http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Felux, Michael (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Ionospheric Gradient Threat Mitigation in Future Dual Frequency GBAS
Felux, Michael,Circiu, Mihaela-Simona,Lee, Jiyun,Holzapfel, Florian Hindawi Limited 2017 International journal of aerospace engineering Vol.2017 No.-
<P>The Ground Based Augmentation System (GBAS) is a landing system for aircraft based on differential corrections for the signals of Global Navigation Satellite Systems (GNSS), such as GPS or Galileo. The main impact on the availability of current single frequency systems results from the necessary protection against ionospheric gradients. With the introduction of Galileo and the latest generation of GPS satellites, a second frequency is available for aeronautical navigation. Dual frequency methods allow forming of ionospheric free combinations of the signals, eliminating a large part of the ionospheric threats to GBAS. However, the combination of several signals increases the noise in the position solution and in the calculation of error bounds. We, therefore, developed a method to base positioning algorithms on single frequency measurements and use the second frequency only for monitoring purposes. In this paper, we describe a detailed derivation of the monitoring scheme and discuss its implications for the use in an aviation context.</P>
-
GBAS ground monitoring requirements from an airworthiness perspective
Felux, Michael,Lee, Jiyun,Holzapfel, Florian John Wiley Sons 2015 GPS SOLUTIONS Vol.19 No.3
<P> The ground-based augmentation system (GBAS) provides corrections for satellite navigation signals together with integrity parameters to aircraft and enables precision approach guidance. It will eventually replace the currently used instrument landing system. GBAS Approach Service Type C stations supporting CAT-I operations have been fully developed and certified, and first stations are operational. For the service type D, which is intended to support CAT-III operations including automatic approaches and landings, requirements have been drafted and are currently undergoing validation. One remaining issue is the requirement for monitoring of ionospheric anomalies in the ground subsystem. Large gradients in the concentration of free electrons in the ionosphere can lead to significant positioning errors when navigation is based on differential methods. We give a review of the derivation of currently proposed performance requirements for such a monitor. Next, we show that the required level of safety from an airworthiness perspective can be achieved even with relaxed monitoring requirements compared to the currently drafted standards. These relaxations result from satellite geometry assessments on the ground and actual approach characteristics toward a runway. We show that with this method, it is sufficient to monitor for gradients in the range of about 450-550 mm/km while current standards require detection already from 300 mm/km. A remote monitoring receiver near the touchdown point can monitor the post-correction differential range error and use it as test statistic for GBAS performance monitoring and protection against ionospheric disturbances. </P>
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
