Attitude angle measurement method and system based on beam pointing and GNSS signals

Abstract

The invention relates to the technical field of satellite navigation measurement, and discloses an attitude angle measurement method and system based on beam pointing and GNSS signals. The method comprises the following steps: traversing an azimuth angle and pitch angle combination in a double-antenna baseline angle space, calculating signal delay according to a GNSS satellite incoming wave direction and converting the signal delay into a phase shift value, setting a phase shifter to form a sum beam and a difference beam by using the phase shift value, measuring a carrier-to-noise ratio difference value and establishing a corresponding relation with a traversal angle, screening a traversal angle with the maximum carrier-to-noise ratio difference value, and calculating a sum beam and a difference beam according to the traversal angle. And determining the azimuth angle and the pitch angle of the dual-antenna baseline. According to the invention, the environmental adaptability and cost effectiveness of attitude measurement are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of satellite navigation measurement, and particularly relates to a method and system for measuring attitude angle based on beam pointing and GNSS signals. BACKGROUND

[0002] Currently, there are mainly two kinds of azimuth angle measurement methods. One is to use a magnetic compass to determine the azimuth angle by measuring the direction of the geomagnetic field, which has the advantages of low cost and simple system. The other is to use double GPS antennas to output the original observation of the navigation satellite and calculate the azimuth angle of the baseline according to the carrier phase difference, which has the advantage of high precision. The pitch angle is generally measured by a 6-axis inertial measurement unit, which measures the pitch angle and roll angle of the baseline through a 3-axis accelerometer and a 3-axis gyroscope. These methods have their own applications in different application scenarios, and constitute the main means of current attitude measurement technology.

[0003] However, the existing technology has obvious deficiencies. The magnetic compass for measuring the azimuth angle is easily affected by the surrounding ferromagnetic medium, and the measurement result is low in precision and large in deviation near steel buildings or metal equipment. The measurement error can be more than 20 degrees. Although the double GPS antenna carrier phase difference scheme has high precision, it requires a double-frequency or multi-frequency GNSS receiver that supports original observation output, and the hardware is expensive. In the application scenario where the shelter and multipath interference are serious, the number of effective satellites received is too small, the quality of the original observation data is reduced, resulting in low precision and large deviation, and even the effective value cannot be calculated. Although the 6-axis inertial measurement unit measures the pitch angle, the accelerometer is affected by temperature and produces temperature drift, and the output pitch angle value changes with temperature. In the working temperature range of minus 40 degrees to plus 85 degrees, the cumulative error can be 2 degrees to 4 degrees.

[0004] The existing methods lack systematic technical solutions in terms of angle space search strategy, beam forming mechanism, carrier-to-noise ratio difference calculation, and angle validity verification. In the angle space traversal process, how to efficiently calculate the signal delay at each traversal angle according to the GNSS satellite wave direction parameter and convert it to a phase shift value lacks a clear coordinate system establishment and propagation path difference calculation method. In the beam forming stage, how to accurately control the phase adjustment of the antenna signal through the phase shifter to realize the in-phase superposition of the beam and the anti-phase superposition of the difference beam lacks detailed phase shifter setting and signal combining processing flow. In the carrier-to-noise ratio measurement link, how to obtain the carrier-to-noise ratio of the sum beam and the difference beam through the navigation chip demodulation processing and calculate the difference, and establish the corresponding relationship between the carrier-to-noise ratio difference and the traversal angle, lacks a systematic measurement and recording mechanism. In the angle screening stage, how to screen the maximum carrier-to-noise ratio difference from the corresponding relationship and verify the validity of the corresponding angle, especially how to determine that the beam pointing is consistent with the satellite wave direction through the consistency of the maximum gain pointing of the sum beam and the maximum null pointing of the difference beam, lacks determination basis and verification logic. SUMMARY

[0005] The application provides a beam pointing and GNSS signal-based attitude angle measurement method and system, which solves the problem that the existing technology cannot reliably measure the azimuth and elevation angles of a double-antenna baseline under complex electromagnetic environments and temperature change conditions, and improves the environmental adaptability and cost-effectiveness of attitude measurement.

[0006] In a first aspect, the application provides a beam pointing and GNSS signal-based attitude angle measurement method, which comprises the following steps: Step S1: traversing different azimuth and elevation angle combinations in a double-antenna baseline angle space, calculating the signal delay of antenna B relative to antenna A at each traversed angle according to the GNSS satellite wave direction, and converting the signal delay into a phase shift value; Step S2: setting a phase shifter with the phase shift value to perform phase shift processing on the antenna B signal and combining it with the antenna A signal to form a sum beam, and setting a phase shifter with the phase shift value plus 180° to form a difference beam; Step S3: measuring the carrier-to-noise ratio of the sum beam and the carrier-to-noise ratio of the difference beam, calculating the carrier-to-noise ratio difference value of the two, and recording the corresponding relationship between the carrier-to-noise ratio difference value and the traversed angle; Step S4: selecting the traversed angle that makes the carrier-to-noise ratio difference value reach the maximum from the corresponding relationship, and the sum beam pointing direction corresponding to the traversed angle is consistent with the GNSS satellite wave direction; Step S5: determining the azimuth and elevation angles of the double-antenna baseline according to the traversed angle.

[0007] In a second aspect, the application provides a beam pointing and GNSS signal-based attitude angle measurement system, which comprises the following modules: A traversing module is configured to traverse different azimuth and elevation angle combinations in a double-antenna baseline angle space, calculate the signal delay of antenna B relative to antenna A at each traversed angle according to the GNSS satellite wave direction, and convert the signal delay into a phase shift value; A phase shifting module is configured to set a phase shifter with the phase shift value to perform phase shift processing on the antenna B signal and combine it with the antenna A signal to form a sum beam, and set a phase shifter with the phase shift value plus 180° to form a difference beam; A recording module is configured to measure the carrier-to-noise ratio of the sum beam and the carrier-to-noise ratio of the difference beam, calculate the carrier-to-noise ratio difference value of the two, and record the corresponding relationship between the carrier-to-noise ratio difference value and the traversed angle; A screening module is configured to select the traversed angle that makes the carrier-to-noise ratio difference value reach the maximum from the corresponding relationship, and the sum beam pointing direction corresponding to the traversed angle is consistent with the GNSS satellite wave direction; generating a module for determining an azimuth angle and an elevation angle of a baseline of the dual antenna according to the traversal angle.

[0008] In a third aspect, a device for measuring an attitude angle based on a beam pointing direction and a GNSS signal is provided, comprising a memory and at least one processor, wherein the memory stores instructions; and the at least one processor invokes the instructions in the memory to cause the device for measuring an attitude angle based on a beam pointing direction and a GNSS signal to perform the method for measuring an attitude angle based on a beam pointing direction and a GNSS signal as described above.

[0009] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores instructions, which, when executed on a computer, cause the computer to perform the method for measuring an attitude angle based on a beam pointing direction and a GNSS signal as described above.

[0010] In the technical scheme provided in the present application, different azimuth angle and elevation angle combinations are traversed in the baseline angle space of the dual antenna, the signal delay of antenna B relative to antenna A at each traversal angle is calculated according to the GNSS satellite wave direction, and the signal delay is converted into a phase shift value, a phase shift calculation mechanism based on spatial angle traversal is established, the dependence on the original observation output of the traditional carrier phase difference scheme is avoided, the requirements on the GNSS receiver hardware are reduced, the ordinary single-frequency navigation chip can realize high-precision angle measurement, and the system cost is significantly reduced. The phase shifter is set by using the phase shift value to perform phase shift processing on the antenna B signal and combined with the antenna A signal to form a sum beam, the phase shifter is set by using the phase shift value plus 180 degrees to form a difference beam, the sum beam and the difference beam are simultaneously formed, the maximum gain characteristic of the sum beam and the maximum null characteristic of the difference beam are utilized, and a significant signal intensity contrast is formed at the same angle pointing, thereby providing a clear physical criterion for subsequent angle determination. The carrier-to-noise ratios of the sum beam and the difference beam are measured, the carrier-to-noise ratio difference value is calculated, and the corresponding relationship between the carrier-to-noise ratio difference value and the traversal angle is recorded. The measurement is performed by using the carrier-to-noise ratio as a conventional output parameter of the navigation chip, without the need for a complex phase measurement circuit, thereby simplifying the system implementation. Meanwhile, the carrier-to-noise ratio difference value as a criterion has strong anti-noise capability, and the stability and reliability of the measurement are improved. The traversal angle that makes the carrier-to-noise ratio difference value maximum is selected from the corresponding relationship, the characteristic that the carrier-to-noise ratio difference value reaches the maximum when the sum beam pointing direction is consistent with the GNSS satellite wave direction is utilized, an explicit angle screening standard is established, it is ensured that the selected angle corresponds to the real signal wave direction, and the misjudgment caused by multipath interference and noise is avoided.

[0011] The present application completes direct conversion from beam pointing to baseline attitude by determining the traversal angle as the azimuth angle and the elevation angle of the baseline of the dual antenna, and based on the physical principle that the dual antenna array beam pointing is uniquely determined by the baseline spatial attitude, when the beam pointing is consistent with the satellite incoming wave direction, the traversal angle reflects the real attitude of the baseline, and the azimuth angle and the elevation angle are measured synchronously. The present application uses GNSS satellite signals as the measurement signal source, and uses the satellite position information in the navigation message as the angle reference, is not affected by the surrounding ferromagnetic substances, overcomes the problem of large measurement error of the magnetic compass scheme in the complex electromagnetic environment, and is not affected by the change of the environment temperature, and overcomes the problem of measurement error accumulation caused by the temperature drift of the inertial measurement unit. Through the beam pointing traversal search method, even if only one GNSS satellite signal is received, the angle calculation can be completed, the requirements for the number of satellites and the signal quality are far lower than those of the carrier phase difference scheme, and in the weak signal environment such as the serious shielding urban canyon and indoor edge, the system can still maintain high availability, the application scene range is expanded, and the robustness and practicality of the system in the complex environment are improved. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on these drawings.

[0013] Figure 1 is an embodiment schematic diagram of the attitude angle measurement method based on the beam pointing and the GNSS signal in the embodiment of the present application. Figure 2 is an embodiment schematic diagram of the attitude angle measurement system based on the beam pointing and the GNSS signal in the embodiment of the present application. Figure 3 is a structural schematic block diagram of the attitude angle measurement device based on the beam pointing and the GNSS signal in the embodiment of the present application. DETAILED DESCRIPTION

[0014] The embodiment of the present application provides a kind of based on beam pointing and GNSS signal's attitude angle measurement method and system.The terms "first", "second", "third", "fourth" and the like (if exist) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence.It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.In addition, the terms "include" or "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0015] For ease of understanding, the specific process of the embodiment of the present application is described below, please refer to Figure 1 One embodiment of the attitude angle measurement method based on beam pointing and GNSS signal in the embodiment of the present application includes: Step S1: traverse different azimuth and elevation angle combinations in the double-antenna baseline angle space, calculate the signal delay of antenna B relative to antenna A under each traversal angle according to the GNSS satellite wave direction, and convert the signal delay into a phase shift value; Step S2: use the phase shift value to set the phase shifter to perform phase shift processing on the antenna B signal and combine with the antenna A signal to form a sum beam, and use the phase shift value plus 180° to set the phase shifter to form a difference beam; Step S3: measure the carrier-to-noise ratio of the sum beam and the carrier-to-noise ratio of the difference beam, calculate the carrier-to-noise ratio difference value and record the corresponding relationship between the carrier-to-noise ratio difference value and the traversal angle; Step S4: select the traversal angle that makes the carrier-to-noise ratio difference value reach the maximum from the corresponding relationship, and the sum beam pointing corresponding to the traversal angle is consistent with the GNSS satellite wave direction; Step S5: determine the azimuth and elevation angle of the double-antenna baseline according to the traversal angle.

[0016] It can be understood that the execution subject of the present application can be a beam pointing and GNSS signal-based attitude angle measurement system, and can also be a terminal or a server, and the specific place is not limited.The embodiment of the present application takes the server as the execution subject for example.

[0017] Specifically, when traversing in the dual-antenna baseline angle space, the azimuth angle traversal range is set to 0-360 degrees, the elevation angle traversal range is set to -10-90 degrees, and all angle combinations are traversed and valued with a certain step angle. At each traversal angle, first, a geographic coordinate system with antenna A as the origin is established, and the spatial coordinate position of antenna B in the coordinate system is calculated according to the current traversed azimuth angle and elevation angle. At the same time, the azimuth angle and elevation angle of the GNSS satellite are parsed from the navigation message output by the navigation chip, and these two parameters describe the direction of arrival of the satellite signal. According to the spatial coordinates of antenna B and the satellite direction of arrival parameters, the propagation path difference of the signal received by antenna B relative to antenna A is calculated, which is the projection length of the antenna B coordinates in the satellite direction of arrival. The propagation path difference is divided by the speed of light to obtain the signal delay of the signal received by antenna B relative to antenna A, which reflects the time difference of the same satellite signal received by the two antennas. Finally, the signal delay is multiplied by the GNSS signal carrier frequency and then multiplied by twice the circular constant to complete the conversion from time delay to phase difference, and the phase shift value is obtained, which is used for subsequent phase shifter setting.

[0018] The calculated phase shift value is input to the control end of the phase shifter, and the phase shifter adjusts the phase of the GNSS signal received by antenna B according to the control signal to make a specific phase difference between the adjusted signal and the antenna A signal. The phase-shifted antenna B signal and the GNSS signal received by antenna A are input into the combiner, and the combiner performs in-phase superposition processing on the two signals, and the signal amplitude is added to enhance when the phases of the two signals remain consistent, forming a sum signal corresponding to a sum beam. The principle of forming a sum beam is to make the signals received by the two antennas in-phase by phase compensation, and the maximum gain is produced in a specific direction. Then the phase shift value is added by 180 degrees and input to the control end of the phase shifter again, and the phase shifter adjusts the phase of the GNSS signal received by antenna B again to make the phase difference between the adjusted signal and the antenna A signal be the original phase shift value plus 180 degrees. The antenna B signal after reverse phase shift processing and the GNSS signal received by antenna A are input into the combiner for anti-phase superposition, and the signal amplitude is subtracted to cancel out when the phases of the two signals are 180 degrees apart, forming a difference signal corresponding to a difference beam. The principle of forming a difference beam is to make the signals received by the two antennas in anti-phase by phase inversion, and a null is produced in a specific direction.

[0019] The sum signal corresponding to the sum beam is input into the navigation chip, and a signal processing circuit inside the navigation chip demodulates the sum signal. The demodulation process includes down-converting the radio frequency signal to an intermediate frequency or a base frequency, filtering out the out-of-band noise, and then performing correlation operation to extract navigation information. After demodulation, the carrier-to-noise ratio value of the sum beam can be obtained at the output end of the navigation chip. The carrier-to-noise ratio represents the ratio of the signal carrier power to the noise power density, and the unit is decibel per hertz. The larger the value, the better the signal quality. Similarly, the difference signal corresponding to the difference beam is input into the navigation chip for the same demodulation process, and the carrier-to-noise ratio value of the difference beam is obtained at the output end of the navigation chip. The carrier-to-noise ratio of the sum beam is subtracted from the carrier-to-noise ratio of the difference beam to obtain the carrier-to-noise ratio difference value at the current traversal angle. This difference value reflects the difference in signal strength between the sum beam and the difference beam at the current pointing angle. The above measurement process is performed for all traversed azimuth and elevation angle combinations, and each traversal angle and its corresponding carrier-to-noise ratio difference value is recorded to establish a mapping relationship between the carrier-to-noise ratio difference value and the traversal angle, forming a corresponding relationship data set.

[0020] All carrier-to-noise ratio difference values recorded in the traversal corresponding relationship are traversed, and the maximum value of the carrier-to-noise ratio difference value is selected by comparing the size of each carrier-to-noise ratio difference value. The traversal angle corresponding to the maximum value is obtained, and at this time the traversal angle is the angle combination that makes the carrier-to-noise ratio difference value maximum. When the carrier-to-noise ratio difference value reaches the maximum value, the carrier-to-noise ratio of the sum beam reaches the maximum value and the carrier-to-noise ratio of the difference beam reaches the minimum value. According to the beam forming theory, the sum beam forms the maximum gain pointing at this angle, and the difference beam forms the maximum null pointing at this angle. The common pointing of the two is the direction of arrival of the GNSS satellite signal. Since the pointing of the dual-antenna array beam is uniquely determined by the spatial attitude of the baseline, when the beam pointing coincides with the satellite direction of arrival, the traversal angle reflects the actual azimuth and elevation of the dual-antenna baseline, thereby confirming that the pointing of the sum beam corresponding to the traversal angle is consistent with the direction of arrival of the GNSS satellite.

[0021] The azimuth component and the elevation component are extracted from the selected traversal angle. The azimuth component represents the angle between the projection of the dual-antenna baseline in the horizontal plane and the north direction, and the elevation component represents the angle between the dual-antenna baseline and the horizontal plane. The extracted azimuth component is determined as the azimuth of the dual-antenna baseline, and the extracted elevation component is determined as the elevation of the dual-antenna baseline. These two angle parameters completely describe the spatial attitude direction of the dual-antenna baseline in the geographic coordinate system, and finally the measurement of the azimuth and elevation of the dual-antenna baseline is completed.

[0022] In a specific embodiment, step S1 includes: A geographic coordinate system with antenna A as the origin is established, the X-axis points to the east, the Y-axis points to the north, and the Z-axis points to the zenith. The spatial coordinates of antenna B in the geographic coordinate system are calculated according to the traversed azimuth and elevation angles. The azimuth and elevation of the GNSS satellite are parsed from the navigation message output by the navigation chip, and the azimuth and elevation of the GNSS satellite are taken as the satellite wave direction parameter; The propagation path difference of the signal received by the antenna B relative to the antenna A is calculated according to the spatial coordinates and the satellite wave direction parameter, and the signal delay is obtained by dividing the propagation path difference by the speed of light; The signal delay is multiplied by the GNSS signal carrier frequency and then multiplied by 2π to obtain the phase shift value.

[0023] Specifically, according to the process of establishing a geographic coordinate system and calculating the spatial coordinates of the antenna B, a three-dimensional geographic coordinate system is established with the antenna A as the coordinate origin, wherein the X axis points to the east direction, the Y axis points to the north direction, and the Z axis points to the zenith direction. After a certain set of azimuth and elevation is determined in the traversal process, the azimuth represents the angle between the projection of the baseline in the horizontal plane and the north direction, and the elevation represents the angle between the baseline and the horizontal plane. According to the traversed azimuth, elevation and known baseline length, the spatial coordinates of the antenna B in the geographic coordinate system are calculated, wherein the X coordinate is equal to the baseline length multiplied by the sine value of the azimuth and then multiplied by the cosine value of the elevation, the Y coordinate is equal to the baseline length multiplied by the cosine value of the azimuth and then multiplied by the cosine value of the elevation, and the Z coordinate is equal to the baseline length multiplied by the sine value of the elevation, so as to determine the spatial position relationship of the antenna B relative to the antenna A through the three coordinate components.

[0024] According to the process of parsing the satellite wave direction parameter, the navigation chip continuously receives the navigation message broadcast by the GNSS satellite, and the navigation message contains the orbit parameter, clock parameter and satellite position information of the satellite. The parsing module inside the navigation chip extracts the ephemeris data of the satellite from the navigation message, calculates the three-dimensional position of the satellite in the geocentric geodetic coordinate system according to the ephemeris data, and then calculates the azimuth and elevation of the satellite relative to the receiver in combination with the current position of the receiver. The azimuth represents the angle between the projection of the satellite in the horizontal plane and the north direction, and the elevation represents the angle between the line of sight direction of the satellite and the horizontal plane. The parsed azimuth and elevation of the GNSS satellite are taken as the satellite wave direction parameter, which describes the spatial direction of the satellite signal reaching the receiving antenna.

[0025] According to the process of calculating the propagation path difference and obtaining the signal delay, the propagation path difference is calculated by using the spatial coordinates of the antenna B and the satellite wave direction parameters. The propagation path difference is equal to the projection length of the antenna B coordinates in the satellite wave direction, and the specific calculation method is to multiply the X coordinate of the antenna B by the sine value of the satellite azimuth angle and then by the cosine value of the satellite elevation angle, and then add the Y coordinate multiplied by the cosine value of the satellite azimuth angle and then by the cosine value of the satellite elevation angle, and then add the Z coordinate multiplied by the sine value of the satellite elevation angle. The propagation path difference represents the distance of the satellite signal propagating more to the antenna B than to the antenna A. The propagation path difference is divided by the speed of light, and the speed of light is 300 million meters per second, to obtain the signal delay, which represents the time difference of the satellite signal received by the antenna B compared with the antenna A, and the unit is second.

[0026] According to the process of converting the signal delay into a phase shift value, the signal delay reflects the delay in the time domain, which needs to be converted into the phase shift in the phase domain. The signal delay is multiplied by the GNSS signal carrier frequency, and the carrier frequency for the GPS L1 frequency band is 1575.42 MHz, and the product represents the number of periods of signal carrier oscillation in the delay time. Then, the number of periods is multiplied by twice the circular constant, because one complete period corresponds to a phase change of twice the circular constant, to obtain the phase shift value, and the unit is radian. The phase shift value describes the difference in phase between the signals received by the antenna B and the antenna A, and the phase shift value is used for the subsequent control of the phase shifter, and the in-phase or anti-phase superposition of the two signals is realized by compensating the phase shift.

[0027] In a specific embodiment, step S2 comprises: The phase shift value is input into the control end of the phase shifter, and the phase of the GNSS signal received by the antenna B is adjusted to obtain the phase-shifted antenna B signal; The phase-shifted antenna B signal and the GNSS signal received by the antenna A are input into the combiner to perform in-phase superposition, to form a sum signal corresponding to the sum beam; The phase shift value is input into the control end of the phase shifter, and the phase of the GNSS signal received by the antenna B is adjusted to obtain the phase-shifted antenna B signal; The phase-shifted antenna B signal and the GNSS signal received by the antenna A are input into the combiner to perform in-phase superposition, to form a sum signal corresponding to the sum beam;

[0028] Specifically, according to the process of phase adjustment of the antenna B signal, the calculated phase shift value is input to the control port of the phase shifter, which is a radio frequency device that can change the phase of the signal, and inside it changes the electrical length of the signal transmission path by controlling the variable capacitance or variable inductance. After receiving the phase shift value input by the control end, the phase shifter adjusts the parameters of the internal device according to the value, and adjusts the phase of the GNSS signal received by the antenna B. The principle of phase adjustment is to realize phase delay or advance by changing the electrical length of the signal transmission path, and the adjustment amount is equal to the input phase shift value. After the phase shifter processing, the phase of the antenna B signal is offset relative to the original phase, and the phase-shifted antenna B signal is obtained. The phase difference between the signal and the GNSS signal received by the antenna A has been compensated to a predetermined value.

[0029] According to the process of forming and beam and signal, the phase-shifted antenna B signal and the GNSS signal received by the antenna A are simultaneously input into the combiner, which is a radio frequency device that combines multiple signals into one signal. Since the phase shifter has compensated the phase of the antenna B signal, the phase of the two signals remains consistent or the phase difference is small, and they are in the same phase state. The combiner performs superposition processing on the two in-phase signals, and the superposition principle is to add the voltage amplitudes of the two signals. Since the phases are consistent, the signal amplitude is superimposed and enhanced, and the power increases close to twice. The signal output by the combiner is the sum signal corresponding to the sum beam, and the sum signal has the maximum gain characteristic in a specific spatial direction, which is determined by the traversal angle corresponding to the phase shift value. When the pointing direction is consistent with the satellite incoming wave direction, the sum signal strength reaches the maximum.

[0030] According to the process of inverse phase shift of the antenna B signal, the phase shift value is added by 180 degrees to form a new control signal, and 180 degrees corresponds to a phase difference of half a wavelength, corresponding to the inverse phase state. The new control signal is input to the control end of the phase shifter, and the phase shifter adjusts the phase of the GNSS signal received by the antenna B according to the new control value. At this time, the adjusted phase amount is the original phase shift value plus 180 degrees, which is more than 180 degrees of phase shift compared to the first phase shift. After this phase adjustment, the phase difference between the antenna B signal and the antenna A signal is 180 degrees, and the two signals are in the inverse phase state, and the inverse phase-shifted antenna B signal is obtained. The phase of the signal is exactly opposite to the phase of the antenna A signal.

[0031] According to the process of forming the difference wave beam difference signal, the phase-inverted and phase-shifted antenna B signal is input into the combiner at the same time as the GNSS signal received by antenna A, at which time the phase difference between the two signals is 180 degrees, and the two signals are in an anti-phase state. The combiner performs superposition processing on the two anti-phase signals. Since the phase difference is 180 degrees, the voltage amplitudes of the two signals are subtracted rather than added, and the signals are canceled rather than enhanced when superimposed. When the amplitudes of the two signals are equal, the superposition result is close to zero, forming a null. The signal output by the combiner is the difference signal corresponding to the difference wave beam, and the difference signal has the maximum null characteristic in a specific spatial direction, i.e., the signal strength is minimum. The pointing direction is also determined by the traversal angle corresponding to the phase shift value, and when the pointing direction is consistent with the satellite incoming wave direction, the difference signal strength reaches a minimum, so that the wave beam and the difference wave beam form maximum gain and maximum null in the same direction, respectively.

[0032] In a specific embodiment, step S3 comprises: The sum signal is input into a navigation chip for demodulation processing, and the carrier-to-noise ratio of the sum wave beam is obtained from the output end of the navigation chip; The difference signal is input into a navigation chip for demodulation processing, and the carrier-to-noise ratio of the difference wave beam is obtained from the output end of the navigation chip; The carrier-to-noise ratio of the sum wave beam is subtracted from the carrier-to-noise ratio of the difference wave beam to obtain a carrier-to-noise ratio difference value corresponding to the current traversal angle; A mapping relationship between the carrier-to-noise ratio difference value and the traversal angle is established to form a corresponding relationship.

[0033] Specifically, according to the process of obtaining the carrier-to-noise ratio of the sum wave beam, the sum signal output by the combiner is connected to the radio frequency input port of the navigation chip. The navigation chip first amplifies the sum signal through a low-noise amplifier to improve the signal strength for subsequent processing. The amplified signal enters a mixer, which mixes the radio frequency signal with the local oscillator signal generated by the local oscillator to down-convert the high-frequency radio frequency signal to an intermediate frequency signal or directly to a baseband signal. The down-converted signal passes through a band-pass filter or a low-pass filter to filter out the out-of-band interference and noise components and retain the useful signal spectrum. The filtered signal enters a correlator module, which performs correlation operation on the received signal and the locally generated pseudo-random code to capture the satellite signal through sliding correlation search and track the code phase and carrier phase of the signal. The navigation chip calculates the carrier power and noise power density of the signal according to the output result of the correlation operation. The carrier power reflects the strength of the signal, and the noise power density reflects the strength of the background noise. The carrier power is divided by the noise power density, and then a logarithmic operation is performed to convert it to a decibel value, obtaining the carrier-to-noise ratio of the sum wave beam, which is in decibel-hertz. This value is read from the output port of the navigation chip.

[0034] According to the process of acquiring the difference beam carrier-to-noise ratio, the difference signal output by the combiner is connected to the radio frequency input port of the navigation chip, and the navigation chip performs the same demodulation process on the difference signal as the sum signal. The difference signal is first amplified by a low-noise amplifier, and then enters a frequency mixer for down-conversion processing, converting the radio frequency difference signal into an intermediate frequency or baseband difference signal. The down-converted difference signal passes through a filter to filter out the out-of-band components and retain the useful signal spectrum. The filtered difference signal enters the correlator module, and the correlator performs pseudo-random code correlation operation on the difference signal to capture and track the satellite signal. Since the difference beam forms a null in some directions, when the beam is pointed in the same direction as the satellite incoming wave, the carrier power of the difference signal will be significantly reduced. The navigation chip calculates the carrier power and noise power density of the difference signal according to the correlation result, divides the carrier power by the noise power density and takes the logarithm to obtain the carrier-to-noise ratio of the difference beam. This value is also read from the output port of the navigation chip.

[0035] According to the process of calculating the carrier-to-noise ratio difference value, after obtaining the carrier-to-noise ratio of the sum beam and the carrier-to-noise ratio of the difference beam at the same traversal angle, the carrier-to-noise ratio value of the sum beam is subtracted from the carrier-to-noise ratio value of the difference beam to perform a simple subtraction operation. Since the carrier-to-noise ratio is in decibel-hertz units, the subtraction operation in the logarithmic domain is equivalent to the division operation in the linear domain, and the carrier-to-noise ratio difference value reflects the relative ratio of the sum beam signal strength to the difference beam signal strength. When the traversal angle makes the beam point close to the satellite incoming wave direction, the sum beam carrier-to-noise ratio increases and the difference beam carrier-to-noise ratio decreases, and the difference between the two increases. When the traversal angle makes the beam point deviates from the satellite incoming wave direction, the sum beam carrier-to-noise ratio decreases and the difference beam carrier-to-noise ratio relatively increases, and the difference between the two decreases. Through the subtraction operation, the carrier-to-noise ratio difference value corresponding to the current traversal angle is obtained, which is a key parameter for judging the consistency of the beam pointing direction and the satellite incoming wave direction.

[0036] According to the process of establishing the corresponding relationship, the above measurement is performed on all azimuth and elevation angle combinations that need to be traversed in the angle space. Each traversal angle will obtain a corresponding carrier-to-noise ratio difference value. Each traversal angle and its corresponding carrier-to-noise ratio difference value are recorded in the form of data pairs. The traversal angle includes two dimensions of azimuth and elevation components, and the carrier-to-noise ratio difference value is a scalar value. By recording all the paired data of traversal angles and carrier-to-noise ratio difference values, a mapping relationship between the carrier-to-noise ratio difference value and the traversal angle is established. This mapping relationship can be represented as a two-dimensional lookup table or data matrix, with the horizontal axis representing the azimuth and the vertical axis representing the elevation. Each element in the matrix stores the carrier-to-noise ratio difference value of the corresponding angle. The corresponding relationship formed contains the carrier-to-noise ratio difference value distribution information of the entire angle space, providing a data basis for subsequent screening of the maximum carrier-to-noise ratio difference value and its corresponding angle.

[0037] In a specific embodiment, step S4 comprises: All the carrier-to-noise ratio difference values in the correspondence relationship are traversed to filter out the maximum value of the carrier-to-noise ratio difference value; The traversed angle corresponding to the maximum value is obtained, and the traversed angle is taken as a candidate baseline angle; According to the fact that the sum beam forms a maximum gain direction at the candidate baseline angle and the difference beam forms a maximum null direction at the candidate baseline angle, it is determined that the beam direction of the candidate baseline angle is consistent with the GNSS satellite incoming wave direction; The candidate baseline angle is confirmed as an effective traversed angle.

[0038] Specifically, according to the process of filtering the maximum value of the carrier-to-noise ratio difference value, all recorded carrier-to-noise ratio difference value data in the established correspondence relationship are read, and the correspondence relationship contains the carrier-to-noise ratio difference value corresponding to each traversed angle in the entire angle space. By traversing these data, each carrier-to-noise ratio difference value is compared one by one, and the largest one is found by using the successive comparison method. The specific comparison process is to set an initial maximum value variable, and the initial value is set as the first carrier-to-noise ratio difference value. Then, the variable is compared with each subsequent carrier-to-noise ratio difference value one by one. If the subsequent value is greater than the current maximum value variable, the maximum value variable is updated to the subsequent value, otherwise the maximum value variable remains unchanged. After traversing all the carrier-to-noise ratio difference values, the maximum value stored in the maximum value variable is the maximum value of the carrier-to-noise ratio difference value. The maximum value represents the most significant difference between the sum beam and the difference beam in all traversed angle combinations, corresponding to the strongest gain of the sum beam and the deepest null of the difference beam.

[0039] According to the process of obtaining the candidate baseline angle, after filtering out the maximum value of the carrier-to-noise ratio difference value, the traversed angle corresponding to the maximum value in the correspondence relationship needs to be found. By searching the correspondence relationship data structure, the data record where the maximum carrier-to-noise ratio difference value is located is located, and the data record contains the traversed angle information. The traversed angle is composed of an azimuth component and an elevation component, the azimuth component represents the included angle between the baseline projection in the horizontal plane and the north direction, and the elevation component represents the included angle between the baseline and the horizontal plane. The traversed angle is extracted from the correspondence relationship as a candidate baseline angle for subsequent verification. The candidate baseline angle represents the beam direction that makes the carrier-to-noise ratio difference value reach the maximum value, which is likely to be consistent with the GNSS satellite incoming wave direction, but still needs to be verified and confirmed by the beam forming theory.

[0040] According to the process of judging the consistency of the beam pointing direction, the formation characteristics of the sum beam and the difference beam at the candidate baseline angle are analyzed. The carrier-to-noise ratio of the sum beam at the candidate baseline angle is the maximum among all the traversed angles, indicating that the sum beam forms a maximum gain pointing direction by in-phase superposition in this direction, and the signal energy is maximally focused and enhanced in this direction. The carrier-to-noise ratio of the difference beam at the candidate baseline angle is the minimum among all the traversed angles, indicating that the difference beam forms a maximum null pointing direction by anti-phase superposition in this direction, and the signal is maximally canceled in this direction. According to the beam forming theory, when the maximum gain pointing direction of the sum beam coincides with the maximum null pointing direction of the difference beam, the common pointing direction is the direction of arrival of the signal. Since the beam pointing direction of the dual-antenna array is uniquely determined by the spatial attitude of the baseline, which includes two degrees of freedom of azimuth and elevation, when the beam pointing direction coincides with the direction of arrival of the satellite, the candidate baseline angle reflects the true spatial attitude of the baseline. By determining that the beam pointing direction of the candidate baseline angle coincides with the direction of arrival of the GNSS satellite, the effectiveness verification of the angle is completed.

[0041] According to the process of confirming the effective traversed angle, after completing the consistency judgment of the beam pointing direction, the candidate baseline angle passes the effectiveness verification, and it is confirmed that the angle is an effective traversed angle. The effective traversed angle indicates that the angle not only makes the carrier-to-noise ratio difference reach the maximum, but also physically corresponds to the attitude of the dual-antenna baseline pointing to the GNSS satellite. Confirming the candidate baseline angle as an effective traversed angle means that the angle can be output as a measurement result and used to represent the azimuth and elevation of the dual-antenna baseline. The confirmation process completes the task of selecting a unique effective angle from numerous traversed angles, and the effective angle is the actual spatial attitude of the dual-antenna baseline in the geographic coordinate system, which can be directly applied to practical application scenarios such as navigation positioning and attitude measurement.

[0042] In a specific embodiment, according to the sum beam forming a maximum gain pointing direction at the candidate baseline angle and the difference beam forming a maximum null pointing direction at the candidate baseline angle, it is determined that the beam pointing direction of the candidate baseline angle coincides with the direction of arrival of the GNSS satellite, comprising: determining that the carrier-to-noise ratio of the sum beam corresponding to the candidate baseline angle is the maximum carrier-to-noise ratio among all the traversed angles, and confirming that the sum beam forms a maximum gain pointing direction at the candidate baseline angle; determining that the carrier-to-noise ratio of the difference beam corresponding to the candidate baseline angle is the minimum carrier-to-noise ratio among all the traversed angles, and confirming that the difference beam forms a maximum null pointing direction at the candidate baseline angle; determining that the candidate baseline angle is the common pointing direction of the sum beam and the difference beam according to the fact that the maximum gain pointing direction and the maximum null pointing direction both point to the candidate baseline angle; Based on the principle that the beam pointing of the dual antenna array is uniquely determined by the baseline spatial orientation, the consistency of the common pointing with the direction of arrival of the GNSS satellite is used as the criterion for determining the effectiveness of the candidate baseline angle.

[0043] Specifically, according to the process of determining and the maximum carrier-to-noise ratio of the sum beam, the sum beam carrier-to-noise ratio value corresponding to the candidate baseline angle is read from the correspondence relationship, and the sum beam carrier-to-noise ratio values corresponding to all other traversal angles are also read. The sum beam carrier-to-noise ratio of the candidate baseline angle is compared with the sum beam carrier-to-noise ratio of all other traversal angles one by one to verify whether the sum beam carrier-to-noise ratio of the candidate baseline angle is the maximum value. The comparison process checks whether there is a value greater than the sum beam carrier-to-noise ratio of the candidate baseline angle by traversing all sum beam carrier-to-noise ratio data, and if there is not, it is confirmed that the sum beam carrier-to-noise ratio corresponding to the candidate baseline angle is the maximum carrier-to-noise ratio among all traversal angles. The sum beam carrier-to-noise ratio reaching the maximum indicates that the signal strength of the sum beam at the candidate baseline angle is the strongest, because the sum beam superimposes the signals of the two antennas in phase, and when the beam pointing is consistent with the signal direction of arrival, the phase difference of the two signals is completely compensated, the signal amplitude after superposition reaches the maximum, and the power is the strongest. It is confirmed that the sum beam forms a maximum gain pointing at the candidate baseline angle, and this maximum gain pointing is the core feature of the beam forming technology, indicating that the receiving ability of the antenna array to the signal in this direction is the strongest.

[0044] According to the process of determining the minimum carrier-to-noise ratio of the difference beam, the difference beam carrier-to-noise ratio value corresponding to the candidate baseline angle is read from the correspondence relationship, and the difference beam carrier-to-noise ratio values corresponding to all other traversal angles are also read. The difference beam carrier-to-noise ratio of the candidate baseline angle is compared with the difference beam carrier-to-noise ratio of all other traversal angles one by one to verify whether the difference beam carrier-to-noise ratio of the candidate baseline angle is the minimum value. The comparison process checks whether there is a value smaller than the difference beam carrier-to-noise ratio of the candidate baseline angle by traversing all difference beam carrier-to-noise ratio data, and if there is not, it is confirmed that the difference beam carrier-to-noise ratio corresponding to the candidate baseline angle is the minimum carrier-to-noise ratio among all traversal angles. The difference beam carrier-to-noise ratio reaching the minimum indicates that the signal strength of the difference beam at the candidate baseline angle is the weakest, because the difference beam superimposes the signals of the two antennas in opposite phase, and when the beam pointing is consistent with the signal direction of arrival, the phase difference of the two signals is 180 degrees, the signal after superposition is maximally cancelled, a null is formed, and the power is the weakest. It is confirmed that the difference beam forms a maximum null pointing at the candidate baseline angle, and this maximum null pointing is a typical feature of the difference beam, indicating that the receiving ability of the antenna array to the signal in this direction is the weakest or even close to zero.

[0045] According to the process of determining the common pointing direction, and the beam forms a maximum gain pointing at the candidate baseline angle, the difference beam forms a maximum null pointing at the candidate baseline angle, and the pointing directions of both are the candidate baseline angle. The maximum gain pointing represents the direction in which the signal energy is focused the strongest, and the maximum null pointing represents the direction in which the signal energy is canceled the most thoroughly. The coincidence of the two pointings at the same angle indicates that the direction corresponding to the angle is the true direction of the signal arrival. According to the physical principle of beam forming, only when the beam pointing is completely consistent with the signal arrival direction, the sum beam can achieve maximum gain and the difference beam can achieve maximum null. The direction that satisfies both conditions simultaneously is unique. The candidate baseline angle is determined as the common pointing direction of the sum beam and the difference beam, which has a clear physical meaning, representing the unification of the best receiving direction and the maximum suppression direction of the GNSS satellite signal by the dual antenna array.

[0046] According to the process of determining the effectiveness of the candidate baseline angle, the beam pointing of the dual antenna array is uniquely determined by the spatial attitude of the baseline, which includes the azimuth angle and the elevation angle of the baseline. These two parameters completely determine the pointing direction of the baseline in three-dimensional space. When the sum beam and the difference beam are formed by phase shifting and combining, the pointing direction of the beam is determined by the baseline attitude. Different baseline attitudes correspond to different beam pointings. The common pointing direction is the direction in which the sum beam and the difference beam simultaneously reach the extreme value, which is selected by measuring the carrier-to-noise ratio difference. The consistency of this direction with the GNSS satellite arrival direction can be guaranteed by physical mechanisms. The GNSS satellite arrival direction can be obtained from the navigation message and is a known reference direction. When the common pointing direction is consistent with the satellite arrival direction, it indicates that the candidate baseline angle indeed reflects the true spatial attitude of the baseline. The consistency of the common pointing direction with the GNSS satellite arrival direction is used as the basis for determining the effectiveness of the candidate baseline angle, completing the closed loop from measurement data to physical verification, and ensuring the reliability and accuracy of the output baseline angle.

[0047] In a specific embodiment, step S5 comprises: extracting the azimuth angle component from the traversed angle, and taking the azimuth angle component as the angle between the dual antenna baseline and the north direction; extracting the elevation angle component from the traversed angle, and taking the elevation angle component as the angle between the dual antenna baseline and the horizontal plane; determining the spatial attitude of the dual antenna baseline in the geographic coordinate system based on the azimuth angle component and the elevation angle component, and outputting the azimuth angle and the elevation angle of the dual antenna baseline as the measurement results.

[0048] Specifically, according to the process of extracting the azimuth component, the traversed angle is an angle combination containing two dimension parameters, one of which is the azimuth and the other is the elevation. The azimuth parameter value is read from the traversed angle data structure, which represents the included angle between the projection of the dual-antenna baseline in the horizontal plane and the north direction. The azimuth component ranges from 0 degree to 360 degrees, 0 degree corresponds to the north direction, 90 degrees corresponds to the east direction, 180 degrees corresponds to the south direction, and 270 degrees corresponds to the west direction. The extracted azimuth component is taken as the included angle between the dual-antenna baseline and the north direction, which describes the pointing azimuth of the baseline in the horizontal plane and is the first key parameter for determining the spatial attitude of the baseline. The azimuth component reflects the rotation angle of the baseline relative to the geographic north pole, which corresponds to the concept of heading angle in navigation positioning applications.

[0049] According to the process of extracting the elevation component, the elevation parameter value is read from the traversed angle data structure, which represents the included angle between the dual-antenna baseline and the horizontal plane. The elevation component usually ranges from -90 degrees to 90 degrees, 0 degree corresponds to the baseline being placed horizontally, positive value corresponds to the baseline being tilted upward, and negative value corresponds to the baseline being tilted downward. The extracted elevation component is taken as the included angle between the dual-antenna baseline and the horizontal plane, which describes the inclination of the baseline in the vertical direction and is the second key parameter for determining the spatial attitude of the baseline. The elevation component reflects the lifting or lowering angle of the baseline relative to the horizontal plane, which corresponds to the concept of pitch angle or roll angle in attitude measurement applications.

[0050] According to the process of determining the spatial attitude of the baseline, based on the extracted azimuth component and the elevation component, the spatial attitude of the dual-antenna baseline is completely described in the geographic coordinate system. The geographic coordinate system takes antenna A as the origin, the X-axis points to the east, the Y-axis points to the north, and the Z-axis points to the zenith, forming a right-handed coordinate system. The azimuth component determines the rotation angle of the baseline in the horizontal plane relative to the north direction, and the elevation component determines the lifting angle of the baseline relative to the horizontal plane. The two angle parameters together determine the unique pointing direction of the baseline in three-dimensional space. Through the combination of azimuth and elevation, the vector direction of the baseline pointing from antenna A to antenna B is completely determined, and the spatial attitude of the baseline contains all the directional information of the baseline. The azimuth and elevation of the dual-antenna baseline are output as the final measurement results, which can be directly used to describe the spatial attitude of the dual-antenna system and applied to heading measurement of navigation positioning systems, attitude calculation of attitude measurement devices, angle calibration of antenna pointing control systems, etc. to complete the whole process of attitude angle measurement based on beam pointing and GNSS signals.

[0051] The above describes the attitude angle measurement method based on beam pointing and GNSS signals in the embodiments of the present application, and the following describes the attitude angle measurement system based on beam pointing and GNSS signals in the embodiments of the present application. Please refer to Figure 2The attitude angle measurement system based on beam pointing and GNSS signals in the embodiment of the application includes the following modules: a traversal module, configured to traverse different combinations of azimuth and elevation angles in a double-antenna baseline angle space, calculate signal delay of antenna B relative to antenna A at each traversal angle according to a GNSS satellite wave direction, and convert the signal delay into a phase shift value; a phase shift module, configured to set a phase shifter to perform phase shift processing on the antenna B signal and combine the antenna B signal with the antenna A signal to form a sum beam using the phase shift value, and set the phase shifter to form a difference beam using the phase shift value plus 180°; a recording module, configured to measure a carrier-to-noise ratio of the sum beam and a carrier-to-noise ratio of the difference beam, calculate a carrier-to-noise ratio difference value of the two carrier-to-noise ratios, and record a corresponding relationship between the carrier-to-noise ratio difference value and the traversal angle; a screening module, configured to screen, from the corresponding relationship, a traversal angle that makes the carrier-to-noise ratio difference value reach a maximum, and the traversal angle corresponds to a sum beam pointing direction consistent with a GNSS satellite wave direction; a generation module, configured to determine an azimuth angle and an elevation angle of a double-antenna baseline according to the traversal angle.

[0052] The above Figure 2 The attitude angle measurement system based on beam pointing and GNSS signals in the embodiment of the application is described in detail from the perspective of modular functional entities, and the attitude angle measurement device based on beam pointing and GNSS signals in the embodiment of the application is described in detail from the perspective of hardware processing.

[0053] Reference Figure 3 The embodiment of the application also provides an attitude angle measurement device based on beam pointing and GNSS signals, which can be a server, and the internal structure thereof can be as shown in Figure 3 The attitude angle measurement device based on beam pointing and GNSS signals includes a processor, a memory, a display screen, an input device, a network interface and a database connected through a system bus. The processor of the computer is configured to provide computing and control capabilities. The memory of the attitude angle measurement device based on beam pointing and GNSS signals includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The database of the attitude angle measurement device based on beam pointing and GNSS signals is configured to store corresponding data in the embodiment. The network interface of the attitude angle measurement device based on beam pointing and GNSS signals is configured to communicate with an external terminal through a network connection. The computer program is executed by the processor to implement the above method.

[0054] Those skilled in the art can understand that,Figure 3 The structure shown in the figure is only a block diagram of part of the structure related to the technical scheme of the present application, and does not constitute a limitation on the beam pointing and GNSS signal based attitude angle measurement device to which the technical scheme of the present application is applied.

[0055] The present application also provides a computer readable storage medium, which can be a non-volatile computer readable storage medium, and can also be a volatile computer readable storage medium, and the computer readable storage medium stores instructions, and when the instructions are run on a computer, the computer executes the steps of the beam pointing and GNSS signal based attitude angle measurement method.

[0056] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, system and unit can refer to the corresponding processes in the foregoing method embodiments, and will not be described here.

[0057] The integrated unit, if realized in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical scheme of the present application or the part of the prior art that essentially contributes or the whole or part of the technical scheme can be embodied in the form of a software product, which is stored in a storage medium and includes a plurality of instructions for causing a beam pointing and GNSS signal based attitude angle measurement device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0058] The above embodiments are only used to illustrate the technical scheme of the present application, rather than limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical scheme recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical scheme deviate from the spirit and scope of the technical scheme of the present application.

Claims

1. A method for measuring attitude angles based on beam pointing and GNSS signals, characterized in that, The method comprises: Step S1: traversing different azimuth and elevation angle combinations in a dual-antenna baseline angle space, calculating the signal delay of antenna B relative to antenna A at each traversed angle according to the GNSS satellite wave direction, and converting the signal delay into a phase shift value; Step S2: setting the phase shifter with the phase shift value to perform phase shift processing on the antenna B signal and combine it with the antenna A signal to form a sum beam, and setting the phase shifter with the phase shift value plus 180° to form a difference beam; Step S3: measuring the carrier-to-noise ratio of the sum beam and the carrier-to-noise ratio of the difference beam, calculating the carrier-to-noise ratio difference value of the two, and recording the corresponding relationship between the carrier-to-noise ratio difference value and the traversed angle; Step S4: screening the traversed angle that makes the carrier-to-noise ratio difference value maximum from the corresponding relationship, and the sum beam corresponding to the traversed angle is directed in the same direction as the GNSS satellite wave direction; Step S5: determining the azimuth and elevation angles of the dual-antenna baseline according to the traversed angle.

2. The method of claim 1, wherein, The step S1 comprises: establishing a geographic coordinate system with antenna A as the origin, the X-axis pointing to the east, the Y-axis pointing to the north, and the Z-axis pointing to the zenith, calculating the spatial coordinates of antenna B in the geographic coordinate system according to the traversed azimuth and elevation angles; parsing the azimuth and elevation angles of the GNSS satellite from the navigation message output by the navigation chip, and taking the azimuth and elevation angles of the GNSS satellite as the satellite wave direction parameters; calculating the propagation path difference of the signal received by antenna B relative to antenna A according to the spatial coordinates and the satellite wave direction parameters, and dividing the propagation path difference by the speed of light to obtain the signal delay; multiplying the signal delay by the GNSS signal carrier frequency and then by 2π to obtain the phase shift value.

3. The method of claim 1, wherein, The step S2 comprises: inputting the phase shift value into the control end of the phase shifter to perform phase adjustment on the GNSS signal received by antenna B to obtain the phase-shifted antenna B signal; inputting the phase-shifted antenna B signal and the GNSS signal received by antenna A into the combiner to perform in-phase superposition, forming the sum signal corresponding to the sum beam; inputting the phase shift value plus 180° into the control end of the phase shifter to perform phase adjustment on the GNSS signal received by antenna B to obtain the reverse phase-shifted antenna B signal; inputting the reverse phase-shifted antenna B signal and the GNSS signal received by antenna A into the combiner to perform reverse superposition, forming the difference signal corresponding to the difference beam.

4. The method of claim 3, wherein, The step S3 comprises: inputting the sum signal into the navigation chip for demodulation processing, and obtaining the carrier-to-noise ratio of the sum beam from the output end of the navigation chip; inputting the difference signal into the navigation chip for demodulation processing, and obtaining the carrier-to-noise ratio of the difference beam from the output end of the navigation chip; subtracting the carrier-to-noise ratio of the difference beam from the carrier-to-noise ratio of the sum beam to obtain the carrier-to-noise ratio difference value corresponding to the current traversed angle; establishing the mapping relationship between the carrier-to-noise ratio difference value and the traversed angle to form the corresponding relationship.

5. The method of claim 1, wherein, The step S4 comprises: traversing all the carrier-to-noise ratio difference values in the corresponding relationship, and screening out the maximum value of the carrier-to-noise ratio difference value; obtaining the traversed angle corresponding to the maximum value, and taking the traversed angle as the candidate baseline angle; According to the fact that the sum beam forms a maximum gain pointing at the candidate baseline angle and the difference beam forms a maximum null pointing at the candidate baseline angle, it is determined that the beam pointing of the candidate baseline angle is consistent with the GNSS satellite incoming wave direction; The candidate baseline angle is confirmed as the effective traversal angle.

6. The method of claim 5, wherein, According to the fact that the sum beam forms a maximum gain pointing at the candidate baseline angle and the difference beam forms a maximum null pointing at the candidate baseline angle, it is determined that the beam pointing of the candidate baseline angle is consistent with the GNSS satellite incoming wave direction, which comprises: It is determined that the carrier-to-noise ratio of the sum beam corresponding to the candidate baseline angle is the maximum carrier-to-noise ratio among all the traversal angles, and it is confirmed that the sum beam forms a maximum gain pointing at the candidate baseline angle; It is determined that the carrier-to-noise ratio of the difference beam corresponding to the candidate baseline angle is the minimum carrier-to-noise ratio among all the traversal angles, and it is confirmed that the difference beam forms a maximum null pointing at the candidate baseline angle; According to the fact that the maximum gain pointing and the maximum null pointing are both pointed at the candidate baseline angle, it is determined that the candidate baseline angle is the common pointing of the sum beam and the difference beam; Based on the principle that the beam pointing of the dual-antenna array is uniquely determined by the baseline spatial attitude, the consistency of the common pointing with the GNSS satellite incoming wave direction is taken as the determination basis for the effectiveness of the candidate baseline angle.

7. The method of claim 2, wherein, The step S5 comprises: Extracting an azimuth angle component from the traversal angle, and taking the azimuth angle component as the included angle between the dual-antenna baseline and the north direction; Extracting an elevation angle component from the traversal angle, and taking the elevation angle component as the included angle between the dual-antenna baseline and the horizontal plane; Determining the spatial attitude of the dual-antenna baseline in the geographic coordinate system based on the azimuth angle component and the elevation angle component, and outputting the azimuth angle and the elevation angle of the dual-antenna baseline as measurement results.

8. A system for measuring attitude angles based on beam pointing and GNSS signals, characterized by The system for implementing the beam pointing and GNSS signal-based attitude angle measurement method according to any one of claims 1-7 comprises: A traversal module for traversing different combinations of azimuth angle and elevation angle in the dual-antenna baseline angle space, calculating the signal delay of antenna B relative to antenna A at each traversal angle according to the GNSS satellite incoming wave direction, and converting the signal delay into a phase shift value; A phase shift module for setting a phase shifter to perform phase shift processing on the antenna B signal by the phase shift value and combining the antenna B signal with the antenna A signal to form a sum beam, and setting a phase shifter to form a difference beam by the phase shift value plus 180°; A recording module for measuring the carrier-to-noise ratio of the sum beam and the carrier-to-noise ratio of the difference beam, calculating the carrier-to-noise ratio difference value of the two, and recording the corresponding relationship between the carrier-to-noise ratio difference value and the traversal angle; A screening module for screening the traversal angle that makes the carrier-to-noise ratio difference value reach the maximum from the corresponding relationship, and the sum beam pointing corresponding to the traversal angle is consistent with the GNSS satellite incoming wave direction; A generation module for determining the azimuth angle and the elevation angle of the dual-antenna baseline according to the traversal angle.

9. A device for measuring attitude angles based on beam pointing and GNSS signals, characterized by An apparatus comprising a memory storing a computer program executable on a processor, the processor implementing the method of measuring attitude angles based on beam pointing and GNSS signals according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program, when executed by the processor, causes the processor to implement the method of measuring attitude angles based on beam pointing and GNSS signals according to any one of claims 1 to 7.

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