0/pi modulated angle-measurement method based on phase accumulative Doppler frequency offset compensation

Abstract

The invention provides a 0 / pi modulated angle-measurement method based on phase accumulative Doppler frequency offset compensation. Two completely same CP data segments (the symbol length is 128) andFrank sequences are inserted after a synchronous sequence in a frame structure; after detecting that a data frame arrives through the synchronous sequence, a receiving end performs complex correlationoperation of the received two Frank sequences; the phase difference of the two Frank sequences is calculated according to an obtained complex correlation value; therefore, the size of frequency offset is calculated, so that frequency offset compensation is completed; and, influence of frequency offset on the angle-measurement performance is reduced by adoption of a non-coherent demodulation-amplitude envelope detection technology. A frequency offset estimation algorithm in the invention is high in precision; influence of the frequency offset on the angle-measurement performance and requirements of a tracking receiver on the phase consistency of sum and difference channels can be reduced; and anti-multipath functional expansion under a time-varying channel can be supported.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and relates to a single-pulse single-channel tracking receiver technology in the field of communication and measurement and control, which can be used for capturing and tracking targets. Background technique [0002] In broadband communication systems, self-tracking radars are usually used to track targets stably, ensure sufficient antenna gain, and ensure long-distance and reliable data transmission. [0003] In a specific application scenario, the antenna tracking system does not send additional beacon signals, but directly uses broadband communication signals to implement beam tracking of the antenna. In order to be applicable to any form of receiving signals, the orthogonal 0 / π modulation method is usually used and four-phase modulation method. [0004] Li Ruibang proposed a quadrature 0 / π modulation method in "Research on Spread Spectrum Signal Tracking Angle Measurement Tech...

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Problems solved by technology

But the disadvantage is that the noise energy is introduced in the time domain correlation process, which limits the application of the system to the environment with high signal-to-noise ratio.

[0005] Wang Xiaomei introduced the four-phase modulation method in "Research on Single-pulse Single-channel Tracking Receiver Technology for Wideband Radar Signal Receiving System" (Xidian University Paper, 2011 (10)), which performs four-phase modulation on the quadrature-combined differential signals. Modulation, the envelope amplitude is obtained by shift correlation operation, and the angle difference information is demodulated. This method can work in the environment of low signal-to-noise ratio, but the disadvantage is that the tracking performance is poor

[0006] Unfortunately, the above two methods do not mention the effect of Doppler frequency offset on the tracking system

In a specific environment, the transmitting and receiving parties often have relatively high-speed movement, which will inevitably bring about the influence of Doppler frequency offset in the communication process of the ultra-high frequency band, which will affect the performance of the tracking system

[0007] In Wang Shanshan's "Single-channel Angle Tracking Receiver Baseband Signal Processing Technology" (Xidian University Paper, 2011 (12)), she proposed to use the "FFT frequency estimation method" to compensate the Doppler frequency offset, but the disadvantage is that Its system resource overhead is large, the frequency estimation performance is poor, and this method is only suitable for frequency offset estimation in the form of beacon signals

[0008] Zhang Peng improved the four-phase modulation method proposed by Wang Xiaomei in "Research on Angle Tracking Technology Based on PCM_FM Telemetry Signal under High Dynamic and Low SNR Conditions" (National University of Defense Technology, 2012 (11)), and introduced "Second-order frequency-locked loop" compensates Doppler frequency offset, but the disadvantage is that its frequency-locking time is long and its real-time performance is poor

[0009] Therefore, the existing broadband signal angle measurement methods cannot take into account the requirements of high-precision frequency offset estimation and compensation, a wide range of applicable signal forms, and good real-time performance.

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