A complementary sequence phase-coded signal intermittent transmission-reception echo reconstruction method

Abstract

The application discloses a complementary sequence phase coding intermittent transmitting and receiving echo reconstruction method, and steps are as follows: first, complementary sequence intermittent transmitting and receiving control signal design; second, phase coding intermittent transmitting and receiving processing; third, phase coding echo reconstruction and information reconstruction. The method uses the characteristics of the intermittent transmitting and receiving control signal, and respectively processes the phase coding intermittent transmitting and receiving, so that the operation is convenient and simple, the reconstruction precision is improved, and echo information loss caused by the intermittent transmitting and receiving processing is solved.

Description

TECHNICAL FIELD

[0001] The application relates to a complementary sequence-based intermittent transmission-reception echo reconstruction method for phase-coded signals and belongs to the field of radar system simulation. BACKGROUND

[0002] Common dark rooms are small, resulting in the mutual coupling phenomenon between the transmitted signals and echoes, which makes it difficult to realize effective echo acquisition and reception. The intermittent processing of signal transmission and reception can effectively solve this problem. As a commonly used pulse signal, the phase-coded signal has good agility and can improve the low-interception capability of the radar system. However, the intermittent transmission and reception of the phase-coded signal in the dark room will cause the complete phase-coded echo signal to be partially truncated, resulting in spectral aliasing and other problems, which brings a lot of inconvenience to the subsequent processing work. At present, there are mainly two methods for reconstructing the target echo of the phase-coded signal: the echo reconstruction method based on the matched filter transform base (Allen Xie, Xiaobin Liu, Feng Zhao, Xiaofeng Ai, Shunping Xiao. PCM signal intermittent transmission-reception echo reconstruction method in radiation simulation [J]. System Engineering and Electronics.) and the echo reconstruction method based on compressed sensing (Yuan Liu. Intermittent sampling transmission and reception processing and echo reconstruction method in radar radiation simulation [D]. Changsha: National University of Defense Technology, 2019.) However, both methods are relatively complex and require certain prior knowledge, so a simpler method is needed to reconstruct the echo of the phase-coded signal after intermittent transmission and reception processing. The application will study the echo reconstruction of the phase-coded signal based on the complementary sequence of the intermittent transmission-reception control signal. SUMMARY

[0003] The technical problem to be solved by the application is to design complementary transmission-reception control sequences, process the phase-coded signals intermittently, and then add the target echoes after intermittent transmission and reception processing to realize accurate reconstruction of the echoes of the phase-coded signals during target detection in the dark room.

[0004] The technical scheme adopted is as follows:

[0005] First, design the complementary sequence intermittent transmission-reception control signal.

[0006] Set K groups of complementary sequence intermittent transmission-reception control signals p k (t), each group of signals is a pulse train with a rectangular envelope, and the intermittent periods of each group of signals are the same, that is, T s , and the pulse width is τ sk, the K group of intermittent transmission control signals should satisfy the condition that the envelope is adjacent to each other and the pulse width is added to the complete intermittent cycle, that is In order to simplify the echo reconstruction method, the pulse width of the first K-1 group is set to a fixed value τ s0 , and the pulse width of the K group is τ s1 = T s mod τ s0 (where mod is the remainder symbol).

[0007] Secondly, the phase coded signal is processed by intermittent transmission.

[0008] The phase coded signal is processed by intermittent transmission, and if the original phase coded signal is s(t), after being processed by K groups of intermittent transmission control signals, the phase coded signal is truncated into K groups of sub-pulse trains, and the signal processed by the kth intermittent transmission is y k (t); the response process of the target can be regarded as the convolution of y k (t) and the impulse function h T (t), and the expression of the phase coded echo signal x k (t) processed by intermittent transmission is:

[0009] Thirdly, the phase coded echo reconstruction and information reconstruction.

[0010] The K groups of phase coded echo signals processed by intermittent transmission obtained in the second step are added to obtain the echo reconstruction of the phase coded signal. The reconstructed phase coded signal is processed by pulse compression to obtain the reconstructed target information.

[0011] , wherein the phase coded signal reconstruction echo is:

[0012]

[0013] The beneficial effects of the present application mainly include:

[0014] The phase coded signal is processed by intermittent transmission by using the characteristics of the intermittent transmission control signal, which is convenient and simple to operate, improves the reconstruction accuracy, and solves the echo information loss caused by intermittent transmission processing. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a phase coded signal echo reconstruction flow chart.

[0016] Figure 2 is a K group of complementary sequence intermittent transmission control signal waveform schematic diagram.

[0017] Fig. 3(a), (b), (c) is the phase coded signal echo processed by K groups of intermittent transmission control signals.

[0018] Figures 4(a), (b), and (c) show a comparison of the output of K groups of echoes and the complete echo after intermittent transmission and reception of the phase-coded signal, respectively, after matched filtering.

[0019] Figure 5 It is a comparison between the time domain of the phase-coded signal after intermittent echo reconstruction and the time domain of the complete echo.

[0020] Figure 6 This is a comparison between the matched filter output and the matched filter output of the complete echo after the intermittent echo reconstruction of the phase-coded signal.

Detailed Implementation Methods

[0021] The invention will be further described below with reference to the accompanying drawings. The steps of the method for echo reconstruction after intermittent transmission and reception processing of phase-coded signals are as follows:

[0022] The first step is to design the intermittent transmit and receive control signal for the complementary sequence.

[0023] like Figure 2 As shown, ideally, the waveform of a single intermittent transmit / receive control signal is a rectangular pulse train, which can be expressed as:

[0024]

[0025] Among them, T s For intermittent periods, τ s The width of the sub-pulse is given by , "*" indicates convolution operation, and rect(·) is a rectangle function with the expression:

[0026]

[0027] The expressions for K different intermittent transmit / receive control signals (K ≥ 2, K ∈ N) are as follows:

[0028]

[0029] Wherein, the pulse width satisfies

[0030]

[0031] To simplify the echo reconstruction method, the pulse width of the first K-1 groups can be set to τ. s0 =τ s Then the pulse width of the Kth group is:

[0032] τ s1 =T s modτ s0 (5)

[0033] Here, mod is the remainder operator.

[0034] Second step, phase coded signal intermittent receiving and transmitting processing.

[0035] Let the phase coded signal be s(t), the expression is:

[0036]

[0037] Where T p is the time width of the pulse signal, M is the number of symbols, τ is the width of a symbol, the total signal time length T p is Mτ, Take -1 or +1, is the modulation phase.

[0038] After the kth group of intermittent receiving and transmitting control signal processing, it is:

[0039] y k (t) = s(t)p k (t) (7)

[0040] The echo is y k (t) and the convolution of the impulse function h T (t) = Aδ(t-Δt), A is the amplitude modulation of the target to the echo, Δt = 2R / C, R is the distance from the target to the antenna, C is the speed of electromagnetic wave propagation, so the echo x k (t) is:

[0041]

[0042] The obtained phase coded echo is shown in Figures 3(a), (b), (c), in which τ s0 is the same, and the time delay of τ sk , 2τ sk , 3τ sk is respectively.

[0043] The phase coded echo obtained by intermittent receiving and transmitting processing is matched filtered, and compared with the complete echo, and the results are shown in Figures 4(a), (b), (c), which are respectively the results after the intermittent receiving and transmitting control signal processing in Figures 3(a), (b), (c) and then matched filtering processing.

[0044] Third step, phase coded echo reconstruction and information reconstruction.

[0045] Let the phase coded reconstructed echo be y(t), then the reconstructed echo is the sum of x k (t), that is:

[0046]

[0047] A comparison of the time domain of the reconstructed phase-coded signal with the time domain of the complete echo. Figure 5 As shown.

[0048] Comparison of the reconstructed signal after matched filtering with the output of the complete echo matched filter. Figure 6 As shown.

[0049] Depend on Figure 5 and Figure 6 As shown in the two figures, the target measurement results of the reconstructed echo and the complete echo are basically consistent. Therefore, by using different transmit and receive control signals to perform intermittent transmit and receive processing on the phase-coded signal, and by adding multiple sets of echoes, it is possible to accurately reconstruct the target echo and obtain a pulse compression result that is basically consistent with the complete pulse.

[0050] Example

[0051] Simulation Experiment of Echo Reconstruction Based on Phase-Coded Signal from Intermittent Transmit / Receive Signals

[0052] The radar signal parameters are set, and the complete phase-coded signal and the phase-coded signal after intermittent transmission and reception are simulated and compared.

[0053] Phase-encoded signal parameter settings:

[0054] Number of symbols: M = 511

[0055] Symbol width: τ = 0.1 μs

[0056] Carrier frequency: f0 = 2MHz

[0057] Intermittent transmit / receive control signal parameter settings:

[0058] Interval period: T s =0.3μs

[0059] Sub-pulse width: τ s =0.1μs

[0060] Set the number of groups: k = 3

[0061] Target parameter settings

[0062] Distance between antenna and target: R = 30m

[0063] Target: RCS = 1m 2

[0064] Antenna transmit / receive gain: G = 30dB

[0065] Transmit power: P = 1W

[0066] Receiver signal-to-noise ratio: SNR = 20dB

[0067] Steps:

[0068] (1) Design the complementary sequence intermittent transmission control signal:

[0069] According to the above parameters, the number of groups k = 3 can be set, and the width of each sub-pulse is τ s = 0.1 μs.

[0070] (2) Intermittent transmission processing of phase encoding signal:

[0071] According to the above parameters, the phase encoding signal is processed by intermittent transmission control, noise is added, and the echo signal is multiplied by 3 groups of intermittent transmission control signals respectively, and 3 groups of processed phase encoding signals are obtained by matching filtering processing.

[0072] (3) Phase encoding echo reconstruction and information reconstruction:

[0073] Add the obtained 3 groups of phase encoding signals to obtain the reconstructed phase encoding signal.

Claims

1. A complementary sequence phase-coded signal intermittent transmission-reception echo reconstruction method, characterized by: The method steps are as follows: First step, complementary sequence intermittent transmission control signal design; Setting intermittent transmission control signal p of K groups of complementary sequences k (t), each group of signals is a pulse train with a rectangular envelope, and the intermittent periods of each group of signals are the same T s , the pulse width is τ sk , and it is required that the K groups of intermittent transmission control signals satisfy that the envelopes are adjacent to each other and the pulse widths are added to be a complete intermittent period, that is wherein k=1, 2, …, K; Second step, phase encoding signal intermittent transmission processing; The phase encoding signal is intermittently transmitted and received. If the original phase encoding signal is s(t), the phase encoding signal is truncated into K groups of sub-pulse trains after being processed by K groups of intermittent transmission and reception control signals. The signal of the kth intermittent transmission and reception processing is y k (t); the response process of the target is considered as the convolution of y k (t) and the impulse function h T (t). The expression of the phase encoding echo signal x k (t) after the intermittent transmission and reception processing is: Third step, phase encoding echo reconstruction and information reconstruction; K groups of phase encoding echo signals obtained in the second step are added to obtain the echo reconstruction of the phase encoding signal; the reconstructed phase encoding signal is subjected to pulse compression processing to obtain the reconstructed target information.

2. The complementary sequence phase-encoded signal intermittent transmission-reception echo reconstruction method according to claim 1, characterized in that: The first step, in order to simplify the echo reconstruction method, set the first K-1 group pulse width is a fixed value τ s0 Then the pulse width of the Kth group is τ s1 = T s mod τ s0 Where mod is the remainder symbol.

3. The complementary sequence phase-encoded signal intermittent transmission-reception echo reconstruction method according to claim 1, characterized in that: The third step is the reconstruction echo of the phase encoding signal, which is:

Images