卫星导航完备性监测的最新进展

自从美国于2000年取消GPS SA政策并开始实施GPS现代化,以及欧洲伽利略导航系统正式开始启动以来,在完备性监测技术方面出现了许多新的发展和动向,本文将对其作简要的介绍。GPS和伽利略的完备性监测新技术主要包括:卫星自主完备性监测(SAIM)、星载和星间完备性监测、伽利略完备性能力评估(GIPA)的概念、用户自主完备性监测(UAIM)等。

Unilateral Acute Idiopathic Maculopathy

Purpose: To discuss the fluorescein angiographic features and diagnosis as well as differential diagnosis.Methods : In our hospital, we have found three cases of UAIM, one of them has eccentric maculopathy, another has papillitis, and the third associates with pregnancy. Each has characteristic clinical findings. We have made the diagnosis base on ophthalmoscopy and fluorescein angiography (FA).Results: Three patients with UAIM have been experienced sudden unilateral decreased visual acuity. The significant changes on fundus are retinal pigment epithelium (RPE) thickening with neurosensory retinal detachment with in the macular area. FA showed early patchy hypofluorescence and hyperfluorescence at the level of the RPE.' Bull' s eye appearance may occur in the macular area after the acute stage of the disease. The clinical findings are similar to what the foreign report described. But there were no previous reports in China. Conclusion : We can establish the diagnosis on the base of clinical and fundus

单侧性急性特发性黄斑病变延伸的临床系列

目的：报道有关单侧性急性特发性黄斑病（ＵＡＩＭ）的新特征。患者：自１９９１年以来，我们已评估了另外１７例ＵＡＩＭ患者。本文报道的就是在其中７例患者中所发现的黄斑病变的新特征。结果：ＵＡＩＭ的新的临床发现包括黄斑偏中心病灶、视网膜下渗出、视盘炎以及双侧性发病。同时，我们还观察了ＵＡＩＭ的发病与妊娠和人类免疫缺陷病毒之间的关系。结论：对这些新发现特征的描述拓宽了我们对ＵＡＩＭ性质的了解。

一种合作目标轨迹的处理方法

在使用声图测量的方法对扫描区域内的目标进行定位时,由于声图定位的局限性,使得目标的定位轨迹出现一定的误差。为了有效减小定位误差,提出了采用"圆筛"和α-β滤波相结合的方法处理目标轨迹。由实验数据处理证明,此方法可以有效减小目标航迹抖动,并且可以实现目标轨迹的平稳过阵。