CN112162234B - Wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment - Google Patents
Wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
- G01S3/46—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
- G01S3/48—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention discloses a wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment, which is characterized by comprising the following steps: step 1, building eight-port four-baseline radio frequency equipment; step 2, determining a baseline interval and an interval factor according to the angle range and the wavelength of the radiation source; step 3, determining the number of steps where the radiation source is located; step 4, restoring the actual phase value; and 5, calculating the angle of the radiation source. The wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency equipment is simple and convenient, has wider angle measurement range and higher precision under the condition of the same cost or volume or the number of antenna units, and can be used for engineering practice.
Description
Technical Field
The invention belongs to the technical field of radar radiation source direction finding methods, and particularly relates to a wide-angle high-precision angle finding method based on eight-port four-baseline radio frequency equipment.
Background
The radar radiation source direction finding technology can demodulate the azimuth of electromagnetic waves by utilizing the principle of different amplitude or phase responses generated by the electromagnetic waves in different directions reaching a direction finding antenna system. Depending on different factors, it can be divided into an amplitude method and a phase method. The phase method angle measurement utilizes the wave path difference of the electromagnetic wave signal of the target radiation reaching the antenna base line to measure the angle, namely, the direction of the signal is determined according to the relative phase difference of the same signal detected by the direction finding antenna system, and then the angle error signal is demodulated through the phase difference, so that the antenna is driven to track the radiation source passively. The relative phase difference is derived from the ratio of the relative wave path difference to the wavelength, and the principle is simpler. However, the phase method has a great disadvantage in angle measurement, when the base line width between two antennas is too large, the measurement is blurred, and when the base line width is too small, the problem of large measurement error is generated. The novel wide angle and high-precision angle measuring method researched by the technical scheme is based on phase method direction finding, a set of simple and feasible novel angle measuring method is researched, and the problem of measurement ambiguity existing in the traditional phase method angle measuring is solved.
1. Principle of double base line angle measurement
Currently, angle measurement equipment based on phase method direction measurement is mainly an interferometer, and utilizes the principle of dual-baseline phase method angle measurement, namely angle measurement is performed by utilizing phase differences among echo signals received by a plurality of antennas. As shown in fig. 1, when an object radiates an electromagnetic wave signal in the θ direction, the electric wave reflected by the object reaching the receiving point is approximately a plane wave. Since the base line interval between the two antennas is d, the received signals reach the difference DeltaR of the base lines to generate phase differenceThe relationship between phase difference and baseline interval is:
where λ is the wavelength of the electromagnetic wave signal radiated by the object. The phase difference resulting from the wave path difference can be measured by a phase meter. Therefore, the angle θ of the electromagnetic wave signal of the target radiation can be derived from the formula (1)
Knowing the wavelength of the electromagnetic wave signal of the target radiation, the azimuth of the target signal can be calculated from the equation (2) by using the phase difference measured by the phase.
2. Problem of angle measurement ambiguity and precision
The simple dual baseline phase method direction finding actually has a great problem, namely the measurement ambiguity problem.
As can be seen from equation (2), if the phase differenceInaccurate measurement of the value may result in angular errors. To study the relevant factors affecting the angular accuracy, the two sides of the formula (1) are differentiated, and the method comprises
As can be seen from the step (3), the reading accuracy is highSmall), or a reduction in the lambda/d value, can improve angular accuracy. In addition, when θ=0, that is, when the target is in the antenna normal direction, the angle measurement error dθ is minimum, and when θ increases, dθ also increases, so that there is also a certain limit to the range of θ in order to secure a certain angle measurement accuracy. Although the reduction of the lambda/d value can also improve the angle measurement accuracy, in a certain angle measurement range theta, when the lambda/d value is reduced to a certain degree, the lambda/d value is reduced to a certain degree>The value may exceed 2 pi, at which timeWhere N is an integer, ψ < 2π, the actual reading of the phaser is ψ. Since the value of N is unknown, true +.>If the value is not determined, a blurring problem (multi-value) occurs.
3. Current methods of solving the ambiguity problem
In order to avoid the measurement ambiguity, only the range of the measured angle can be reduced, but when the measurement range is reduced, the measurement accuracy is correspondingly reduced, that is, the problem that the measurement accuracy contradicts the measurement range exists. The key to solve the contradiction is to solve the blurring problem, so how to deblur becomes a hot spot to be considered when the phase method is applied to direction finding, and many methods for solving the blurring problem are researched and developed.
1. Robust baseline solution blurring
In order to solve the problem of direction finding ambiguity in the direction finding by a phase method, a staggered baseline interferometer direction finding method for solving the ambiguity problem by utilizing the Chinese remainder theorem is provided by imitating a multi-frequency continuous wave distance finding technology, the remainder theorem is applied to interferometer direction finding, and a basic angle finding schematic diagram of the method for solving the ambiguity is shown in figure 2.
An M-dimensional baseline interferometer with baseline lengths of l respectively i (i=1, 2,., M-1), a base baseline l is taken 0 ≤λ min 2, all baselines are l 0 Integer multiple of (1) has
l 1 :l 2 :…:l M-1 ＝m 1 :m 2 :…:m M-1 (4)
Wherein m is i (i=1, 3,., M-1) is an integer
The interferometer measures a baseline interval of l i At the time, the corresponding phase difference isWhile the actual phase difference is 2 pi l i sin theta/lambda, the relation between the two is
Wherein k is i Indicating a baseline interval of l i Direction finding ambiguity number at that time.
Equation (5) is a system of equations with the same homonym as the remainder in the real number domain with divisor as an integer, if the choice is from pairwise interpoly, it can be known from the Chinese remainder theorem thatThe determined maximum unambiguous direction finding range has a unique set of solutions k i . However, the method is easy to cause disambiguation failure due to phase errors caused by antenna units, microwave channels, receivers and the like, and has large calculated amount.
2. Virtual baseline defuzzification
By virtual baseline is meant the difference in length between two different baselines. When the length difference is smaller than the half wavelength of the highest frequency of the broadband signal, the phase difference of the virtual base line is the phase without ambiguity. The schematic diagram is shown in FIG. 3, the base line1. Baseline spacing of 2 from baseline 2, 3 is l, respectively 1 ，l 2 (l 2 ＞l 1 ) Subtraction of two different baseline intervals gives a spacing of l 2 -l 1 Virtual short baseline of (2), baseline interval of virtual short baseline and corresponding phase differenceThe relation of (2) is that
However, the virtual baseline method can cause deblurring errors and even can not deblur due to the influence of systematic errors and random errors in wide angle direction finding.
3. Long and short base line defuzzification
The long and short baseline method is also called a three-baseline angle measurement method, which is to use three baselines with proper two different baseline intervals to regulate, one baseline is long and the other baseline is short. The schematic diagram is shown in fig. 4, 1 and 3 antennas with large intervals are used for obtaining high-precision measurement, and 1 and 2 antennas with small intervals are used for solving the measurement multiple-value property. Let the object radiate electromagnetic wave signal with direction theta outwards and the distance between the antennas 1,2 be d 12 The distance between the antennas 1,3 is d 13 . Properly select d 12 The phase difference between the signals received by the antennas 1 and 2 is satisfied in the angle measurement range
Read by the phase meter 1.
According to the requirement, a larger d is selected 13 The phase difference of the signals received by the antennas 1,3 is
In this case, the phase meter 2 reads psi less than 2pi, and the following relationship is used to determine the value of N
When the error of the phase meter 1 is within an acceptable range, based on the readings of the phase meter 1And (10) can be calculatedAnd then according to the formula (9), the value of N and the value of theta can be determined. d, d 13 The lambda value is large, ensuring the required accuracy.
Although the method for measuring angles of long and short baselines can solve the problem of direction finding ambiguity by using a short baseline and solve the problem of direction finding range by using a long baseline, in broadband direction finding, when a target signal is a high-frequency signal, the method has high requirements on the short baseline, and often cannot be widely applied due to engineering limitation of physical realization of the short baseline.
Disclosure of Invention
The invention aims to provide a wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment, which solves the problem that the existing angle measurement method cannot realize high measurement precision and wide measurement range at the same time.
The technical scheme adopted by the invention is as follows: a wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment comprises the following steps:
step 1, building eight-port four-baseline radio frequency equipment;
step 2, determining a baseline interval and an interval factor according to the angle range and the wavelength of the radiation source;
step 3, determining the number of steps where the radiation source is located;
step 4, restoring the actual phase value;
and 5, calculating the angle of the radiation source.
The beneficial effects of the invention are as follows: the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency equipment is simple and convenient, has wider angle measurement range (can measure all angles) and higher precision under the condition of the same cost or volume or the number of antenna units, and can be used for engineering practice.
Drawings
FIG. 1 is a schematic diagram of a dual baseline goniometer;
FIG. 2 is a schematic diagram of a spread baseline solution ambiguity;
FIG. 3 is a schematic diagram of a virtual baseline defuzzification;
FIG. 4 is a schematic diagram of a long and short baseline defuzzification;
FIG. 5 is a schematic diagram of a wide angle high precision angle measurement method based on an eight port four baseline radio frequency device of the present invention;
FIG. 6 is a schematic diagram of input and output parameters of a wide angle high precision angle measurement method based on an eight-port four-baseline radio frequency device of the present invention;
fig. 7 is a contrast chart of a fuzzy phase value and an actual phase difference of a wave path difference measured by a wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment, wherein k=1.3, and the incident angle is (-80 degrees, 80 degrees);
fig. 8 is a graph comparing an angle value measured by a wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment of the invention with an incident angle of (-80 degrees, 80 degrees) with an actual incident angle, wherein k=1.3;
fig. 9 is a step chart obtained by subtracting angle values at two base line intervals measured by a wide-angle high-precision angle measurement method based on eight-port four-base line radio frequency equipment in the invention, wherein the incident angle is (-80 degrees, 80 degrees) with k=1.3;
fig. 10 is a graph comparing a phase curve restored by a step method with an actual phase curve by using the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the invention with k=1.3 and an incident angle of (-80 degrees, 80 degrees);
fig. 11 is a graph of phase values measured by a phase curve restored by a step method compared with actual phase values by using the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the invention, wherein k=1.3, and the incident angle is (-80 degrees, 80 degrees);
fig. 12 is a graph of the angle value measured by the phase curve restored by the step method compared with the actual angle value by using the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the invention, wherein the incident angle is (-90 degrees, 90 degrees) with k=1.3;
fig. 13 shows that k=1.4, the wave path difference measured by the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device is d, and the incident angle is (-90 degrees, 90 degrees) 1 Fuzzy phase value=18 mm;
fig. 14 shows that k=1.4, the wave path difference measured by the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the invention is d when the incident angle is (-90 degrees, 90 degrees) 2 Fuzzy phase value=84 mm;
fig. 15 shows that k=1.4, the wave path difference measured by the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the invention is d when the incident angle is (-90 degrees, 90 degrees) 1 A blur angle value of =18 mm;
fig. 16 shows that k=1.4, the wave path difference measured by the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the invention is d when the incident angle is (-90 degrees, 90 degrees) 2 A blur angle value of =84 mm;
fig. 17 is a step diagram of a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device of the invention with an incident angle of (-90 deg., 90 deg.) in k=1.4;
fig. 18 shows a phase value measured by a phase curve restored by a step method according to the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the present invention, wherein k=1.4, and the incident angle is (-80 °,80 °);
fig. 19 is a diagram showing the angle value measured by the phase curve restored by the step method by using the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the present invention with k=1.4 and the incident angle being (-80 °,80 °);
fig. 20 is a step diagram of a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device of the invention with k=3.6 and an incident angle of (-90 °,90 °;
fig. 21 is a diagram of k=3.6, and the incident angle is (-90 °,90 °) in the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device according to the present invention, using a phase value measured by a phase curve restored by a step method;
fig. 22 is a graph of k=3.6, and the incident angle is (-90 °,90 °) in the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device according to the present invention, using the angle value measured by the phase curve restored by the step method;
fig. 23 is a step diagram of a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device of the present invention with k=5.3 and an incident angle of (-90 °,90 °;
fig. 24 is a diagram showing the angle value measured by a phase curve restored by a step method according to the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the present invention, wherein k=5.3, and the incident angle is (-90 °,90 °);
fig. 25 shows an angle value measured by a phase curve restored by a step method according to the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the present invention, wherein k=5.3, and the incident angle is (-90 °,90 °);
fig. 26 is a step diagram of a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device of the present invention with k=2 and an incident angle of (-90 °,90 °).
Detailed Description
The invention will be described in detail with reference to the accompanying drawings and detailed description.
The invention provides a wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment, which comprises the steps of firstly building the eight-port four-baseline radio frequency equipment, namely providing the radio frequency equipment, wherein two ports are arranged in each direction around the radio frequency equipment, baselines are arranged on the four ports of the radio frequency equipment in the opposite directions, and a Schottky diode detector is respectively connected with the other four ports of the radio frequency equipment, and the method comprises the following steps:
first, determining baseline interval and interval factor according to angle range and wavelength of radiation source
First, the principle of the method is shown in FIG. 5, d 1 For the interval between baselines 5, 7, d 2 For the interval between the base lines 6, 8, the ports 1,2, 3, 4 are respectively connected with the sameThe radiation source angle can be calculated through the reading of the detectors.
Assume an angle θ of an electromagnetic wave signal of target radiation 0 Within (-80 °,80 °), the wavelength λ=12.5 mm of the signal, the frequency being 24GHz. Unlike prior methods, the method of the present invention requires only a ratio of two baseline intervals, k=d 2 /d 1 1 (hereinafter referred to as spacing factor) is certain, so d is selected for convenient engineering implementation 1 =18 mm, on the other hand, the spacing factor can be arbitrarily chosen (principle will be analysed in the second part) except for some special values, whereD is then 2 ＝60mm。
Eight-port angle measurement principle:
as is known from fig. 5, the phase differences of the signals received by the four receiving antennas can be expressed as The eight-port network proposed by Zhang Xuchun is composed of 4 180-degree directional couplers (namely annular bridge) and 1 90-degree item shifter, and the concept of incident wave and reflected wave in S parameters of a microwave network is utilized, and an eight-port schematic diagram is drawn independently as shown in FIG. 6, and phi is further caused 1 ＝d 1 2π sin θ/λ、φ 2 ＝d 2 2 pi sin theta/lambda
According to the S parameter characteristics of the eight-port network
Combined with (11) and (12)
Taking squares of the modulus values on both sides of each equation in the equation (13), the ratio of the reflected voltage on the left side of the equation to the incident voltage becomes the ratio of the reflected power on each port to the incident power, and the result after conversion is simplified as follows:
and due to P i /P k ＝|S ik | 2 Can be obtained by combining (14)
φ 1 、φ 2 The phase difference measured by the two baseline intervals respectively shows that the eight ports can measure the phase difference of the two baseline intervals, but the two phase differences have the fuzzy problem as the prior method, so the step concept is proposed.
Step two, determining the number of steps where the radiation source is located
Two baseline intervals d can be measured using an eight port device 1 、d 2 Is a fuzzy phase difference phi with fuzzy value 1 And phi 2 . The step principle proposed by the method of the invention shows that when the incident angle theta 0 Within (-80, 80) range, at different theta 0 Within the value interval of θ' =arc sin (Φ 2 λ/2πd 2 )-arc sin(φ 1 λ/2πd 1 ) There are only 13 fixed values, 20, 8, -4, -16, 24, 12, 0, -12, -24, 16, 4, -8, -20, numbered 1 to 13 in left to right order, respectively. The second step is to determine the step number where θ' is located based on the actual measured value.
The step principle:
first, when the radiation source reaches the receiving device, it is separated by a distance d between two baselines 1 And d 2 In the following, the actual phase difference and the fuzzy phase value of the wave path difference measured by the eight-port device are shown in fig. 7. At this time, it can be seen that both baseline intervals have a phase ambiguity problem, and that the ambiguity-free phase intervals of different baseline intervals are different.
Then according to equation (2), the measured fuzzy phase value is resolved into an angle value, and the relationship between the angle value and the actual incident angle is shown in fig. 8.
When the angle values measured at these two base line intervals are subtracted, i.e., θ' =arc sin (Φ) 2 λ/2πd 2 )-arc sin(φ 1 λ/2πd 1 )，φ 3 ＝φ 2 -φ 1 A step map with multiple steps as shown in fig. 9 is obtained, and the values of each step are different, i.e. the correspondence between the measured angle difference value at two different base line intervals and the true angle value of the callback signal is the step shape. However, each step is not perfectly flat, and there is a small deviation, that is, the angle difference value after the actual subtraction is not a constant over the corresponding part interval, but the number of steps is substantially equal, so that the steps are more obvious in step effect and easier to determine, and we allow the angle difference values to fluctuate within a range of + -1, thus obtaining 13 steps with heights of 20, 8, -4, -16, 24, 12, 0, -12, -24, 16, 4, -8, -20 respectively, numbered 1 to 13 in the order from left to right.
The second step of the method of the invention is to determine the step number based on the actual measured value. Wide angle measurement (-80 deg., 80 deg.) and even omnidirectional measurement (-90 deg., 90 deg.) can be realized by different values of the steps, and since wide base line d can be adopted 2 Test results of 60mm, the advantage of high accuracy is guaranteed.
Third, the actual phase value is restored
Because each step corresponds to an angle interval, the step value can be restored to the actual phase value by adopting a certain restoration criterion. For this purpose, a reduction criterion is established:
let L be the number of steps, XFor the position number of the steps, the interval factor t=1 or 2 or 3 or 4 is manual adjustment of 360-degree interval according to the specific condition of angle measurement, and the phase difference measured under any baseline is selectedIndicating the nth baseline with the actual phase value +.>The method comprises the following steps:
simulation verification is performed according to the above-described restoration procedure, and in this example, when t=2, the blurred phase value can be restored to an actual phase value.
Using equation (16), the actual phase of the reduction can be derived
Fourth, calculating the angle of the radiation source
When the actual phase value is obtained, then according to(N is an integer) the actual incident angle theta can be easily calculated 0 。
By means of the mode, the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency equipment is simple and convenient, the angle measurement range is wider (all angles can be measured) under the condition of the same cost or volume or the number of antenna units, and the precision is higher.
1. Evidence of high accuracy advantage
The recovered fuzzy phase value is compared with the actual phase value, the recovery degree is observed, and the simulation result is shown in fig. 10. It can be seen that the phase curve after the reduction completely coincides with the actual phase curve, which means that the phase after the reduction according to this method is completely equal to the actual phase.
From the actual phase value after the restoration, it can be calculated according to equation (2)The angle of incidence is calculated, and the relationship between the calculated angle and the actual angle of incidence is shown in fig. 11. As can be seen from the observation simulation results, the angle value measured by the method is completely equal to the actual real angle value, which shows that the wide angle measurement (-80 degrees, 80 degrees) can be realized by different values of the steps, and the wide baseline d can be adopted 2 Test results of 60mm, the advantage of high accuracy is guaranteed.
2. Evidence of wide angle advantage
The above discussion is of the measurement of the angle of incidence in the (-80 °,80 °) interval, but it has not been demonstrated that this method can measure the angle of incidence in the (-90 °, -80 °) and (80 °,90 °) intervals. The maximum angular range of the method of the invention is next studied.
Therefore, the incident angle is only required to be expanded to (-90 degrees, 90 degrees), then the angle measurement principle is simulated, the incident angle in the interval (-90 degrees, 90 degrees) can be measured under the feasible interval factor k, namely the method can measure targets at all angles in the space, and the simulation result is shown in figure 12.
In conclusion, the method can be realized in physical practice, and the incident angle in a wide angle range can be measured with high precision.
Examples
This section illustrates the selection range of interval factors k and interval factors t.
The above is given in terms of spacing factorUnder the condition of simulation, the interval factors are assigned one by one, and the angle measurement principle under different interval factors is simulated one by one.
1. Let d when k=1.4 1 ＝18mm，d 2 ＝84mm
The fuzzy phase measured at the two baselines is derived from equation (1) as shown in fig. 13 and 14. The fuzzy phase is calculated by the equation (2), and the angle value with the fuzzy which is tested at this time is obtained as shown in fig. 15 and 16.
The two angle values were subtracted to obtain a step, and the step was as shown in fig. 17. The number of steps at this time is 10, -15, 25, 0, -25, 15, -10, respectively. To restore the actual phase, take t=1, and the restoration result is shown in fig. 18. The observation result shows that the two curves of the restored phase and the actual phase completely coincide, which indicates that the restored phase is completely equal to the actual phase and the fuzzy phase is successfully restored.
Since the phase has been restored to the actual phase, the calculated angle value is also exactly equal to the actual incident angle value, and the calculation result is shown in fig. 19.
Therefore, the method of the present invention is effective when the spacing factor k=1.4.
2. Let d when k=3.6 1 ＝18mm，d 2 ＝84mm
According to the method, the step diagram is shown in fig. 20, 15 steps are obtained at the moment, namely 16, 4, -7, -18, 23, 22, 11, 0, -11, -22, -23, 18, 7, -4 and 16, and t=2 are taken, so that the two curves of the actual phase and the actual phase pair which are restored are completely matched, and the fact that the restored phase is completely equal to the actual phase is proved. The angle value calculated from the reduction phase is also exactly equal to the actual incident angle value, and the result is shown in fig. 22. Illustrating k=3.6, the method of the present invention works.
3. Let d when k=5.3 1 ＝18mm，d 2 ＝84mm
Still according to the above method, a step diagram as shown in FIG. 23 was obtained, for a total of 21 steps, 21, 13, 5, -2, -10, -17, -18, 23, 15, 8, 0, -8, -15, -23, -18, 17, 10, 2, -5, -13, -21, respectively. Taking t=3, the comparison of the reduction phase and the angle value calculated from the reduction phase with the actual value is shown in fig. 24 and 25, the curve matches the actual, indicating that the method of the present invention is also effective when k=5.3.
4. Summary
And then taking other values of k, and carrying out simulation one by one according to the process, wherein simulation results are not listed one by one.
It was found that when k=2, the step pattern is shown in fig. 26, the heights of the steps are 20, 0, -20, and the same steps exist, and the method condition of the present invention cannot be satisfied.
The value range of k is determined to be (1.0, 5.0), and k is scanned at intervals of 0.1, and the following conclusion is obtained through multiple simulation.
When k epsilon (1.0, 5.0), the angle measurement can be performed by the method of the invention under other interval factors except k= 1.5,2.0,2.5,3.0,3.5,4.0,4.9,5.08 values.
Further by way of generalization, the interval factor t=1 when k e (1.1,2.9) and the interval factor t=2 when k e (3.0,5.0) are shown in table 1.
TABLE 1
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Claims (5)
1. The wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency equipment is characterized by comprising the following steps of:
step 1, building eight-port four-baseline radio frequency equipment;
step 2, determining a ratio of a baseline interval to two baseline intervals, namely an interval factor, according to the angle range and the wavelength of the radiation source;
step 3, determining the number of steps where the radiation source is located; the method comprises the following steps:
step 3.1, calculating two baseline intervals d of the radiation source in the estimated range by using the measurement principle shown in the formula (15) 1 、d 2 Is of the fuzzy phase difference phi 1 And phi 2 ：
In the formula (15), S i6 ＝P i /P 6 ，i＝1,2,3,4；P i The power of the signal output by the Schottky diode detector connected with the ith port of the radio frequency equipment is P 6 The magnitude of signal power received for a baseline connected with a No. 6 port of the radio frequency equipment;
step 3.2, according to the fuzzy phase difference phi 1 And phi 2 And (2) calculating a corresponding fuzzy angle value;
in the formula (2), lambda is the wavelength of the electromagnetic wave signal of the target radiation;
step 3.3, subtracting the two fuzzy angle values calculated in the step 3.2 to obtain a step diagram, wherein the total number of steps is L, and the steps are numbered according to the relation from small to large of the corresponding radiation source angles and are 1,2, … and L;
step 3.4, measuring a corresponding fuzzy phase difference phi of the actual radiation source under the interval of two baselines by adopting eight-port four-baseline radio frequency equipment 1 And phi 2 ；
Step 3.5, calculating the corresponding actual fuzzy angle value under the interval of two baselines by using the fuzzy phase difference and the formula (2) in the step 3.4;
step 3.6, subtracting the two actual fuzzy angle values in the step 3.5 to obtain an actual step value;
step 3.7, determining a step number X where the radiation source is positioned through the actual step value obtained in step 3.6 and the step diagram obtained in step 3.3;
step 4, restoring the actual phase value;
and 5, calculating the angle of the radiation source.
2. The wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment as set forth in claim 1, wherein the step 1 is specifically: providing a radio frequency device, wherein two ports are arranged in each direction around the radio frequency device, base lines are arranged on the four ports of the radio frequency device relative to the two directions, and a Schottky diode detector is connected to the other four ports of the radio frequency device.
3. The wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment according to claim 2, wherein the step 2 is specifically: determining a baseline interval d between two baselines based on the angular range and wavelength of the radiation source 1 And spacing factor k, k>1, thereby determining a baseline interval d between the other two relative baselines 2 ＝k*d 1 。
4. The wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency equipment as set forth in claim 3, wherein the step 4 is specifically:
step 4.1, selecting the phase difference measured under any base line=1, 2, indicating the nth baseline;
step 4.2, obtaining the actual phase value by the following formula
In the formula (16), t is an interval factor, and the size is determined by an interval factor k; the interval factor t=1 when k e (1.1,2.9) and t=2 when k e (3.0,5.0).
5. The wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency equipment as set forth in claim 4, wherein the step 5 is specifically: according to the actual phase value obtained in step 4Obtaining the radiation source angle theta through a formula (2) 0 。
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