CN112162234A - 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 PDF

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CN112162234A
CN112162234A CN202011042094.0A CN202011042094A CN112162234A CN 112162234 A CN112162234 A CN 112162234A CN 202011042094 A CN202011042094 A CN 202011042094A CN 112162234 A CN112162234 A CN 112162234A
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CN112162234B (en
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张旭春
杨潇
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Air Force Engineering University of PLA
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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
    • 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

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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 of: 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 of the radiation source; 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 a 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

Wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment
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 direction of electromagnetic waves by utilizing the principle that the electromagnetic waves in different directions reach different amplitudes or phase responses generated by a direction finding antenna system. Depending on different factors, it can be classified into an amplitude method and a phase method. The phase method angle measurement utilizes the wave path difference between the electromagnetic wave signals radiated by a target and the antenna base line to measure the angle, namely, the direction of the signals is determined according to the relative phase difference of the same signals detected and received by a direction-finding antenna system, and then angle error signals are demodulated through the phase difference, and the antenna is driven to perform passive tracking on a radiation source. 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 that measurement is blurred when the baseline width between the two antennas is too large, and a large measurement error is caused when the baseline width is too small. The novel wide-angle and high-precision angle measurement method researched by the technical scheme is based on phase method direction measurement, a set of simple and feasible novel angle measurement method is researched, and the problem of measurement ambiguity existing in the traditional phase method angle measurement is solved.
One, two base line angle measuring principle
At present, the angle measuring device based on the phase method direction measurement is mainly an interferometer, which uses the angle measuring principle of the double-baseline phase method, that is, uses the phase difference between echo signals received by a plurality of antennas to measure the angle. As shown in fig. 1, when the target radiates an electromagnetic wave signal in the θ direction, the electric wave reflected by the target reaching the receiving point is approximated to a plane wave. Because the base line interval between the two antennas is d, the signals received by the two antennas reach the difference of the wave path lengths of the two base lines, namely Delta R, so as to generate phase difference
Figure BDA0002706944290000021
The relationship between the phase difference and the baseline interval is:
Figure BDA0002706944290000022
where λ is the wavelength of the electromagnetic wave signal radiated by the target. 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 radiated from the target can be derived from equation (1)
Figure BDA0002706944290000023
Knowing the wavelength of the electromagnetic wave signal radiated from the target, the azimuth of the target signal can be calculated from the equation (2) by using the phase difference measured by the phase meter.
Second, the problems of angle measurement blur and precision
The simple two-baseline phase method direction finding actually has a great problem, namely the measurement ambiguity problem.
From the equation (2), if the phase difference is small
Figure BDA0002706944290000024
Inaccurate value measurement will result in angle measurement errors. In order to research the relevant factors influencing the angle measurement precision, the two sides of the formula (1) are differentiated, namely
Figure BDA0002706944290000025
As can be seen from the formula (3), the reading accuracy is high
Figure BDA0002706944290000026
Small) or reduced lambda/d values, the accuracy of the angle measurement can be improved. In addition, when θ is 0, that is, when the target is in the antenna normal direction, the angle measurement error d θ is minimum, and when θ increases, d θ also increases, so that the range of θ is also limited to a certain extent to ensure a certain angle measurement accuracy. Although the angle measurement accuracy can be improved by reducing the value of λ/d, when the value of λ/d is reduced to a certain extent in a certain angle measurement range θ,
Figure BDA0002706944290000027
the value may exceed 2 pi, in which case
Figure BDA0002706944290000028
Where N is an integer, psi < 2 pi, and the actual reading of the phase meter is psi. Since the value of N is unknown, it is true
Figure BDA0002706944290000029
The value cannot be determined and a blurring problem (multivalue) occurs.
Third, the current method for solving the fuzzy problem
The measurement range is reduced when the measurement range is reduced, which means that the measurement accuracy and the measurement range are contradictory. The key to solve the contradiction is to solve the ambiguity problem, so how to deblur becomes a hot spot to be considered by applying the phase method to direction finding, and a plurality of methods for solving the ambiguity problem are researched and developed.
1. Stagger baseline deblurring
In order to solve the problem of direction finding ambiguity in the phase method direction finding, a direction finding method of a staggered baseline interferometer for solving the ambiguity problem by using the Chinese remainder theorem is provided by imitating the multi-frequency continuous wave distance measuring technology, the remainder theorem is applied to the direction finding of the interferometer, and a basic angle measuring schematic diagram of the ambiguity solving method is shown in FIG. 2.
An M-dimensional baseline interferometer with length of li(i-1, 2.., M-1), taking a base baseline l0≤λ min2, all base lines are l0Integer multiple of (a) of
l1:l2:…:lM-1＝m1:m2:…:mM-1 (4)
Wherein m isi(i ═ 1, 3.., M-1) is an integer
The interferometer measures the spacing between the base lines as liWhen corresponding to a phase difference of
Figure BDA0002706944290000031
And the actual phase difference is 2 pi lisin theta/lambda in a relationship of
Figure BDA0002706944290000032
Wherein k isiIndicates that the spacing between the base lines is liThe number of direction finding ambiguities in time.
Figure BDA0002706944290000033
The formula (5) is a system of equations with the same remainder having the same remainder in the real number domain and the divisor being an integer, if two are selected to be co-prime, the equation can be known according to the Chinese remainder theorem
Figure BDA0002706944290000034
Having a unique set of solutions k within the determined maximum unambiguous direction finding rangei. However, in this method, phase errors caused by antenna elements, microwave channels, receivers, and the like easily cause ambiguity resolution failure, and the calculation amount is large.
2. Virtual baseline disambiguation
The term "virtual baseline" refers to 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 baselines is the unambiguous phase. The schematic diagram is shown in FIG. 3, where the base line intervals of base lines 1 and 2 and base lines 2 and 3 are respectively l1，l2(l2＞l1) Subtracting two different baseline intervals can yield an interval of l2-l1The baseline interval and the corresponding phase difference of the virtual short baseline
Figure BDA0002706944290000041
In a relationship of
Figure BDA0002706944290000042
However, in the wide-angle direction finding, the virtual baseline method causes ambiguity resolution errors due to the influence of system errors and random errors, and even cannot resolve ambiguity.
3. Long and short baseline ambiguity resolution
The long and short baseline method is also called a three-baseline angle measurement method, and is implemented by using three baselines with proper two different baseline intervals, wherein 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 multivalue. Assuming that the electromagnetic wave signal with the target radiating direction theta is outwards, the distance between the antennas 1 and 2 is d12The distance between the antennas 1,3 is d13. By selecting d appropriately12So that the phase difference between the signals received by the antennas 1 and 2 can satisfy the requirement in the angle measurement range
Figure BDA0002706944290000043
Figure BDA0002706944290000044
Read by the phase meter 1.
According to requirements, larger d is selected13The phase difference of the signals received by the antennas 1,3 is
Figure BDA0002706944290000045
Where the phase meter 2 reads psi less than 2 pi, the following relationship may be used to determine the value of N
Figure BDA0002706944290000046
When the error of the phase meter 1 is within the acceptable range, the reading of the phase meter 1 is taken
Figure BDA0002706944290000051
And equation (10) can calculate
Figure BDA0002706944290000052
Then, according to the formula (9), the value of N and the value of theta can be determined. d13The/lambda value is larger, and the required precision is ensured.
Although the method for measuring the angle of the long and short baselines can solve the problem of ambiguity of direction measurement by using the short baselines and the problem of direction measurement range by using the long baselines, in the broadband direction measurement, when a target signal is a high-frequency signal, high requirements are required on the short baselines, and the method cannot be widely applied due to engineering limitation of physical realization of the short baselines.
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, and 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 of the radiation source;
step 4, restoring the actual phase value;
and 5, calculating the angle of the radiation source.
The invention has the beneficial effects that: the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency equipment is simple and convenient, has a 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 goniometry;
FIG. 2 is a ragged baseline deblurring diagram;
FIG. 3 is a diagram of a virtual baseline deblurring principle;
FIG. 4 is a long and short baseline deblurring schematic;
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 according to 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 eight-port four-baseline radio frequency equipment according to the present invention;
fig. 7 is a comparison graph of the fuzzy phase value and the actual phase difference of the wave path difference measured by the wide-angle high-precision angle measuring method based on the eight-port four-baseline radio frequency equipment, wherein k is 1.3, and the incident angle is (-80 degrees and 80 degrees);
fig. 8 is a comparison graph of the angle value measured by the wide-angle high-precision angle measuring method based on the eight-port four-baseline radio frequency device in the invention and the actual incident angle, wherein k is 1.3, and the incident angle is (-80 degrees, 80 degrees);
fig. 9 is a step diagram obtained by subtracting angle values at two baseline intervals measured by the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device of the present invention, where k is 1.3 and the incident angle is (-80 °,80 °);
fig. 10 is a comparison graph of a phase curve restored by a step method in a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device according to the present invention and an actual phase curve, wherein k is 1.3, and an incident angle is (-80 °,80 °);
fig. 11 is a graph comparing a phase value measured by a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device according to the present invention with an actual phase value by using a phase curve restored by a step method, wherein k is 1.3, and an incident angle is (-80 degrees, 80 degrees);
fig. 12 is a comparison graph of an angle value measured by a wide-angle high-precision angle measuring method based on an eight-port four-baseline radio frequency device according to the present invention, and an actual angle value, where k is 1.3, and an incident angle is (-90 °,90 °) by using a phase curve restored by a step method;
fig. 13 shows that k is 1.4, and the wave path difference measured by the wide-angle high-precision angle measuring method based on the eight-port four-baseline radio frequency device is d within the range of the incidence angle of (-90 degrees and 90 degrees)1Fuzzy phase values of 18 mm;
fig. 14 shows that k is 1.4, and the wave path difference measured by the wide-angle high-precision angle measuring method based on the eight-port four-baseline radio frequency equipment is d within the range of the incidence angle of (-90 degrees and 90 degrees)2Fuzzy phase values of 84 mm;
fig. 15 shows that k is 1.4, and the wave path difference measured by the wide-angle high-precision angle measuring method based on the eight-port four-baseline radio frequency equipment is d within the range of the incidence angle of (-90 degrees and 90 degrees)1Fuzzy angle value of 18 mm;
fig. 16 shows that k is 1.4, and the wave path difference measured by the wide-angle high-precision angle measuring method based on the eight-port four-baseline radio frequency equipment is d within the range of the incidence angle of (-90 degrees and 90 degrees)2Fuzzy 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 according to the present invention, where k is 1.4 and the incident angle is (-90 °,90 °);
fig. 18 shows that k is 1.4, and the incident angle is (-80 °,80 °) the phase value measured by 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 phase curve restored by the step method;
fig. 19 shows angle values measured by a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device according to the present invention using a phase curve restored by a step method, where k is 1.4 and the incident angle is (-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, wherein k is 3.6, and the incident angle is (-90 degrees and 90 degrees);
fig. 21 shows that k is 3.6, and the incident angle is (-90 °,90 °) the phase value measured by the wide-angle high-precision angle measurement method based on the eight-port four-baseline rf device according to the present invention using the phase curve restored by the step method;
fig. 22 shows angle values measured by a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device according to the present invention using a phase curve restored by a step method, where k is 3.6 and the incident angle is (-90 °,90 °);
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, where k is 5.3 and the incident angle is (-90 °,90 °) according to the present invention;
fig. 24 shows angle values measured by a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device according to the present invention using a phase curve restored by a step method, where k is 5.3 and the incident angle is (-90 °,90 °);
fig. 25 shows angle values measured by a wide-angle high-precision angle measurement method based on an eight-port four-baseline radio frequency device according to the present invention using a phase curve restored by a step method, where k is 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, wherein k is 2, and the incidence angle is (-90 degrees and 90 degrees).
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The invention provides a wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment, which comprises the following 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 four ports of the radio frequency equipment opposite to the two directions, and the other four ports of the radio frequency equipment are respectively connected with a Schottky diode detector:
first, determining a baseline spacing and spacing factor based on the angular range and wavelength of the radiation source
First, a schematic diagram of the method is given as shown in FIG. 5, d1Is the spacing between the base lines 5, 7, d2The four Schottky diode detectors are respectively connected to the ports 1,2, 3 and 4 for the interval between the baselines 6 and 8, and the radiation source angle can be calculated through the reading of the detectors.
Assuming an angle theta of an electromagnetic wave signal radiated from a target0Within (-80 °,80 °), the signal has a wavelength λ of 12.5mm and a frequency of 24 GHz. Unlike prior methods, the method of the present invention requires only the ratio of the two baseline intervals, k ═ d2/d1More than 1 (hereinafter referred to as interval factor) is constant, so that d is selected for convenient engineering realization118mm, on the other hand, the spacing factor can be arbitrarily chosen (the principle will be analyzed in the second section) except for certain special values, where it is chosen
Figure BDA0002706944290000095
Then d2＝60mm。
The principle of eight-port angle measurement:
it is known from fig. 5 that the phase difference of the signals received by the four receiving antennas can be expressed as
Figure BDA0002706944290000091
Figure BDA0002706944290000092
The eight-port network proposed by Zhanxuchun is composed of 4 180-degree directional couplers (annular bridge) and 1 90-degree neck shifter, and utilizes incident wave and reflection in S parameter of microwave networkThe concept of wave, drawing the schematic diagram of eight ports separately as shown in FIG. 6, and let phi1＝d12π sin θ/λ、φ2＝d 22 π sin θ/λ is
Figure BDA0002706944290000093
According to the S parameter characteristics of the eight-port network
Figure BDA0002706944290000094
The combinations (11) and (12) have
Figure BDA0002706944290000101
The square of the modulus value is taken on both sides of each equation in equation (13), the ratio of the left-hand reflected voltage to the entrance voltage of the equation becomes the ratio of the reflected power to the incident power of each port, and the converted result is simplified as follows:
Figure BDA0002706944290000102
and due to Pi/Pk＝|Sik|2The combination formula (14) can be obtained
Figure BDA0002706944290000103
Figure BDA0002706944290000111
φ1、φ2The phase difference measured for the two baseline intervals respectively shows that the eight port can measure the phase difference of the two baseline intervals, but as with the existing method, the two phase differences have the fuzzy problem,the concept of a step is proposed for this purpose.
Second, determining the number of steps of the radiation source
Two baseline separation d can be measured using an eight-port device1、d2Has a blur value of1And phi2. The principle of the step proposed by the method of the invention is explained when the incident angle theta0Within the range of (-80 deg., 80 deg.), at different theta0In the interval of values of (d), θ' ═ arc sin (Φ)2λ/2πd2)-arc sin(φ1λ/2πd1) There are only 13 fixed values, 20, 8, -4, -16, 24, 12, 0, -12, -24, 16, 4, -8, -20, respectively, numbered 1 to 13 in left to right order. The second step is to determine the step number where θ' is located according to the actually measured value.
Step principle:
first when the radiation source reaches the receiving device, at two base line intervals d1And d2Next, the actual phase difference and the ambiguous phase value of the path difference measured by the eight-port device are shown in fig. 7. It can be seen at this point that there is a phase ambiguity problem for both baseline intervals, and that the unambiguous phase regions for the different baseline intervals differ.
Then, according to equation (2), the measured ambiguity 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 subtracting the measured angle values for these two baseline intervals, i.e. θ' ═ arc sin (φ)2λ/2πd2)-arc sin(φ1λ/2πd1)，φ3＝φ2-φ1And obtaining a step diagram with a plurality of steps as shown in fig. 9, wherein the values of each step are different, that is, the correspondence between the measured angle difference value under two different baseline intervals and the real angle value of the callback signal is the step shape. However, each step is not very flat and has a small deviation, that is, the actual subtracted angle difference is not a constant in the corresponding partial interval, but the number of the steps is approximately equal, and in order to make the step effect more obvious and determine the step more easily, we can determine the step more easilyThese angular differences are allowed to fluctuate within a range of ± 1, resulting in a determined 13 steps with a height of 20, 8, -4, -16, 24, 12, 0, -12, -24, 16, 4, -8, -20, respectively, numbered 1 to 13 in order from left to right.
The second step of the method of the invention is therefore to determine the step number from the actual measurement. The wide angle measurement of (-80 degrees, 80 degrees) and even the omnidirectional measurement of (-90 degrees, 90 degrees) can be realized by different values of the steps, and the wide base line d can be adopted2The test result of 60mm ensures the advantage of high precision.
Thirdly, restoring the actual phase value
Because each step corresponds to an angle interval, the step value can be reduced to an actual phase value by adopting a certain reduction criterion. For this purpose, a reduction criterion is established:
let L be the step number, X be the position number of step, interval factor t be 1 or 2 or 3 or 4 for according to the concrete condition of angle measurement, to 360 intervals manual adjustment, select the phase difference that measures under the arbitrary baseline
Figure BDA0002706944290000121
Representing the nth baseline with an actual phase value
Figure BDA0002706944290000122
Comprises the following steps:
Figure BDA0002706944290000123
simulation verification is performed according to the above-mentioned reduction process, and in this example, when t is 2, the blurred phase value can be reduced to the actual phase value.
By using the formula (16), the actual phase of the reduction can be obtained
Figure BDA0002706944290000131
Fourthly, calculating the angle of the radiation source
When the actual phase value is obtained, it is based on
Figure BDA0002706944290000132
(N is an integer), the actual incident angle theta can be easily calculated0。
Through the mode, the wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency equipment is simple, convenient and fast, wide in angle measurement range (capable of measuring all angles) and high in precision under the condition of the same cost or volume or number of antenna units.
High-precision merit evidence
The restored blurred phase value is compared with the actual phase value, the restoration degree is observed, and the simulation result is shown in fig. 10. It can be seen that the phase curve after reduction is identical to the actual phase curve, indicating that the phase reduced according to this method is identical to the actual phase.
From the reduced actual phase value, the incidence angle can be calculated according to equation (2), and the relationship between the calculated angle and the actual incidence angle is shown in fig. 11. The simulation result is observed, the angle value measured by the method of the invention is completely equal to the actual real angle value, which shows that the wide angle measurement of (-80 degrees and 80 degrees) can be realized by different values of the step, and the wide baseline d can be adopted2The test result of 60mm ensures the advantage of high precision.
Two, wide angle merit evidence
The measurement of the incident angle in the range of (-80 deg., 80 deg.) was discussed above, but it has not been proven that the method can measure the incident angle in the range of (-90 deg., 80 deg.) and (80 deg., 90 deg.). The maximum goniometric range of the method of the invention is investigated next.
Therefore, only the incident angle needs to be expanded to (-90 degrees and 90 degrees), and then the angle measurement principle is simulated, so that the incident angle in the (-90 degrees and 90 degrees) interval can be measured under a feasible interval factor k, that is, the method can measure targets with all angles in the space, and the simulation result is shown in fig. 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 of the spacing factor k and the interval factor t.
The factor in the interval is given above
Figure BDA0002706944290000141
And (3) under the condition of simulation, assigning the interval factors one by one, and performing simulation verification on the angle measurement principle of different interval factors one by one.
When k is 1.4, let d1＝18mm，d2＝84mm
The fuzzy phases measured at the two baselines are shown in fig. 13 and 14 from equation (1). The blur phase is resolved by equation (2) to obtain the angle value with blur tested at this time, as shown in fig. 15 and 16.
The two measured angle values are subtracted to find the step, which is shown in fig. 17. The number of steps is 7 in this case, and 10, -15, 25, 0, -25, 15, and-10, respectively. To restore the actual phase, t is taken to be 1, and the restoration result is shown in fig. 18. The observation result shows that the two curves of the reduced phase and the actual phase are completely consistent, which shows that the reduction phase is completely equal to the actual phase, and the fuzzy phase is successfully reduced.
Since the phase has been restored to the actual phase, the calculated angle value is also completely 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 is 1.4.
Two, when k is 3.6, let d1＝18mm，d2＝84mm
Still according to the above method, a step diagram is obtained as shown in fig. 20, at this time, 15 steps are provided, which are respectively 16, 4, -7, -18, 23, 22, 11, 0, -11, -22, -23, 18, 7, -4, -16, and t is taken to be 2, then the restored actual phase and the actual phase pair are completely matched as shown in fig. 21, and it is proved that the restored phase and the actual phase are completely equal. The angle value calculated from the reduction phase is also completely equal to the actual angle of incidence value, and the result is shown in fig. 22. When k is 3.6, the method of the present invention is effective.
When k is 5.3, let d1＝18mm，d2＝84mm
Still according to the above method, a step map as shown in FIG. 23 is obtained, which has 21 steps, 21, 13, 5, -2, -10, -17, -18, 23, 15, 8, 0, -8, -15, -23, -18, 17, 10, 2, -5, -13, -21. Taking t to be 3, the reduction phase and the comparison of the angle value calculated from the reduction phase with the actual value are shown in fig. 24 and 25, and the curve is matched with the actual value, and when k is 5.3, the method of the present invention is also effective.
Fourthly, summarize
And then, taking other values for k, and simulating one by one according to the process, wherein simulation results are not listed one by one.
It was found that when k is 2, the step pattern is as shown in fig. 26, the height of the step is 20, 0, -20, and the same step exists, and the method condition of the present invention cannot be satisfied.
And determining the value range of k as (1.0, 5.0), scanning k at intervals of 0.1, and performing multiple times of simulation to obtain the following conclusion.
When k belongs to (1.0, 5.0), the angle can be measured by the method under other interval factors except that k is 1.5,2.0,2.5,3.0,3.5,4.0,4.9 and 5.08 values.
Further, by the generalization, the interval factor t is 1 when k ∈ (1.1,2.9), and 2 when k ∈ (3.0,5.0), as shown in table 1.
TABLE 1
Figure BDA0002706944290000151
Figure BDA0002706944290000161

Claims (6)

1. A wide-angle high-precision angle measurement method based on eight-port four-baseline radio frequency equipment 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 of the radiation source;
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 the eight-port four-baseline radio frequency device as claimed in claim 1, wherein the step 1 specifically comprises: providing radio frequency equipment, wherein two ports are arranged in each direction around the radio frequency equipment, base lines are arranged on four ports of the radio frequency equipment relative to the two directions, and the other four ports of the radio frequency equipment are respectively connected with a Schottky diode detector.
3. The wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device as claimed in claim 2, wherein the step 2 specifically comprises: determining a base line interval d between two base lines according to the angle range and wavelength of the radiation source1And spacing factor k, k>1, and determining the baseline separation d between two other relative baselines2＝k*d1。
4. The wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device according to claim 3, wherein the step 3 specifically comprises:
step 3.1, calculating two baseline intervals d when the radiation source is in the estimation range by using the measurement principle shown in the formula (15)1、d2Is fuzzy phase difference phi1And phi2：
Figure FDA0002706944280000021
In the formula (15), Si6＝Pi/P6，i＝1,2,3,4；PiThe signal power output by a Schottky diode detector connected with the i-th port of the radio frequency equipment is P6The signal power received by a base line connected with a No. 6 port of the radio frequency equipment is large;
step 3.2, according to the fuzzy phase difference phi1And phi2And (2) resolving a corresponding fuzzy angle value;
Figure FDA0002706944280000022
3.3, subtracting the two fuzzy angle values calculated in the step 3.2 to obtain a step map, wherein the total number of steps is L, and the steps are numbered according to the relationship from small to large of the corresponding radiation source angle and are 1,2, … and L;
step 3.4, measuring the corresponding fuzzy phase difference phi of the actual radiation source under the interval of two baselines by adopting eight-port four-baseline radio frequency equipment1And phi2；
Step 3.5, resolving corresponding actual fuzzy angle values under two baseline intervals by using the fuzzy phase difference and the formula (2) in the step 3.4;
3.6, subtracting the two actual fuzzy angle values in the step 3.5 to obtain an actual step value;
and 3.7, determining the step number X of the radiation source according to the actual step value obtained in the step 3.6 and the step map obtained in the step 3.3.
5. The wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device as claimed in claim 4, wherein the step 4 specifically comprises:
step 4.1, selecting the phase difference measured under any base line
Figure FDA0002706944280000023
n is 1,2, and represents the nth baseline;
step 4.2, generalCalculating the actual phase value by the following formula
Figure FDA0002706944280000024
Figure FDA0002706944280000031
In the formula (16), t is an interval factor, and the size is determined by an interval factor k; the interval factor t is 1 when k ∈ (1.1,2.9), and 2 when k ∈ (3.0, 5.0).
6. The wide-angle high-precision angle measurement method based on the eight-port four-baseline radio frequency device according to claim 5, wherein the step 5 specifically comprises: according to the actual phase value obtained in step 4
Figure FDA0002706944280000032
The radiation source angle theta is obtained by the formula (2)0。
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