The integration of water quality analysis simulation program (WASP) with a geographical information system (GIS) is presented.This integration was undertaken to enhance the data analysis and management ability of the ...The integration of water quality analysis simulation program (WASP) with a geographical information system (GIS) is presented.This integration was undertaken to enhance the data analysis and management ability of the widely used water quality model.Different types of data involved in WASP modeling were converted and integrated into GIS using a database method.The spatial data modeling and analysis capability of GIS were used in the operation of the model.The WASP water quality model was coupled with the environmental fluid dynamics code (EFDC) hydrodynamic model.A case study of the Lower Charles River Basin (Massachusetts,USA) water quality model system was conducted to demonstrate the integration process.The results showed that high efficiency of the data process and powerful function of data analysis could be achieved in the integrated model,which would significantly improve the application of WASP model in water quality management.展开更多
在全球卫星导航系统(GNSS)中,延长相关累积时间可以有效提高弱信号捕获灵敏度,但是"北斗"中圆地球轨道/倾斜地球同步轨道(MEO/IGSO)卫星信号的捕获性能很大程度上受到二次编码(NH)码的影响:调制NH码的信号在每一个码元周期(1 ...在全球卫星导航系统(GNSS)中,延长相关累积时间可以有效提高弱信号捕获灵敏度,但是"北斗"中圆地球轨道/倾斜地球同步轨道(MEO/IGSO)卫星信号的捕获性能很大程度上受到二次编码(NH)码的影响:调制NH码的信号在每一个码元周期(1 ms)内都有可能发生跳变,对相关累积时间造成一定影响,从而会导致系统捕获灵敏度的下降。为此,提出了一种针对NH码的码元遍历搜索算法,通过遍历累积时间内NH码的所有组合,消除NH码码元引起的误差。实验结果显示,所提算法可以在一定程度上提高卫星信号的捕获成功率,尤其可以至少提高2 d B弱信号的捕获灵敏度。同时,算法可以为信号跟踪提供更加准确的载波频率。展开更多
基金Project supported by the National Basic Research Program (973) (No.2007CB407306)the National Major Projects on Control and Rectification of Water Body Pollution (No.2008ZX07314-004-002),China and the China Scholar Council
文摘The integration of water quality analysis simulation program (WASP) with a geographical information system (GIS) is presented.This integration was undertaken to enhance the data analysis and management ability of the widely used water quality model.Different types of data involved in WASP modeling were converted and integrated into GIS using a database method.The spatial data modeling and analysis capability of GIS were used in the operation of the model.The WASP water quality model was coupled with the environmental fluid dynamics code (EFDC) hydrodynamic model.A case study of the Lower Charles River Basin (Massachusetts,USA) water quality model system was conducted to demonstrate the integration process.The results showed that high efficiency of the data process and powerful function of data analysis could be achieved in the integrated model,which would significantly improve the application of WASP model in water quality management.
文摘在全球卫星导航系统(GNSS)中,延长相关累积时间可以有效提高弱信号捕获灵敏度,但是"北斗"中圆地球轨道/倾斜地球同步轨道(MEO/IGSO)卫星信号的捕获性能很大程度上受到二次编码(NH)码的影响:调制NH码的信号在每一个码元周期(1 ms)内都有可能发生跳变,对相关累积时间造成一定影响,从而会导致系统捕获灵敏度的下降。为此,提出了一种针对NH码的码元遍历搜索算法,通过遍历累积时间内NH码的所有组合,消除NH码码元引起的误差。实验结果显示,所提算法可以在一定程度上提高卫星信号的捕获成功率,尤其可以至少提高2 d B弱信号的捕获灵敏度。同时,算法可以为信号跟踪提供更加准确的载波频率。
