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Satellite-Based Augmentation Systems (SBASs) enhance the global navigation satellite system (GNSS) to support all phases of flight by providing required accuracy, integrity, continuity, and availability. The Korean SBAS program was recently initiated to develop a single-frequency SBAS aiming to provide Approach Procedure with Vertical guidance (APV)-I Safety-of-Life (SoL) service to aviation users by 2022 within the Korean region. We assess the preliminary availability of the single-frequency SBAS which will be deployed in the Korean peninsula. The resulting system performance shall be used as a baseline to design system components and specifications. The fundamental components of SBAS architecture, SBAS monitor network, geostationary earth orbiting satellite parameters, and ionospheric grid point mask, are defined and their effects on system performance are investigated. Ionospheric correction and integrity algorithm parameters including an ionospheric irregularity threat model are determined using data collected from the Korean GNSS network. The coverage of 99.9 % availability for APV-I service increases from approximately 70 % for the baseline case to 100 % when SBAS monitor stations are expanded to overseas. Even with the expanded monitor network, however, 90 % and less than 95 % availability for LPV-200 service can be achieved only in a very limited region. 相似文献
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GNSS satellite-based augmentation systems for Australia 总被引：1，自引：0，他引：1
Suelynn Choy Joost Kuckartz Andrew G. Dempster Chris Rizos Matt Higgins 《GPS Solutions》2017,21(3):835-848
We provided an overview of various satellite-based augmentation systems (SBAS) options for augmented GNSS services in Australia, and potentially New Zealand, with the aim to tease out key similarities and differences in their augmentation capabilities. SBAS can technically be classified into two user categories, namely SBAS for aviation and “non-aviation” SBAS. Aviation SBAS is an International Civil Aviation Organization (ICAO) certified civil aviation safety-critical system providing wide-area GNSS augmentation by broadcasting augmentation information using geostationary satellites. The primary aim was to improve integrity, availability and accuracy of basic GNSS signals for aircraft navigation. On the other hand, “non-aviation” SBAS support numerous GNSS applications using positioning techniques such as wide-area differential-GNSS (DGNSS) and precise point positioning (PPP). These services mainly focus on delivering high-accuracy positioning solutions and guaranteed levels of availability, and integrity remains secondary considerations. Next-generation GNSS satellites capable of transmitting augmentation signals in the L1, L5 and L6 frequency bands will also be explored. These augmentation signals have the data capacity to deliver a range of augmentation services such as SBAS, wide-area DGNSS and PPP, to meet the demands of various industry sectors. In addition, there are well-developed plans to put in place next-generation dual-frequency multi-constellation SBAS for aviation. Multi-constellation GNSS increases robustness against potential degradation of core satellite constellations and extends the service coverage area. It is expected that next-generation SBAS and GNSS will improve accuracy, integrity, availability and continuity of GNSS performance. 相似文献
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为了提高GPS卫星导航系统服务性能,很多国家和地区建立了独立的星基增强系统(SBAS),通过提供广播星历差分与完好性增强信息,满足高精度高完好性用户使用需求。本文介绍了美国WAAS和欧洲EGNOS等星基增强系统的广播星历差分完好性信息电文编码格式,并对实际星基增强系统的广播星历差分与完好性电文进行解析。由于不同的星基增强系统采用的信息处理模式不同,针对WAAS和EGNOS两个不同地区建立的星基增强系统,对广播星历差分慢变改正／快变改正的变化特征进行了比较分析。研究了星基增强系统广播星历差分完好性信息用户使用算法,基于国际GNSS服务组织(IGS)提供的GPS实测数据,对WAAS系统和EGNOS系统的广播星历差分服务精度和完好性性能进行了对比分析。结果表明,WAAS系统的伪距单点定位精度约为1.2 m, EGNOS系统的伪距单点定位精度约为1.8 m,与GPS基本导航服务相比,伪距单点定位精度可提高约22％和16％。两个星基增强系统利用完好性电文计算的完好性保护限值大致相当,均在16 m以内,能够对定位误差进行包络。 相似文献
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InSAR(Interferometric Synthetic Aperture Radar,InSAR)技术是随着合成孔径雷达发展起来的一种雷达干涉测量新技术,它可获得地表目标点的精确三维空间位置以及细微形变信息。基于雷达干涉测量发展的短基线(Small BAseline Subset,SBAS)干涉测量,可对缓慢地表形变进行高精度的监测。本文以广东省普宁市为实验区,选用2007~2010年间共10景ALOS/PALSAR数据,采用SBAS技术获取了该地区的形变时间序列和平均沉降速率,结果表明普宁市区存在多个严重的沉降漏斗,年最大沉降速率达15cm/a。利用观测时段内两期的水准点观测资料对SBAS时序结果进行验证,对比结果发现两者较差最大为46mm,最小为21mm,表明SBAS技术进行地面沉降监测的可靠性和有效性。 相似文献
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Virtual differential GPS based on SBAS signal 总被引：2，自引：0，他引：2
In order to access the satellite-based augmentation system (SBAS) service, the end user needs access to the corresponding geostationary earth orbit (GEO) satellites that broadcast the augmentation information for the region. This is normally not a problem for aviation and maritime applications, because an open sky is typically available for such applications. However, it is difficult to access the GEO satellites directly at high latitudes for land applications because of the low elevation angles to the GEO satellites (e.g., 4–22° in Finland to the European geostationary navigation overlay services [EGNOS] GEO satellites). Results from a driving test of 6,100 km in Finland show that the EGNOS GEO satellites can be accessed in only 51.8% of the driving routes. Furthermore, it is also difficult to access the GEO satellites from city canyons, because the high buildings block the GEO signals. This article presents a solution to solve this problem by creating virtual differential GPS (DGPS) reference stations using the SBAS signal in space (SIS). The basic concept is to convert the SBAS signal to Radio Technical Commission for Maritime Services (RTCM) signals, and broadcast the converted RTCM signals over the wireless Internet using the Internet radio technology. Therefore, access to the SBAS service will not be limited by low elevation angles to the GEO satellites because the converted RTCM data streams are disseminated over the wireless Internet. Furthermore, the SBAS service can then be accessed via a legacy DGPS receiver. Two test cases have been carried out with the prototype system developed by the Finnish Geodetic Institute. The test results showed that the positioning accuracy of the virtual DGPS solution was about 1–2 m at 95%, which was similar to that of the standard WAAS/EGNOS solution. The positioning accuracy was not degraded, compared to that of the standard wide area augmentation system–European geostationary navigation overlay services (WAAS/EGNOS) solution, as long as the distance between the rover receiver and the virtual DGPS reference station was less than 150 km. A preliminary driving test of 400 km carried out in southern Finland showed that the availability of the virtual DGPS solutions was 98.6% along the driving route. 相似文献
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I. J. Dowman 《The Photogrammetric Record》1998,16(91):5-18
The basic concepts and tools of automatic image registration are presented and the problems which exist are discussed. The paper describes work carried out at University College London on the registration of two images and on the registration of images with maps. It is shown that strategies have been developed which are applicable to different types of image and reference data and that with the tuning of well tried algorithms it is possible to achieve the required matching. The PAIRS technique for automatic registration of optical images from satellites has been implemented and tested and is now being developed for use with optical and microwave images. The ARCHANGEL system for registration of images with maps or vector data is also being implemented and initial results show considerable promise. 相似文献
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多系统全球卫星导航系统(GNSS)的出现为天基增强系统(SBAS)电离层格网模型的性能提升提供了可能,但多系统GNSS测量对电离层格网模型性能提升是有条件的. 为此,利用中国区域GPS观测模拟分析了多系统GNSS测量对中国区域电离层格网模型可用性的影响. 结果表明:多系统GNSS测量可有效提高电离层格网模型的覆盖范围. 中国南方地区存在低纬赤道电离异常(EIA)现象,严重影响SBAS电离层格网模型实现性能,单纯增加GNSS测量不能有效应对低纬电离异常现象影响. 中国北方地区电离层延迟变化平缓,在多系统GNSS测量情况下可以考虑减少地面监测站数量,仍能保持系统原有性能. 相似文献
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SBAS监测技术作为微波遥感技术,通过最小二乘或奇异值分解的方法,对多个构成三角网的干涉对进行干涉处理,从而得到某个地区的时间序列形变规律。本文使用SBAS技术对覆盖临沧市2019年2月—2020年7月的30景Sentinel-1A雷达数据进行处理。通过剖面和时间序列分析方法对该区域进行分析,研究其地表沉降成因和规律,以此判断该地区是否存在地质灾害的隐患区域,为临沧市以后的防灾减灾工作提供参考意见。 相似文献
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Manohar Yadav Salil Goel A. K. Singh Bharat Lohani 《Journal of the Indian Society of Remote Sensing》2014,42(2):301-310
There is a growing demand for technologies that support capturing of comprehensive and good quality 3D spatial data at a faster rate with low investment and minimal effort, while also causing least disturbance to other activities in the area. Mobile mapping systems (MMS), which are being developed in a few western countries, solve this problem but their import is highly expensive. While the components of a MMS are easily available off-the-shelf at lower cost, the main reason for their high cost is the intellectual property involved in the sensor design, integration, calibration, and the related software. Developing the intellectual property locally can bring down the cost of MMS to a large extent. Keeping this in mind, a MMS has been developed in this research using the locally available sensors. This paper describes the methodology to integrate navigation and mapping sensors including the developed calibration procedures. It further describes the time synchronization technique developed for multi-sensor data fusion and algorithms implemented by software package for data processing. The sensors integrated in the MMS include a standard GPS, IMU and a standard laser scanner. A Kalman filter is implemented to integrate the GPS and IMU data, which provides position and orientation information for the sensors. A simulation software package is also developed to verify, understand and develop the equations used in MMS. Field tests have been performed using the developed MMS and the results are shown for a few cases. Results validate the designed algorithms and indicate the successful development of the MMS, which has potential to be further developed and used in field. Though a number of papers are available on MMS, the thrust of this paper is to present a complete methodology for developing a MMS using locally available sensors. Unlike available papers, this paper outlines all aspects of design, calibration and operation, where each of these aspects is handled in a novel way as demanded by the available sensors. This is particularly useful for individuals or organizations interested in procuring sensor components off-the-shelf and develop their own (low cost) Mobile Mapping system. 相似文献
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针对雷达差分干涉测量技术（differential interferometry synthetic aperture radar,DInSAR）易受时空失相关、大气相位延迟等因素的影响,采用小基线集技术（small baseline subset,SBAS）对13景TerraSAR-X数据进行时序处理,估算并去除了残余数字高程模型误差、大气延迟误差和轨道误差,分析了研究区域2012-2013年沉降速率,发现2310和1301两工作面最大下沉速率分别为40 mm/a和50 mm/a;分析时序累计沉降值发现,2306、2308、2310这3个工作面在2012年11月15日之前地面沉降并不明显;在2310和1301工作面分别提取3个失相干现象表现较为缓慢的候选点进行时序分析,发现沉降值和时间成线性变化关系,且开采时间越早,其沉降特性越符合线性变化;将SBAS和DInSAR两种方法获得的累计沉降值进行差值分析,发现两种方法的差值在5 mm以内;在2310工作面走向方向和倾向方向选取若干观测点,并提取各观测点的时序沉降值对工作面时序沉降进行量化分析,实验表明SBAS-InSAR技术在矿区地表沉降监测与分析方面具有良好的应用前景。 相似文献
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非线性最小残差绝对值和最小平差的遗传算法 总被引：1，自引：1，他引：0
遗传算法是一种基于自然选择和自然遗传学机理的全局优化搜索算法。文章在扼要介绍遗传算法的基础上,设计了非线性残差绝对值和最小的遗传算法,并将其运用于非线性残差绝对值和最小的平差模型中,并通过实例验证了该算法的有效性。 相似文献
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进行SBAS技术时,选择的干涉对一般会出现一景影像和其他几景影像干涉的现象,导致构建的线性形变模型病态。在这种情况下,最小二乘法求解SBAS线性形变模型已不太适合。针对这一问题,本文结合Liu估计的有偏迭代法在求解病态线性模型时能够克服病态性对结果的影响,提出将此方法应用到求解SBAS线性形变模型中。以覆盖济宁地区的13景ENVISAT ASAR数据展开了SBAS技术在城市地面沉降监测中的应用实验,分别利用LS法、基于Liu估计的有偏迭代法解算形变模型。结果表明,基于Liu估计的有偏迭代法获得研究区的年平均沉降速率标准差比LS法获得的低1.4,且其求解的结果相较于LS法获得的结果更准确、稳定。 相似文献
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介绍了OmniStar星基差分服务的工作原理及其特点,通过测试数据验证其定位精度的稳定性和收敛速度。通过长时段定位结果与IGS联测数据的对比,分析了OmniSTAR星基差分静态定位精度状况和收敛时间,讨论了利用这种技术在物探测量中获取精确WGS84起算坐标的可行性。 相似文献