Research

Altimetry

Coastal Altimetry · Delay/Doppler Processing · Parameter Estimation

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Coastal altimetry, delay/Doppler altimetry, modeling altimetric signals, parameter estimation, signal filtering.

01

From Conventional to Delay/Doppler Altimetry

Ph.D. thesis — Supervisors: Corinne Mailhes, Jean-Yves Tourneret

For more than twenty years, conventional altimeters like Topex, Poseidon-2 or Poseidon-3 have been delivering waveforms used to estimate parameters such as the range between the satellite and the observed scene, the wave height, and the wind speed. Several waveform models and estimation processing have been developed for the oceanic data. A great effort has been devoted to process coastal echoes to move altimetric measurements closer to the coast.

The first part considers coastal waveforms and proposes a new altimetric model accounting for the possible presence of peaks affecting altimetric echoes. The second part develops models for delay/Doppler altimetry, which aims at reducing measurement noise and increasing along-track resolution compared to conventional altimetry.

A. Halimi, "From conventional to delay/Doppler altimetry," Ph.D. thesis, National Polytechnic Institute of Toulouse, 2013.
02

Parameter Estimation for Peaky Altimetric Waveforms

A new altimetric model accounts for the possible presence of peaks in coastal altimetric waveforms. These peaks, caused by bright targets in the altimeter footprint, corrupt the Brown model typically used for open ocean waveforms. The proposed model enables parameter estimation closer to the coast.

A. Halimi, C. Mailhes, J.-Y. Tourneret, P. Thibaut and F. Boy, "Parameter Estimation for Peaky Altimetric Waveforms," IEEE Trans. Geoscience and Remote Sensing, vol. 51, no. 3, pp. 1568-1577, March 2013.
03

Semi-Analytical Model for Delay/Doppler Altimetry

A semi-analytical model for delay/Doppler altimetry and its estimation algorithm. The model accounts for antenna mispointing effects and provides improved parameter estimation.

A. Halimi, C. Mailhes, J.-Y. Tourneret, P. Thibaut and F. Boy, "A semi-analytical model for Doppler altimetry and its estimation algorithm," IEEE Trans. Geoscience and Remote Sensing, vol. 52, no. 7, pp. 4248-4258, July 2014.

A. Halimi, C. Mailhes, J.-Y. Tourneret, F. Boy and T. Moreau, "Including Antenna Mispointing in a Semi-Analytical Model for Delay/Doppler Altimetry," IEEE Trans. Geoscience and Remote Sensing, vol. 53, no. 2, pp. 598-608, Feb. 2015.
04

Bayesian Estimation of Smooth Altimetric Parameters

Bayesian estimation exploiting the temporal smoothness of estimated parameters along satellite tracks, improving estimation quality for range, significant wave height, and wind speed.

A. Halimi, C. Mailhes, J.-Y. Tourneret and H. Snoussi, "Bayesian Estimation of Smooth Altimetric Parameters: Application to Conventional and Delay/Doppler Altimetry," IEEE Trans. Geoscience and Remote Sensing, vol. 54, no. 4, 2015.
05

Denoising Smooth Signals Using a Bayesian Approach

A Bayesian approach for denoising smooth signals with application to altimetry, using a hierarchical Bayesian model with appropriate priors for the unknown parameters.

A. Halimi, G. Buller, S. McLaughlin, and P. Honeine, "Denoising Smooth Signals Using a Bayesian Approach: Application to Altimetry," IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 10, no. 4, April 2017.
Related Publications
  1. A. Halimi, C. Mailhes, J.-Y. Tourneret, P. Thibaut, and F. Boy, "Parameter estimation for peaky altimetric waveforms," IEEE Trans. Geoscience and Remote Sensing, vol. 51, no. 3, pp. 1568–1577, 2013.
  2. A. Halimi, C. Mailhes, J.-Y. Tourneret, P. Thibaut, and F. Boy, "A semi-analytical model for delay/Doppler altimetry and its estimation algorithm," IEEE Trans. Geoscience and Remote Sensing, vol. 52, no. 7, pp. 4248–4258, 2014.
  3. A. Halimi, C. Mailhes, J.-Y. Tourneret, and H. Snoussi, "Bayesian estimation of smooth altimetric parameters: Application to conventional and delay/Doppler altimetry," IEEE Trans. Geoscience and Remote Sensing, vol. 53, no. 4, pp. 2200–2212, 2015.
  4. A. Halimi, C. Mailhes, and J.-Y. Tourneret, "Estimation of the antenna mispointing effects on altimetry waveforms," in Proc. IEEE IGARSS, 2015.
  5. A. Halimi, J.-Y. Tourneret, and C. Mailhes, "Denoising altimetry waveforms by adaptation of the total variation method," IEEE Geoscience and Remote Sensing Letters, vol. 14, no. 11, pp. 2091–2095, 2017.