基于接收信号强度指示(RSSI,Received Signal Strength Indicator)的定位算法,由于无线信号受到多径衰减、障碍物、噪声等因素的影响,定位误差值一直较大。通过对基于RSSI定位算法的分析,在矩形栅格划分概率定位算法的基础之上,提出一...基于接收信号强度指示(RSSI,Received Signal Strength Indicator)的定位算法,由于无线信号受到多径衰减、障碍物、噪声等因素的影响,定位误差值一直较大。通过对基于RSSI定位算法的分析,在矩形栅格划分概率定位算法的基础之上,提出一种改进型算法——三角形栅格划分概率定位算法。实验结果显示,节点定位误差进一步减小,进一步提高了节点定位精度。展开更多
A new method is presented to fabricate the triangular fiber Bragg grating(TFBG).The fabrication device is simple,only requires a single exposure and does not need to write complicated program.The transfer matrix metho...A new method is presented to fabricate the triangular fiber Bragg grating(TFBG).The fabrication device is simple,only requires a single exposure and does not need to write complicated program.The transfer matrix method is used to design the fiber Bragg grating,and the grating resonant wavelength and the grating reflectivity can be controlled in order to achieve the triangular spectrum.With different fiber tilt angles,the available bandwidth of TFBG,the linearity and the oblique gradient are also different.In the experiment,the angles 1°,1.5° and 2° are chosen.The results show that the best angle value is 1.5°,and the TFBG has a good linearity,greater gradient and wider available bandwidth.展开更多
文摘基于接收信号强度指示(RSSI,Received Signal Strength Indicator)的定位算法,由于无线信号受到多径衰减、障碍物、噪声等因素的影响,定位误差值一直较大。通过对基于RSSI定位算法的分析,在矩形栅格划分概率定位算法的基础之上,提出一种改进型算法——三角形栅格划分概率定位算法。实验结果显示,节点定位误差进一步减小,进一步提高了节点定位精度。
基金supported by the National Natural Science Foundation of China (Nos.60771008 and 60837002)the Natural Science Foundation of Beijing (No.4082024)+1 种基金the Ph.D. Programs Foundation of Ministry of Education of China (No.20090009110003)the Foundation for the Returning Scholars (No.2008890)
文摘A new method is presented to fabricate the triangular fiber Bragg grating(TFBG).The fabrication device is simple,only requires a single exposure and does not need to write complicated program.The transfer matrix method is used to design the fiber Bragg grating,and the grating resonant wavelength and the grating reflectivity can be controlled in order to achieve the triangular spectrum.With different fiber tilt angles,the available bandwidth of TFBG,the linearity and the oblique gradient are also different.In the experiment,the angles 1°,1.5° and 2° are chosen.The results show that the best angle value is 1.5°,and the TFBG has a good linearity,greater gradient and wider available bandwidth.
