CN114966533B - Direction finding method of phase interferometer of direction finding positioning system - Google Patents

Abstract

The invention discloses a direction-finding positioning system phase interferometer direction-finding method, which comprises the following steps: the terminal broadcasts a data packet signal with mark information and sine wave according to a protocol; after the base station receives the identification mark information, the radio frequency switch is controlled to time-share gate the antenna according to a preset sequence to receive sine wave signals in the data packet signals; preprocessing the received signals, eliminating phase difference caused by mismatch of radio frequency channels and receiving and transmitting carrier frequencies, and constructing multichannel received signals; selecting a baseline calculation phase difference, selecting a baseline group calculation, a phase difference and a difference phase difference, and combining a fuzzy phase combination to construct a plurality of groups of complex numbers containing arrival angle information; filtering complex elements with low clustering degree by a clustering method and calculating all possible arrival angles; and finally, obtaining an estimated value of the signal arrival angle through an energy method. The invention can enable the base station to quickly and accurately estimate the arrival angle of the terminal broadcast signal, and has lower complexity and cost.

Description

Direction finding method of phase interferometer of direction finding positioning system

Technical Field

The invention relates to the technical field of radio signal direction finding, in particular to a direction finding method of a phase interferometer of a direction finding positioning system.

Background

The purpose of radio direction finding is to detect the incoming wave direction of a radiation source, and the radio direction finding has wide application in the military and civil fields, such as electronic reconnaissance, radar, secondary radar, mobile communication, indoor positioning and the like. Compared with other direction-finding methods, the phase interferometer direction-finding method has the advantages of simple structure and easy realization. Compared with other array types, the circular array has higher array plane space utilization rate in two-dimensional direction finding. In most cases, a uniform circular array is typically used.

When the phase interferometer direction finding algorithm is applied to the front end of the base station, the direction finding positioning system faces the problems of multiple channels, large data volume, poor instantaneity and the like. The invention can enable the base station to quickly and accurately estimate the arrival angle of the terminal broadcast signal, and has lower complexity and cost.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides the direction-finding method of the phase interferometer of the direction-finding positioning system, which can enable a base station to quickly and accurately estimate the arrival angle of a terminal broadcast signal and has the technical characteristics of lower complexity.

In order to achieve the above object, the technical scheme adopted for solving the technical problems is as follows:

a direction finding method of a phase interferometer of a direction finding positioning system comprises the following steps:

Step S1: the terminal broadcasts a data packet signal with sign information, wherein the data packet signal comprises a section of continuous sine wave signal for direction finding;

Step S2: after the central communication antenna of the base station receives the identification mark information, the base station controls the radio frequency switch to time-division gate the direction-finding antenna and the communication antenna according to a preset sequence to receive sine wave signals in the data packet signals;

Step S3: preprocessing a received signal, eliminating phase difference caused by radio frequency channel phase difference and receiving-transmitting carrier frequency mismatch, and constructing a multichannel received signal;

Step S4: selecting direction-finding array elements with mutual interval p to form a base line and calculate a phase difference, selecting the base line with mutual interval q and calculate a sum phase difference and a difference phase difference, and combining a fuzzy phase combination to form a plurality of groups of complex numbers { f _i ^pq };

Step S5: analyzing the clustering degree of each element in a certain group of complex numbers and other groups of elements by a clustering method, filtering elements with low clustering degree or modulus value larger than 1, and calculating all possible arrival angles by using the residual elements;

Step S6: for each possible angle of arrival, generating a steering vector by using array element position, wavelength and circular array radius information, combining vectors formed by signals received by each antenna to generate a signal s, calculating signal energy, and taking the angle with the strongest energy as an estimated value.

Further, the step S1 includes the following steps:

Step S11: the mark information at least comprises a MAC address for identifying and distinguishing the terminal and a characteristic identification code for identifying and distinguishing the terminal containing sine waves;

Step S12: the sine wave signal s (t) is generated by modulating the direction-finding information code with the frequency f _sin, that is, s (t) =exp { j2 pi f _sin t }.

Further, the step S2 includes the following steps:

step S21: the base station comprises an array antenna, the array antenna consists of a communication antenna array element and N direction finding antenna array elements, the direction finding antennas are uniformly distributed along the circumference with the radius of R, the array elements are sequentially numbered 1,2, N, the communication antenna array elements are positioned at the center of a uniform circular array, and the number is 0;

step S22: the radio frequency switch gates the communication antenna to receive the space radio signal;

Step S23: when detecting the characteristic identification code for identifying the sine wave, the base station controls the radio frequency switch to time-sharing gate the direction-finding antenna and the communication antenna according to a preset sequence to receive the sine wave signal;

step S24: the preset array element gating sequence is communication antenna array elements, direction finding antenna array elements, communication antenna array elements and direction finding antenna array elements alternately gating, and optionally, the gating sequence is cycled for several rounds to finally gate the communication antenna array elements;

step S25: the gating period T _sw, and 2f _sinT_sw is an integer;

Step S26: the receiving wavelength of the gating array element is lambda, and the angle of pitch theta and azimuth of the antenna array When the sine wave signal s (T) is in the direction, s (T-2T _sw)＝exp{j(2πf_sint-2π·2f_sinT_sw)}＝exp{j2πf_sin T } = s (T);

When the communication antenna is gated, i.e., i=0, n=0, 2,..2N-2,

y_i(t)＝s(t-nT_sw)exp{j2πΔf(t-nT_sw)}，

When the direction finding antenna is gated, i.e., i=1,..n, n=1, 3,..2N-1,

Wherein Δf is a frequency difference caused by mismatch of the receiving and transmitting carrier frequencies;

step S27: the mismatch of the receiving and transmitting carrier frequencies is generated by the combined action of Doppler frequency offset and receiving and transmitting local oscillation mismatch which are introduced by the mutual motion between the terminal and the base station.

Further, the step S3 includes the following steps:

step S31: compensating the phase difference of the radio frequency channel, and calibrating the phase difference through a stationary signal source in the normal direction of the far field of the antenna array;

Step S32: compensating for phase differences caused by mismatch of the transmit and receive carrier frequencies, and constructing a multichannel receive signal r _i (t), i=1, 2,..n, satisfying:

wherein exp { jγ } is constant;

Step S33: the longer the r _i (t) signal length is, the higher the measurement accuracy of the phase difference is, and the following relationship exists between the measurement accuracy of the phase difference and the signal to noise ratio in single measurement: epsilon is the signal-to-noise ratio, and the precision is improved to be L=t _sw/T_s,T_s sample time interval.

Further, the step S4 includes the following steps:

Step S41: selecting a baseline (i, i+p) and a baseline (i+q, i+q+p), which are not parallel;

The base line (i, i+p) consists of mod (i-1, N) +1 and mod (i+p-1, N) +1 direction-finding antenna array elements, and the phase difference is as follows:

Step S42: combining wavelength, antenna array size and direction finding range, the maximum phase ambiguity number is The fuzzy phase difference set is { phi _i,i+p+2M_i,i+p pi }/>, and

Similarly, the phase difference of the base lines (i+q, i+q+p) is:

Step S43: combining wavelength, antenna array size and direction finding range, the maximum phase ambiguity number is The fuzzy phase difference set is { phi _i+q,i+q+p+2M_i+q,i+q+p pi }/>, and

The sum of the phase differences of the base line (i, i+p) and the base line (i+q, i+q+p) is:

the difference between the base line (i, i+p) and the base line (i+q, i+q+p) phase difference is:

step S44: definition of the definition

Combining the fuzzy phase difference sets to construct a set of complex numbers:

the value of the i is changed by the value of i (i=1, 2, n.), constructing N sets of complex numbers.

Further, the step S5 includes the following steps:

Step S51: taking a certain group of complex numbers f _i ^pq as a reference, wherein each element in the group is close to a certain element of the other groups, namely the clustering degree is highest, the elements which are close to each other correspond to the real incoming wave direction, the distances between each element in the group and each element of the other groups are calculated, and if the element modulus value is larger than 1, the distances between the elements are set as maximum values;

Step S52: searching the shortest distance from each element in the group to the elements of the other groups, summing N-1 shortest distances corresponding to each element, and finding out the element class with the smallest distance in the group;

Step S53: at least one element class exists in the group, and all possible arrival angles are calculated according to elements in the element class:

further, the step S6 includes the following steps:

Step S61: for each possible angle of arrival Generating an Nx1 guide vector A by combining the wavelength and the array element position of the antenna array;

step S62: the signals R _i (t) after the phase difference is eliminated by utilizing each array element form an N multiplied by L data vector R;

step S63: calculating s=a ^H R to obtain a1×l data vector S, and obtaining the element energy sum P, i.e., p= Σ|s _i|²,s_i, of the i-th element in the data vector S;

Step S64: each possible angle of arrival corresponds to an energy, and the angle to which the energy is maximum corresponds is used as the unambiguous angle of arrival estimate.

Compared with the prior art, the invention has the following advantages and positive effects due to the adoption of the technical scheme:

The direction-finding positioning system phase interferometer direction-finding method can enable the base station to quickly and accurately estimate the arrival angle of the terminal broadcast signal, and has the technical characteristics of low complexity.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present invention, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is evident that the drawings in the following description are only some embodiments of the invention and that other drawings may be obtained from these drawings by those skilled in the art without inventive effort. In the accompanying drawings:

FIG. 1 is a flow chart of a direction finding method of a phase interferometer of a direction finding positioning system according to the present invention;

fig. 2 is a schematic diagram of an antenna array according to the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

As shown in fig. 1, the embodiment discloses a direction-finding method of a phase interferometer of a direction-finding positioning system, which comprises the following steps:

Step S1: the terminal broadcasts a data packet signal with sign information, wherein the data packet signal comprises a section of continuous sine wave signal for direction finding;

Step S2: after the central communication antenna of the base station receives the identification mark information, the base station controls the radio frequency switch to time-division gate the direction-finding antenna and the communication antenna according to a preset sequence to receive sine wave signals in the data packet signals;

Step S3: preprocessing a received signal, eliminating phase difference caused by radio frequency channel phase difference and receiving-transmitting carrier frequency mismatch, and constructing a multichannel received signal;

Step S4: selecting direction-finding array elements with mutual interval p to form a base line and calculate a phase difference, selecting the base line with mutual interval q and calculate a sum phase difference and a difference phase difference, and combining a fuzzy phase combination to form a plurality of groups of complex numbers { f _i ^pq };

Step S5: analyzing the clustering degree of each element in a certain group of complex numbers and other groups of elements by a clustering method, filtering elements with low clustering degree or modulus value larger than 1, and calculating all possible arrival angles by using the residual elements;

Step S6: for each possible arrival angle, generating a guide vector by using information such as array element position, wavelength, circular array radius and the like, combining vector generated signals s formed by signals received by each antenna, calculating signal energy, and taking the angle with the strongest energy as an estimated value.

Further, the step S1 includes the following steps:

Step S11: the mark information at least comprises a MAC address for identifying and distinguishing the terminal and a characteristic identification code for identifying and distinguishing the terminal containing sine waves;

Step S12: the sine wave signal s (t) is generated by modulating the direction-finding information code with the frequency f _sin, that is, s (t) =exp { j2 pi f _sin t }.

Further, the step S2 includes the following steps:

step S21: the base station comprises an array antenna, the array antenna consists of a communication antenna array element and N direction finding antenna array elements, the direction finding antennas are uniformly distributed along the circumference with the radius of R, the array elements are sequentially numbered 1,2, N, the communication antenna array elements are positioned at the center of a uniform circular array, and the number is 0;

step S22: the radio frequency switch gates the communication antenna to receive the space radio signal;

Step S23: when detecting the characteristic identification code for identifying the sine wave, the base station controls the radio frequency switch to time-sharing gate the direction-finding antenna and the communication antenna according to a preset sequence to receive the sine wave signal;

step S24: the preset array element gating sequence is communication antenna array elements, direction finding antenna array elements, communication antenna array elements and direction finding antenna array elements alternately gating, and optionally, the gating sequence is cycled for several rounds to finally gate the communication antenna array elements;

step S25: the gating period T _sw, and 2f _sinT_sw is an integer;

Step S26: the receiving wavelength of the gating array element is lambda, and the angle of pitch theta and azimuth of the antenna array When the sine wave signal s (T) is in the direction, s (T-2T _sw)＝exp{j(2πf_sint-2π·2f_sinT_sw)}＝exp{j2πf_sin T } = s (T);

When the communication antenna is gated, i.e., i=0, n=0, 2,..2N-2,

y_i(t)＝s(t-nT_sw)exp{j2πΔf(t-nT_sw)}，

When the direction finding antenna is gated, i.e., i=1,..n, n=1, 3,..2N-1,

Wherein Δf is a frequency difference caused by mismatch of the receiving and transmitting carrier frequencies;

step S27: the mismatch of the receiving and transmitting carrier frequencies is generated by the combined action of Doppler frequency offset and receiving and transmitting local oscillation mismatch which are introduced by the mutual motion between the terminal and the base station.

Further, the step S3 includes the following steps:

Step S31: compensating the phase difference of the radio frequency channel, wherein the phase difference is calibrated through a stationary signal source in the normal direction of the far field of the antenna array, and because the phase difference introduced by the incident angle does not exist in the received signals of each antenna at the moment, the analyzed phase difference is caused by mismatch of the radio frequency channel, components and receiving and transmitting carrier frequencies;

Step S32: compensating for phase differences caused by mismatch of the transmit and receive carrier frequencies, and constructing a multichannel receive signal r _i (t), i=1, 2,..n, satisfying:

wherein exp { jγ } is constant;

Step S33: the longer the r _i (t) signal length is, the higher the measurement accuracy of the phase difference is, and the following relationship exists between the measurement accuracy of the phase difference and the signal to noise ratio in single measurement: epsilon is the signal-to-noise ratio, and the precision is improved to be L=t _sw/T_s,T_s sample time interval.

Further, the step S4 includes the following steps:

Step S41: selecting a baseline (i, i+p) and a baseline (i+q, i+q+p), which are not parallel;

The base line (i, i+p) consists of mod (i-1, N) +1 and mod (i+p-1, N) +1 direction-finding antenna array elements, and the phase difference is as follows:

Step S42: combining wavelength, antenna array size and direction finding range, the maximum phase ambiguity number is The fuzzy phase difference set is { phi _i,i+p+2M_i,i+p pi }/>, and

Similarly, the phase difference of the base lines (i+q, i+q+p) is:

Step S43: combining wavelength, antenna array size and direction finding range, the maximum phase ambiguity number is The fuzzy phase difference set is { phi _i+q,i+q+p+2M_i+q,i+q+p pi }/>, and

The sum of the phase differences of the base line (i, i+p) and the base line (i+q, i+q+p) is:

the difference between the base line (i, i+p) and the base line (i+q, i+q+p) phase difference is:

step S44: definition of the definition

Combining the fuzzy phase difference sets to construct a set of complex numbers:

the value of the i is changed by the value of i (i=1, 2, n.), constructing N sets of complex numbers.

Further, the step S5 includes the following steps:

Step S51: taking a certain group of complex numbers f _i ^pq as a reference, wherein each element in the group is close to a certain element of the other groups, namely the clustering degree is highest, the elements which are close to each other correspond to the real incoming wave direction, the distances between each element in the group and each element of the other groups are calculated, and if the element modulus value is larger than 1, the distances between the elements are set as maximum values;

Step S52: searching the shortest distance from each element in the group to the elements of the other groups, summing N-1 shortest distances corresponding to each element, and finding out the element class with the smallest distance in the group;

Step S53: at least one element class exists in the group, and all possible arrival angles are calculated according to elements in the element class:

further, the step S6 includes the following steps:

Step S61: for each possible angle of arrival Generating an Nx1 guide vector A by combining the wavelength and the array element position of the antenna array;

step S62: the signals R _i (t) after the phase difference is eliminated by utilizing each array element form an N multiplied by L data vector R;

step S63: calculating s=a ^H R to obtain a1×l data vector S, and obtaining the element energy sum P, i.e., p= Σ|s _i|²,s_i, of the i-th element in the data vector S;

Step S64: each possible angle of arrival corresponds to an energy, and the angle to which the energy is maximum corresponds is used as the unambiguous angle of arrival estimate.

Examples:

the terminal adopts a Bluetooth communication protocol to broadcast a data packet signal with sign information, the data packet signal comprises a section of continuous sine wave signal for direction finding, and the data packet comprises the following information:

Byte numbers 7 to 12 represent MAC addresses for identifying and distinguishing terminals;

byte numbers 15 to 17 represent feature identification codes for identifying the sine wave included therein;

Byte numbers 27-43 represent direction-finding information codes, such as a CH37 broadcast channel, with a signal bandwidth of 1MHz, wherein the direction-finding information codes are as follows: the signal generated after CH37 channel whitening filtering and GFSK modulation is a sine wave of 250kHz, i.e., f _sin =250 kHz, with 0xCC, 0x27, 0x45, 0x67, 0xF7, 0xDB, 0x34, 0xC4, 0x03, 0x8E, 0x5C, 0x0B, 0xAA, 0x97, 0x30, 0x56, 0xE 6.

The base station comprises an array antenna, the array antenna consists of a communication antenna array element and 6 direction-finding antenna array elements, the antenna array is shown in figure 2, the direction-finding antennas are uniformly distributed along the circumference with the radius of R=lambda/2, the array elements are spaced with radian omega=pi/3, and the numbers 1,2 are sequentially given, the number is equal to 6, and the communication antenna array elements are positioned at the center of a uniform circular array and are numbered as 0;

The pitch angle is defined as the included angle between the signal incidence direction and the XOY plane, and the azimuth angle is defined as the included angle between the projection of the signal incidence direction on the XOY plane and the X axis.

When detecting the characteristic identification code for identifying the sine wave, the base station controls the radio frequency switch to time-divisionally gate the direction-finding antenna and the communication antenna according to a preset sequence to receive the sine wave signal, wherein the preset array element gating sequence is 0,1,0,2,0,3, … …,0,6, and the gating duration T _sw＝2μs,2f_sinT_sw =1;

The receiving wavelength is lambda, and the antenna array pitch angle theta and azimuth angle The directional sine wave signal s (t), when the communication antenna is gated, i.e., i=0, n=0, 2,..2N-2,

y_i(t)＝s(t-nT_sw)exp{j2πΔf(t-nT_sw)}，

When the direction finding antenna is gated, i.e., i=1,..n, n=1, 3,..2N-1,

Wherein Δf is a frequency difference caused by mismatch of the receiving and transmitting carrier frequencies.

Compensating the phase difference of the radio frequency channel, wherein the phase difference is calibrated through a stationary signal source in the normal direction of the far field of the antenna array, and because the phase difference introduced by the incident angle does not exist in the received signals of each antenna at the moment, the phase difference is caused by mismatch of the radio frequency channel, components and a receiving and transmitting local oscillator;

Compensating for phase differences caused by mismatch of the transmit and receive carrier frequencies, and constructing a multi-channel received signal r _i (t), i=1, 2,..n, satisfying

Wherein exp { jγ } is constant;

The signal length of the sampling time interval T _s＝0.25μs,r_i (T) is L=8, and the measurement accuracy of the phase difference is Epsilon is the signal to noise ratio.

Setting p=3, q=1;

the baseline (i, i+3) is not parallel to the baseline (i+1, i+4);

The base line (i, i+3) consists of mod (i-1, 6) +1 and mod (i+3-1, 6) +1 antenna elements with the phase difference:

Combining wavelength, antenna array size and direction finding range, the maximum phase ambiguity number is The fuzzy phase difference set is { phi _i,i+3+2M_i,i+3π},M_i,i+3 epsilon [ -1,1];

similarly, the phase difference of the base lines (i+1, i+4) is:

Combining wavelength, antenna array size and direction finding range, the maximum phase ambiguity number is The fuzzy phase difference set is { phi _i+1,i+4+2M_i+1,i+4π},M_i+1,i+4 epsilon [ -1,1];

The sum of the phase differences of the base line (i, i+3) and the base line (i+1, i+4) is:

the difference between the base line (i, i+3) and the base line (i+1, i+4) phase difference is:

Definition of the definition

Combining the fuzzy phase difference sets to construct a set of complex numbers:

By the value change of i (i=1, 2,..6), 6 sets of complex numbers were constructed.

Taking the first group complex number f ₁ ^pq as a reference, wherein each element in the group is close to one element of the other groups, namely the clustering degree is highest, the elements which are close to each other correspond to the real incoming wave direction, the distances between each element in the group and each element of the other groups are calculated, and if the element modulus value is larger than 1, the distances between the elements are set as maximum values;

Searching the shortest distance from each element in the group to the elements in the other groups, summing up 5 shortest distances corresponding to each element, and finding out the element class with the smallest distance in the group;

at least one element class exists in the group, and all possible arrival angles are calculated according to elements in the element class:

For each possible angle of arrival Combining the wavelength and the array element position of the antenna array to generate a6 multiplied by 1 guide vector A;

The signals after the phase difference of the radio frequency channels is eliminated by utilizing each array element form a 6 multiplied by 8 dimensional data vector R;

Calculating s=a ^H R to obtain a1×8-dimensional data vector S, and obtaining the element energy sum P thereof, i.e., p= Σ|s _i|²,s_i is the ith element in the data vector S;

each possible angle of arrival corresponds to an energy, and the angle to which the energy is maximum corresponds is used as the unambiguous angle of arrival estimate.

The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (7)

1. The direction finding method of the phase interferometer of the direction finding positioning system is characterized by comprising the following steps of:

Step S1: the terminal broadcasts a data packet signal with sign information, wherein the data packet signal comprises a section of continuous sine wave signal for direction finding;

Step S2: after the central communication antenna of the base station receives the identification mark information, the base station controls the radio frequency switch to time-division gate the direction-finding antenna and the communication antenna according to a preset sequence to receive sine wave signals in the data packet signals;

Step S3: preprocessing a received signal, eliminating phase difference caused by radio frequency channel phase difference and receiving-transmitting carrier frequency mismatch, and constructing a multichannel received signal;

Step S4: selecting direction-finding array elements with mutual interval p to form a base line and calculate a phase difference, selecting the base line with mutual interval q and calculate a sum phase difference and a difference phase difference, and combining a fuzzy phase combination to form a plurality of groups of complex numbers { f _i ^pq };

Step S5: analyzing the clustering degree of each element in a certain group of complex numbers and other groups of elements by a clustering method, filtering elements with low clustering degree or modulus value larger than 1, and calculating all possible arrival angles by using the residual elements;

Step S6: for each possible angle of arrival, generating a steering vector by using array element position, wavelength and circular array radius information, combining vectors formed by signals received by each antenna to generate a signal s, calculating signal energy, and taking the angle with the strongest energy as an estimated value.

2. The direction-finding positioning system phase interferometer direction-finding method according to claim 1, wherein the step S1 comprises the steps of:

Step S11: the mark information at least comprises a MAC address for identifying and distinguishing the terminal and a characteristic identification code for identifying and distinguishing the terminal containing sine waves;

Step S12: the sine wave signal s (t) is generated by modulating the direction-finding information code with the frequency f _sin, that is, s (t) =exp { j2 pi f _sin t }.

3. The direction-finding positioning system phase interferometer direction-finding method according to claim 1, wherein the step S2 comprises the steps of:

step S21: the base station comprises an array antenna, the array antenna consists of a communication antenna array element and N direction finding antenna array elements, the direction finding antennas are uniformly distributed along the circumference with the radius of R, the array elements are sequentially numbered 1,2, N, the communication antenna array elements are positioned at the center of a uniform circular array, and the number is 0;

step S22: the radio frequency switch gates the communication antenna to receive the space radio signal;

Step S23: when detecting the characteristic identification code for identifying the sine wave, the base station controls the radio frequency switch to time-sharing gate the direction-finding antenna and the communication antenna according to a preset sequence to receive the sine wave signal;

step S24: the preset array element gating sequence is communication antenna array elements, direction finding antenna array elements, communication antenna array elements and direction finding antenna array elements alternately gating, and optionally, the gating sequence is cycled for several rounds to finally gate the communication antenna array elements;

step S25: the gating period T _sw, and 2f _sinT_sw is an integer;

Step S26: the receiving wavelength of the gating array element is lambda, and the angle of pitch theta and azimuth of the antenna array When the sine wave signal s (T) is in the direction, s (T-2T _sw)＝exp{j(2πf_sint-2π·2f_sinT_sw)}＝exp{j2πf_sin T } = s (T);

When the communication antenna is gated, i.e., i=0, n=0, 2,..2N-2,

y_i(t)＝s(t-nT_sw)exp{j2πΔf(t-nT_sw)}，

When the direction finding antenna is gated, i.e., i=1,..n, n=1, 3,..2N-1,

Wherein Δf is a frequency difference caused by mismatch of the receiving and transmitting carrier frequencies;

step S27: the mismatch of the receiving and transmitting carrier frequencies is generated by the combined action of Doppler frequency offset and receiving and transmitting local oscillation mismatch which are introduced by the mutual motion between the terminal and the base station.

4. The direction-finding positioning system phase interferometer direction-finding method according to claim 1, wherein the step S3 comprises the steps of:

step S31: compensating the phase difference of the radio frequency channel, and calibrating the phase difference through a stationary signal source in the normal direction of the far field of the antenna array;

Step S32: compensating for phase differences caused by mismatch of the transmit and receive carrier frequencies, and constructing a multichannel receive signal r _i (t), i=1, 2,..n, satisfying:

wherein exp { jγ } is constant;

Step S33: the longer the r _i (t) signal length is, the higher the measurement accuracy of the phase difference is, and the following relationship exists between the measurement accuracy of the phase difference and the signal to noise ratio in single measurement: Epsilon is the signal-to-noise ratio, and the precision is improved to/>, when L times of measurement are carried out L=t _sw/T_s,T_s sample time interval.

5. The direction-finding positioning system phase interferometer direction-finding method according to claim 1, wherein the step S4 comprises the steps of:

Step S41: selecting a baseline (i, i+p) and a baseline (i+q, i+q+p), which are not parallel;

The base line (i, i+p) consists of mod (i-1, N) +1 and mod (i+p-1, N) +1 direction-finding antenna array elements, and the phase difference is as follows:

Step S42: combining wavelength, antenna array size and direction finding range, the maximum phase ambiguity number is Fuzzy phase difference set as/>

Similarly, the phase difference of the base lines (i+q, i+q+p) is:

Step S43: combining wavelength, antenna array size and direction finding range, the maximum phase ambiguity number is The fuzzy phase difference set is { phi _i+q,i+q+p+2M_i+q,i+q+p pi }/>, and

The sum of the phase differences of the base line (i, i+p) and the base line (i+q, i+q+p) is:

the difference between the base line (i, i+p) and the base line (i+q, i+q+p) phase difference is:

step S44: definition of the definition

Combining the fuzzy phase difference sets to construct a set of complex numbers:

the value of the i is changed by the value of i (i=1, 2, n.), constructing N sets of complex numbers.

6. The direction-finding positioning system phase interferometer direction-finding method according to claim 1, wherein the step S5 comprises the steps of:

Step S51: taking a certain group of complex numbers f _i ^pq as a reference, wherein each element in the group is close to a certain element of the other groups, namely the clustering degree is highest, the elements which are close to each other correspond to the real incoming wave direction, the distances between each element in the group and each element of the other groups are calculated, and if the element modulus value is larger than 1, the distances between the elements are set as maximum values;

Step S52: searching the shortest distance from each element in the group to the elements of the other groups, summing N-1 shortest distances corresponding to each element, and finding out the element class with the smallest distance in the group;

Step S53: at least one element class exists in the group, and all possible arrival angles are calculated according to elements in the element class:

7. The direction-finding positioning system phase interferometer direction-finding method according to claim 1, wherein the step S6 comprises the steps of:

Step S61: for each possible angle of arrival Generating an Nx1 guide vector A by combining the wavelength and the array element position of the antenna array;

step S62: the signals R _i (t) after the phase difference is eliminated by utilizing each array element form an N multiplied by L data vector R;

step S63: calculating s=a ^H R to obtain a1×l data vector S, and obtaining the element energy sum P, i.e., p= Σ|s _i|²,s_i, of the i-th element in the data vector S;

Step S64: each possible angle of arrival corresponds to an energy, and the angle to which the energy is maximum corresponds is used as the unambiguous angle of arrival estimate.