CN104375045A - Method for eliminating multi-path reflection interference error in HIRF test - Google Patents

Abstract

The invention relates to a method for eliminating the multi-path reflection interference error in an HIRF test. The method comprises the steps that first, the position of a center test point and the positions of N auxiliary test points are determined according to the HIRF test, and a ground multi-path reflection reference model is established; second, a ray path tracking method is used for calculating the total electric field strength of the center test point and the total electric field strength of the N auxiliary test points; third, a least square error approach method is used for determining the undetermined coefficients in a total electric field strength function of the center test point, and a collineation electromagnetic wave component and a ground reflection electromagnetic wave component at the center test point are separated; fourth, the elimination factors of ground multi-path reflection interference are determined, and the ground multi-path reflection interference error of the center test point is eliminated. The method is used for eliminating the ground multi-path reflection interference error of the data of the HIRF test, it is guaranteed that the data of the HIRF test are correct, and influences caused by the ground multi-path reflection interference error in an aerospace vehicle HIRF ground-based simulation test are eliminated.

Description

The removing method of ground Multipath reflection mushing error in a kind of HIRF test

Technical field

The present invention relates to a kind of HIRF at aerospace vehicle (High Intensity Radio Field, high radiation field) in ground simulation test, eliminate the method for ground Multipath reflection mushing error, belong to aerospace vehicle electromagnetic environmental effects field tests.

Background technology

The artificial electromagnetic interference (EMI) in the outside that aerospace vehicle is subject to comprises the electromagnetic radiation from airport (GCR etc.), ground transmitter (Commercial Radio etc.), naval vessel (navar etc.) and aerial (tracking radar etc.), and the summation of these radiation is called HIRF environment.In recent ten years, along with the development of the radio frequency source of radar, microwave cellular communication, manual communication's network and equipment, the HIRF environment that present aerospace vehicle faces becomes and becomes increasingly complex, and the impact that the flight safety of HIRF on aerospace vehicle is brought also day by day manifests.

In order to protect the adverse effect of critical system from HIRF of aerospace vehicle; CAAC has promulgated corresponding standard, and the research and development program element defining the serial civil aviation spacecrafts such as the large aircraft of national Efforts To Develop must carry out the test of HIRF seaworthiness airworthiness compliance test.

HIRF test in reality is ground simulation test, and by the restriction of the factors such as aerospace vehicle dimension and weight, HIRF test is generally all carried out in open outside place.Owing to there is ground Multipath reflection interference, causing ground simulation test can not reflect the state of flight of aerospace vehicle truly, there is the error of ground Multipath reflection interference in test result.

The present invention, from above-mentioned mentioned problem, is intended to the removing method proposing ground Multipath reflection mushing error in a kind of HIRF test, thus can eliminates the adverse effect of the ground Multipath reflection mushing error in HIRF test.

Summary of the invention

The object of this invention is to provide the removing method of ground Multipath reflection mushing error in a kind of HIRF test, for realizing Processing for removing HIRF test data being carried out to ground Multipath reflection mushing error, guarantee the correctness of HIRF test data, thus solve in aerospace vehicle HIRF ground simulation test because of impact that ground Multipath reflection mushing error produces.

For achieving the above object, the invention provides the removing method of ground Multipath reflection mushing error in a kind of HIRF test, comprise following steps:

S1, according to HIRF test determine test point position, center and N number of subtest point position, configuration set up ground Multipath reflection interference model; Wherein, described ground Multipath reflection interference model comprises transmitter antenna gain (dBi), position of transmitting antenna and height and ground reflection coefficent;

The formate field intensity of S2, employing raypath back tracking method difference computing center's test point and N number of subtest point; Wherein, the function that described formate field intensity is is independent variable with transmitter antenna gain (dBi), test point position with height, ground reflection coefficent;

S3, test Zhong center test point and N number of subtest point according to HIRF and test the amplitude of field strength data obtained, adopt the undetermined coefficient that least squares error approximatioss is determined in the formate field intensity function of center test point, realize being separated of direct projection electromagnetic wave component and ground return electromagnetic wave component in the receiving antenna Received signal strength at test point place, center;

S4, according to direct projection electromagnetic wave component and ground return electromagnetic wave component, determine the excretion factor of ground Multipath reflection interference, and Processing for removing is carried out to the ground Multipath reflection mushing error of center test point.

In described step S1, in the process setting up ground Multipath reflection interference model, measuring distance R between emitting antenna and test point position, center need meet the following conditions: the half-power beam width (also referred to as 3dB beam angle) of emitting antenna can irradiate the cabin to be measured of aerospace vehicle completely, and ground Multipath reflection meets mirror-reflection condition.

The condition that measuring distance R between described emitting antenna and test point position, center specifically need meet is:

According to Rayleigh criterion, when only considering the mirror-reflection on ground, the relief height h on ground should meet:

Wherein: for the grazing angle that the electromagnetic wave launched by emitting antenna and ground are formed, λ ₀for the wavelength that this electromagnetic wave is corresponding;

The height H of measuring distance R and receiving antenna setting position need meet:

Simultaneous formula (1) and formula (2) can obtain, and when ground Multipath reflection meets mirror-reflection, measuring distance R need meet:

$R<\frac{H}{{\mathrm{\&lambda;}}_0}\sqrt{{\left(32h\right)}^2-{\mathrm{\&lambda;}}_0^2}---\left(3\right).$

In described step S1, centered by the test point of center, about it, front and back, symmetry chooses N number of subtest point on upper and lower three directions.

In described step S2, the step of the formate field intensity at the wherein some test point places in computing center's test point and N number of subtest point, is specially:

S21, arrange receiving antenna in current test point position, it is for the measurement of the formate field intensity to current test point place; By transmission antennas transmit and the electromagnetic wave directly arriving current test point without ground return is called direct projection electromagnetic wave, the electric field strength that described direct projection electromagnetic wave is formed at current test point place is:

$E_{\mathrm{ind}\left(i\right)}=\sqrt{\frac{Z_0{\mathrm{PG}}_i}{4\mathrm{\&pi;}}}\&CenterDot;\frac{e^{-j{\stackrel{\&RightArrow;}{k}}_i\&CenterDot;{\stackrel{\&RightArrow;}{r}}_i}}{r_i}\&CenterDot;{\stackrel{\&RightArrow;}{a}}_{\mathrm{ri}}---\left(4\right);$

Wherein, Z ₀for air wave impedance; P is the radiation power of emitting antenna; G _ifor emitting antenna is in the gain in direct projection electromagnetic wave direction; for the electromagnetic wave vector of direct projection; for the distance vector between emitting antenna and receiving antenna; for unit vector; J is imaginary unit, is expressed as i is the subscript of current test point, is expressed as i=1,2 ... N+1, wherein during i=1, represents test point centered by current test point, i=2 ... during N+1, represent that current test point is subtest point;

Direct projection electromagnetic wave in S22, above-mentioned formula (4) is respectively at the field intensity component in three orthogonal directions at current test point place:

Wherein, θ _eifor electric field polarization angle, θ _i, be respectively the electromagnetic incident angle of pitch of direct projection and position angle;

S23, by transmission antennas transmit and the electromagnetic wave arriving current test point after ground return is called ground return electromagnetic wave, the electric field strength that described ground return electromagnetic wave is formed at current test point place is:

$E_{\mathrm{ref}\left(i\right)}=\sqrt{\frac{Z_0{\mathrm{PG}}_{\mathrm{fi}}}{4\mathrm{\&pi;}}}\&CenterDot;\frac{e^{-j{\stackrel{\&RightArrow;}{k}}_{\mathrm{fi}}\&CenterDot;{\stackrel{\&RightArrow;}{r}}_{\mathrm{fi}}}}{r_{\mathrm{fi}}}\&CenterDot;{\stackrel{\&RightArrow;}{a}}_{\mathrm{rfi}}\&CenterDot;{\mathrm{\&Gamma;}}_{\mathrm{fi}}{e}^{{\mathrm{i\&theta;}}_{\mathrm{fi}}}---\left(6\right);$

Wherein, G _fifor emitting antenna is in the gain in ground return electromagnetic wave direction, for the electromagnetic wave vector of ground return, for the distance vector between emitting antenna mirror image and receiving antenna, for unit vector, Γ _fiand θ _fibe respectively amplitude and the phase place of the ground reflection coefficent in ground return electromagnetic wave direction;

Ground return electromagnetic wave in S24, above-mentioned formula (6) is respectively at the field intensity component in three orthogonal directions at current test point place:

Wherein, θ _fi, be respectively the electromagnetic incident angle of pitch of ground return and position angle;

S25, simultaneous formula (5) and formula (7) can obtain, and the formate field intensity component in three orthogonal directions after current test point place direct projection electromagnetic wave and ground return electromagnetic wave interference is respectively:

$\left\{\begin{array}{c}{E}_{x\left(i\right)}=E_{\mathrm{indx}\left(i\right)}+E_{\mathrm{refx}\left(i\right)}\\ E_{y\left(i\right)}=E_{\mathrm{indy}\left(i\right)}+E_{\mathrm{refy}\left(i\right)}\\ E_{z\left(i\right)}=E_{\mathrm{indz}\left(i\right)}+E_{\mathrm{refz}\left(i\right)}\end{array}\right.---\left(8\right);$

Therefore, the formate field intensity amplitude at current test point place is:

$E_{\left(i\right)}=(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})=\sqrt{E_{x\left(i\right)}^2+E_{y\left(i\right)}^2+E_{z\left(i\right)}^2}---\left(9\right).$

Described step S3 specifically comprises following steps:

S31, the amplitude of field strength obtaining center test point and N number of subtest point in HIRF test are E _{test (i)};

S32, test the amplitude of field strength of center test point and the N number of subtest point obtained according to HIRF, and according to the amplitude of field strength of the center test point calculated in raypath back tracking method and N number of subtest point, adopt the unknown quantity that least squares error approximatioss is determined in formula (9).

Described step S32 specifically comprises following steps:

S321, for center test point and N number of subtest point, calculate its amplitude of field strength obtained in raypath back tracking method and the square error value of amplitude of field strength obtained in HIRF tests:

δ _(i)(G _i,G _fi,Γ _fi,θ _fi)＝(E _(i)(G _i,G _fi,Γ _fi,θ _fi)-E _test(i)) ²(10)；

The accumulation square error value of S322, computing center's test point and N number of subtest point:

$\mathrm{\&delta;}(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})=\underset{i=1}{\overset{N+1}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_{\left(i\right)}(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})---\left(11\right);$

S323, respectively at G _i, G _fi, Γ _fi, θ _fiiterative computation is carried out, as δ (G in the constant interval of four independents variable _i, G _fi, Γ _fi, θ _fi) when reaching minimum value, can G be determined _i, G _fi, Γ _fi, θ _fibest-fit values;

S324, by G _i, G _fi, Γ _fi, θ _fisubstitute in formula (5) and formula (7) respectively, the direct projection electromagnetic wave at test point place, center and the electromagnetic component of ground return can be separated, and the field intensity E of the direct projection electromagnetic wave in formula (4) in center test point can be calculated _{ind (1)}.

In described step S323, G _i, G _fiwithin the scope of transmitter antenna gain (dBi), Γ _fi, θ interior in [-1,1] scope _fiat [-180,180] scope internal linear interval, value carries out iterative computation.

Described step S4 specifically comprises following steps:

The excretion factor of S41, the Multipath reflection interference of calculating ground:

Correct _(dB)＝20log(E _ind(1)/E _test(1)) (12)；

Wherein, E _{test (1)}for testing the amplitude of field strength at the test point place, center obtained according to HIRF;

S42, by excretion factor Correct _(dB)to HIRF test data E _{test (dB)}correct, the elimination of ground Multipath reflection mushing error can be realized, be expressed as:

Revise data _(dB)=E _{test (dB)}+ Correct _(dB)(13);

Wherein, E _{test (dB)}=20log (E _{test (i)}).

The removing method of ground Multipath reflection mushing error in HIRF test of the present invention, also comprise: step S5, repetition above-mentioned steps S1 ~ S4, in HIRF test, complete the ground Multipath reflection interference cancellation operation to each center test point that other are determined.

In sum, in HIRF test provided by the present invention, the removing method of ground Multipath reflection mushing error, realizes the Processing for removing of ground multipath error, guarantees the correctness of HIRF test data.The present invention has very strong practicality and good application prospect, especially in the HIRF ground simulation test of the large aerospace spacecrafts such as domestic large aircraft, military spacecraft, plays the important and pivotal role.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of the removing method of ground Multipath reflection mushing error during HIRF provided by the invention tests;

Fig. 2 is the schematic diagram of checkout area point in the present invention;

Fig. 3 is the schematic diagram of ground Multipath reflection mushing error excretion factor in the present invention;

Fig. 4 is the schematic diagram of the correction result in the present invention after the elimination of ground Multipath reflection mushing error.

Embodiment

Below in conjunction with Fig. 1 ~ Fig. 4, describe a preferred embodiment of the present invention in detail.

As shown in Figure 1, be the process flow diagram of the removing method of ground Multipath reflection mushing error in HIRF test provided by the invention, the method includes the steps of:

S1, according to HIRF test determine test point position, center and N number of subtest point position, configuration set up ground Multipath reflection interference model; Wherein, described ground Multipath reflection interference model comprises transmitter antenna gain (dBi), position of transmitting antenna and height and ground reflection coefficent.

As shown in Figure 2, in described step S1, in the process setting up ground Multipath reflection interference model, measuring distance R between emitting antenna and test point position, center need meet the following conditions: the half-power beam width (also referred to as 3dB beam angle) of emitting antenna can irradiate the cabin to be measured of aerospace vehicle completely, and ground Multipath reflection meets mirror-reflection condition.

Concrete, according to Rayleigh criterion, when only considering the mirror-reflection on ground, the relief height h on ground should meet:

Wherein: for the grazing angle that the electromagnetic wave launched by emitting antenna and ground are formed, λ ₀for the wavelength that this electromagnetic wave is corresponding;

The height H of measuring distance R and receiving antenna setting position need meet:

Simultaneous formula (1) and formula (2) can obtain, and when ground Multipath reflection meets mirror-reflection, measuring distance R need meet:

$R<\frac{H}{{\mathrm{\&lambda;}}_0}\sqrt{{\left(32h\right)}^2-{\mathrm{\&lambda;}}_0^2}---\left(3\right).$

As shown in Figure 2, in described step S1, centered by center test point (representing by round dot in figure), about it, front and back, the upper symmetry of upper and lower three directions (being represented by dotted lines in figure) choose N number of subtest point.

The formate field intensity of S2, employing raypath back tracking method difference computing center's test point and N number of subtest point; The function that described formate field intensity is is independent variable with transmitter antenna gain (dBi), test point position with height, ground reflection coefficent.

In described step S2, the step of the formate field intensity at the wherein some test point places in computing center's test point and N number of subtest point, is specially:

S21, arrange receiving antenna in current test point position, it is for the measurement of the formate field intensity to current test point place; By transmission antennas transmit and the electromagnetic wave directly arriving current test point without ground return is called direct projection electromagnetic wave, the electric field strength that described direct projection electromagnetic wave is formed at current test point place is:

$E_{\mathrm{ind}\left(i\right)}=\sqrt{\frac{Z_0{\mathrm{PG}}_i}{4\mathrm{\&pi;}}}\&CenterDot;\frac{e^{-j{\stackrel{\&RightArrow;}{k}}_i\&CenterDot;{\stackrel{\&RightArrow;}{r}}_i}}{r_i}\&CenterDot;{\stackrel{\&RightArrow;}{a}}_{\mathrm{ri}}---\left(4\right);$

Wherein, Z ₀for air wave impedance; P is the radiation power of emitting antenna; G _ifor emitting antenna is in the gain in direct projection electromagnetic wave direction; for the electromagnetic wave vector of direct projection; for the distance vector between emitting antenna and receiving antenna; for unit vector; J is imaginary unit, is expressed as i is the subscript of current test point, is expressed as i=1,2 ... N+1, wherein during i=1, represents test point centered by current test point, i=2 ... during N+1, represent that current test point is subtest point;

Direct projection electromagnetic wave in S22, above-mentioned formula (4) is respectively at the field intensity component in three orthogonal directions at current test point place:

Wherein, θ _eifor electric field polarization angle, θ _i, be respectively the electromagnetic incident angle of pitch of direct projection and position angle;

S23, by transmission antennas transmit and the electromagnetic wave arriving current test point after ground return is called ground return electromagnetic wave, the electric field strength that described ground return electromagnetic wave is formed at current test point place is:

$E_{\mathrm{ref}\left(i\right)}=\sqrt{\frac{Z_0{\mathrm{PG}}_{\mathrm{fi}}}{4\mathrm{\&pi;}}}\&CenterDot;\frac{e^{-j{\stackrel{\&RightArrow;}{k}}_{\mathrm{fi}}\&CenterDot;{\stackrel{\&RightArrow;}{r}}_{\mathrm{fi}}}}{r_{\mathrm{fi}}}\&CenterDot;{\stackrel{\&RightArrow;}{a}}_{\mathrm{rfi}}\&CenterDot;{\mathrm{\&Gamma;}}_{\mathrm{fi}}{e}^{{\mathrm{i\&theta;}}_{\mathrm{fi}}}---\left(6\right);$

Wherein, G _fifor emitting antenna is in the gain in ground return electromagnetic wave direction, for the electromagnetic wave vector of ground return, for the distance vector between emitting antenna mirror image and receiving antenna, for unit vector, Γ _fiand θ _fibe respectively amplitude and the phase place of the ground reflection coefficent in ground return electromagnetic wave direction;

Ground return electromagnetic wave in S24, above-mentioned formula (6) is respectively at the field intensity component in three orthogonal directions at current test point place:

Wherein, θ _fi, be respectively the electromagnetic incident angle of pitch of ground return and position angle;

S25, simultaneous formula (5) and formula (7) can obtain, and the formate field intensity component in three orthogonal directions after current test point place direct projection electromagnetic wave and ground return electromagnetic wave interference is respectively:

$\left\{\begin{array}{c}{E}_{x\left(i\right)}=E_{\mathrm{indx}\left(i\right)}+E_{\mathrm{refx}\left(i\right)}\\ E_{y\left(i\right)}=E_{\mathrm{indy}\left(i\right)}+E_{\mathrm{refy}\left(i\right)}\\ E_{z\left(i\right)}=E_{\mathrm{indz}\left(i\right)}+E_{\mathrm{refz}\left(i\right)}\end{array}\right.---\left(8\right);$

Therefore, the formate field intensity amplitude at current test point place is:

$E_{\left(i\right)}=(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})=\sqrt{E_{x\left(i\right)}^2+E_{y\left(i\right)}^2+E_{z\left(i\right)}^2}---\left(9\right);$

As can be seen from formula (9), the formate field intensity amplitude of each test point can be expressed as the function of antenna gain, ground reflection coefficent amplitude and the phase place of emitting antenna on direct projection electromagnetic wave direction and ground return electromagnetic wave direction.

S3, test Zhong center test point and N number of subtest point according to HIRF and test the amplitude of field strength data obtained, adopt the undetermined coefficient that least squares error approximatioss is determined in the formate field intensity function of center test point, realize being separated of direct projection electromagnetic wave component and ground return electromagnetic wave component in the receiving antenna Received signal strength at test point place, center.

Described step S3 specifically comprises following steps:

S31, the amplitude of field strength obtaining center test point and N number of subtest point in HIRF test are E _{test (i)}; In HIRF test, the amplitude of field intensity can only be obtained, and the phase place of field intensity can not be obtained;

S32, test the amplitude of field strength of center test point and the N number of subtest point obtained according to HIRF, and according to the amplitude of field strength of the center test point calculated in raypath back tracking method and N number of subtest point, employing least squares error approximatioss determines the unknown quantity in formula (9), and detailed process is as follows:

S321, for center test point and N number of subtest point, calculate its amplitude of field strength obtained in raypath back tracking method and the square error value of amplitude of field strength obtained in HIRF tests:

δ _(i)(G _i,G _fi,Γ _fi,θ _fi)＝(E _(i)(G _i,G _fi,Γ _fi,θ _fi)-E _test(i)) ²(10)；

The accumulation square error value of S322, computing center's test point and N number of subtest point:

$\mathrm{\&delta;}(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})=\underset{i=1}{\overset{N+1}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_{\left(i\right)}(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})---\left(11\right);$

S323, respectively at G _i, G _fi, Γ _fi, θ _fiiteration is carried out, as δ (G in the constant interval of four independents variable _i, G _fi, Γ _fi, θ _fi) when reaching minimum value, can G be determined _i, G _fi, Γ _fi, θ _fibest-fit values;

Wherein, G _i, G _fiwithin the scope of transmitter antenna gain (dBi), Γ _fi, θ interior in [-1,1] scope _fiat [-180,180] scope internal linear interval, value carries out iteration.

S324, by G _i, G _fi, Γ _fi, θ _fisubstitute in formula (5) and formula (7) respectively, the direct projection electromagnetic wave at test point place, center and the electromagnetic component of ground return can be separated, and the field intensity E of the direct projection electromagnetic wave in formula (4) in center test point can be calculated _{ind (1)}.

S4, according to direct projection electromagnetic wave component and ground return electromagnetic wave component, determine the excretion factor of ground Multipath reflection interference, and Processing for removing is carried out to the ground Multipath reflection mushing error of center test point.

Described step S4 specifically comprises following steps:

The excretion factor of S41, the Multipath reflection interference of calculating ground:

Correct _(dB)＝20log(E _ind(1)/E _test(1)) (12)；

Wherein, E _{test (1)}for testing the amplitude of field strength at the test point place, center obtained according to HIRF;

Above-mentioned excretion factor can be the curve that single test point changes with wave frequency, also can be the curve that unifrequency changes with test position; Be illustrated in figure 3 the curve synoptic diagram that excretion factor list test point changes with wave frequency, wherein only show and process the excretion factor numerical value of these four frequencies of 2GHz, 4GHz, 8GHz and 16GHz;

S42, by excretion factor Correct _(dB)to HIRF test data E _{test (dB)}correct, the elimination of ground Multipath reflection mushing error can be realized, be expressed as:

Revise data _(dB)=E _{test (dB)}+ Correct _(dB)(13);

Wherein E _{test (dB)}=20log (E _{test (i)}).

As shown in Figure 4, for the correction result of HIRF field strength measurement data after excretion factor process, as can be seen from the figure, correction result after the Multipath reflection mushing error Processing for removing of ground of the present invention is compared with the amplitude of field strength of the no reflection events wave interference of theory calculate, error is less than 0.5dB, thus has absolutely proved the validity of error cancelling method provided by the present invention.

S5, repetition above-mentioned steps S1 ~ S4, in HIRF test, complete the ground Multipath reflection interference cancellation operation to each center test point that other are determined.

In sum, in HIRF test provided by the present invention, the removing method of ground Multipath reflection mushing error, realizes the Processing for removing of ground multipath error, guarantees the correctness of HIRF test data.The present invention has very strong practicality and good application prospect, especially in the HIRF ground simulation test of the large aerospace spacecrafts such as domestic large aircraft, military spacecraft, plays the important and pivotal role.

Although content of the present invention has done detailed introduction by above preferred embodiment, will be appreciated that above-mentioned description should not be considered to limitation of the present invention.After those skilled in the art have read foregoing, for multiple amendment of the present invention and substitute will be all apparent.Therefore, protection scope of the present invention should be limited to the appended claims.

Claims (10)

1. the removing method of ground Multipath reflection mushing error in HIRF test, is characterized in that, comprise following steps:

S1, according to HIRF test determine test point position, center and N number of subtest point position, configuration set up ground Multipath reflection interference model;

Wherein, described ground Multipath reflection interference model comprises transmitter antenna gain (dBi), position of transmitting antenna and height and ground reflection coefficent;

The formate field intensity of S2, employing raypath back tracking method difference computing center's test point and N number of subtest point;

Wherein, the function that described formate field intensity is is independent variable with transmitter antenna gain (dBi), test point position with height, ground reflection coefficent;

S3, test Zhong center test point and N number of subtest point according to HIRF and test the amplitude of field strength data obtained, adopt the undetermined coefficient that least squares error approximatioss is determined in the formate field intensity function of center test point, realize being separated of direct projection electromagnetic wave component and ground return electromagnetic wave component in the receiving antenna Received signal strength at test point place, center;

S4, according to direct projection electromagnetic wave component and ground return electromagnetic wave component, determine the excretion factor of ground Multipath reflection interference, and Processing for removing is carried out to the ground Multipath reflection mushing error of center test point.

2. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 1, it is characterized in that, in described step S1, in the process setting up ground Multipath reflection interference model, measuring distance R between emitting antenna and test point position, center need meet the following conditions: the half-power beam width (also referred to as 3dB beam angle) of emitting antenna can irradiate the cabin to be measured of aerospace vehicle completely, and ground Multipath reflection meets mirror-reflection condition.

3. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 2, it is characterized in that, the condition that the measuring distance R between described emitting antenna and test point position, center specifically need meet is:

According to Rayleigh criterion, when only considering the mirror-reflection on ground, the relief height h on ground should meet:

Wherein: for the grazing angle that the electromagnetic wave launched by emitting antenna and ground are formed, λ ₀for the wavelength that this electromagnetic wave is corresponding;

The height H of measuring distance R and receiving antenna setting position need meet:

Simultaneous formula (1) and formula (2) can obtain, and when ground Multipath reflection meets mirror-reflection, measuring distance R need meet:

$R<\frac{H}{{\mathrm{\&lambda;}}_0}\sqrt{{\left(32h\right)}^2-{\mathrm{\&lambda;}}_0^2}---\left(3\right).$

4. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 3, it is characterized in that, in described step S1, centered by the test point of center, about it, front and back, symmetry chooses N number of subtest point on upper and lower three directions.

5. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 4, it is characterized in that, in described step S2, the step of the formate field intensity at the wherein some test point places in computing center's test point and N number of subtest point, is specially:

S21, arrange receiving antenna in current test point position, it is for the measurement of the formate field intensity to current test point place; By transmission antennas transmit and the electromagnetic wave directly arriving current test point without ground return is called direct projection electromagnetic wave, the electric field strength that described direct projection electromagnetic wave is formed at current test point place is:

$E_{\mathrm{ind}\left(i\right)}=\sqrt{\frac{Z_0{\mathrm{PG}}_i}{4\mathrm{\&pi;}}}\&CenterDot;\frac{e^{-j{\stackrel{\&RightArrow;}{k}}_i\&CenterDot;{\stackrel{\&RightArrow;}{r}}_i}}{r_i}\&CenterDot;{\stackrel{\&RightArrow;}{a}}_{\mathrm{ri}}---\left(4\right);$

Wherein, Z ₀for air wave impedance; P is the radiation power of emitting antenna; G _ifor emitting antenna is in the gain in direct projection electromagnetic wave direction; for the electromagnetic wave vector of direct projection; for the distance vector between emitting antenna and receiving antenna; for unit vector; J is imaginary unit, is expressed as i is the subscript of current test point, is expressed as i=1,2 ... N+1, wherein during i=1, represents test point centered by current test point, i=2 ... during N+1, represent that current test point is subtest point;

Direct projection electromagnetic wave in S22, above-mentioned formula (4) is respectively at the field intensity component in three orthogonal directions at current test point place:

Wherein, θ _eifor electric field polarization angle, θ _i, be respectively the electromagnetic incident angle of pitch of direct projection and position angle;

S23, by transmission antennas transmit and the electromagnetic wave arriving current test point after ground return is called ground return electromagnetic wave, the electric field strength that described ground return electromagnetic wave is formed at current test point place is:

$E_{\mathrm{ref}\left(i\right)}=\sqrt{\frac{Z_0{\mathrm{PG}}_{\mathrm{fi}}}{4\mathrm{\&pi;}}}\&CenterDot;\frac{e^{-j{\stackrel{\&RightArrow;}{k}}_{\mathrm{fi}}\&CenterDot;{\stackrel{\&RightArrow;}{r}}_{\mathrm{fi}}}}{r_{\mathrm{fi}}}\&CenterDot;{\stackrel{\&RightArrow;}{a}}_{\mathrm{rfi}}\&CenterDot;{\mathrm{\&Gamma;}}_{\mathrm{fi}}{e}^{i{\mathrm{\&theta;}}_{\mathrm{fi}}}---\left(6\right);$

Wherein, G _fifor emitting antenna is in the gain in ground return electromagnetic wave direction, for the electromagnetic wave vector of ground return, for the distance vector between emitting antenna mirror image and receiving antenna, for unit vector, Γ _fiand θ _fibe respectively amplitude and the phase place of the ground reflection coefficent in ground return electromagnetic wave direction;

Ground return electromagnetic wave in S24, above-mentioned formula (6) is respectively at the field intensity component in three orthogonal directions at current test point place:

Wherein, θ _fi, be respectively the electromagnetic incident angle of pitch of ground return and position angle;

S25, simultaneous formula (5) and formula (7) can obtain, and the formate field intensity component in three orthogonal directions after current test point place direct projection electromagnetic wave and ground return electromagnetic wave interference is respectively:

$\left\{\begin{array}{c}{E}_{x\left(i\right)}=E_{\mathrm{indx}\left(i\right)}+E_{\mathrm{refx}\left(i\right)}\\ E_{y\left(i\right)}=E_{\mathrm{indy}\left(i\right)}+E_{\mathrm{refy}\left(i\right)}\\ E_{z\left(i\right)}=E_{\mathrm{indz}\left(i\right)}+E_{\mathrm{refz}\left(i\right)}\end{array}\right.---\left(8\right);$

Therefore, the formate field intensity amplitude at current test point place is:

$E_{\left(i\right)}(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})=\sqrt{E_{x\left(i\right)}^2+E_{y\left(i\right)}^2+E_{z\left(i\right)}^2}---\left(9\right).$

6. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 5, it is characterized in that, described step S3 specifically comprises following steps:

S31, the amplitude of field strength obtaining center test point and N number of subtest point in HIRF test are E _{test (i)};

S32, test the amplitude of field strength of center test point and the N number of subtest point obtained according to HIRF, and according to the amplitude of field strength of the center test point calculated in raypath back tracking method and N number of subtest point, adopt the unknown quantity that least squares error approximatioss is determined in formula (9).

7. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 6, it is characterized in that, described step S32 specifically comprises following steps:

S321, for center test point and N number of subtest point, calculate its amplitude of field strength obtained in raypath back tracking method and the square error value of amplitude of field strength obtained in HIRF tests:

δ _(i)(G _i,G _fi,Γ _fi,θ _fi)＝(E _(i)(G _i,G _fi,Γ _fi,θ _fi)-E _test(i)) ²(10)；

The accumulation square error value of S322, computing center's test point and N number of subtest point:

$\mathrm{\&delta;}(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})=\underset{i=1}{\overset{N+1}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_{\left(i\right)}(G_i,G_{\mathrm{fi}},{\mathrm{\&Gamma;}}_{\mathrm{fi}},{\mathrm{\&theta;}}_{\mathrm{fi}})---\left(11\right);$

S323, respectively at G _i, G _fi, Γ _fi, θ _fiiterative computation is carried out, as δ (G in the constant interval of four independents variable _i, G _fi, Γ _fi, θ _fi) when reaching minimum value, can G be determined _i, G _fi, Γ _fi, θ _fibest-fit values;

S324, by G _i, G _fi, Γ _fi, θ _fisubstitute in formula (5) and formula (7) respectively, the direct projection electromagnetic wave at test point place, center and the electromagnetic component of ground return can be separated, and the field intensity E of the direct projection electromagnetic wave in formula (4) in center test point can be calculated _{ind (1)}.

8. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 7, is characterized in that, in described step S323, and G _i, G _fiwithin the scope of transmitter antenna gain (dBi), Γ _fi, θ interior in [-1,1] scope _fiat [-180,180] scope internal linear interval, value carries out iterative computation.

9. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 8, it is characterized in that, described step S4 specifically comprises following steps:

The excretion factor of S41, the Multipath reflection interference of calculating ground:

Correct _(dB)＝20log(E _ind(1)/E _test(1)) (12)；

Wherein, E _{test (1)}for testing the amplitude of field strength at the test point place, center obtained according to HIRF;

S42, by excretion factor Correct _(dB)to HIRF test data E _{test (dB)}correct, the elimination of ground Multipath reflection mushing error can be realized, be expressed as:

Revise data _(dB)=E _{test (dB)}+ Correct _(dB)(13);

Wherein, E _{test (dB)}=20log (E _{test (i)}).

10. the removing method of ground Multipath reflection mushing error in HIRF test as claimed in claim 9, it is characterized in that, also comprise: step S5, repetition step S1 ~ S4, in HIRF test, complete the ground Multipath reflection interference cancellation operation to each center test point that other are determined.