高动态GNSS信号多普勒模拟任意阶直接数字合成器设计

为高精度模拟高动态条件下GNSS信号的多普勒特性，提出一种任意阶直接数字合成信号合成器的设计方法。设计任意阶直接数字合成信号合成器的结构；通过理论分析，推导各级累加器相位初值的计算公式；给出字长选择方法。经仿真验证，该方法能精确模拟GNSS信号的多普勒特性。此外，提出的直接数字合成器设计方法不受阶数的限制，可普遍应用于各类信号模拟器的设计。
In order to accurately simulate the Doppler characteristics of high dynamic GNSS signals, a method for designing any-order DDS (direct digital synthesis) signal synthesizer was proposed. An any-order DDS synthesizer structure was designed; a formula for calculating the initial phase of every accumulator in DDS synthesizer was derived by using theoretical analysis; a technique to determine the DDS word length was developed. Finally, the simulation accuracy of the proposed method for the Doppler characteristics of GNSS signals was validated through simulations. In addition, since the proposed method for designing DDS synthesizer has no order limitation, it can be widely used in different types of signal simulators.