阅读说明：本技术 一种非固定频率脉冲信号低成本高精度测向方法 (Low-cost high-precision direction-finding method for non-fixed-frequency pulse signal ) 是由 王智显 黄光明 龚军涛 刘兰 陈晨 张爱洲 高峰 缪方雷 白华 于 2020-11-05 设计创作，主要内容包括：本发明公开了一种非固定频率脉冲信号低成本高精度测向方法,包括以下步骤：S1、根据辐射源脉冲信号的波长和测向的方位角度计算基线长度的下限；S2、计算双通道接收机中两个通道信号的无模糊相位差,并根据无模糊相位差计算基线长度的上限；S3、基于基线长度、信号不同时段的频率测量值与相位差测量值,计算目标的方位角。本发明测向精度高、系统性能好；设备简单、轻便,便于小型化和系统集成；研制费用低、工程可实现性强。(The invention discloses a low-cost high-precision direction-finding method for a non-fixed frequency pulse signal, which comprises the following steps of: s1, calculating the lower limit of the length of the baseline according to the wavelength of the radiation source pulse signal and the azimuth angle of direction finding; s2, calculating the non-fuzzy phase difference of two channel signals in the dual-channel receiver, and calculating the upper limit of the length of the baseline according to the non-fuzzy phase difference; and S3, calculating the azimuth angle of the target based on the length of the base line, the frequency measurement value and the phase difference measurement value of the signal in different periods. The invention has high direction finding precision and good system performance; the equipment is simple and portable, and is convenient for miniaturization and system integration; low development cost and strong engineering realizability.)

1. A low-cost high-precision direction-finding method for pulse signals with non-fixed frequencies is characterized by comprising the following steps:

s1, calculating the lower limit of the length of the baseline according to the wavelength of the radiation source pulse signal and the azimuth angle of direction finding;

s2, calculating the non-fuzzy phase difference of two channel signals in the dual-channel receiver, and calculating the upper limit of the length of the baseline according to the non-fuzzy phase difference;

and S3, calculating the azimuth angle of the target based on the length of the base line, the frequency measurement value and the phase difference measurement value of the signal in different periods.

2. The method for low-cost high-precision direction finding of non-fixed frequency pulse signals according to claim 1, wherein the calculation formula of the lower limit of the length of the base line in the step S1 is as follows:

in the above formula, D is the base length, λ_maxIs the wavelength maximum, σ, of the radiation source pulse signal_ΦIn order to measure the accuracy of the phase difference of the system,for direction finding accuracy, θ_minIs the minimum value of the azimuth angle of the direction finding.

3. The method according to claim 2, wherein the calculation formula of the unambiguous phase difference in step S2 is as follows:

in the above formula, Φ is the unambiguous phase difference between the two channel signals, and c is the propagation velocity of the electromagnetic wave.

4. The method for low-cost high-precision direction finding of non-fixed frequency pulse signals according to claim 3, wherein the calculation formula of the upper limit of the length of the base line in the step S2 is as follows:

in the above formula, f_maxFor maximum frequency of different pulses of the signal, θ_maxIs the maximum azimuth angle of direction finding, lambda_minIs the wavelength minimum of the radiation source pulse signal.

5. The method according to claim 4, wherein the calculation formula of the azimuth angle of the target in step S3 is:

in the above formula, θ is the azimuth angle of the target, f (i) and f (j) are the signal frequencies of the i-th time period and the j-th time period respectively, Φ_Measuring(i) And phi_Measuring(j) The phase differences are respectively f (i) and f (j).

6. A low-cost high-precision direction-finding method for pulse signals with non-fixed frequency according to claim 5, characterized in that the corresponding phase differences Φ (i) and f (j)_Measuring(i) And phi_Measuring(j) The calculation formula of (2) is as follows:

Φ_measuring(j)-Φ_Measuring(i)＝Φ(j)-Φ(i)-[K(j)-K(i)]×2π

In the above formula, Φ (i) and Φ (j) are blur-free phase differences corresponding to f (i) and f (j), respectively, and k (i) and k (j) are blur numbers corresponding to f (i) and f (j), respectively.

Technical Field

The invention relates to the technical field of electronic information direction finding, in particular to a low-cost high-precision direction finding method for a non-fixed frequency pulse signal.

Background

To realize the measurement of the arrival angle of the non-matched pulse signal, there are three general ways of amplitude-specific direction finding, lens multi-beam and interferometer direction finding, and the advantages and disadvantages are shown in table 1. As can be seen from table 1, in order to achieve high-precision direction finding, a multi-baseline interferometer direction finding technology is generally adopted.

TABLE 1 comparison of advantages and disadvantages of commonly used direction finding techniques

In a certain observation area, in order to meet the requirement of high-precision direction finding of a radiation source pulse signal, the length of a base line of an interferometer is generally required to be increased as much as possible, but phase ambiguity is caused. In order to know the phase ambiguity, one method is to roughly measure the direction by comparing the amplitude, but the cost of a direction-finding system is higher, and for a high-precision direction-finding system, the phase ambiguity of a long base line cannot be smoothly removed by simply measuring the direction by comparing the amplitude; another method is to perform interferometer direction finding by multi-baseline successive ambiguity resolution, but this requires a plurality of receiving systems, and the complexity and cost of the equipment are also high.

Disclosure of Invention

Aiming at the defects in the prior art, the low-cost high-precision direction finding method for the pulse signals with the non-fixed frequency solves the problems of low precision, complexity and high cost of the existing direction finding method.

In order to achieve the purpose of the invention, the invention adopts the technical scheme that: a low-cost high-precision direction-finding method for a non-fixed frequency pulse signal comprises the following steps:

s1, calculating the lower limit of the length of the baseline according to the wavelength of the radiation source pulse signal and the azimuth angle of direction finding;

s2, calculating the non-fuzzy phase difference of two channel signals in the dual-channel receiver, and calculating the upper limit of the length of the baseline according to the non-fuzzy phase difference;

and S3, calculating the azimuth angle of the target based on the length of the base line, the frequency measurement value and the phase difference measurement value of the signal in different periods.

Further: the calculation formula of the lower limit of the base length in step S1 is:

in the above formula, D is the base length, λ_maxIs the wavelength maximum, σ, of the radiation source pulse signal_ΦIn order to measure the accuracy of the phase difference of the system,for direction finding accuracy, θ_minIs the minimum value of the azimuth angle of the direction finding.

Further: the calculation formula of the unambiguous phase difference in step S2 is:

in the above formula, Φ is the unambiguous phase difference between the two channel signals, and c is the propagation velocity of the electromagnetic wave.

Further: the calculation formula of the upper limit of the base length in step S2 is:

in the above formula, f_maxFor maximum frequency of different pulses of the signal, θ_maxIs the maximum azimuth angle of direction finding, lambda_minIs the wavelength minimum of the radiation source pulse signal.

Further: the calculation formula of the azimuth of the target in the step S3 is:

in the above formula, θ is the azimuth angle of the target, f (i) and f (j) are the signal frequencies of the i-th time period and the j-th time period respectively, Φ_Measuring(i) And phi_Measuring(j) The phase differences are respectively f (i) and f (j).

Further: the phase difference phi of f (i) and f (j)_Measuring(i) And phi_Measuring(j) The calculation formula of (2) is as follows:

Φ_measuring(j)-Φ_Measuring(i)＝Φ(j)-Φ(i)-[K(j)-K(i)]×2π

In the above formula, Φ (i) and Φ (j) are blur-free phase differences corresponding to f (i) and f (j), respectively, and k (i) and k (j) are blur numbers corresponding to f (i) and f (j), respectively.

The invention has the beneficial effects that:

1) the invention has high direction finding precision and good system performance: compared with the traditional multi-channel amplitude comparison direction finding and dielectric lens multi-beam direction finding system, the direction finding precision is high; compared with a multi-baseline interferometer direction-finding system, the method provided by the invention has the advantages of simple system, more stable performance and stronger robustness on the premise of ensuring high direction-finding precision.

2) The invention has simple and portable equipment, is convenient for miniaturization and system integration: because the invention only adopts 2 channels to realize the high-precision direction finding of the system, compared with the direction finding method of the multi-baseline interferometer, the device is simpler and lighter, and is very beneficial to miniaturization and system integration.

3) The invention has low development cost and strong engineering realizability: because the high-precision direction finding only adopts two channels, the development cost of the system is lower, and the engineering realizability is stronger. For example, for an interferometer with the direction finding accuracy of 1 degree in the X-band, 6 receiving channels may be needed originally, and now only 2 receiving channels are needed, so that the cost is changed to 1/3 originally.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a flow chart of an embodiment.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

As shown in fig. 1, a low-cost high-precision direction-finding method for a non-fixed-frequency pulse signal includes the following steps:

s1, the wavelength range of the pulse signal according to the radiation source is (lambda)_min,λ_max) The azimuth angle range of direction finding is (theta)_min,θ_max) Calculating the lower limit of the length of the base line; the lower limit of the base length is calculated by the formula:

in the above formula, D is the base length, λ_maxIs the wavelength maximum, σ, of the radiation source pulse signal_ΦIn order to measure the accuracy of the phase difference of the system,for direction finding accuracy, θ_minIs the minimum value of the azimuth angle of the direction finding.

S2, calculating the non-fuzzy phase difference of two channel signals in the dual-channel receiver, and calculating the upper limit of the length of the baseline according to the non-fuzzy phase difference;

the formula for calculating the unambiguous phase difference is as follows:

in the above formula, Φ is the unambiguous phase difference between the two channel signals, and c is the propagation velocity of the electromagnetic wave.

If the minimum and maximum frequencies of the different pulses of the measured signal are respectively f_minMHz、f_maxMHz, the variation range of the phase difference represented by the above formula is:

then to ensure that the difference between the phase differences of any two direction-finding pulses is not ambiguous, it can be derived from the above equation

The upper limit of the base length is calculated from the above equation:

in the above formula, f_maxFor maximum frequency of different pulses of the signal, θ_maxIs the maximum azimuth angle of direction finding, lambda_minIs the wavelength minimum of the radiation source pulse signal.

And S3, calculating the azimuth angle of the target based on the length of the base line, the frequency measurement value and the phase difference measurement value of the signal in different periods.

Measuring the signal frequencies f (i), f (j) and the corresponding phase difference phi of the ith and the jth periods by a frequency domain correlation method due to the different frequencies of the frequency non-fixed pulse signals in different periods_Measuring(i)、Φ_Measuring(j) The corresponding fuzzy numbers are K (i) and K (j), and the phase differences without fuzzy are phi (i) and phi (j), respectively

Φ_Measuring(j)-Φ_Measuring(i)＝Φ(j)-Φ(i)-[K(j)-K(i)]×2π (6)

By substituting formula (2) for formula (6)

Since D satisfies formula (5), k (j) is k (i). Is obtainable from the formula (7)

When f (j) -f (i) ≠ 0, it can be obtained from the formula (8)

In the above equation, θ is the azimuth of the target.

In one embodiment of the invention, for a pulse radiation source target signal, frequency conversion receiving and frequency domain correlation processing is carried out through a dual-channel receiver, and frequency and phase difference measurement values of the pulse radiation source signal are obtained, as shown in fig. 2. And finally, acquiring the azimuth angle of the radiation source signal through angle calculation processing.

For a typical L-band non-fixed frequency signal, a two-channel high-precision direction finding scheme is shown in fig. 2. For radiation signals with an airspace of between minus 45 degrees and theta and between 45 degrees, the double-channel direction-finding precision is 0.5 degree when the base length is 1.5 meters.