, the threshold discriminators and simulation results are presented, as well as comparison of the robust  discriminators against  the  optimal (within the  classical model  framework) one.  Despite the  robust  types  yield to the  optimal one  in the  accuracy  of TOA estimate, the  loss is not  catastrophic and  often  can be treated as an acceptable pay-ment for low sensibility  to the deviation of scattering  characteristics of a sounded surface  from  classical models.