浙江平原时序InSAR地面沉降监测

针对浙江省地面沉降监测需求,研究利用时序InSAR技术进行浙江省平原区地面沉降监测的技术流程。以上虞区块为例,反演得到上虞地区2013-2014年度地面沉降信息;结合同期外业水准测量数据,在传统点-点、点-面验证基础上,提出点-线验证方式,将几种分析评价方法进行了对比,对InSAR地面沉降监测精度进行评价分析;最后结合外业实地调查的情况,证明了InSAR技术监测大范围地面沉降分布状况和发现区域沉降中心的有效性和精确性。     

一种简易的GNSS接收机自检方法

针对GNSS接收机检定费用较高、检定机构数量少且检定周期长的问题,该文提出了一种简易快速的GNSS接收机检定方法。该方法根据GNSS接收机天线相位中心的几何关系,通过自设简易检定场,利用相对定位法及超短基线法分别检测接收机天线的相位中心偏差和内部噪声水平,并编写了相应的计算程序对检测数据进行快速的处理。4次独立实验结果表明:该文实验方案具有较高的精度和可靠性,适用于快速对GNSS接收机天线相位中心偏差和内部噪声水平进行自检。     

BDS/GPS短基线解算的随机模型研究

针对BDS轨道高度存在差异进而影响短基线解算结果的问题,该文利用两组实测数据,研究BDS和BDS/GPS组合系统的短基线解算精度及可靠性,并探讨4种随机模型的性能。结果表明,BDS和BDS/GPS组合系统短基线解算精度能够达到厘米级,且模糊度解算的可靠性更高;4种随机模型性能相当,随着基线长度增加,MINQUE模型的优势降低;不同类型卫星轨道高度差异较大,高度角模型不适宜BDS和BDS/GPS组合系统短基线解算。     

Measurement of subsidence in the Yangbajing geothermal fields,Tibet, from TerraSAR-X InSAR time series analysis

Yangbajain contains the largest geothermal energy power station in China. Geothermal explorations in Yangbajain first started in 1976, and two plants were subsequently built in 1981 and 1986. A large amount of geothermal fluids have been extracted since then, leading to considerable surface subsidence around the geothermal fields. In this paper, InSAR time series analysis is applied to map the subsidence of the Yangbajain geothermal fields during the period from December 2011 to November 2012 using 16 senses of TerraSAR-X stripmap SAR images. In the case of the TerraSAR-X data, most orbital fringes were removed using precise orbits during the interferometric processing. However, residual orbital ramps remain in some interferograms due to the uncertainties in the TerraSAR-X orbits. To remove the residual orbital ramps, we estimated a best-fit ‘twisted plane’ for each epoch interferogram using quadratic polynomial models based on a network approach. This method removes most of the long-wavelength signals, including orbit ramps and atmospheric effects. The vertically strati?ed component (Topography Correlated Atmospheric Delay, TCAD) was also removed using a network approach. If the influence of seasonal frozen ground (SFG) is not taken into consideration, our results show that the subsidence rate around power plant I (the south plant) is approximately 20?mm/yr with a peak of 30?mm/yr. The subsidence rate around power plant II (the north plant) is approximately 10?mm/yr, when accounting for the influence of SFG on the power plant and its surrounding ground surface. Our results show that ground motion is caused by seasonal frozen ground and is strongly related to the temperature change.     

What can we learn from aerosol measurements at baseline stations?

In this paper the results of existing baseline aerosol monitoring programs are reviewed. For this purpose, aerosol data from five baseline stations in both hemispheres are analysed. Their information content is compared to that which can be derived when utilizing experiences of recent field experiments and the present state of aerosol sciences in general. Recommendations for extensions and reductions of baseline aerosol measurements are given.     

Segregation and Interpretation of Ozone and Carbon Monoxide Measurements by Air Mass Origin at the TOR Station Mace Head, Ireland from 1987 to 1995

Three independent methods have been used to sort the ozone, carbonmonoxide, and other radiatively important trace gases measured at Mace Head,Ireland, and thereby distinguish clean air masses transported over the NorthAtlantic from the more polluted air masses which have recently travelledfrom the European continent. Over the period April 1987–June 1995 theNorthern Hemisphere surface ozone baseline concentrations exhibited a meanconcentration of 34.8 ppb, with a small positive trend (+0.19 ppbyr^-1), while the corresponding trend in air originating fromthe polluted European areas was negative (–0.39 ppbyr^-1). Carbon monoxide measurements from March 1990 toDecember 1994 showed negative trends for both the unpolluted (–0.17ppb yr^-1) and polluted data (–13.6 ppbyr^-1). Overall the continent of Europe was shown to be a smallnet sink of 2.6 ppb for all occasions when European air was transported tothe North Atlantic.     

Improved Method to Detect and Repair Cycle Slip for GNSS Medium–Long Baseline in Real-Time Marine Surveys

Distance-related errors complicate the resolution of real-time ambiguity in medium–long baseline marine surveys. Therefore, detection and recovery of cycle slips in real time is required to ensure high accuracy of global navigation satellite system positioning and navigation in marine surveys. To resolve this, an improved method was presented, where linear combinations of the triple-differenced (TD) between carriers L₁ and L₂ were formed for a wide lane and free ionosphere. To overcome severe ill-conditioned problems of the normal equation, the Tikhonov regularization method was used. The construction of a regularized matrix by combining a priori information of known coordinates of reference stations, followed by the determination of the corresponding regularized parameter are suggested. A float solution was calculated for the TD ambiguity. The search cycle slip (TD integer ambiguity) was obtained using the least-squares ambiguity decorrelation adjustment (LAMBDA) method. Using our method, cycle slips of several reference station baselines with lengths of a few hundred to one thousand kilometers were detected in real time. The results were consistent with professional software, with a success rate of 100%.     

空间技术观测数据对全球七大板块运动参数的精化

采用截止到2003年GPS观测数据和1997年的VLBI观测数据,利用它们的站速度信息,组合解算完全基于空间技术的板块运动参数;通过对站速度残差的精化分析,得出更加稳健的现时板块运动参数;并通过反复试算得出稳定台站的选取以及台站的分布对板块运动欧拉极有很大的影响。     

首都圈长水准与跨断层流动观测资料的综合研究

为了更深入地研究大面积形变与断层活动之间的关系，对首都圈１９８８～１９８９年复测的长水准资料中跨过明显活动断裂的测线单独进行了分析，并与相应的流动跨断层短水准短基线资料进行了对比，证明八宝山等北东向断裂带的中段和南段活动较为强烈，而北段相对活动较弱，结合大面积水准平差给出垂直运动速率分布图，分析认为该地区是应力比较容易集中的地段，对未来的震情监视与研究有一定的指导意义。     

四点长基线深海定位模型建立方法及精度分析

高精度水下定位技术对于维护国家海疆安全、海洋权益和国民经济建设具有十分重要意义和实际应用价值。根据射线在水中的传播特性,利用双曲面定位方法建立长基线深海定位模型,通过计算机仿真获得4 000 m水下信源在10 km~2正方形范围内的定位误差精度及分布规律。结果表明:浮标网络中心位置定位精度最高,可得到亚米级;离中心位置越远,定位精度越差。