SBAS(卫星增强系统)
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卫星导航差分系统和增强系统(十一)刘天雄【期刊名称】《卫星与网络》【年(卷),期】2018(000)012【总页数】4页(P66-69)【作者】刘天雄【作者单位】【正文语种】中文3.4.1 美国广域增强系统(WAAS)3.4.1.1 系统组成广域增强系统(Wide Area Augmentation System,WAAS)是美国联邦航空管理局(Frderal avaiation administration,FAA)主导的星基增强系统(Satellite Based Augmentation Svstem,SBAS),为满足美国民用航空对GPS更高的定位精度要求,特别是完好性要求,1992年,FAA在美国GPS广域差分系统(Wide Area Differential GPS,WADGPS)的基础上,设计了利用位于地球同步静止轨道的通信卫星(GEO卫星)广播GPS差分修正数据和完好性信息,实现在北美地区GPS的SBAS服务。
WAAS的GEO卫星不仅播发增强信号,作为完好性告警通道,同时还播发测距信号,利用GEO卫星覆盖范围大且位置相对稳定的特点,提高GPS星座用户可见卫星数量。
WA A S 由地面段(WA A S G r o u n d Segment)、空间段(WAAS SpaceSegment)和用户段(WAAS User Segment)三部分组成,其中地面段由38个广域参考站(Widearea Reference Stations,WRSs)、3个位于美国本土大陆两端的广域主控站(Wide-area Master Stations,WMSs)、6个地面上行链路站(Ground Uplink Stations,GUS)、2个系统运行中心(operational centers,OC)以及陆地通信网络(Terrestrial communication Network,TCN)组成,其中地面上行链路站一般又称为地球站(Ground Earth Stations,GESs)。
SBAS
一、
SBAS 即Satellite Based Augmentation Systems (DGNSS/DGPS/WAAS/EGNOS) 是利用地球静止轨道卫星建立的地区性广域差分增强系统。
目前全球发展的SBAS系统有:
欧空局接收卫星导航系统(EGNOS),覆盖欧洲大陆;
美国的DGPS(Differential GPS),美国雷声公司的广域增强系统(WAAS),覆盖美洲大陆;
日本的多功能卫星增强系统(MSAS),覆盖亚洲大陆;
印度的GPS辅助型静地轨道增强导航(GAGAN)。
三者具有完全兼容的互操作性。
其特点是:
1、通过地球静止卫星(GEO)发布包括GPS卫星星历误差改正、卫星钟差改正和电离层改的信息;
2、通过GEO卫星发播GPS和GEO卫星完整的数据;
3、GEO卫星的导航载荷发射GPS L1测距信号。
二、
SBAS即门店听觉系统,是Store Brand Auditory System的缩写。
SBAS主要包括:
1、品牌主题曲
这是品牌的精神内核以及门店听觉的灵魂。
2、品牌LOGO
品牌听觉标识,让陌生人认识品牌接近品牌的最好名片。
3、广告音乐
功用在于在发布门店信息的第一时间传到消费者的耳朵里,吸引火爆人气。
4、氛围音乐
营造购物氛围,强化消费者的购物欲。
SBAS的功能:
1、吸引门店人气。
2、完善品牌识别系统。
3、强化品牌特色。
4、发布促销信息。
5、提高消费者购物欲望。
6、营造购物氛围。
大多数机场的进近程序都是在传统导航方法下运行的,包括只提供水平引导的VOR/DME、NDB/DME等非精密进近,以及提供水平和垂直引导的ILS精密进近。
传统导航方法受导航台的束缚和限制,定位方法主要是θ-θ和ρ-θ定位,其定位误差较大。
PBN(Performance-based Navigation,基于性能的导航):指在相应的导航基础设施条件下,航空器在指定的空域内或者沿航路、仪表飞行程序飞行时,对系统精度、完好性、可用性、连续性以及功能等方面的性能要求。
PBN运行的导航设施主要是提供全球覆盖、全天候、连续不间断、高精度导航的GNSS(全球导航卫星系统)。
PBN中最重要的两个性能是精度和完好性。
最后进近阶段的PBN运行程序就是RNP(Required Navigation Performance,所需导航性能)进近。
RNP进近主要分为RNP APCH和RNP AR APCH两类。
RNP APCH是基本RNP进近,精度可达0.3nm。
RNP AR APCH程序只能用于RNP APCH程序不能满足的一些特殊需求的情况,需要特殊授权,包括航空器需满足特定要求、机组需进行专门训练等,精度可达0.3~0.1nm。
为了改善GNSS接收机定位精度问题,可利用GNSS增强系统作为RNP进近的主用导航设备,以提高精度、完好性、可用性、连续性等导航性能,满足RNP进近要求。
GNSS增强系统包括ABAS(机载增强系统)、GBAS(地基增强系统)和SBAS(星基增强系统)及混合系统。
导航应用是将导航规范和导航设施结合起来,在航路、终端区、进近或运行区域的实际应用,包括RNAV/RNP航路、标准仪表进离场程序、进近程序等。
RNP导航规范具有机载性能监控和告警功能,RNAV则不具备。
RVAV和RNP后面所跟的数字代表导航精度值,例如RNP-1导航规范,要求在95%的飞行时间内,航空器位置必须满足标称航迹位置左右前后1海里以内的精度值要求。
SBAS 即Space Based Augmentation System,是利用地球静止轨道卫星建立的地区性广域差分增强系统。
目前全球发展的SBAS系统有:欧空局接收卫星导航系统(EGNOS),欧洲大陆美国雷声公司的广域增强系统(W AAS),美洲大陆日本的多功能卫星增强系统(MSAS),亚洲大陆三者具有完全兼容的互操作性。
其特点是:1、通过地球静止卫星(GEO)发布包括GPS卫星星历误差改正、卫星钟差改正和电离层改的信息;2、通过GEO卫星发播GPS和GEO卫星完整的数据;3、GEO卫星的导航载荷发射GPS L1测距信号。
SBAS覆盖图WAAS 这个名词、全名为Wide Area Augmentation System,即广域增强系统。
WAAS是美国联邦航空局(FAA)及美国交通部为提升飞行精确度而发展出来的,因为目前单独使用GPS 并无法达到联邦航空局针对精确飞行导航所设定的要求。
WAAS 包含了约25个地面参考站台,位置散布于美国境内,负责监控GPS 卫星的资料。
其中两个分别位于美国东西岸的主站台搜集其它站台传来的资料,并据此计算出GPS 卫星的轨道偏移量、电子钟误差,以及由大气层及电离层所造成的讯息延迟时间,汇整后经由两颗位在赤道上空之同步卫星的其中之一传播出去。
此W AAS 讯号的发送频率与GPS 讯号的频率相同,因此任何具备WAAS 功能的GPS 机台都可接收此讯号,并藉此修正定位信息。
WAAS 可以校正由电离层干扰、时序控制不正确以及卫星轨道错误等因素所造成的GPS 讯号误差,也能提供各卫星是否正常运转之信息。
虽然W AAS 目前尚未正式通过美国航空局的飞行使用认证,但此系统已开放给一般民众使用,例如从事航海或其它休闲活动的人们。
W AAS提供校正GPS讯号的功能,让您得到更精确的定位。
到底能提升多少精确度呢?官方给出的数据是,可以平均提升最多五倍的精确度!目前无W AAS功能的普通GPS接收机的正常精确度是15米,而一台具备W AAS功能的GPS接收机能在95%的情况下提供您误差小于三公尺的精准定位,而且您不必为了使用WAAS功能而支付任何使用费。
使用卫星增强型全球定位系统的独立机载导航设备1.目的本技术标准规定(CTSO)适用于为使用卫星增强型(SBAS)全球定位系统(GPS)的独立机载导航设备申请CTSO批准书(CTSOA)的制造人。
本CTSO规定了设备为获得批准和使用适用的CTSO标记进行标识所必须满足的最低性能标准。
2.适用范围本CTSO适用于自其生效之日起新提交的申请。
a.以前版本的CTSO将不再有效。
自本CTSO生效之日起,局方不再受理按以前版本的最低性能标准噪声值为3dB的Class Gamma1和Class Gamma 2提交的申请。
但如果生效之日后六个月内,局方获知申请人未按照以前版本的最低性能标准进行研制,局方将与制造人共同确定噪声值;b. 按以前的CTSO-C146批准的Class 3(Gamma)和Class 4(Delta),(及没有规定噪声值为3 dB的Class Gamma 1和Gamma 2)的独立GPS/SBAS设备可以按批准时的规定继续制造;c. 按本CTSO批准的独立的GPS/SBAS设备,设计大改应获得CAAC的批准。
参见CCAR-21第21.313条。
3.要求在本CTSO生效之日或生效之后制造并欲使用本CTSO标记进行标识的新型独立的GPS/SBAS设备,必须满足RTCA/DO-229D《全球定位系统/广域增强系统机载设备最低操作性能标准》(2006.12.13发布),第2部分,及本CTSO附录1所做的修订部分,Gamma 和Delta 类设备在RTCA/DO-229D中1.4节中已定义。
a.功能本CTSO标准适用于能接收计划飞行航路,并提供键入该路径的偏差指令的设备。
飞行员和自动驾驶仪将使用利用这些偏差引导飞机。
除自动相关监视,本CTSO标准并不关注与其他航空电子设备相关的综合问题,如独立的GPS/SBAS设备是否可能会无意中给自动驾驶仪失控指令。
b. 失效状态类别(1)本CTSO第3节和第3.a节所定义功能的失效属于:较大的失效状态,包括航路、终端和进近形态的侧向导航(LNA V)功能丧失和功能失效,进近形态下侧向导航(LNA V)/垂直导航(VNA V)导航数据丧失;●较大的失效状态,包括无垂直引导航向信标进近(LP)功能丧失和有垂直引导航向信标进近(LPV)导航数据丧失;●危险的失效状态,包括进近(LP 和LPV)导航数据失效。
SBAS(卫星增强系统)SBAS (Satellite-Based Augmentation System),即基于卫星的增强系统。
SBAS 系统主要由四部分组成:地面参考基站,主控站,上传站和地球同步卫星等。
下面以WAAS为例,介绍该卫星系统的工作原理:WAAS 是为民用飞行开发的极精确的导航系统。
在WAAS以前,美国的国家飞行系统(NAS)并没有足够的能力为所有区域的所有用户提供水平与垂直导航,有了WAAS后就有了给所有用户提供导航的能力。
WAAS为各种类型的飞行器各飞行阶段提供服务,确保飞行过程、升空、着陆时的安全。
WAAS 不像传统的地面导航辅助系统,它包含了所有的国家飞行系统(NAS),WAAS 给GPS 接收机提供增强信息,提高接收机的定位精度。
WAAS 系统主要由四部分组成:地面广域参考基站,WAAS主控站,WAAS上传站和地球同步卫星等,其工作可以分为四个过程:一、基站接收GPS信号在美国境内,广泛地分布着广域参考基站(Wide Area Reference Station(WRS)),每个基站都已知其准确的地理位置,通过接收GPS信号,探测出GPS信号中的误差。
二、基站向主控站传输GPS误差数据广域参考基站(WRS)收集的GPS信息,通过地面的通讯网络传输到WAAS主控站(WMS),主控站生成WAAS 增强信息,这些信息包含了GPS接收机中消除GPS信号误差的信息,使GPS接收机大大改善了定位精度和可靠性。
三、WAAS增强信息上传增强信息由WASS主控站(WMS)传输到WAAS上传站,上传站调制成导航数据,并上传到地球同步通讯卫星。
四、增强信息的传播地球同步通讯卫星以GPS信号频率向地面广播有增强信息的导航数据,地面接收机接收WASS增强信号,得到GPS误差数据补偿定位,得到更加精确的定位。
WAAS也能给GPS接收机提供GPS系统误差或其他不良影响的信息,其也有严格的安全标准,当存在危险的误导信息时,WAAS能在六秒内发布给用户。
sbas电文格式
SBAS(Satellite-Based Augmentation System)电文格式是用于卫星导航增强系统的数据传输格式。
它通常用于向地面用户提供关于卫星导航信号质量、完好性和校正信息的数据。
SBAS电文格式的具体细节可能因不同的卫星导航系统和增强系统而有所差异。
以下是一般情况下SBAS电文格式的一些常见元素:
1. 电文头(Header):包含电文的标识和同步信息,用于接收设备正确解析电文。
2. 发射站标识(Transmitter Identification):指示发送SBAS电文的地面站或卫星的标识信息。
3. 卫星状态(Satellite Status):提供关于可见卫星的状态信息,如卫星的健康状况、信号质量等。
4. 完好性信息(Integrity Information):包含有关卫星导航信号的完好性参数,如保护级别、完好性风险值等,用于评估导航解的可靠性。
5. 校正信息(Correction Information):提供对卫星导航信号的校正数据,如伪距校正、相位校正等,以改善导航解的精度。
6. 其他辅助信息:可能包含其他辅助数据,如电离层模型参数、对流层模型参数等,用于进一步提高导航解的精度和可靠性。
㊀㊀第52卷㊀第7期测㊀绘㊀学㊀报V o l .52,N o .7㊀2023年7月A c t aG e o d a e t i c ae tC a r t o g r a ph i c aS i n i c a J u l y,2023引文格式:郑帅勇.S B A S 星历星钟增强技术研究[J ].测绘学报,2023,52(7):1231.D O I :10.11947/j.A G C S .2023.20210724.Z H E N GS h u a i y o n g .R e s e a r c ho n t h e t e c h n o l o g i e s o f S B A S c l o c k Ge p h e m e r i s a u g m e n t a t i o n [J ].A c t aG e o d a e t i c a e t C a r t o g r a ph i c a S i n i c a ,2023,52(7):1231.D O I :10.11947/j.A G C S .2023.20210724.S B A S 星历星钟增强技术研究郑帅勇天津理工大学集成电路科学与工程学院,天津300384R e s e a r c h o n t h e t e c h n o l o g i e s o f S B A Sc l o c k Ge p h e m e r i sa u gm e n t a t i o n Z H E N GS h u a i y o n gS c h o o l o f I n t e g r a t e dC i r c u i t S c i e n c ea n dE n g i n e e r i n g ,T i a n j i nU n i v e r s i t y o f T e c h n o l o g y ,T i a n ji n 300384,C h i n a ㊀㊀随着全球卫星导航系统(G l o b a lN a v i ga t i o nS a t e l l i t e S ys t e m ,G N S S )的发展,G N S S 逐渐被应用于航空导航服务.为了满足航空导航性能要求,世界各国致力于G N S S 增强系统尤其是星基增强系统(s a t e l l i t e Gb a s e da u g m e n t a t i o n s ys t e m ,S B A S )的研究,以提升G N S S 的精度㊁完好性㊁连续性和可用性.S B A S 已成为提升G N S S 综合性能尤其是完好性的重要解决措施.美国和欧洲的S B A S 已经能够为航空用户提供垂直引导的定位器性能标准(l o c a l i z e r p e r f o r m a n c e w i t hv e r t i c a l g u i d a n c e200,L P V 200)等级导航服务,S D C M ㊁M S A S ㊁K A S S 和G A G A N 等S B A S 所提供的导航服务信号也逐渐覆盖中国周边地区.而北斗星基增强系统(B D S B A S )还处于建设阶段,迫切需要开展星基增强系统相关研究为B D S B A S 建设和后续性能提升提供技术支持.作为S B A S 系统段的关键技术,星历星钟增强技术关乎B D S B A S 的服务性能,如S B A S 系统段星历星钟增强信息处理效率影响告警时间长短㊁星钟快变误差修正效果影响卫星差分改正数性能㊁星历星钟降效参数准确性将影响服务完好性和连续性㊁刚入境卫星由于收敛时间较长将导致B D S B A S 服务区内可增强卫星数目较少从而服务等级下降.B D S B A S 建设需要攻克这些星历星钟增强技术难题.因此,针对S B A S 星历星钟增强关键技术开展一系列研究,主要包括星钟快变误差修正㊁星历星钟完好性监测㊁星历星钟降效参数求解和连续性性能评估,主要工作内容汇总如下:(1)针对星钟误差修正精度不足的问题,提出了一种基于用户等效测距误差的星钟快速改正数求解算法.该算法根据星钟偏差二阶残余误差特性构造K a l m a n 滤波器状态方程,用经长期改正数修正之后的用户等效测距误差构造K a l m a n 滤波器观测方程.考虑到卫星服务区内低仰角的观测受噪声影响较大,采用环状模型处理多径和接收机热噪声以提升观测质量.利用S a g e 自适应滤波器对系统噪声阵和观测噪声阵进行实时更新,抑制状态方程扰动和观测异常.结果表明:与广域增强系统(w i d e a r e a a u g m e n t a t i o ns ys t e m ,WA A S )算法相比,该算法的星钟误差修正精度明显提升.(2)针对监测网边缘区域星历星钟完好性难以保障的问题,有别于美国WA A S 海外扩展建站的思路,提出了一种基于伪距残差和星站几何的卫星完好监测算法.该算法考虑多误差源㊁星站几何和电文量化与播发对完好性信息的影响,结合卫星运动过程中星站几何变化趋势,对卫星完好性监测进行分段处理,构造了星历星钟协方差阵的凹槽模型,以量化误差最小化的方式处理完好性信息.该算法将星站几何信息引入到卫星完好性监测,改善了监测网边缘区域的卫星完好性,缓解了B D S B A S 短期内无法海外建站的困难.结果表明:该算法相对于直接统计法,伪距域包络率和服务域可用性分别提升24.99%和6.83%,十分接近WA A S 相应指标.(3)针对用户错过部分增强电文时S B A S 完好性降低的问题,提出了一种基于舍入误差和外推误差的星历星钟降效参数求解算法.该算法在分析S B A S 电文参数的估计模糊度㊁高阶误差㊁舍入误差以及外推误差之后,对这些误差采用相应的概率分布进行描述,给出S B A S 电文参数超出有效时间间隔后引起的残余误差.通过求解残余误差的上确界来推导相应降效参数.该算法首次公开介绍了星历星钟降效参数求解方法,为B D S B A S 降效参数求解提供了理论依据.结果表明:该算法降效参数估计值与WA A S 相应参数十分接近.(4)针对稀疏样本难以准确评估系统连续性的问题,提出了一种基于W e i b u l l 分布的可调参数的连续性评估算法.该算法对G N S S 中断数据进行最大似然估计拟合处理以确定W e i b u l l 分布参数估计值,将均方误差最小的一组参数估计值作为W e i b u l l 分布最终参数估计结果并求取G N S S 连续性.该算法可以根据中断数据来灵活确定系统故障率,为B D S B A S 性能测试评估提供了一种技术途径.结果表明:该算法性能较传统算法提升40.42%,更加接近官方报告结果.在完成如上算法的设计与验证后,利用WA A S 数据进行性能分析以评估所提算法的整体性能.结果表明:与WA A S 算法相比,所提算法空间信号改正精度明显提升,伪距域包络率降低0.06%,L P V 200可用性降低2.10%,与国外已有系统达到同等水平.然后,将所提算法应用于中国区域,以评估所提算法的先进性并预报中国区域S B A S 性能.结果表明:与直接统计法相比,所提算法空间信号改正精度接近,伪距域包络率提升45.39%,L P V 200可用性提升2.32%,性能优于直接统计法.所提算法可以为中国大部分地区提供类一类垂直引导的进近程序(a p p r o a c h p r o c e d u r ew i t h v e r t i c a l gu i d a n c e GI ,A P V GI )等级服务甚至部分地区提供L P V 200等级服务.相关内容及成果已作为关键技术应用于北斗星基增强系统民用服务平台的监测站和信息处理中心.中图分类号:T N 967.1㊀㊀㊀㊀文献标识码:D文章编号:1001G1595(2023)07G1231G01基金项目:复杂电子系统仿真重点实验室开放基金(614201004012103);卫星导航系统与装备技术国家重点实验室开放基金(C E P N T 2022B 03);自然资源部国土卫星遥感应用重点实验室开放基金(K L S MN R G202310)收稿日期:2021G12G28作者简介:郑帅勇(1991 ),男,2021年毕业于北京航空航天大学,获工学博士学位(指导教师:黄智刚教授,李锐高级工程师),研究方向为卫星导航.A u t h o r :Z H E N G S h u a i y o n g (1991 ),m a l e ,r e c e i v e d h i sd o c t o r a ld e g r e ef r o m B e i h a n g U n i v e r s i t y i n 2021,m a j o r s i ns a t e l l i t en a v i ga t i o n .E Gm a i l :s y z h e n g 21@e m a i l .t ju t .e d u .c n Copyright ©博看网. All Rights Reserved.。
2020年6月第3期现代导航·157·星基增强系统技术发展及应用研究郑金华1,第五兴民2(1 中国电子科技集团公司第二十研究所,西安710068;2中国民用航空西北地区空中交通管理局,西安710082)摘 要:全球导航卫星系统(GNSS)是实现基于性能导航(PBN)的重要手段,星基增强系统(SBAS)对GNSS进行增强使其能够满足民航的高完好性标准要求。
本文介绍了SBAS的概念和原理,并以广域增强系统(WAAS)为例,详细介绍了SBAS的系统架构、数据处理流程、系统运行及管理和系统应用与服务,分析了SBAS的航空应用方法,并指出了利用双频多星座SBAS实现CAT-I精密进近的发展趋势和SBAS拓展到其他行业的应用趋势。
关键词:星基增强系统;完好性;双频多系统中图分类号:TN911 文献标识码:A 文章编号:1674-7976-(2020)-03-157-06 Research on SBAS Technology Development and ApplicationZHENG Jinhua,DIWU XingminAbstract: The Global Navigation Satellite System (GNSS) is an important mean of implementing Performance Based Navigation (PBN). Satellite Based Augmentation System (SBAS) augment GNSS to meet the high integrity requirement of civil aviation. This paper introduces the concept and principle of SBAS. Taking Wide Area Augmentation System (WAAS) as an example, the system architecture, data processing flow, system operation and management as well as system application and service are introduced in detail. The method of SBAS in civil aviation application is analyzed. The development trend of using DFMC SBAS to realize CAT-I precision approach and the trend of applying SBAS service in other industries are indicated.Key words: SBAS; Integrity; DFMC0引言星基增强系统(Satellite Based Augmentation System, SBAS)是满足航空等高生命安全需求行业应用的重要基础设施,完好性服务是SBAS的核心内容。
Number:CTSO-C145eApproved by:Xu ChaoqunChina Civil Aviation Technical Standard OrderAirborne Navigation Sensors Using The Global Positioning SystemAugmented By The Satellite Based Augmentation System (SBAS)1. Purpose.This China Civil Aviation Technical Standard Order (CTSO) is for manufacturers applying for airborne navigation sensors using the global positioning system (GPS) augmented by the satellite based augmentation system (SBAS) CTSO authorization (CTSOA). This CTSO prescribes the minimum performance standards(MPS) that airborne navigation sensors using the GPS augmented by the SBAS must first meet for approval and identification with the applicable CTSO marking.2. Applicability.This CTSO affects new application submitted after its effective date.Major design changes to article approved under this CTSO will require a new authorization in accordance with section 21.353 of CCAR-21R4.3. RequirementsNew models of airborne navigation sensors using the GPS augmented by the SBAS identified and manufactured on or after the effective date of this CTSO must meet the MPS qualification and documentation requirements for functional equipment Class Beta in RTCA, Inc. document RTCA/DO-229E, Minimum Operational Performance Standards for Global Positioning System/Satellite-Based Augmentation System Airborne Equipment dated December 15, 2016, Section 2.1. Class Beta equipment is defined in RTCA/DO-229E, Section 1.4 and Appendix 2 adds a new section 1.8.3.Note: Manufacturers have the option to use the RTCA/DO-229E change described in Appendix 3. The change is based on a past commonly granted deviation.a. An alternate method for applicants is to apply for CTSO-C145e using their existing approved design data plus additional substantiation data showing compliance with the changes in RTCA/DO-229E. The three areas where requirements changed are: 1) expanding the SBAS pseudorandom noise (PRN) codes (i.e., PRN range of 120 thru 158); 2) ensuring a graceful degradation to GPS-only operations; and, 3) prohibiting use of the broadcast Navigation Message Correction Table.Note 1: It is not necessary for applicants to re-submit previously approved deviations. Previously approved deviations, and any limitations,will apply to the CTSO-C145e CTSOA.Note 2: Applicants with Class 1 and 2, revision ‘b’ equipment must not have claimed the 3db broadband intrasystem noise credit.b. CTSO-C145e applicants have the option to use a CTSO-C204a SBAS CCA functional sensor. Applicants choosing to use a CTSO-C204a SBAS CCA can take certification compliance credit by virtue of the CTSO-C204a CTSOA for:z Meeting the MPS section 2.1 requirements;z The hardware/software qualification;z The failure condition classification; and,z MPS section 2.5 performance testing (functional qualification) except those specified in Appendix 1 of this CTSO.c. The CTSO-C145e applicant using a CTSO-C204a SBAS CCA functional sensor shall perform the testing described in Appendix 1 and satisfy the remaining paragraphs in this CTSO not covered by the bullets above to receive a CTSO-C145e CTSOA.Note: The end-use manufacturer using a CTSO-C204a SBAS CCA functional sensor as part of their CTSO-C145e application assumes full responsibility for the design and function under their CTSO-C145e authorization.d. Functionality.This CTSO’s standards apply to equipment intended to provideposition, velocity, time information for a navigation management unit application that outputs deviation commands keyed to a desired flight path, or a non-navigation application such as automatic dependent surveillance-broadcast (ADS-B) or terrain awareness and warning system (TAWS). In navigation applications, pilots or autopilots will use the deviations output by the navigation management unit to guide the aircraft. In non-navigation applications, the position, velocity, time outputs will provide the necessary input for the end-use equipment. These TSO standards do not address integration issues with other avionics.e. Failure Condition Classifications.(1) Failure of the function defined in paragraph 3.d resulting in misleading information for en route, terminal, approach lateral navigation (LNA V), and approach LNA V/vertical navigation (VNA V) position data is a Major failure condition.(2) Failure of the function defined in paragraph 3.d resulting in misleading information for approach localizer performance without vertical guidance (LP), and approach localizer performance with vertical guidance (LPV) position data is a Hazardous failure condition.(3) Loss of the function defined in paragraph 3.d for enroute through approach LP/LPV position data is a Major failure condition.(4) Design the system to at least these failure condition classifications.f. Functional Qualification.(1) Demonstrate the required functional performance under the test conditions specified in RTCA/DO-229E, Section 2.5, or(2) When using a CTSO-C204a SBAS CCA functional sensor, demonstrate the required performance under the test conditions in appendix 1 of this CTSO.g. Environmental Qualification.Demonstrate the required performance under the test conditions specified in RTCA/DO-229E, Section 2.4 using standard environmental conditions and test procedures appropriate for airborne equipment. RTCA/DO-229E requires the use of RTCA/DO-160E, Environmental Conditions and Test Procedures for Airborne Equipment, dated December 9, 2004, Sections 4.0 through 8.0 and 10.0 through 25.0. You may use a different standard environmental condition and test procedure than RTCA/DO-160E, provided the standard is appropriate for the SBAS sensor.Note1: The use of RTCA/DO-160D (with Changes 1 and 2 only, incorporated) or earlier versions is generally not considered appropriate and will require substantiation via the deviation process as discussed in paragraph 3.k of this CTSO.Note 2: Applicants using a CTSO-C204a SBAS CCA sensor must perform the environmental qualification with the SBAS CCA in theend-use equipment.h. Software Qualification.If the article includes software, develop the software according to RTCA/DO-178C, Software Considerations in Airborne Systems and Equipment Certification, dated December 13, 2011, including referenced supplements as applicable, to at least the software level consistent with the failure condition classification defined in paragraph 3.e of this CTSO. The applicant may also develop the software according to RTCA/DO-178B, dated December 1, 1992.(2) Applicants using a CTSO-C204a SBAS CCA sensor may use CTSO-C204a as substantiation for the software qualification.i. Electronic Hardware Qualification.If the article includes complex custom airborne electronic hardware, develop the component according to RTCA/DO-254, dated April 19, 2000, Design Assurance Guidance for Airborne Electronic Hardware, to at least the design assurance level consistent with the failure condition classification defined in paragraph 3.e of this CTSO. For custom airborne electronic hardware determined to be simple, RTCA/DO-254, paragraph1.6 applies.(2) Applicants using a CTSO-C204a SBAS CCA sensor may use CTSO-C204a as substantiation for the hardware qualification.j. Barometric-aided Fault Detection and Exclusion (FDE).If the equipment uses barometric-aiding to enhance FDE availability, then the equipment must meet the requirements in RTCA/DO-229E, appendix G.k. Deviations.For using alternative or equivalent means of compliance to the criteria in this CTSO, the applicant must show that the equipment maintains an equivalent level of safety. Apply for a deviation under the provision of 21.368(a) in CCAR-21R4.4. Marking.a. Mark at least one major component permanently and legibly with all the information in 21.423(b) of CCAR-21R4. The marking must include the serial number.b. Also, mark the following permanently and legibly, with at least the manufacturer’s name, subassembly part number, and the CTSO number:(1) Each component that is easily removable (without hand tools); and,(2) Each subassembly of the article that manufacturer determined may be interchangeable.c. If the article includes software and/or airborne electronic hardware, then the article part numbering scheme must identify the software andairborne electronic hardware configuration. The part numbering scheme can use separate, unique part numbers for software, hardware, and airborne electronic hardware.d. The applicant may use electronic part marking to identify software or airborne electronic hardware components by embedding the identification within the hardware component itself (using software) rather than marking it on the equipment nameplate. If electronic marking is used, it must be readily accessible without the use of special tools or equipment.e. At least one major component must be permanently and legibly marked with the operational equipment class (for example, Class 2) as defined in RTCA/DO-229E, Section 1.4.2.5. Application Data Requirements.The applicant must furnish the responsible certification personnel with the related data to support design and production approval. The application data include a statement of conformance as specified in section 21.353(a)(1) in CCAR-21R4 and one copy each of the following technical data:a. A Manual(s) containing the following:(1) Operating instructions and equipment limitations sufficient to describe the equipment’s operational capability.(2) Describe in detail any deviations.(3) Installation procedures and limitations sufficient to ensure that the SBAS sensor, when installed according to the installation or operational procedures, still meets this CTSO’s requirements. Limitations must identify any unique aspects of the installation. The limitations must include a note with the following statement:“This article meets the minimum performance and quality control standards required by a CTSO. Installation of this article requires separate approval.”(4) For each unique configuration of software and airborne electronic hardware, reference the following:(a) Software part number including revision and design assurance level;(b) Airborne electronic hardware part number including revision and design assurance level;(c) Functional description.(5) A summary of the test conditions used for environmental qualifications for each component of the article. For example, a form as described in RTCA/DO-160G, Environmental Conditions and Test Procedures for Airborne Equipment, Appendix A.(6) Schematic drawings, wiring diagrams, and any other documentation necessary for installation of the SBAS sensor.(7) List of replaceable components, by part number, that makes up the SBAS sensor. Include vendor part number cross-references, when applicable.(a) If the equipment can satisfy the requirements of RTCA/DO-229E only when used with a particular antenna, make the use of that antenna (by part number) a requirement on the installation. Include this requirement in the installation manual (IM) as a limitation.(b) If the equipment is installed with a standard antenna, include maximum tolerable currents and voltages into the antenna port. See CTSO-C144a, Passive Airborne Global Navigation Satellite System (GNSS) Antenna, applicable only to operational Class 1 equipment, or CTSO-C190, Active Airborne Global Navigation Satellite System (GNSS) Antenna, applicable to all equipment operational classes.b. Instructions covering periodic maintenance, calibration, and repair, for the continued airworthiness of the SBAS sensor. Include recommended inspection intervals and service life, as appropriate.c. If not using a CTSO-C204a SBAS functional sensor and the article includes software: a plan for software aspects of certification (PSAC), software configuration index, and software accomplishment summary.d. If not using a CTSO-C204a SBAS functional sensor and the article includes simple or complex custom airborne electronic hardware: aplan for hardware aspects of certification (PHAC), hardware verification plan, top-level drawing, and hardware accomplishment summary (or similar document, as applicable).e. A drawing depicting how the article will be marked with the information required by paragraph 4 of this CTSO.f. Adequate specifics on the interface between the SBAS sensor and other systems to ensure proper functioning of the integrated system. If the equipment depends on any external inputs (like baro-aided FDE) to satisfy the requirements of RTCA/DO-229E, make those inputs a requirement in the installation. Include this requirement in the IM as a limitation.g. If the software qualification limits eligibility of the equipment to certain aircraft types, identify the qualification level, and that the equipment is not eligible for all aircraft types. For example, RTCA/DO-178B (or RTCA/DO-178C) Level C software may be associated with a hazardous failure condition for certain aircraft types. Identify other limitations applicable to the failure condition classification, for example, that two installed units are necessary.h. If the equipment has not been demonstrated as compatible with satellite communications (SatCom) record in the limitations section that the equipment should not be installed in SatCom equipped aircraft.i. Identify functionality or performance contained in the article notevaluated under paragraph 3 of this CTSO (that is, non-CTSO functions). Non-CTSO functions are accepted in parallel with the CTSO authorization. For those non-CTSO functions to be accepted, you must declare these functions and include the following information with your CTSO application:(1) Description of the non-CTSO function(s), such as performance specifications, failure condition classifications, software, hardware, and environmental qualification levels. Include a statement confirming that the non-CTSO function(s) do not interfere with the article’s compliance with the requirements of paragraph 3.(2) Installation procedures and limitations sufficient to ensure that the non-CTSO function(s) meets the declared functions and performance specification(s) described in paragraph 5.i.(1).(3) Instructions for continued performance applicable to the non-CTSO function(s) described in paragraph 5.i.(1).(4) Interface requirements and applicable installation test procedures to ensure compliance with the performance data defined in paragraph 5.i.(1).(5) Test plans, analysis and results, as appropriate, to verify that performance of the hosting CTSO article is not affected by the non-CTSO function(s).(6) Test plans, analysis and results, as appropriate, to verify thefunction and performance of the non-CTSO function(s) as described in paragraph 5.i.(1).(7) Alternatively, identify non-CTSO functionality or performance contained in the article not evaluated under paragraph 3 and submit previously accepted data for the non-CTSO function for acceptance in parallel with this CTSO application.j. The quality system description required by section 21.358 of CCAR-21R4, including functional test specifications. The quality system should ensure that it will detect any change to the approved design that could adversely affect compliance with the CTSO MPS, and reject the article accordingly.k. Material and process specifications list.l. List of all drawings and processes (including revision level) that define the article’s design.m. Manufacturer’s CTSO qualification report showing results of testing accomplished according to paragraph 3.f of this CTSO.6. Manufacturer Data Requirements.Besides the data given directly to the authorities, have the following technical data available for review by the authorities:a. Functional qualification specifications for qualifying each production article to ensure compliance with this CTSO.b. Equipment calibration procedures.c. Schematic drawings.d. Wiring diagrams.e. Material and process specifications.f. The results of the environmental qualification tests conducted according to paragraph 3.g of this CTSO.g. If the article includes software, the appropriate documentation defined in the version of RTCA/DO-178 or RTCA/DO-178C specified by paragraph 3.h of this CTSO, including all data supporting the applicable objectives in Annex A, Process Objectives and Outputs by Software Level.h. If the article includes complex custom airborne electronic hardware, the appropriate hardware life cycle data in combination with design assurance level, as defined in RTCA/DO-254, Appendix A, Table A-l. For simple custom airborne electronic hardware, the following data: test cases or procedures, test results, test coverage analysis, tool assessment and qualification data, and configuration management records, including problem reports.i. If not using CTSO-C204a, all the data necessary to evaluate the geo stationary (GEO) satellite bias as defined in RTCA/DO-229E, Section 2.1.4.1.5.j. If the article contains non-CTSO function(s), the applicant mustalso make available items 6.a through 6.h as they pertain to the non-CTSO function(s).7. Furnished Data Requirements.a. If furnishing one or more articles manufactured under this CTSO to one entity (such as an operator or repair station), provide one copy or technical data and information specified in paragraphs 5.a and 5.b of this CTSO. Add any data needed for the proper installation, certification, use, or for continued compliance with the CTSO, of the SBAS sensor.b. If the article contains declared non-CTSO function(s), include one copy of the data in paragraphs 5.i.(1) through 5.i.(4).8. Availability of Referenced Documents.Order RTCA documents from:Radio Technical Commission for Aeronautics, Inc.1150 18th Street NW, Suite 910, Washington D.C. 20036You may also order them online from the RTCA Internet website at: .APPENDIX 1. END-USE EQUIPMENT MANUFACTURER TESTS FOR SBAS CCA FUNCTIONAL POSITION, VELOCITY, TIME (PVT) SENSORS USED FOR NA VIGATION AND NON-NA VIGATION APPLICATIONS1. Scope.This appendix describes the required supplementary equipment level testing, in addition to the environmental testing of RTCA/DO-229E, section 2.4, required by the end-use equipment manufacturer to receive a CTSO-C145e Class Beta authorization when using a CTSO-C204a SBAS CCA functional sensor. These test procedures are intended to streamline and simplify the CTSO-C145e authorization process for the end-use equipment manufacturer by allowing credit for the design and selected testing done at the SBAS CCA functional sensor level. However, the end-use equipment manufacturer retains full responsibility for the design and control of the article per their CTSO-C145e CTSOA.2. General Principles.(a) Testing methods for GPS/SBAS equipment have been standardized by RTCA/DO-229E and serve as the basis for CTSO-C145e. RTCA/DO-229E was written with the perspective of equipment that canbe installed on aircraft. Section 2.4 specifically addresses the issues of the environment in which the equipment operates and provides approved test methods to validate performance in this environment. Section 2.4represents RTCA consensus in identifying which RTCA/DO-229E requirements are sensitive to environmental effects. These requirements are listed in the environmental tables referenced in section 2.4.1.(b) The determination that a MOPS requirement is susceptible to the environment does not depend on whether or not the implementation is a CCA within some host equipment. This is the same concept as an equipment enclosure designed to protect against a benign environment compared to one designed for a severe environment; the identification of susceptible requirements is the same.(c) Therefore this appendix uses the tables of RTCA/DO-229E, section 2.4.1 to identify the MOPS requirements susceptible to environmental affects for an SBAS CCA functional sensor in the end-use equipment. The focus is on the change in environment seen by the SBAS CCA functional sensor as a result of its installation in the end-use equipment. For example, other components inside the end-use equipment may radiate RF energy that could interfere with the GPS functions; therefore the ambient testing done at CCA level is not equivalent to tests done in the end-use equipment. This is the basis for defining the RTCA/DO-229E, section 2.5 performance tests that need to be repeated by the end-use equipment manufacturer.(d) The Class Beta environmental table referenced in RTCA/DO-229E, section 2.4.1 are the prime source to determine theMOPS performance requirements susceptible to environmental conditions. Based on the table, the susceptible requirements can be grouped in two categories: those susceptible to most types of environmental conditions (described in section 3) and those susceptible to just a few (described in section 4).Note: The Tables for Class Beta-1, -2, and -3 equipment identify similar requirements susceptible to the installed environment. The only difference is the applicable MOPS requirements consistent with the operational class (i.e., class -1, - 2, or -3).3. Performance Requirements Susceptible to Most Environmental Conditions.The RTCA/DO-229E requirements for Accuracy (2.1.3.1, 2.1.4.1, and 2.1.5.1) and Sensitivity and Dynamic Range (2.1.1.10) are sensitive to most environmental conditions. However, these requirements are linked to the message loss rate requirement in 2.1.1.3.2. Section 3.1 and 3.2 below identifies the testing end-use equipment manufacturers are required to repeat to demonstrate the SBAS CCA functional sensor continues to meet the Accuracy, Dynamic Range, and Message Loss Rate performance requirements after installation in the end-use equipment. All tests will be run under conditions where the end-use equipment functions are fully enabled to create the worst-case environment.3.1 RTCA/DO-229E, 2.5.8 Accuracy Test.(a) The accuracy test described in section 2.5.8 is actually a joint test covering both accuracy, and sensitivity and dynamic range. This joint testing also applies under environment as stated in section 2.4.1.1.5 with environmental adaptation as described in section 2.4.1.1.1.(b) The demonstration of accuracy is done in accordance with section 2.5.8.1 only for the test case with a broadband external interference noise. This test must be repeated when the CCA is installed in the end-use equipment and it is sufficient to perform it using broadband interference.(1) The environmental testing is limited to broadband interference as it represents the worst case signal to noise condition which is the most sensitive to environmental effects. This applies equally to the environment for the CCA created by the end-use equipment.(2) Section 2.5.8 contains a measurement accuracy test in 2.5.8.1 with the detailed test procedure in 2.5.8.2. The 2.5.8.1 test must be run under the worst case environment identified in the “Additional considerations for internal interference sources” section below. The measurement accuracy testing can be combined with the message loss rate testing in 2.5.2.1.(3) Section 2.5.8.3 is a 24-Hour actual satellite accuracy test. The section 2.5.8.3 test exposes the equipment to a variety of signal conditions and data processing conditions over varying satellite geometrythat will increase confidence that no unforeseen interactions between components within the end-use equipment and the SBAS CCA functional sensor goes undetected. The 24 hr testing in 2.5.8.3 can be combined with the 24 hr message loss rate testing in 2.5.2.4 (see Additional Considerations for Internal Interference Sources section).(4) Section 2.5.8.4 (SBAS Tracking Bias) is an analysis of the GPS hardware and is therefore not necessary to repeat at the end-use equipment level as long as no extra RF components that affect the RF filtering response are inserted in the RF path. Otherwise the end-use equipment manufacturer must repeat the SBAS Tracking Bias test as well.(c) The test threshold is relaxed from 110% to 125% as specified in table 2-25 of the 2.5.8.2.1 test procedure to shorten test time. However, Section 2.5.8 testing (excluding the SBAS Tracking Bias test in 2.5.8.4) for the CCA in the end-use equipment shall be under ambient conditions per section 2.5 with the 110% test pass threshold for maximum test sensitivity.(d) The Section 2.5.8 testing (excluding the SBAS Tracking Bias test in 2.5.8.4) will be repeated against the accuracy requirement consistent with the desired operational class (i.e., 2.1.3.1, 2.1.4.1, and 2.1.5.1 accuracy requirements as appropriate).(e) Only the broadband external interference noise test case usingminimum satellite power will be executed in most cases to shorten test time. Section 2.5.8.1 testing will be repeated for both minimum and maximum satellite power for the worst case environment only.3.2 RTCA/DO-229E, 2.5.2 Message Loss Rate Test.(a) Section 2.5.2 specifies the message loss rate test for the 2.1.1.3.2 message loss rate requirement. This test is conducted in conjunction with the 2.5.8 accuracy testing. Section 2.5.2.2 defines the test procedure to collect data verifying the SBAS message loss rate in the presence of interference using the test cases where the SBAS satellite is at minimum power. Section 2.5.2.3 defines the pass/fail criteria.(b) The test in section 2.5.2.2 will be performed during the measurement accuracy broadband interference test case described in paragraph 3.1.(c) The test procedure in section 2.5.2.4.1 is run in conjunction with the 2.5.8.3 24-hour accuracy test. Section 2.5.2.4.2 defines the pass/fail criteria for the test case described in paragraph 3.1(b)(3).4. Performance Requirements Partially Susceptible to Environmental Conditions.(a) The class Beta tables (tables 2-14, 2-16, and 2-18) in section2.4.1 of RTCA/DO-229E indicates the requirements for Initial Acquisition Time (2.1.1.7) and Satellite Reacquisition Time (2.1.1.9) are sensitive to four environmental conditions: Icing, Lightning InducedTransient Susceptibility, Lightning Direct Effects, and Normal/Abnormal Operating Conditions. The requirements for Loss of Navigation (2.1.1.13.2, 2.1.4.12.2, and 2.1.5.12.2) and Loss of Integrity (2.1.1.13.1, 2.1.4.12.1, and 2.1.5.12.1) are sensitive to low and high operating temperature.(b) The Lightning Induced Transient Susceptibility, Lightning Direct Effects, or Icing environmental conditions are not pertinent to the environment created by the end-use equipment relative to the SBAS CCA functional sensor. However, the end-use equipment manufacturer remains responsible for meeting the overall environmental qualification at the end-use equipment level.(c) Loss of navigation and loss of integrity indications are limited to temperature testing and the information in RTCA/DO-229E, sections 2.4.1.1.2 and 2.4.1.1.3 is appropriate. The purpose is to ensure that the interface used to indicate the loss of navigation is functional under environmental conditions after the SBAS CCA functional sensor is installed in the end-use equipment. Sections 2.4.1.1.2 and 2.4.1.1.3 indicate that any source that generates the indication can be used since it is the interface and not the detection mechanism that is verified. The temperature testing done at the end-use equipment level is the worst-case scenario. It is not necessary to repeat the CCA level test at room temperature in the end-use equipment since the environmentalqualification adequately addresses testing for these requirements.(d) RTCA/DO-160E section 16 relates to aircraft power supply (refer to TSO paragraph 3.g for environmental qualification requirements). Sections 16.5.1.2 and 16.6.1.2 are for supply voltage modulation (ac) /ripple (dc). Given the potential susceptibility of the SBAS CCA functional sensor to power supply noise, it is prudent to repeat tests at the end-use equipment level on this basis.(e) Sections 4.1 and 4.2 identify the testing end-use equipment manufacturers are required to repeat to demonstrate the SBAS CCA functional sensor continues to meet the Acquisition Time and Reacquisition Time performance requirements relative to Normal/Abnormal Operating Conditions after installation in the end-use equipment. All tests will be run under conditions where the end-use equipment functions are fully enabled to create the worst-case environment.4.1 2.5.4 Initial Acquisition Test Procedures.The information in RTCA/DO-229E, section 2.4.1.1.4 on the initial acquisition test in section 2.5.4 applies. The end-use equipment manufacturer shall repeat the initial acquisition testing described in RTCA/DO-229E, section 2.5.4.4.2 2.5.6 Satellite Reacquisition Time Test.The end-use equipment manufacturer is required to repeat the。
SBAS(卫星增强系统)
SBAS (Satellite-Based Augmentation System),即基于卫星的增强系统。
SBAS 系统主要由四部分组成:地面参考基站,主控站,上传站和地球同步卫星等。
下面以WAAS为例,介绍该卫星系统的工作原理:
WAAS 是为民用飞行开发的极精确的导航系统。
在WAAS以前,美国的国家飞行系统(NAS)并没有足够的能力为所有区域的所有用户提供水平与垂直导航,有了WAAS后就有了给所有用户提供导航的能力。
WAAS为各种类型的飞行器各飞行阶段提供服务,确保飞行过程、升空、着陆时的安全。
WAAS 不像传统的地面导航辅助系统,它包含了所有的国家飞行系统(NAS),WAAS 给GPS 接收机提供增强信息,提高接收机的定位精度。
WAAS 系统主要由四部分组成:地面广域参考基站,WAAS主控站,WAAS上传站和地球同步卫星等,其工作可以分为四个过程:
一、基站接收GPS信号
在美国境内,广泛地分布着广域参考基站(Wide Area Reference Station(WRS)),每个基站都已知其准确的地理位置,通过接收GPS信号,探测出GPS信号中的误差。
二、基站向主控站传输GPS误差数据
广域参考基站(WRS)收集的GPS信息,通过地面的通讯网络传输到WAAS主控站(WMS),主控站生成WAAS 增强信息,这些信息包含了GPS接收机中消除GPS信号误差的信息,使GPS 接收机大大改善了定位精度和可靠性。
三、WAAS增强信息上传
增强信息由WASS主控站(WMS)传输到WAAS上传站,上传站调制成导航数据,并上传到地球同步通讯卫星。
四、增强信息的传播
地球同步通讯卫星以GPS信号频率向地面广播有增强信息的导航数据,地面接收机接收WASS 增强信号,得到GPS误差数据补偿定位,得到更加精确的定位。
WAAS也能给GPS接收机提供GPS系统误差或其他不良影响的信息,其也有严格的安全标准,当存在危险的误导信息时,WAAS能在六秒内发布给用户。
当前全球的SBAS系统有美国的WAAS(Wide Area Augmentation System),欧洲的EGNOS (European Geostationary NavigationOverlay Service)和日本的MSAS ( Multi-functional Satellite Augmentation System )。
其主要服务区域如下:
2007年9月起,WAAS服务区域扩展到了加拿大和墨西哥。
欧洲开发了同时对GPS和GLONASS广域星基增强系统。
它的原理与美国的WAAS类似,包括相应的地面设施和空间卫星,以提高GPS和GLONASS系统的精度、完好性和可用性。
欧洲GNSS的目标是分二步走,GNSS-1和GNSS-2,首先发展一个民间GNSS-1,其主要内容是对现有GPS和GLONASS的星基进行增强,即利用静止卫星,面向欧洲范围内的导航提供服务,即European Geostationary Navigation Overlay Service (欧洲静地星导航重叠服务). 虽然目前中国的GPS使用者暂时无法享受到WAAS带来的好处。
但目前已有许多国家正在发展类似的卫星校正系统,例如日本的Multi-Functional Satellite Augmentation System (MSAS)系统,该信号亚洲东部地区都可以搜索到。