Non-coherent scattering radar signal processing method based on frequency hopping and multiphase alternate codes

Abstract

The invention discloses a non-coherent scattering radar signal processing method based on frequency hopping and multiphase alternate codes. The method mainly solves the problems that existing non-coherent scattering radar is low in height resolution ratio, long in detection period and limited in coding mode. According to the technical scheme, the method comprises the following steps that all sets of the multiphase alternate codes are modulated respectively according to different frequencies, and radar pulses arranged in sequence without any time slot are generated and transmitted through a radar transmitter; radar echo signals are filtered respectively according to transmitting modulation frequencies so as to obtain detection data, corresponding to the same height range, of all the sets of the multiphase alternate codes, post-detection filtering is carried out on each set of coding echo signals, a self-correlation function is worked out, multi-period accumulation and fuzzy revising are carried out, and therefore the power spectral density of scattered signals of an ionized layer is worked out. The method can increase the height resolution ratio of the radar, shorten the detection period of the radar, expand the signal coding modes and be used for detection of the ionized layer.

Description

technical field [0001] The invention belongs to the technical field of signal and information processing, relates to a signal coding and signal processing method of an incoherent scattering radar, and can be used for ionospheric detection. Background technique [0002] With the development of science and technology, the impact of the ionosphere on human activities such as radio communication, navigation, broadcasting, and space exploration has become more and more significant. Ionospheric detection technology has gradually attracted the attention of scholars and scientific research institutions at home and abroad. my country has built the first incoherent scattering radar in Asia in Qujing, Yunnan, for ionospheric detection. Incoherent scatter radar is the most effective tool for detecting the ionosphere on the ground. By estimating the autocorrelation function and power spectral density of the echo signal, the parameters of the ionosphere such as electron density, electron ...

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Problems solved by technology

Two-phase alternating code modulation can obtain better height resolution, and can calculate autocorrelation function and power spectral density with multiple time delays, but its code length and code group number are strictly limited, which must be an integer power of 2 , so it is impossible to flexibly design the detection waveform

When the number of groups is large and multiple accumulations are required, the detection time is too long, and for areas where some ionospheric parameters change rapidly, it cannot meet the needs of rapidly changing ionospheric detection, resulting in large detection errors

In addition, the number of symbols in each group of alternating codes is determined. In order to increase the detection distance, the symbol width needs to be increased when the transmission power is constant to increase the transmission energy, but this will lead to a decrease in height resolution.

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