为了降低基于接收信号强度(Received signal strength Index,RSS)测距误差对节点定位的影响,解决基于RSS测距定位误差较大的问题,提出了基于优化RSS测距的平方最小平方定位算法(Square-least Square localization algorithm based on im...为了降低基于接收信号强度(Received signal strength Index,RSS)测距误差对节点定位的影响,解决基于RSS测距定位误差较大的问题,提出了基于优化RSS测距的平方最小平方定位算法(Square-least Square localization algorithm based on improved RSS,SLS-I-RSS)。SLS-I-RSS算法先通过多组锚节点间的距离和接收功率作为参考,降低基于RSS测距误差,然后再建立定位优化问题,并将定位优化问题转成规则化信任区域子问题,最后,再利用拉格朗日优化算法求解优化问题。实验结果表明,提出的SLS-I-RSS算法能够有效地降低定位误差,比传统的基于RSS定位算法减少了约12%~20%,但算法复杂度略有增加。展开更多
调频全角是轴对称MEMS陀螺上检测角度的控制方法,主要是在一个谐振子上叠加陀螺质量块的顺时针(CW)振动模式和逆时针(CCW)振动模式,进而得到这2种模式的频率信息来实现角度检测。在高Q值陀螺中存在系统稳定较慢和顺逆时针模式相互耦合问...调频全角是轴对称MEMS陀螺上检测角度的控制方法,主要是在一个谐振子上叠加陀螺质量块的顺时针(CW)振动模式和逆时针(CCW)振动模式,进而得到这2种模式的频率信息来实现角度检测。在高Q值陀螺中存在系统稳定较慢和顺逆时针模式相互耦合问题,为此文中提出一种全角控制技术优化方法。该方法在现有调频全角顺逆时针控制系统上添加自动增益控制(automatic gain control,AGC)模块,用于顺逆时针模式的幅度控制,从而解决了上述2种问题,降低了角度检测阈值。实验结果表明,该控制方法下的系统稳定时间从4 s降低到0.4 s,角速率输入阈值从11(°)/s降为0.5(°)/s以下。展开更多
In order to overcome the limitation of cross correlation coregistration method for Synthetic Aperture Radar(SAR) interferometric pairs with low coherence,a new image coregistration algorithm based on Fringe Definition...In order to overcome the limitation of cross correlation coregistration method for Synthetic Aperture Radar(SAR) interferometric pairs with low coherence,a new image coregistration algorithm based on Fringe Definition Detection(FDD) is presented in this paper.The Fourier transformation was utilized to obtain spectrum characteristics of interferometric fringes.The ratio between spectrum mean and peak was proposed as the evaluation index for identifying homologous pixels from interferometric images.The satellites ERS-1/2 C-band SAR acquisitions covering the Yangtze River plain delta,eastern China and ALOS/PALSAR L-band images over the Longmen Shan mountainous area,southwestern China were respectively employed in the experiment to validate the proposed coregistration method.The testing results suggested that the derived Digital Elevation Model(DEM) from FDD method had good agreement with that from the cross correlation method as well as the reference DEM at high coherence area.However,The FDD method achieved a totally improved topographic mapping accuracy by 24 percent in comparison to the cross correlation method.The FDD method also showed better robustness and achieved relatively higher performance for SAR image coregistration in mountainous areas with low coherence.展开更多
文摘为了降低基于接收信号强度(Received signal strength Index,RSS)测距误差对节点定位的影响,解决基于RSS测距定位误差较大的问题,提出了基于优化RSS测距的平方最小平方定位算法(Square-least Square localization algorithm based on improved RSS,SLS-I-RSS)。SLS-I-RSS算法先通过多组锚节点间的距离和接收功率作为参考,降低基于RSS测距误差,然后再建立定位优化问题,并将定位优化问题转成规则化信任区域子问题,最后,再利用拉格朗日优化算法求解优化问题。实验结果表明,提出的SLS-I-RSS算法能够有效地降低定位误差,比传统的基于RSS定位算法减少了约12%~20%,但算法复杂度略有增加。
文摘调频全角是轴对称MEMS陀螺上检测角度的控制方法,主要是在一个谐振子上叠加陀螺质量块的顺时针(CW)振动模式和逆时针(CCW)振动模式,进而得到这2种模式的频率信息来实现角度检测。在高Q值陀螺中存在系统稳定较慢和顺逆时针模式相互耦合问题,为此文中提出一种全角控制技术优化方法。该方法在现有调频全角顺逆时针控制系统上添加自动增益控制(automatic gain control,AGC)模块,用于顺逆时针模式的幅度控制,从而解决了上述2种问题,降低了角度检测阈值。实验结果表明,该控制方法下的系统稳定时间从4 s降低到0.4 s,角速率输入阈值从11(°)/s降为0.5(°)/s以下。
基金supported by the National Natural Science Foundation of China(Grant Nos.41472255,51178404)Open Research Fund by Sichuan Engineering Research Center for Emergency Mapping & Disaster Reduction(Program K2014B006)Fundamental Research Funds for the Central Universities(Grant Nos.SWJTU12ZT07,2682014BR014)
文摘合成的孔雷达(SAR ) stereo-radargrammetry 的片面上升或下降限制了由于短空间基线(100 km ) 和小交叉角度的地志的印射的精确性。以便改进从卫星转菠的 SAR radargrammetry 产生数字举起模型(DEM ) 的表演和可靠性，从与长空间的基线(1000 km ) 的几何配置登上并且下降轨道的联合的两方面的 stereo-radargrammetry 的探索在这研究被进行。在到放方程的地球表面和 Doppler 的 SAR 传感器之间的观点范围几何学被采用建立实体镜的交叉模型。两方面的 radargrammetric 举起的测量无常根据在输入 SAR 图象之间的同类的点的雷达视差被估计。ALOS/PALSAR (先进土地观察卫星 / 阶段数组类型 L 乐队合成的孔雷达) 的二立体声对有轨道的分离的获得在有在西南的中国卷地形学的西方四川低岬盆上的几乎 1080 km 在学习被采用在撞击了这个区域的 2008 Wenchuan 地震以后获得新地面数据。对两方面的 radargrammetric DEM 的量的精确性评价与参考被执行回答 GPS 观察。试验性的结果证明没有使用的地面控制点(GCP ) ，举起精确性到达 5.5 m，并且精确性是进一步的改善了到 1.5 m，一仅仅 GPS GCP 用作最少的限制。理论分析和严峻的结果证明从上升并且下降的轨道的两方面的长基线 SAR radargrammetry 能是为大区域、高的精确性的一种很有希望的技术选择地志的印射。
基金supported by the Natural Science Foundation of China (Grant Nos. 41072220, 51178404)National Basic Research Program of China (973 Program) under Grant 2012CB719901Fundamental Research Funds for the Central Universities(GrantNos.SWJTU09CX010, SWJTU11ZT13, SWJTU12ZT07)
文摘In order to overcome the limitation of cross correlation coregistration method for Synthetic Aperture Radar(SAR) interferometric pairs with low coherence,a new image coregistration algorithm based on Fringe Definition Detection(FDD) is presented in this paper.The Fourier transformation was utilized to obtain spectrum characteristics of interferometric fringes.The ratio between spectrum mean and peak was proposed as the evaluation index for identifying homologous pixels from interferometric images.The satellites ERS-1/2 C-band SAR acquisitions covering the Yangtze River plain delta,eastern China and ALOS/PALSAR L-band images over the Longmen Shan mountainous area,southwestern China were respectively employed in the experiment to validate the proposed coregistration method.The testing results suggested that the derived Digital Elevation Model(DEM) from FDD method had good agreement with that from the cross correlation method as well as the reference DEM at high coherence area.However,The FDD method achieved a totally improved topographic mapping accuracy by 24 percent in comparison to the cross correlation method.The FDD method also showed better robustness and achieved relatively higher performance for SAR image coregistration in mountainous areas with low coherence.
