A method and device for identifying a 2fsk modulated signal

Abstract

The present application provides a method and device for identifying a 2FSK modulated signal. After the anti-UAV system monitors the signal, it first obtains an FM signal from the monitored signal, calculates the phase difference of the FM signal, and then uses The calculated phase difference constructs a new signal, wherein the real part of the new signal is the phase difference of the FM-type signal, and the imaginary part of the new signal is the inverse sequence of the phase difference of the FM-type signal. Calculate the fourth-order spectral peak prominence of the new signal, and determine whether the FM signal is a 2FSK modulated signal by comparing the fourth-order spectral peak prominence of the new signal with the preset fourth-order spectral peak prominence threshold . In the identification method provided by the present application, the involved calculation process is less, the parameters involved in the calculation process are less, and the calculation process is relatively simple, which can effectively improve the efficiency of judging whether the passive signal to be identified is a 2FSK modulated signal .

Description

technical field [0001] The present application relates to the technical field of communications, and in particular to a method and device for identifying a 2FSK modulated signal. Background technique [0002] Under the current social background, drone technology has been widely used in both military and civilian applications. In order to prevent the intrusion of illegal drones, anti-drone systems have emerged. The anti-drone system can determine whether there is a drone intrusion by identifying the modulation format of the monitored signal. [0003] UAVs usually use binary digital frequency modulation (Binary Frequency Shift Keying, 2FSK) to modulate the signal to obtain a 2FSK modulated signal and transmit it. Existing anti-drone systems can only distinguish the modulation types of the monitored signals, for example, they can only distinguish whether the monitored signals are obtained through amplitude modulation, phase modulation or frequency modulation. However, 2FSK is...

AI Technical Summary

Problems solved by technology

[0004] The modulation mode of the monitored signal can be judged by the eigenvalue extraction method or the high-order cumulant calculation method. However, the eigenvalue extraction method needs to know the symbol rate of the monitored signal in advance. In the case of whether the received signal belongs to the UAV launch, it is impossible to know the model of the UAV, and it is impossible to know the symbol rate of the monitored signal in advance. There are two ways to judge the modulation mode of the signal

However, the high-order cumulant calculation method can only identify the baseband signal. Therefore, if there is a carrier in the monitored signal, it is necessary to accurately estimate the carrier and then calculate it. The process of carrier estimation requires a large amount of calculation and requires high accuracy. , will greatly reduce the efficiency of judging the modulation mode of the monitored signal

Images