Using autocorrelation information of the pseudorange errors generated by se- lective availability (SA) frequency dithering, we have constructed a simple first order stochas- tic model for SA effects. This model has be...Using autocorrelation information of the pseudorange errors generated by se- lective availability (SA) frequency dithering, we have constructed a simple first order stochas- tic model for SA effects. This model has been used in a Kalman filter to account for the stochastic behavior of SA dithering in estimating satellite clock information in wide area dif- ferential GPS. We have obtained fifteen percent improvement in the user positioning using the correlation information on the satellite clock information in a Kalman filter, when comparing the results obtained using a regular least square estimation.展开更多
The maritime navigation accuracy requirements for radionavigation systems such as GPS are specified by the International Maritime Organization (IMO). Maritime navigation usually consists of three major phases identifi...The maritime navigation accuracy requirements for radionavigation systems such as GPS are specified by the International Maritime Organization (IMO). Maritime navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with an accuracy requirement that ranges from 10 m to 0.1 m. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP) and with the advent of the new IGS-Real-Time-Service (RTS), it is necessary to assess the possibility of a wider role of the PPP-based positioning technique in maritime applications. This paper investigates the performance of an autonomous real-time PPP-positioning solution by using the IGS- RTS service for maritime applications that require an accurate positioning system. To examine the performance of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is investigated. It is shown that the real-time IGS-RTS PPP-based GPS positioning technique fulfills IMO requirements for maritime applications with an accuracy requirement ranges from 10 m for Ocean/Coastal/Port approach/Inland waterways navigation to 1.0 m for in port navigation but cannot fulfill the automatic docking application with an accuracy requirement of 0.10 m. To further investigate the real-time PPP-based GPS positioning technique, a comparison is made between the real-time IGS-RTS PPP-based positioning technique and the real-time PPP-based positioning by using the predicted part of the IGS Ultra-Rapid products and the real-time GPS positioning technique with the Wide Area Differential GPS service (WADGPS). It is shown that the IGS-RTS PPP-based positioning technique is superior to the IGS-Ultra-Rapid PPP-based and WADGPS-based positioning techniques.展开更多
3.4.1美国广域增强系统WAAS3.4.1.1系统组成广域增强系统(Wide Area Augmentation System,WAAS)是美国的星基增强系统,是为满足美国民用航空对GPS更高的精度和完好性要求,1992年,美国联邦航空管理局(FAA)在WADGPS的基础上设计的。其利用...3.4.1美国广域增强系统WAAS3.4.1.1系统组成广域增强系统(Wide Area Augmentation System,WAAS)是美国的星基增强系统,是为满足美国民用航空对GPS更高的精度和完好性要求,1992年,美国联邦航空管理局(FAA)在WADGPS的基础上设计的。其利用GEO地球同步静止轨道卫星广播GPS差分修正数据和完好性信息电文,实现在北美地区GPS系统的完好性增强。WAAS系统的GEO卫星不仅作为完好性告警通道,播发增强信号的同时还提供测距服务,利用GEO卫星覆盖范围大且位置相对稳定的特点,对地面用户高仰角高,作为一个稳定的测距信号源,可补充GPS星座用户可见卫星数量。展开更多
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...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。展开更多
基金Project Supported by the Hong Kong Polytechnic University Research Grand(No. 353/392
文摘Using autocorrelation information of the pseudorange errors generated by se- lective availability (SA) frequency dithering, we have constructed a simple first order stochas- tic model for SA effects. This model has been used in a Kalman filter to account for the stochastic behavior of SA dithering in estimating satellite clock information in wide area dif- ferential GPS. We have obtained fifteen percent improvement in the user positioning using the correlation information on the satellite clock information in a Kalman filter, when comparing the results obtained using a regular least square estimation.
文摘The maritime navigation accuracy requirements for radionavigation systems such as GPS are specified by the International Maritime Organization (IMO). Maritime navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with an accuracy requirement that ranges from 10 m to 0.1 m. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP) and with the advent of the new IGS-Real-Time-Service (RTS), it is necessary to assess the possibility of a wider role of the PPP-based positioning technique in maritime applications. This paper investigates the performance of an autonomous real-time PPP-positioning solution by using the IGS- RTS service for maritime applications that require an accurate positioning system. To examine the performance of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is investigated. It is shown that the real-time IGS-RTS PPP-based GPS positioning technique fulfills IMO requirements for maritime applications with an accuracy requirement ranges from 10 m for Ocean/Coastal/Port approach/Inland waterways navigation to 1.0 m for in port navigation but cannot fulfill the automatic docking application with an accuracy requirement of 0.10 m. To further investigate the real-time PPP-based GPS positioning technique, a comparison is made between the real-time IGS-RTS PPP-based positioning technique and the real-time PPP-based positioning by using the predicted part of the IGS Ultra-Rapid products and the real-time GPS positioning technique with the Wide Area Differential GPS service (WADGPS). It is shown that the IGS-RTS PPP-based positioning technique is superior to the IGS-Ultra-Rapid PPP-based and WADGPS-based positioning techniques.
文摘3.4.1美国广域增强系统WAAS3.4.1.1系统组成广域增强系统(Wide Area Augmentation System,WAAS)是美国的星基增强系统,是为满足美国民用航空对GPS更高的精度和完好性要求,1992年,美国联邦航空管理局(FAA)在WADGPS的基础上设计的。其利用GEO地球同步静止轨道卫星广播GPS差分修正数据和完好性信息电文,实现在北美地区GPS系统的完好性增强。WAAS系统的GEO卫星不仅作为完好性告警通道,播发增强信号的同时还提供测距服务,利用GEO卫星覆盖范围大且位置相对稳定的特点,对地面用户高仰角高,作为一个稳定的测距信号源,可补充GPS星座用户可见卫星数量。
文摘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。
