针对高动态场景下多普勒频移问题和缺少定量分析,该文以研究正交调制的多普勒频移响应机理为基点,对多普勒频移对正交调制系统的影响进行了研究,从星座图判决区间的角度推导了多进制数字相位调制信号和多进制正交幅度调制信号在多普勒...针对高动态场景下多普勒频移问题和缺少定量分析,该文以研究正交调制的多普勒频移响应机理为基点,对多普勒频移对正交调制系统的影响进行了研究,从星座图判决区间的角度推导了多进制数字相位调制信号和多进制正交幅度调制信号在多普勒频移下的误符号率公式。理论分析和实验结果表明:多普勒频移对正交调制的影响是星座的旋转,误符号率公式推导结果与实际误符号率基本相同,系统的性能随着调制指数和运动速度的增加而下降。在信噪比为20 d B时,多进制数字相位调制信号的抗多普勒频移能力要强于多进制正交幅度调制信号。展开更多
In the strapdown inertial navigation system, the Fiber Optical Gyro(FOG) must have high precision to give accurate navigation information. In this paper, a digital closed loop detection method based on the ramp wave m...In the strapdown inertial navigation system, the Fiber Optical Gyro(FOG) must have high precision to give accurate navigation information. In this paper, a digital closed loop detection method based on the ramp wave modulating technigue is introduced. DSP and FPGA have many advantages in digital signal proeessing. In the design, by using DSP, a complex arithmetic operation is completed to meet the needs of closed loop control of FOG within a short time. All kinds of control signals are produced easily by FPGA, under which DSP could work properly. Combining the DSP and FPGA,the detecting method is implemented successfully. In the end, the result of test and performance is given. From the result we can conclude that the precision of FOG is improved and the noises are limited to a low level.展开更多
Mechanical micro-vibration of a target may induce phase modulations on the radar echo,and the vibration can be detected to identify micro-motion target. In this paper,a new method to detect a micro-motion target and o...Mechanical micro-vibration of a target may induce phase modulations on the radar echo,and the vibration can be detected to identify micro-motion target. In this paper,a new method to detect a micro-motion target and obtain its range and micro-motion frequency is proposed in which multiple periods stepped-frequency continuous-wave signal and Moving Target Indication (MTI) filter are adopted. The simulation results illustrate the validity of this method and present the detection of the target range and the vibration frequency. The experiment gives promising results.展开更多
文摘针对高动态场景下多普勒频移问题和缺少定量分析,该文以研究正交调制的多普勒频移响应机理为基点,对多普勒频移对正交调制系统的影响进行了研究,从星座图判决区间的角度推导了多进制数字相位调制信号和多进制正交幅度调制信号在多普勒频移下的误符号率公式。理论分析和实验结果表明:多普勒频移对正交调制的影响是星座的旋转,误符号率公式推导结果与实际误符号率基本相同,系统的性能随着调制指数和运动速度的增加而下降。在信噪比为20 d B时,多进制数字相位调制信号的抗多普勒频移能力要强于多进制正交幅度调制信号。
文摘In the strapdown inertial navigation system, the Fiber Optical Gyro(FOG) must have high precision to give accurate navigation information. In this paper, a digital closed loop detection method based on the ramp wave modulating technigue is introduced. DSP and FPGA have many advantages in digital signal proeessing. In the design, by using DSP, a complex arithmetic operation is completed to meet the needs of closed loop control of FOG within a short time. All kinds of control signals are produced easily by FPGA, under which DSP could work properly. Combining the DSP and FPGA,the detecting method is implemented successfully. In the end, the result of test and performance is given. From the result we can conclude that the precision of FOG is improved and the noises are limited to a low level.
文摘Mechanical micro-vibration of a target may induce phase modulations on the radar echo,and the vibration can be detected to identify micro-motion target. In this paper,a new method to detect a micro-motion target and obtain its range and micro-motion frequency is proposed in which multiple periods stepped-frequency continuous-wave signal and Moving Target Indication (MTI) filter are adopted. The simulation results illustrate the validity of this method and present the detection of the target range and the vibration frequency. The experiment gives promising results.
