...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>IEEE Transactions on Geoscience and Remote Sensing >A Semi-Analytical Model for Delay/Doppler Altimetry and Its Estimation Algorithm
【24h】

A Semi-Analytical Model for Delay/Doppler Altimetry and Its Estimation Algorithm

机译：延迟/多普勒测高的半解析模型及其估计算法

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The concept of delay/Doppler (DD) altimetry (DDA) has been under study since the mid-1990s, aiming at reducing the measurement noise and increasing the along-track resolution in comparison with the conventional pulse-limited altimetry. This paper introduces a new model for the mean backscattered power waveform acquired by a radar altimeter operating in synthetic aperture radar mode, as well as an associated least squares (LS) estimation algorithm. As in conventional altimetry (CA), the mean power can be expressed as the convolution of three terms: the flat surface impulse response (FSIR), the probability density function of the heights of the specular scatterers, and the time/frequency point target response of the radar. An important contribution of this paper is to derive an analytical formula for the FSIR associated with DDA. This analytical formula is obtained for a circular antenna pattern, no mispointing, no vertical speed effect, and a uniform scattering. The double convolution defining the mean echo power can then be computed numerically, resulting in a 2-D semi-analytical model called the DD map (DDM). This DDM depends on three altimetric parameters: the epoch, the sea surface wave height, and the amplitude. A multi-look model is obtained by summing all the reflected echoes from the same along-track surface location of interest after applying appropriate delay compensation (range migration) to align the DDM on the same reference. The second contribution of this paper concerns the estimation of the parameters associated with the multi-look semi-analytical model. An LS approach is investigated by means of the Levenberg–Marquardt algorithm. Simulations conducted on simulated altimetric waveforms allow the performance of the proposed estimation algorithm to be appreciated. The analysis of Cryosat-2 waveforms shows an improvement in parameter estimation when compared to the CA.
机译：自1990年代中期以来，一直在研究延迟/多普勒（DD）测高仪（DDA）的概念，与传统的脉冲限制测高仪相比，该仪器旨在降低测量噪声并提高沿线分辨率。本文介绍了一种由合成孔径雷达模式下的雷达高度计获取的平均背向散射功率波形的新模型，以及相关的最小二乘（LS）估计算法。与常规测高法（CA）中一样，平均功率可以表示为三个项的卷积：平面脉冲响应（FSIR），镜面散射体高度的概率密度函数以及时间/频点目标响应雷达。本文的重要贡献是推导了与DDA相关的FSIR的解析公式。对于圆形天线方向图，没有指向错误，没有垂直速度影响和均匀散射的情况，可以获得此解析公式。然后可以对定义平均回波功率的双卷积进行数值计算，从而得到称为DD映射（DDM）的2-D半分析模型。该DDM取决于三个高度参数：历元，海面波高和振幅。通过在应用适当的延迟补偿（范围偏移）以将DDM对准相同参考点之后，对来自同一关注的沿轨道表面位置的所有反射回波求和，可以获得多视图模型。本文的第二个贡献涉及与多外观半分析模型相关的参数的估计。通过Levenberg-Marquardt算法研究了LS方法。在模拟的高度波形上进行的模拟可以使所提出的估计算法的性能得到赞赏。与CA相比，对Cryosat-2波形的分析显示出参数估计的改进。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号