Augmentation Performance of QZSS L1-SAIF Signal
Augmentation Performance of QZSS L1-SAIF Signal
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发表时间：
2007-01
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通讯作者：
T. Sakai;S. Fukushima;N. Takeichi;Ken Ito
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作者：
T. Sakai;S. Fukushima;N. Takeichi;Ken Ito
QZSS（准天顶卫星系统）是一个日本卫星导航计划，计划在2009年发射一个区域服务覆盖。为了从高仰角向城市峡谷广播无线电信号，QZS（准天顶卫星）将发射到倾角为45度的24小时椭圆轨道上，卫星保持在一定的地理经度范围内，每天至少在日本上空停留8小时。QZSS将提供补充和增强信号，以便为用户提供最大的利益。QZSS将在GPS L1频率上广播GPS增强信息。为此，基于SBAS标准开发了L1-SAIF（带完整性功能的子级增强）信号，因为它们在几乎相同的服务区域提供相似的功能。在水平方向定位精度目标为1米。QZSS还将为移动用户的安全提供必要的完整性功能。L1-SAIF增强消息被设计成与SBAS消息高度兼容；扩展消息是为了提高增强系统的性能而设计的。使用ENRI开发的原型SBAS软件对L1-SAIF增强消息进行了性能分析。该原型具有模拟L1-SAIF MCS并生成增强消息流的能力，该消息流可用于评估任何用户位置的实际位置精度。结果表明，目标精度是可以达到的。原型机从2006年4月开始连续运行进行长期试验，至今运行稳定，未发现任何故障。此外，最近还开发了实时消息生成器，并与GEONET观测点的实时数据连接进行了测试。即使在实时模式下，原型也是功能稳定的。
QZSS (quasi-zenith satellite system) is a Japanese satellite navigation program with a regional service coverage planned to be launched in 2009. In order to broadcast radiosignals from high elevation angle into urban canyons, the QZS (quasi-zenith satellite) will be launched into a 24-hour elliptic orbit inclined 45 degrees on which a satellite is kept within a certain range of geographic longitude and stays above Japan at least 8 hours everyday. QZSS will offer both supplement and augmentation signals in order to offer the maximum benefit to users. QZSS will broadcast GPS augmentation messages on the GPS L1 frequency. For this purpose L1-SAIF (submeterclass augmentation with integrity function) signal has been developed based on SBAS standard because both of them offer similar function to the almost same service area. The target of positioning accuracy with augmentation was set as 1 meter for horizontal. QZSS will also provide the integrity function necessary for safety of mobile users. L1-SAIF augmentation messages are being designed to be upper compatible with SBAS messages; The extended messages are designed to enhance the performance of augmentation system. Performance analysis of the L1-SAIF augmentation message has been conducted using the prototype SBAS software developed by ENRI. This prototype has capability to simulate L1-SAIF MCS and to generate augmentation message stream which could be used to evaluate the actual position accuracy at any user location. According to the result the target accuracy is likely achievable. The prototype has been operating continuously since April 2006 for long-term test, and so far it is stable and any troubles have never been detected. Furthermore, most recently realtime message generator has been developed and tested with realtime data connection from GEONET observation sites. The prototype is functional and stable even in realtime mode.