【摘要】：衛(wèi)星雷達(dá)高度計(jì)(Satellite radar altimeter)是海洋實(shí)時(shí)監(jiān)測(cè)的一個(gè)重要工具。到目前為止,全世界已有不少國(guó)家發(fā)射了載有雷達(dá)高度計(jì)的衛(wèi)星。星載雷達(dá)高度計(jì)的測(cè)高具有全天候全天時(shí)和全球范圍探測(cè)能力,能時(shí)刻監(jiān)測(cè)和觀察海洋環(huán)境,獲得包括有效波高值、風(fēng)速、海表面溫度等多種海洋動(dòng)力環(huán)境參數(shù),并直接為災(zāi)害性的海況預(yù)警預(yù)報(bào)提供實(shí)時(shí)監(jiān)測(cè)數(shù)據(jù);也為海洋環(huán)境保護(hù)、海洋資源開發(fā)、海洋防災(zāi)減災(zāi)、海洋科學(xué)研究以及國(guó)防建設(shè)等提供權(quán)威的支撐服務(wù)。基于這些因素,我國(guó)也于2011年發(fā)射了HY-2衛(wèi)星。通過對(duì)HY-2(海洋2號(hào))衛(wèi)星工作原理的深研究,我們對(duì)星載雷達(dá)高度計(jì)測(cè)高的各個(gè)環(huán)節(jié)可能存在的誤差有了深入的了解。本文主要針對(duì)國(guó)家海洋局海上環(huán)境預(yù)報(bào)中心所提供的數(shù)據(jù),對(duì)測(cè)高過程中回波波形因素和電離層對(duì)信號(hào)的延遲誤差及其修正給出了分析和研究。首先,為計(jì)算海洋海平面的高度,根據(jù)已有的模型對(duì)星載雷達(dá)高度計(jì)的回波波形進(jìn)行跟蹤和分析,找出影響回波波形的各種因素,利用回歸分析和離散點(diǎn)交叉算法得出衛(wèi)星軌跡的交叉點(diǎn),并進(jìn)行相應(yīng)的標(biāo)定;其次,利用幾種插值算法計(jì)算各交叉點(diǎn)上有效波高、海洋風(fēng)速和海平面高度,分析比較不同差值方法的結(jié)果得到最優(yōu)差值方法;最后,針對(duì)國(guó)家海洋局海上環(huán)境預(yù)報(bào)中心所提供的數(shù)據(jù)分析了電離層延遲誤差,對(duì)比了已知的幾種電離層模型與自身雙頻改正效果,結(jié)果表明GIM模型改正效果最好,并建議在雙頻改正效果不理想的地方采用GIM模型改正。此外,本文用時(shí)間序列分析中濾波原理,對(duì)有效波高進(jìn)行去燥處理得出信噪比較高的波形數(shù)據(jù),利用這些數(shù)據(jù)可以進(jìn)而對(duì)脈沖信號(hào)與海面作用誤差即電磁偏差進(jìn)行分析;電離層延遲的誤差主要是由于電磁信號(hào)在電離層中傳播發(fā)生折射造成的,可以通過采用雙頻(Ku波段和C波段)測(cè)量模式來降低電離層的影響,利用貝葉斯統(tǒng)計(jì)理論對(duì)這兩波段(Ku波段和C波段)測(cè)高噪聲進(jìn)行均方差處理,使電離層延遲誤差減少到厘米以內(nèi)。同時(shí),采用上述方法對(duì)T/P和JASON-1,2系列衛(wèi)星數(shù)據(jù)進(jìn)行處理,將所得到的結(jié)果與HY-2A衛(wèi)星數(shù)據(jù)處理結(jié)果進(jìn)行比較,方便尋找誤差來源進(jìn)而減少誤差以及分析模型的優(yōu)劣程度。海洋雷達(dá)測(cè)高衛(wèi)星測(cè)高數(shù)據(jù)的誤差分析和標(biāo)定對(duì)測(cè)高數(shù)據(jù)的應(yīng)用具有重要作用,隨著HY-2A衛(wèi)星的數(shù)據(jù)處理技術(shù)的不斷改進(jìn),相應(yīng)的誤差分析也要隨之改進(jìn),進(jìn)而提高測(cè)高精度,提高衛(wèi)星數(shù)據(jù)的科學(xué)應(yīng)用價(jià)值。
[Abstract]:Satellite radar altimeter (Satellite radar altimeter) is an important tool for real-time ocean monitoring. So far, many countries around the world have launched satellites carrying radar altimeter. Space-borne radar altimeter with all-weather altimeter? Full-time and global detection capability to monitor and observe the marine environment at all times, and to obtain a variety of marine dynamic environmental parameters, including effective wave height, wind speed, sea surface temperature, and so on. It also directly provides real-time monitoring data for early warning and forecasting of disastrous sea conditions. It also provides authoritative support for marine environmental protection, marine resources development, marine disaster prevention and mitigation, marine scientific research and national defense construction. Based on these factors, China also launched the HY-2 satellite in 2011. Through the deep study of the working principle of the HY-2 satellite, we have a deep understanding of the possible errors in the altimeter height measurement of the spaceborne radar. Based on the data provided by the Marine Environment Forecast Center of the State Oceanic Administration, the factors of echo waveform and the delay error of ionosphere signal during altimetry and their correction are analyzed and studied in this paper. Firstly, in order to calculate the sea level height, the echo waveforms of spaceborne radar altimeter are tracked and analyzed according to the existing models, and various factors affecting the echo waveforms are found out. The intersection point of satellite trajectory is obtained by regression analysis and discrete point crossover algorithm, and the corresponding calibration is carried out. Secondly, several interpolation algorithms are used to calculate the effective wave height, ocean wind speed and sea level height at each intersection, and the optimal difference method is obtained by analyzing and comparing the results of different difference methods. Finally, the ionospheric delay error is analyzed according to the data provided by the Marine Environment Forecast Center of the State Oceanic Administration, and several known ionospheric models are compared with their own dual-frequency correction effects. The results show that the GIM model has the best correction effect. It is suggested that GIM model should be used where the effect of dual frequency correction is not satisfactory. In addition, this paper uses the filtering principle of time series analysis to dedryness the effective wave height to get the waveform data with high signal-to-noise ratio, which can be used to analyze the interaction error between pulse signal and sea surface, that is, electromagnetic deviation. The error of ionospheric delay is mainly due to the refraction of electromagnetic signal propagation in the ionosphere. The influence of ionosphere can be reduced by using dual-frequency (Ku band and C-band) measurement mode. Bayesian statistical theory is used to deal with the mean variance of the altimetry noise in these two bands (Ku band and C band), so that the error of ionospheric delay can be reduced to less than cm. At the same time, the above-mentioned methods are used to process the Tp and JASON-1,2 series of satellite data, and the results obtained are compared with those of the HY-2A satellite data processing. It is convenient to find the error source and then reduce the error and analyze the merits and demerits of the model. The error analysis and calibration of ocean radar altimetry data plays an important role in the application of altimetry data. With the continuous improvement of HY-2A satellite data processing technology, the corresponding error analysis should be improved accordingly. Furthermore, the accuracy of altimetry is improved and the scientific application value of satellite data is improved.
【學(xué)位授予單位】：河南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P715.6

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