GEO卫星机会源近岸海面高度测量性能评估

Performance Assessment of Coastal Sea Surface Height Measurement Using Opportunity-Source Signal from GEO Satellite

基于同步地球轨道(Geostationary Earth Orbit,GEO)卫星的机会源技术已被证明其在近岸海面高度测量中的应用潜力,但目前研究主要围绕可行性论证展开,极少开展全方位的测量性能评估.为此,从仿真和试验两个角度评估了信号带宽、非相干累加次数、信噪比及波形峰值跟踪算法对GEO卫星机会源海面测高性能的影响.评估结果表明当非相干累加次数和信噪比大于最优非相干累加次数和最优信噪比时,测高性能将不再显著提升.因此,通过选择最优非相干累加次数,以及设计合理的接收天线增益、射频增益及接收机带宽使信噪比大于最优信噪比对GEO卫星机会源海面测高至关重要.通过对比插值和拟合两种波形跟踪算法发现拟合法能提供比插值法更高的测量精度.利用北斗B3I信号和ASTRA 19.2 E卫星信号开展GEO卫星海面测高的试验评估.试验结果表明:在非相干累加次数大于10000、信噪比大于7 dB时,北斗B3I信号和ASTRA 19.2 E卫星信号可分别提供精度约为0.20 m和0.10 m的海面高度.针对GEO卫星多频或多通道传输特点,提出了基于信号频谱合成提高海面测高精度的方法.当利用中卫1号卫星10个通道信号进行合成时,插值法和拟合法的仿真测距精度分别为3.50 cm和0.69 cm.

It is potential to measure sea surface height using opportunity of source from geostationary earth orbit(GEO)satellites.Most studies focus on the experimental demonstrations,but few works comprehensively assess its perfor⁃mance.Based on this,the paper evaluates the influence of the signal bandwidth,incoherent integration number,signal-tonoise ratio(SNR)and retracking algorithm on the oceanic altimetry performance.It is found that once the incoherent inte⁃gration number and SNR are over the optimal incoherent integration number and SNR,the improvements of the altimetry performances are insignificant.Therefore,choosing optical incoherent average number,and designing the receiver antenna gain,radio-frequency gain,and receiver bandwidth to obtain optical SNR are needed.The fitting method can provide a bet⁃ter precision than the interpolation method.The data from the BeiDou B3I signal and ASTRA 19.2 E satellite experiments are used to assess the GEO opportunity-source altimetry.The experiment results show that for the incoherent average num⁃ber and SNR over 10000 and 7 dB,respectively,the altimetry precision of about 0.20 m and 0.10 m can be obtained,re⁃spectively.Due to multi-frequency or multi-channel transmission,the spectral synthesis is proposed to improve the altime⁃try precision.The simulation results show that the synthetized signal from 10-channel signals of Zhongwei-1 satellite pro⁃vides a precision of 3.50 cm and 0.69 cm for the interpolation and fitting method.