阅读说明：本技术 一种四臂螺旋天线数据拟合测角方法 (Data fitting angle measurement method for four-arm helical antenna ) 是由 魏宪举 王鹏 陈玲 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种四臂螺旋天线数据拟合测角方法,涉及雷达技术领域,该方法获取待测目标的四个原始天线波束后,利用预先拟合的第一函数关系得到第一角度第一预估值,第一角度是目标来向与天线坐标系的水平面之间的夹角,利用预先拟合的第二函数关系得到俯仰角预估值和方位角预估值,并得到第一角度第二预估值和第二角度预估值,第二角度预估值是待测目标的目标来向在水平面上的投影与预定指向之间的夹角,然后根据第一角度第一预估值、第一角度第二预估值和第二角度预估值修正得到待测目标的俯仰角和方位角；该方法采用数据拟合方法可以方便的得到测角结果,节约了内存开销且测角效率高。(The invention discloses a data fitting angle measurement method for a four-arm helical antenna, which relates to the technical field of radar, and comprises the steps of obtaining a first angle estimated value by utilizing a first function relation which is pre-fitted after four original antenna wave beams of a target to be measured are obtained, obtaining a pitch angle estimated value and an azimuth angle estimated value by utilizing a second function relation which is pre-fitted, obtaining a first angle estimated value and a second angle estimated value, and correcting the second angle estimated value to obtain a pitch angle and an azimuth angle of the target to be measured according to the first angle estimated value, the first angle estimated value and the second angle estimated value; the method can conveniently obtain the angle measurement result by adopting a data fitting method, saves the memory overhead and has high angle measurement efficiency.)

1. A method for measuring an angle by data fitting of a four-arm helical antenna is characterized by comprising the following steps:

carrying out direction finding on sample targets at different angles by using a passive direction finding system based on a four-arm helical antenna, and determining the target direction of the sample targets in an antenna coordinate system and four corresponding original antenna beams acquired through the four-arm helical antenna in each direction finding to obtain a group of sample data;

fitting based on sample data to obtain a first functional relation, wherein the first functional relation is a functional relation between a first angle and four original antenna beams, and the first angle is an included angle between a target incoming direction and a horizontal plane of the antenna coordinate system;

fitting based on sample data to obtain a second functional relation, wherein the second functional relation is a functional relation between the pitch angle and the azimuth angle which are determined based on the target direction and the four original antenna beams;

acquiring four original antenna beams of a target to be measured by using a passive direction finding system based on a four-arm helical antenna;

obtaining a first angle first estimated value based on the first functional relation by utilizing four original antenna beams of the target to be measured;

obtaining a pitch angle estimated value and an azimuth angle estimated value based on the second functional relation by utilizing four original antenna beams of the target to be detected, and obtaining a first angle second estimated value and a second angle estimated value based on the pitch angle estimated value and the azimuth angle estimated value, wherein the second angle estimated value is an included angle between the projection of the target to be detected on the horizontal plane and a preset direction;

and correcting the pitch angle pre-estimated value and the azimuth angle pre-estimated value according to the first angle first pre-estimated value, the first angle second pre-estimated value and the second angle pre-estimated value to obtain the pitch angle and the azimuth angle of the target to be detected.

2. The method of claim 1, wherein said modifying said pitch angle estimate and said azimuth angle estimate based on said first angle first estimate, said first angle second estimate, and said second angle estimate to obtain a pitch angle and an azimuth angle of said target comprises:

when the difference value between the first angle first estimated value and the first angle second estimated value reaches a preset threshold value, correcting the pitch angle estimated value and the azimuth angle estimated value by using the first angle first estimated value and the second angle estimated value to obtain a pitch angle and an azimuth angle of the target to be detected;

and when the difference value between the first angle first estimated value and the first angle second estimated value does not reach the preset threshold value, taking the pitch angle estimated value as the pitch angle of the target to be detected, and taking the azimuth angle estimated value as the azimuth angle of the target to be detected.

3. The method of claim 2, wherein said correcting said pitch angle estimate and said azimuth angle estimate using said first angle first estimate and said second angle estimate to obtain a pitch angle and an azimuth angle of said target comprises:

correcting the pitch angle estimate to β -tan^-1(cosφ₀tanθ₁) Obtaining the pitch angle of the target to be measured, and correcting the estimated azimuth angle to alpha sin^-1(sinφ₀sinθ₁) Obtaining the azimuth angle phi of the target to be measured₀For said second angle estimate, theta₁A first estimate is made for the first angle.

4. The method of claim 1, wherein said deriving a first angle second estimate and a second angle estimate based on said pitch angle estimate and said azimuth angle estimate comprises:

determining the second estimated value of the first angle as theta₂＝cos^-1(cos(β₀)cos(α₀) Determine said second angle estimate as phi)₀＝tan^-1(tan(β₀)/sin(α₀) Wherein α) is₀For the estimation of said azimuth angle, β₀And estimating the pitch angle.

5. The method according to any of claims 1-4, wherein the target of the sample target in each set of sample data is oriented to a first angle indicative of the sample target, said fitting based on the sample data resulting in a first functional relationship comprises:

for each sample data, calculating sum beams and difference beams of four original antenna beams of the sample data, and calculating the ratio of the difference beams to the sum beams to obtain difference mode sum mode ratios;

and fitting to obtain the first functional relation based on the corresponding relation between the first angle and the difference mode and the mode ratio in each group of sample data, wherein the first function reflects the functional relation between the first angle and the difference mode and the mode ratio.

6. The method according to any one of claims 1-4, wherein the target of the sample target in each set of sample data indicates a pitch angle and an azimuth angle of the sample target, and the fitting based on the sample data results in the second functional relationship, including:

for each sample data, calculating sum beams and difference beams of four original antenna beams of the sample data, and performing different beam operations on the sum beams and the difference beams respectively to obtain four off-axis orthogonal beams;

determining a first parameter from one set of two diagonal off-axis orthogonal beams and the sum beam, and determining a second parameter from the other set of two diagonal off-axis orthogonal beams and the sum beam;

and fitting based on sample data to obtain a functional relation between the azimuth angle and the first parameter and fitting to obtain a functional relation between the pitch angle and the second parameter to obtain the second functional relation.

7. The method of claim 6, wherein fitting a functional relationship between an azimuth angle and a first parameter and fitting a functional relationship between a pitch angle and a second parameter based on sample data comprises: according to a ═ b₀+b₁·k₁Is fitted to obtain a functional relationship between the azimuth angle and the first parameter, in terms of β ═ c₀+c₁·k₂Is fitted to obtain a functional relationship between the pitch angle and the second parameter, where α is the azimuth angle, b₀、b₁Is aNumber, k₁Is a first parameter, beta is the pitch angle, c₀、c₁Is a coefficient, k₂Is the second parameter.

8. The method of claim 6, wherein determining a first parameter from one of the two diagonal off-axis orthogonal beams and the sum beam and determining a second parameter from the other of the two diagonal off-axis orthogonal beams and the sum beam comprises:

determining the first parameter asDetermining the second parameter asWherein, B₁And B₃Is a set of two diagonal off-axis orthogonal beams, B₂And B₄Is another set of two diagonally opposite, off-axis orthogonal beams, M₁Is the sum beam, the symbol | | | represents the amplitude of the beam.

9. The method of claim 6, wherein said computing a sum beam and a difference beam of four original antenna beams of said sample data and performing different beam operations on said sum beam and difference beam respectively to obtain four off-axis orthogonal beams comprises:

determining a sum beam as M₁P1-j P2-P3+ j P4, difference beam M₂P1-P2+ P3-P4, P1, P2, P3, P4 are four original antenna beams, respectively;

determining four off-axis orthogonal beams B₁、B₂、B₃、B₄Are respectively asWherein, B₁And B₃As a set of two diagonal off-axis orthogonal beams, B₂And B₄Is another set of two off-axis orthogonal beams that are diagonal.

Technical Field

The invention relates to the technical field of radars, in particular to a data fitting angle measurement method for a four-arm helical antenna.

Background

Angle measurement is the most critical application of radar signal processing, angle measurement provides basic information for further processing and utilization of rear-end radar signals, and the two most commonly used angle measurement systems at present are single-pulse angle measurement and phase interferometer angle measurement. The phase interferometer angle measurement system obtains error signals related to the magnitude and direction of a target deviation signal axis by using the signal phase difference of continuous wave carriers of paired antenna receiving templates, and although the phase interferometer angle measurement system is high in tracking accuracy, the debugging difficulty is high, and the ambiguity resolution problem exists. Therefore, the single-pulse angle measuring system which has a simple structure and is widely applied is more commonly used at present, although the angle measuring precision is slightly worse than that of a phase interferometer.

In the single-pulse angle measurement theory, target angle error information can be determined only by one echo pulse, and in engineering, a plurality of echo pulses are usually accumulated to improve the detection probability and the angle error measurement precision. The single-pulse angle measuring system utilizes the paired wave beams to receive the amplitude or phase of a target signal and simultaneously compares the amplitude or phase to obtain an error signal related to the magnitude and direction of a target deviation equal signal axis. Therefore, the single-pulse angle measurement is further divided into a phase-comparison single-pulse angle measurement and a amplitude-comparison single-pulse angle measurement: compared with monopulse angle measurement, the method is more applied to an array antenna system with scattered feed sources, and phase differences of signals are compared to obtain an angle error value; the amplitude-comparison single-pulse angle measurement is mostly used for a surface antenna system with a concentrated feed source, and the amplitude difference of signals is compared to obtain an angle error value.

Amplitude-contrast monopulse goniometry uses multiple independent antennas to generate multiple independent contiguous beams covering 360 degrees of azimuth, these antennas using the same directional pattern function F (theta) and being evenly distributed, the field angles theta of adjacent antennas_s360 DEG/M, each antenna has an azimuth F_i(θ)＝F(θ-iθ_s) i is 0,1, …, M-1, K is the number of antennas. Four antennas, six antennas and eight antennas are commonly used, the working principles of the antennas are basically similar, and the direction finding precision is improved along with the increase of the number of the antennas. Taking a four-antenna omnidirectional amplitude monopulse angle measurement system including four antennas as an example, referring to fig. 1, a four-antenna directional diagram and a corresponding digital receiver system block diagram are shown, where the field angle of each antenna is 90 degrees,the received signal of each antenna has a respective amplitude response of K_iThe logarithmic envelope signal of the output pulse is s_i＝log[K_iF(θ-iθ_s)A(t)]i is 0,1, …, M-1, where a (t) is the amplitude modulation of the radar signal, and the logarithmic envelope signal is fed to a signal processor, which generates a corresponding angle estimate. Specifically, the method comprises the following steps: in the system, a pair of adjacent beams respectively output strongest and second strongest signals, and the radar azimuth can be determined by comparing the relative magnitude of the envelope amplitudes of the signals output by the pair of adjacent beams. As shown in fig. 2, assuming that the antenna pattern satisfies the symmetry of the amplitude direction shown in fig. 2, i.e., F (θ) ═ F (- θ), the radar direction is located between the two antennas and is offset from the signal direction of the antennas, etc., by the angleWhen the corresponding channel output signals are respectivelyI.e. after subtraction, the logarithmic voltage ratio in decibels R isIf the F (theta) function is in the interval [ -theta ]_s,θ_s]Has monotonicity in the inside, namely satisfies F (theta)₁)<F(θ₂)θ₁,θ₂∈[-θ_s,θ_s]Then the logarithmic voltage ratio R toThe angle information of the target can be obtained according to the size of R.

The planar helical antenna can determine angle information through the beam relationship between the symmetrical arms, and the four-arm helix can determine the azimuth and the elevation through the relationship between the two symmetrical arms to achieve the purpose of angle measurement, because the planar helical antenna has wide beams, wide frequency bands,Circular polarization and other characteristics are widely applied in the fields of GPS, PCS and the like. In a passive direction-finding system based on a quadrifilar helical antenna, angle measurement can be performed by adopting the method, but for an actual angle-finding system, the specific calculation R and R are caused by the fact that the directional diagram function of the antenna is complicatedThe function between the two is not an analytic solution, the relation between the angle of each direction and the beam size of the radar antenna is obtained through experiments in engineering application, a specific lookup table is manufactured, and the corresponding angle is obtained through the lookup table in the actual use process. However, the table lookup method has two disadvantages: 1, table data occupies a large number of memory units; 2, the table look-up method wastes the search time, the search algorithm is not well executed, the search time is correspondingly slow, and certain challenges are brought to the real-time processing system.

Disclosure of Invention

The invention provides a data fitting angle measurement method for a four-arm helical antenna aiming at the problems and the technical requirements, and the technical scheme of the invention is as follows:

a data fitting angle measurement method for a four-arm helical antenna comprises the following steps:

carrying out direction finding on sample targets at different angles by using a passive direction finding system based on a four-arm helical antenna, and determining the target direction of the sample targets in an antenna coordinate system and four corresponding original antenna beams acquired through the four-arm helical antenna in each direction finding to obtain a group of sample data;

fitting based on sample data to obtain a first functional relation, wherein the first functional relation is a functional relation between a first angle and four original antenna beams, and the first angle is an included angle between a target incoming direction and a horizontal plane of an antenna coordinate system;

fitting based on sample data to obtain a second functional relation, wherein the second functional relation is a functional relation between the pitch angle and the azimuth angle which are determined based on the target direction and the four original antenna beams;

acquiring four original antenna beams of a target to be measured by using a passive direction finding system based on a four-arm helical antenna;

obtaining a first angle first estimated value based on a first functional relation by utilizing four original antenna beams of a target to be measured;

obtaining a pitch angle estimated value and an azimuth angle estimated value based on a second function relation by utilizing four original antenna beams of the target to be detected, and obtaining a first angle second estimated value and a second angle estimated value based on the pitch angle estimated value and the azimuth angle estimated value, wherein the second angle estimated value is an included angle between the projection of the target to be detected on the horizontal plane and a preset direction;

and correcting the pitch angle pre-estimated value and the azimuth angle pre-estimated value according to the first angle first pre-estimated value, the first angle second pre-estimated value and the second angle pre-estimated value to obtain the pitch angle and the azimuth angle of the target to be detected.

The further technical scheme is that the pitch angle and azimuth angle of the target to be measured are obtained according to the first angle estimated value, the second angle estimated value and the second angle estimated value, and the pitch angle estimated value and the azimuth angle estimated value are corrected, and the method comprises the following steps:

when the difference value between the first angle first estimated value and the first angle second estimated value reaches a preset threshold value, correcting the pitch angle estimated value and the azimuth angle estimated value by using the first angle first estimated value and the second angle estimated value to obtain a pitch angle and an azimuth angle of the target to be measured;

and when the difference value between the first angle first estimated value and the first angle second estimated value does not reach a preset threshold value, taking the pitch angle estimated value as the pitch angle of the target to be detected, and taking the azimuth angle estimated value as the azimuth angle of the target to be detected.

The further technical scheme is that the pitch angle estimation value and the azimuth angle estimation value are corrected by utilizing the first angle estimation value and the second angle estimation value to obtain the pitch angle and the azimuth angle of the target to be measured, and the method comprises the following steps:

corrected pitch angle estimate as β tan^-1(cosφ₀tanθ₁) Obtaining the pitch angle of the target to be measured, and correcting the estimated value of the azimuth angle to alpha sin^-1(sinφ₀sinθ₁) Obtaining the azimuth angle phi of the target to be measured₀For second angle estimationValue of theta₁A first estimate is made for the first angle.

The further technical scheme is that a first angle second estimated value and a second angle estimated value are obtained based on a pitch angle estimated value and an azimuth angle estimated value, and the method comprises the following steps:

determining the first angle and the second estimated value as theta₂＝cos^-1(cos(β₀)cos(α₀) Determine a second angle estimate as phi₀＝tan^-1(tan(β₀)/sin(α₀) Wherein α) is₀For azimuthal prediction, beta₀Is an estimate of pitch angle.

According to a further technical scheme, a first angle of a sample target is indicated to a target of the sample target in each group of sample data, and a first functional relation is obtained based on sample data fitting, wherein the method comprises the following steps:

for each sample data, calculating sum beams and difference beams of four original antenna beams of the sample data, and calculating the ratio of the difference beams to the sum beams to obtain difference mode sum mode ratios;

and fitting to obtain a first functional relation based on the corresponding relation between the first angle and the difference mode and the mode ratio in each group of sample data, wherein the first function reflects the functional relation between the first angle and the difference mode and the mode ratio.

According to a further technical scheme, the pitch angle and the azimuth angle of the sample target are indicated to the target of the sample target in each group of sample data, and a second functional relation is obtained based on sample data fitting, and the method comprises the following steps:

for each sample data, calculating sum beams and difference beams of four original antenna beams of the sample data, and performing different beam operations on the sum beams and the difference beams respectively to obtain four off-axis orthogonal beams;

determining a first parameter according to one set of two diagonal off-axis orthogonal beams and a sum beam, and determining a second parameter according to the other set of two diagonal off-axis orthogonal beams and the sum beam;

and fitting based on the sample data to obtain a functional relation between the azimuth angle and the first parameter, and fitting to obtain a functional relation between the pitch angle and the second parameter to obtain a second functional relation.

The further technical scheme is that a functional relation between the azimuth angle and the first parameter is obtained through fitting based on sample data, and a functional relation between the pitch angle and the second parameter is obtained through fitting, and the method comprises the following steps: according to a ═ b₀+b₁·k₁Is fitted to obtain a functional relationship between the azimuth angle and the first parameter, in terms of β ═ c₀+c₁·k₂Is fitted to obtain a functional relationship between the pitch angle and the second parameter, where α is the azimuth angle, b₀、b₁Is a coefficient, k₁Is a first parameter, beta is the pitch angle, c₀、c₁Is a coefficient, k₂Is the second parameter.

A further technical solution is that, determining a first parameter according to one set of two diagonal off-axis orthogonal beams and a sum beam, and determining a second parameter according to the other set of diagonal two off-axis orthogonal beams and the sum beam, including:

determining a first parameter asDetermining the second parameter asWherein, B₁And B₃Is a set of two diagonal off-axis orthogonal beams, B₂And B₄Is another set of two diagonally opposite, off-axis orthogonal beams, M₁Is a sum beam, the symbol | | | represents the amplitude of the beam.

The method further adopts the technical scheme that the method comprises the steps of calculating sum beams and difference beams of four original antenna beams of sample data and respectively carrying out different beam operations on the sum beams and the difference beams to obtain four off-axis orthogonal beams, and comprises the following steps:

determining a sum beam as M₁P1-j P2-P3+ j P4, difference beam M₂P1-P2+ P3-P4, P1, P2, P3, P4 are four original antenna beams, respectively;

determining four off-axis orthogonal beams B₁、B₂、B₃、B₄Are respectively asWherein, B₁And B₃As a set of two diagonal off-axis orthogonal beams, B₂And B₄Is another set of two off-axis orthogonal beams that are diagonal.

The beneficial technical effects of the invention are as follows:

the application discloses a data fitting angle measurement method for a four-arm helical antenna, which adopts a data fitting algorithm to reduce the problems of overlarge memory occupation and low table look-up efficiency caused by a table look-up method; the fitting algorithm can conveniently obtain angle measurement results, meanwhile, the stored parameters are few, the memory cost is saved, the two major defects caused by the current table look-up method structure are overcome, the method can be widely applied to passive seeker antennas, the four-arm helical antenna is adopted for angle measurement, and the frequency band range can be 580M-2G.

Drawings

Fig. 1 is a four-antenna omnidirectional amplitude monopulse measurement schematic block diagram.

Fig. 2 is an amplitude pattern of adjacent antennas.

Fig. 3 is a flowchart of a method of the present application for a four-arm helical antenna data fitting goniometry method.

Detailed Description

The following further describes the embodiments of the present invention with reference to the drawings.

The application discloses a data fitting angle measurement method for a quadrifilar helix antenna, please refer to fig. 3, the method comprises the following steps:

step S1, performing direction finding on the sample target at different angles by using a passive direction finding system based on the quadrifilar helix antenna, and determining a target arrival direction of the sample target in the antenna coordinate system and corresponding four original antenna beams P1, P2, P3, and P4 acquired through the quadrifilar helix antenna in each direction finding to obtain a set of sample data. In the present application, the target direction of the sample target indicates the pitch angle β and the azimuth angle α of the sample target, and also indicates a first angle θ and a second angle Φ of the sample target, the first angle is an angle between the target direction and a horizontal plane of the antenna coordinate system, that is, an XY plane, and the second angle is an angle between a projection of the target direction onto the horizontal plane, that is, the XY plane, and a predetermined direction, which is predefined in advance, and usually a direction of an X axis or a Y axis of the antenna coordinate system is taken as the predetermined direction.

The (α, β) and (θ, Φ) can be converted into each other by coordinate conversion, so that the target orientation of the sample target can actually include only one set of angles of (α, β) and (θ, Φ), and the other set of angles can be converted accordingly. Or the target direction of arrival may actually include both (α, β) and (θ, Φ), for example, a set of sample data obtained at each direction finding may be represented as { (α, β), (θ, Φ), (P1, P2, P3, P4) }.

Step S2, fitting to obtain a first functional relationship based on the sample data, where the first functional relationship is a functional relationship between the first angle θ and the four original antenna beams. Alternatively, in the present application, the first functional relationship does not directly reflect the functional relationship between the first angle θ and the four original antenna beams, but reflects the first angle θ and the differential mode-sum mode ratioFunctional relationship between them, i.e.f₁() Is a first functional relationship, wherein M₁Is a sum beam, M₂For a difference beam, the symbol | | | represents the amplitude of the beam. Thus, in fitting to obtain the first functional relationship, first for each sample data, the sum beam M of the four original antenna beams P1, P2, P3, P4 of the sample data is calculated₁Sum and difference beam M₂The calculation method is M₁＝P1-j*P2-P3+j*P4，M₂P1-P2+ P3-P4, and then calculate the difference beam M₂And beam M₁The ratio of (A) to (B) yields a difference mode and a mode ratioAnd then based on the first angle theta and the difference mode and the mode ratio in each group of sample dataFitting the corresponding relation to obtain a first functional relation f₁()。

And step S3, fitting based on the sample data to obtain a second functional relation, wherein the second functional relation is a functional relation between the pitch angle beta and the azimuth angle alpha which are determined based on the target direction and the four original antenna beams. Similarly, the present application does not directly determine the functional relationship between β, α and the four original antenna beams, but first computes, for each sample data, the sum beam M of the four original antenna beams P1, P2, P3, P4 of the sample data₁Sum and difference beam M₂The calculation method is as described in step S2 above. Then respectively to sum beams M₁Sum and difference beam M₂Carrying out different beam operations to obtain four off-axis orthogonal beams B₁、B₂、B₃、B₄The calculation method comprises the following steps:

wherein, B₁And B₃As a set of two diagonal off-axis orthogonal beams, B₂And B₄Is another set of two off-axis orthogonal beams that are diagonal. Two off-axis orthogonal beams B from one set of diagonals₁And B₃And beam M₁Determining a first parameter k₁From another set of diagonal two off-axis orthogonal beams B₂And B₄And beam M₁Determining a second parameter k₂Specifically, the method comprises the following steps: the first parameter isDetermining the second parameter asTherefore, each group of sample data can be processed to obtain a target to determine the pitch angle beta and the azimuth angle alpha and the corresponding first parameter k₁And a second parameter k₂。

Fitting based on the sample dataObtaining an azimuth angle alpha and a first parameter k₁The pitch angle beta and the second parameter k are obtained by functional relation between the two and fitting₂And obtaining a second functional relation through the functional relation between the first and second groups. The application uses polynomial fitting, i.e. according to α ═ b₀+b₁·k₁The azimuth angle alpha and the first parameter k are obtained by form fitting₁According to β ═ c₀+c₁·k₂Form fitting to obtain a pitch angle beta and a second parameter k₂Functional relationship between b₀、b₁Is a coefficient of, c₀、c₁Is a coefficient.

And step S4, acquiring four original antenna beams of the target to be measured by using the passive direction finding system based on the four-arm helical antenna. Obtaining a first angle first estimated value by utilizing four original antenna beams of the target to be measured based on a first function relation, and obtaining a difference mode and a mode ratio by processing the four original antenna beams firstly, similar to the fitting processThen substituting the first function relation to obtain a corresponding first angle first estimated value theta₁。

Step S5, obtaining a pitch angle estimated value beta based on a second functional relation by using four original antenna wave beams of the target to be measured₀Sum azimuth angle estimate α₀Similar to the fitting process described above, the first parameter k is obtained by processing four original antenna beams₁And a second parameter k₂Then substituting the second function relationship to obtain a pitch angle estimated value beta₀Sum azimuth angle estimate α₀。

Estimation value beta based on pitch angle₀Sum azimuth angle estimate α₀Obtaining a second estimated value theta of the first angle₂And a second angle estimate phi₀Obtained according to the following formula: determining the first angle and the second estimated value as theta₂＝cos^-1(cos(β₀)cos(α₀) Determine a second angle estimate as phi₀＝tan^-1(tan(β₀)/sin(α₀))

In the step of S6,a first estimated value theta according to the first angle₁A second estimated value theta of the first angle₂And a second angle estimate phi₀Corrected pitch angle estimate beta₀Sum azimuth angle estimate α₀And obtaining the pitch angle and the azimuth angle of the target to be detected. Specifically, the method comprises the following steps:

(1) when the first angle is the first estimated value theta₁And a second estimated value theta of the first angle₂When the difference between the first and second angles reaches a predetermined threshold T, a first predicted value theta is used₁And a second angle estimate phi₀Corrected pitch angle estimate beta₀Sum azimuth angle estimate α₀And obtaining the pitch angle and the azimuth angle of the target to be detected. The predetermined threshold is a user-defined value, and the value of the predetermined threshold is typically 0.02.

Using theta₁And phi₀The method for obtaining the pitch angle and the azimuth angle through correction comprises the following steps: corrected pitch angle estimate as β tan^-1(cosφ₀tanθ₁) Obtaining the pitch angle of the target to be measured, and correcting the estimated value of the azimuth angle to alpha sin^-1(sinφ₀sinθ₁) And obtaining the azimuth angle of the target to be measured.

(2) When the first angle is the first estimated value theta₁And a second estimated value theta of the first angle₂When the difference between the pitch angle and the pitch angle does not reach the predetermined threshold value T, the pitch angle estimated value beta obtained in step S5 is directly used₀As the pitch angle of the target to be measured, the azimuth angle estimated value alpha is estimated₀As the azimuth of the object to be measured.

What has been described above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiment. It is to be understood that other modifications and variations directly derivable or suggested by those skilled in the art without departing from the spirit and concept of the present invention are to be considered as included within the scope of the present invention.