An Autonomous Attitude Estimation Method for Antenna Array in High-Precision Anti-jamming Navigation

Abstract

The invention relates to the technical field of high-precision anti-interference satellite navigation, and specifically discloses an autonomous estimation method for antenna array attitude of high-precision anti-interference navigation, comprising: designing a multi-antenna carrier tracking loop to measure carrier phase in an interference environment; utilizing carrier phase double difference between array elements to eliminate clock error and ionosphere and troposphere delay; utilizing the constraint that array element spacing does not exceed half a wavelength of the carrier to solve the unique solution of each baseline vector from the carrier phase double difference equation; obtaining a rough estimation of array attitude from the least square solution of the equation group satisfied by each baseline vector; compensating for the phase error of each array element by utilizing the rough estimation of attitude; iterating three times to obtain an accurate estimation of array attitude in the order of calculating carrier phase double difference between array elements, solving multiple baseline vectors, roughly estimating array attitude, and compensating for array element phase error; and requiring no additional installation of attitude sensors, INS and GNSS antennas, no reliance on other navigation sources, no calibration, no accumulation of estimation errors, and short initialization time.

Description

Technical Field

[0001] The present invention relates to the technical field of high-precision anti-interference satellite navigation, and in particular to a method for autonomously estimating the antenna array attitude of high-precision anti-interference navigation. Background Art

[0002] The outstanding features of high-precision anti-interference satellite navigation applications such as precision approach and landing of aircraft, landing of aircraft on aircraft carriers, formation flying and automatic aerial refueling, rapid direction finding and autonomous north seeking of missile launchers / aircraft are complex interference environments and high requirements for positioning and orientation.

[0003] The complexity of the interference environment is mainly manifested in the variety of interference types and changes. From the perspective of interference mechanism, the interference types are divided into suppression interference, deception interference, and suppression and deception combined interference. Deception interference is further divided into regeneration and forwarding types. Interference changes mainly include the number, direction, modulation, frequency, intensity, etc. of interference that changes rapidly or slowly over time. Positioning and orientation requirements include real-time or near real-time positioning services at the decimeter / centimeter level and orientation services better than 1 degree / 0.5 degree.

[0004] High-precision positioning and orientation in complex interference environments requires solving three strongly coupled problems: complex interference detection and real-time suppression, satellite signal distortion tracing and control, and high-precision positioning and orientation with low distortion.

[0005] Through theoretical deduction, simulation analysis and experimental verification, the inventors decoupled the above three problems into three categories, seven subcategories and 10 sequential topics as shown in the table below.

[0006] Based on this, 10 high-precision anti-interference navigation invention patents corresponding to the above topics are planned and laid out, as shown in Table 1.

[0007] Table 1 List of decoupling and disassembly of high-precision positioning and orientation problems in complex interference environments

[0008]

[0009] In the present invention, the second category, the fourth subcategory, and the seventh invention listed in Table 1 - the autonomous estimation method of the antenna array attitude are analyzed and explained.

[0010] The demand for antenna array attitude estimation mainly comes from channel amplitude and phase inconsistency control, multi-beam anti-interference, and strong short-delay deception interference detection. In channel amplitude and phase inconsistency control, it is necessary to obtain the direction of the satellite signal wave according to the antenna array attitude, and then index and query the upward amplitude and phase correction parameters. In multi-beam anti-interference and strong short-delay deception interference detection, it is necessary to obtain the direction of the satellite signal wave and the steering vector according to the antenna array attitude, and then calculate the weight vector.

[0011] The existing antenna array attitude estimation methods mainly include attitude estimation methods based on attitude sensors or inertial navigation systems, and attitude estimation methods based on the combination of dual-antenna GNSS and inertial navigation systems.

[0012] An antenna array attitude estimation method based on attitude sensor is characterized in that an attitude sensor composed of a three-axis gyroscope, a three-axis accelerometer, a three-axis electronic compass, an ARM processor, etc. is fixedly connected to the antenna array. The three-axis gyroscope measures angular velocity, the three-axis accelerometer measures acceleration, the three-axis electronic compass uses the geomagnetic field to determine the North Pole, the ARM processor calibrates angular velocity, acceleration, magnetic data, etc., and performs attitude measurement based on quaternion sensor data algorithm, and outputs three-dimensional attitude data represented by quaternion, Euler angle, etc. in real time.

[0013] The antenna array attitude estimation method based on the inertial navigation system uses inertial instruments (gyroscopes, accelerometers) to measure the angular motion and linear motion in the inertial space, and solves the position, velocity and attitude (yaw, pitch, roll) of the antenna array according to the differential equations of motion.

[0014] The attitude estimation method based on the combination of dual-antenna GNSS and inertial navigation system first obtains the initial heading value required by the inertial navigation system through dual-antenna carrier phase differential direction processing by an array element in the array antenna, GNSS antennas with a spacing of more than 1 meter, and satellite navigation equipment, and then obtains the antenna array attitude by combining satellite navigation and inertial navigation.

[0015] In addition to the need to install additional attitude sensors, inertial navigation systems, and GNSS antennas, the three existing antenna array attitude estimation methods also have disadvantages such as difficulty in calibration, heading drift, and long initialization time. The specific disadvantages are as follows:

[0016] The antenna array attitude estimation method based on attitude sensor requires the installation of an additional fixed attitude sensor, which is easily affected by the surrounding magnetic field environment (including the magnetic field generated by electronic equipment, metal objects, magnets, etc.), is difficult to calibrate, and costs less than 1,000 yuan.

[0017] The antenna array attitude estimation method based on the inertial navigation system requires the installation of an additional fiber-optic inertial navigation system. The heading initialization time is 3 to 5 minutes, the heading will drift, and the price is 80,000 to 100,000 yuan.

[0018] The antenna array attitude estimation method based on the combination of dual-antenna GNSS and inertial navigation system requires the additional installation of a MEMS inertial navigation system and a pair of GNSS antennas with a spacing of more than 1 meter. The heading initialization time is within 1 minute and the price is about 20,000 yuan.

[0019] Based on this technical background, the present invention studies a method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation. Summary of the invention

[0020] In view of the shortcomings of the prior art, the present invention provides a method for autonomously estimating the antenna array face attitude for high-precision anti-interference navigation. By designing a multi-antenna carrier tracking loop, carrier phase measurement in an interference environment is realized; the carrier phase double difference between each array element and a reference array element is used to solve the baseline vector of each array element pointing to the reference array element; and the antenna array face attitude is solved by the antenna array face equation satisfied by multiple baseline vectors. No additional attitude sensors, inertial navigation systems and GNSS antennas are required, and no external navigation sources are relied on. No calibration is required, attitude estimation errors are not accumulated, and the initialization time is short.

[0021] In order to achieve the above object, the present invention provides a method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation, comprising:

[0022] Design a multi-antenna carrier tracking loop to measure the satellite signal carrier phase at each array element in an interference environment;

[0023] According to the sequence of double difference calculation of carrier phase between array elements, solution of multiple baseline vectors, rough estimation of antenna array attitude, and compensation of array element phase error, an accurate estimation of antenna array attitude is obtained iteratively.

[0024] The beneficial effects of the present invention include:

[0025] (1) The present invention proposes a method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation. By designing a multi-antenna carrier tracking loop, the carrier phase is measured in an interference environment. The method iterates three times in the order of double-difference calculation of carrier phases between array elements, solution of multiple baseline vectors, rough estimation of array attitude, and compensation of array element phase errors. The method does not require the installation of attitude sensors, INS, or GNSS antennas, does not rely on other navigation sources, does not require calibration, does not accumulate estimation errors, and has a short initialization time.

[0026] (2) The present invention proposes a method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation. The method first uses a multi-antenna carrier tracking loop based on a multi-beam anti-interference signal to assist the carrier tracking channel of each array element to eliminate the satellite signal sign bit. The carrier tracking threshold is then reduced through long-term coherent accumulation, thereby realizing the carrier phase measurement of each array element on the common-view satellite in an interference environment.

[0027] (3) The present invention proposes a method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation, which uses the double difference of carrier phase between array elements to eliminate satellite clock error, satellite ephemeris error, receiver clock error, ionospheric delay, and tropospheric delay. Then, the constraint that the array element spacing does not exceed half the wavelength of the carrier is used to select the unique solution of each baseline vector (that is, the vector of each array element pointing to the reference array element) from five candidate solutions, thereby avoiding the problem of ambiguity in the resolution of each baseline vector.

[0028] (4) The present invention proposes a method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation. The method uses the rough estimation index of the array attitude to query the phase error correction parameter table of each array element. After compensating the error of the phase distortion introduced by each array element, it jumps to the double difference calculation of the carrier phase between the array elements, solves multiple baseline vectors, and roughly estimates the array attitude. This method is iterated three times to achieve accurate estimation of the antenna array attitude.

[0029] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

[0031] Figure 1 The present invention is a flowchart of a method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation.

[0032] Figure 2 This is a schematic diagram of the composition of a multi-antenna carrier tracking loop in a specific implementation of a method for autonomously estimating antenna array attitude for high-precision anti-interference navigation proposed by the present invention.

[0033] Figure 3 This is a schematic diagram of the test results of a multi-antenna carrier tracking loop in a specific implementation of the method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation proposed by the present invention. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0035] The present invention provides a method for autonomously estimating the attitude of an antenna array for high-precision anti-interference navigation. Figure 1 As shown, including:

[0036] Design a multi-antenna carrier tracking loop to measure the satellite signal carrier phase at each array element in an interference environment;

[0037] According to the sequence of double difference calculation of carrier phase between array elements, solution of multiple baseline vectors, rough estimation of antenna array attitude, and compensation of array element phase error, an accurate estimation of antenna array attitude is obtained iteratively.

[0038] In the present invention, a multi-antenna carrier tracking loop is designed based on a multi-beam anti-interference post signal to assist each array element carrier tracking channel, so that each array element can measure the carrier phase of the satellite signal in an interference environment; the satellite clock error, satellite ephemeris error, receiver clock error, ionospheric delay, and tropospheric delay are eliminated through the carrier phase double difference between each array element and the reference array element; the constraint condition that the array element spacing does not exceed half the wavelength of the carrier is used to screen out the unique solution of the baseline vector of each array element pointing to the reference array element from the five candidate solutions of the equation satisfied by the carrier phase double difference; the homogeneous equation satisfied by each baseline vector The least squares solution of the equation group is used to obtain a rough estimate of the antenna array attitude; the rough estimate of the array attitude is used to query the phase error correction parameters of each array element, and the error of the phase distortion of each array element is compensated; according to the order of double difference calculation of carrier phase between array elements, solution of multiple baseline vectors, rough estimation of antenna array attitude, and compensation of array element phase error, an accurate estimate of the antenna array attitude is obtained by iterating three times; no additional attitude sensor, inertial navigation system and GNSS antenna is required, it does not rely on other external navigation sources, does not require calibration, attitude estimation error does not accumulate, and the initialization time is short.

[0039] According to the present invention, a multi-antenna carrier tracking loop is designed to measure the satellite signal carrier phase at each array element in an interference environment, including:

[0040] Design a multi-antenna carrier tracking loop based on multi-beam anti-jamming signals to assist the carrier tracking channels of each array element, eliminate the satellite signal sign bit, and allow long-term coherent accumulation;

[0041] The carrier tracking threshold is lowered and the carrier tracking sensitivity is improved through long-term coherent accumulation, and the carrier phase of each array element to the common-view satellite in an interference environment is measured.

[0042] The formula used to measure the satellite signal carrier phase at each array element in an interference environment is as follows:

[0043] ;

[0044] ;

[0045] in, , Divided into element 1 and element 2 pairs of satellites The fractional part of the carrier phase observation, , They are array element 1 and array element 2 for satellites. The integer ambiguity of the carrier phase observation is is the carrier wavelength of the observed frequency, , Divided into array element 1 and array element 2 and satellite The geometric distance between , It is divided into array element 1 and array element 2, followed by the deviation of the satellite navigation processing unit clock relative to the satellite navigation system clock, that is, the receiver clock error. For satellite The deviation of the clock relative to the satellite navigation system, that is, the satellite clock error, , is the error caused by the ionosphere, troposphere, multipath effect, and receiver noise. is the speed of light in a vacuum.

[0046] According to the present invention, the double difference calculation of carrier phase between array elements includes:

[0047] Calculate the carrier phase single difference between each array element and the reference array element to eliminate satellite clock error, satellite ephemeris error, ionospheric delay, and tropospheric delay;

[0048] The double difference of the carrier phase between each array element and the reference array element is calculated to further eliminate the receiver clock error.

[0049] According to the present invention, calculating the carrier phase single difference between each array element and the reference array element includes:

[0050] Array element 1 is used as the reference array element, and the carrier phase of the same satellite observed by array element 1 and array element 2 is single-differenced to eliminate the satellite clock error, satellite ephemeris error, ionospheric delay, and tropospheric delay;

[0051] The formula used to calculate the single difference of the carrier phase between element 2 and element 1 is:

[0052]

[0053] ;

[0054] in,

[0055] ;

[0056] ;

[0057] in, , , They are array element 1, array element 2 and satellite Coordinates in the agreed geocentric rectangular coordinate system.

[0058] According to the present invention, the simplified formula used to calculate the carrier phase single difference between array element 2 and array element 1 is:

[0059] ;

[0060] in, , is the phase center position coordinate of the array antenna;

[0061] The simplified condition of the formula used to calculate the single difference of the carrier phase between element 2 and element 1 is:

[0062] 1) Since the satellite orbit altitude is 20,000-30,000 kilometers, the satellite signal incident on the array antenna is equivalent to a plane wave, and the unit direction vector of array element 1 pointing to the satellite is parallel to the unit direction vector of array element 2 pointing to the satellite, that is:

[0063] ;

[0064] and then:

[0065]

[0066] = ;

[0067] 2) The phase center position coordinates of the array antenna are recorded as , the same as above, using the satellite signal equivalent to a plane wave The formula is:

[0068] ;

[0069] 3) For array elements 1 and 2 whose spacing does not exceed half the wavelength of the carrier wave, the paths of satellite signals propagating to the two array elements are almost the same. By subtracting the carrier phase observations of the two array elements, eliminating the ionosphere and troposphere delays, and ignoring the multipath effect and the influence of receiver noise, we can obtain .

[0070] According to the present invention, calculating the carrier phase double difference between each array element and the reference array element includes:

[0071] When array element 1 and array element 2 simultaneously observe the , Satellites are used to further eliminate the receiver clock error by using the double difference of carrier phase. The double difference formula used is:

[0072]

[0073]

[0074] .

[0075] According to the present invention, multiple baseline vector solutions include:

[0076] Substitute the carrier phase double difference, the coordinates of the phase center position of the array antenna, the five possible values ​​of the integer ambiguity, and the satellite coordinates into the carrier phase double difference calculation formula to solve the five candidate solutions of the baseline vector of each array element pointing to the reference array element;

[0077] Using the constraint that the distance between each array element and the reference array element does not exceed half the wavelength of the carrier, the unique solution of each baseline vector is selected from the five candidate solutions;

[0078] There are five possible values ​​for the integer ambiguity. The derivation process includes:

[0079] 1) Since the distance between array element 1 and array element 2 does not exceed half the wavelength of the carrier, the phase difference caused by the path difference in the carrier phase observation does not exceed half a cycle. and Either the same or adjacent, then It can only take three values: 0, -1 and 1;

[0080] 2) Due to and can only take three values: 0, -1 and 1. It can only take five values: 0, -1, -2, 1 and 2;

[0081] The carrier phase double difference, array antenna phase center position coordinates, , and satellite , Substitute the coordinates into the double difference formula , and get 5 vector solutions;

[0082] From the five solutions, we get a solution that satisfies the constraint that the array element spacing does not exceed half the carrier wavelength. This solution is the baseline vector from array element 2 to array element 1, expressed as: ;

[0083] The same method is used to obtain the baseline vectors of other array elements pointing to array element 1, which can be expressed as: ,in, .

[0084] According to the present invention, the rough estimation of the antenna array attitude includes:

[0085] Substitute the unique solution of each baseline vector into the general equation of the plane where the antenna array face is located to obtain a homogeneous system of equations. A rough estimate of the antenna array face attitude is obtained from the least squares solution of the homogeneous system of equations.

[0086] According to the present invention, the general equation expression of the plane where the antenna array surface is located is:

[0087] ;

[0088] The expression of the homogeneous equation system is:

[0089] ;

[0090] in, ;

[0091] The least squares solution of the homogeneous equations is the normal vector of the plane where the antenna array is located, that is, , which is a rough estimate of the antenna array attitude.

[0092] According to the present invention, array element phase error compensation includes:

[0093] The direction of the satellite signal is obtained by using a rough estimate of the array attitude, the satellite position, and the phase center position of the array antenna.

[0094] The phase error correction parameter table of each array element is then queried based on the direction index of the satellite signal, and then error compensation is performed on the phase distortion introduced by each array element.

[0095] In the present invention, a multi-antenna carrier tracking loop is designed to measure the satellite signal carrier phase at each array element in an interference environment; according to the order of double-difference calculation of carrier phase between array elements, solution of multiple baseline vectors, rough estimation of antenna array face attitude, and compensation of array element phase error, an accurate estimation of antenna array face attitude is iteratively obtained, thereby realizing autonomous and accurate estimation of antenna array face attitude in an interference environment.

[0096] The present invention will be described in more detail below by way of examples.

[0097] Embodiment 1:

[0098] like Figure 1 As shown, this embodiment proposes a method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation, including carrier phase measurement in an interference environment, double difference calculation of carrier phase between array elements, multiple baseline vector solution, antenna array attitude estimation, array element phase error compensation, etc., as follows:

[0099] 1) Measuring carrier phase in interference environment:

[0100] By adding a multi-antenna carrier tracking loop after each array element, carrier phase measurement in an interference environment can be achieved. The composition of the multi-antenna carrier tracking loop is as follows Figure 2 As shown;

[0101] Figure 2 The multi-antenna carrier tracking loop shown in the figure first uses the multi-beam anti-interference signal to assist the carrier tracking channel of each array element, eliminates the sign bit of the satellite signal, and allows long-term coherent accumulation; then, through long-term coherent accumulation, the carrier tracking threshold is reduced, the carrier tracking sensitivity is improved, and the carrier phase measurement in the interference environment is realized;

[0102] The carrier phase observation of element 1 in the array antenna to satellite j is:

[0103] ;

[0104] in, For array element 1 pair of satellites The fractional part of the carrier phase observation, For array element 1 pair of satellites The integer ambiguity of the carrier phase observation; is the carrier wavelength of the observed frequency, For array element 1 and satellite The geometric distance between is the deviation of the clock of the satellite navigation processing unit connected to the array element 1 relative to the satellite navigation system (i.e., the receiver clock error), For satellite The deviation of the clock relative to the satellite navigation system (i.e., satellite clock error), The error is caused by other factors (ionosphere, troposphere, multipath effect, receiver noise, etc.). is the speed of light in vacuum;

[0105] Array element 2 pairs of satellites The carrier phase observation is:

[0106] ;

[0107] The measured results of the tracking sensitivity of the multi-antenna carrier tracking loop are as follows: Figure 3 As shown;

[0108] The tracking threshold of the multi-antenna carrier tracking loop, that is, the minimum carrier-to-noise ratio at which the carrier phase tracking error is better than 0.04 cycles, has been reduced from 28Hz of the conventional carrier tracking loop to below 15dBHz; therefore, in an interference environment with an interference-to-signal ratio of 60dB, the carrier phase of each array element can be measured normally;

[0109] 2) Calculate the double difference of carrier phase between array elements:

[0110] Single-difference the carrier phase observations of elements 1 and 2 to cancel the same satellite Clock Difference Available

[0111] ;

[0112] in,

[0113] ;

[0114] ;

[0115] In the above formula, , , They are array elements 1, 2 and satellites. Coordinates in the agreed geocentric rectangular coordinate system;

[0116] Since the distance between array elements 1 and 2 does not exceed half the wavelength of the carrier, the phase difference caused by the path difference in the carrier phase observation does not exceed half a cycle; thus, the integer ambiguity and Either the same or adjacent, then It can only take three values: 0, -1 and 1;

[0117] Since the satellite orbit altitude is 20,000 to 30,000 kilometers, the satellite signal incident on the array antenna can be regarded as a plane wave; in this way, the unit direction vector of array element 1 pointing to the satellite is parallel to the unit direction vector of array element 2 pointing to the satellite, that is:

[0118] ;

[0119] and then,

[0120] ;

[0121] The phase center position coordinates of the array antenna are , using the incident satellite signal as a plane wave, the above formula can be rearranged as:

[0122] ;

[0123] For array elements 1 and 2 whose spacing does not exceed half the wavelength of the carrier, the propagation paths of the satellite signals incident on the two array elements are almost the same; the difference of the carrier phase observations of the two array elements can eliminate the ionosphere and troposphere delays, and further ignore the small amount of influence such as multipath effect and receiver noise to obtain ;therefore,

[0124] :

[0125] If array elements 1 and 2 simultaneously observe , The double difference of carrier phase observations further eliminates the receiver clock error, that is,

[0126]

[0127] ;

[0128] 3) Solve multiple baseline vectors:

[0129] because and can only take three values: 0, -1 and 1. It can only take five values: 0, -1, -2, 1 and 2;

[0130] The carrier phase double difference, array antenna phase center position coordinates, , and satellite , Substituting the coordinates into the above formula, 5 solutions can be obtained; but only one of them satisfies the condition that the array element spacing does not exceed half the carrier wavelength. This solution is the baseline vector of array element 2 pointing to array element 1. ;

[0131] Similarly, the baseline vectors of other array elements pointing to array element 1 can be obtained: ,here ;

[0132] 4) Roughly estimate the antenna array attitude:

[0133] By array element Located on the antenna array, its coordinates satisfy the plane equation ; Thus, the above The baseline vector satisfies the following homogeneous equations:

[0134] ;

[0135] generally , then the above equations are overdetermined;

[0136] The least squares solution of the overdetermined equations can be obtained by the least squares method, that is, the normal vector of the plane where the antenna array is located , that is, the posture of the antenna array in the agreed geocentric rectangular coordinate system;

[0137] Since non-ideal factors such as array element amplitude and phase errors and mutual coupling between array elements will introduce phase distortion into the satellite signal, and the phase distortion is related to the direction in which the satellite signal is incident on the antenna array, the antenna array normal vector obtained by the double difference of the uncorrected carrier phase observation is a rough estimate of the array attitude.

[0138] 5) Index compensation array element phase error:

[0139] The direction of the satellite signal is obtained by using a rough estimate of the array attitude, the satellite position, and the phase center position of the array antenna. The phase error correction parameter table of each array element is then queried using the satellite signal direction index to compensate for the satellite signal phase distortion.

[0140] The inconsistency of array element amplitude has no effect on the carrier phase observation of the array element, so amplitude compensation is not necessary.

[0141] 6) Accurately estimate the antenna array attitude:

[0142] After compensating for the phase distortion, go to steps 2) to 5). After repeating this process twice, an accurate estimate of the antenna array attitude can be obtained.

[0143] Taking a 7-element uniform circular array (one element is located at the center of the circle, and the other 6 elements are evenly distributed on the circumference of a circle with a radius of half the carrier wavelength) as an example, the baseline vector obtained by iterating three times according to the above steps is shown in Table 2 below;

[0144] Table 2 Vectors of array elements 2 to 7 pointing to center element 1

[0145]

[0146] The data in the table show that after three iterations, the estimation accuracy in the x, y, and z directions is better than 0.8 mm, 5.7 mm, and 1 mm, respectively, meeting the accuracy requirements of attitude estimation.

[0147] The embodiment of the present invention proposes an autonomous estimation method for the antenna array attitude of high-precision anti-interference navigation. The method measures the carrier phase in an interference environment by designing a multi-antenna carrier tracking loop; eliminates the clock error and the ionospheric and tropospheric delays by using the double difference of the carrier phase between array elements; solves the unique solution of each baseline vector from the double difference of the carrier phase equation by using the constraint that the array element spacing does not exceed half the wavelength of the carrier; obtains a rough estimate of the array attitude by the least square solution of the equation group satisfied by multiple baseline vectors; compensates for the phase error of each array element by using the rough estimation of the attitude; obtains an accurate estimate of the array attitude by iterating three times in the order of calculating the double difference of the carrier phase between array elements, solving multiple baseline vectors, roughly estimating the array attitude, and compensating for the array element phase error; does not require the installation of attitude sensors, INS and GNSS antennas, does not rely on other navigation sources, does not require calibration, does not accumulate estimation errors, and has a short initialization time.

[0148] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for autonomously estimating the antenna array attitude for high-precision anti-interference navigation, characterized in that: include: Design a multi-antenna carrier tracking loop to measure the satellite signal carrier phase at each array element in an interference environment; According to the order of double difference calculation of carrier phase between array elements, multiple baseline vector solution, rough estimation of antenna array attitude, and array element phase error compensation, the accurate estimation of antenna array attitude is iteratively obtained. Designing a multi-antenna carrier tracking loop to measure the satellite signal carrier phase at each array element in an interference environment includes: Design a multi-antenna carrier tracking loop based on multi-beam anti-jamming signals to assist the carrier tracking channels of each array element, eliminate the satellite signal sign bit, and allow long-term coherent accumulation; Through long-term coherent accumulation, the carrier tracking threshold is reduced, the carrier tracking sensitivity is improved, and the carrier phase of each array element to the common-view satellite in the interference environment is measured; The formula used to measure the satellite signal carrier phase at each array element in the interference environment is as follows: in, Divided into element 1 and element 2 pairs of satellites The fractional part of the carrier phase observation, They are array element 1 and array element 2 for satellites. The integer ambiguity of the carrier phase observation is is the carrier wavelength of the observed frequency, Divided into array element 1 and array element 2 and satellite The geometric distance between It is divided into array element 1 and array element 2, followed by the deviation of the satellite navigation processing unit clock relative to the satellite navigation system clock, that is, the receiver clock error. For satellite The deviation of the clock relative to the satellite navigation system, that is, the satellite clock error, is the error caused by the ionosphere, troposphere, multipath effect, and receiver noise. is the speed of light in vacuum; Array element phase error compensation includes: Obtaining the direction of the satellite signal using the rough estimate of the array attitude, the satellite position, and the phase center position of the array antenna; Then, the phase error correction parameter table of each array element is queried according to the direction index of the satellite signal, and then error compensation is performed on the phase distortion introduced by each array element.

2. The method according to claim 1, characterized in that The double difference calculation of carrier phase between array elements includes: Calculate the carrier phase single difference between each array element and the reference array element to eliminate satellite clock error, satellite ephemeris error, ionospheric delay, and tropospheric delay; The double difference of the carrier phase between each array element and the reference array element is calculated to further eliminate the receiver clock error.

3. The method according to claim 2, characterized in that Calculating the carrier phase single difference between each array element and the reference array element includes: The array element 1 is used as a reference array element, and a single difference is made between the carrier phases of the same satellite observed by the array element 1 and the array element 2 to eliminate the satellite clock error, satellite ephemeris error, and ionospheric delay and tropospheric delay; The formula used to calculate the carrier phase single difference between array element 2 and array element 1 is: ； in, in, They are the coordinates of array element 1, array element 2 and satellite in the agreed geocentric rectangular coordinate system.

4. The method according to claim 3, characterized in that: The simplified formula for calculating the single difference of the carrier phase between array element 2 and array element 1 is: ； in, , is the phase center position coordinate of the array antenna; The simplified condition of the formula used to calculate the carrier phase single difference between array element 2 and array element 1 is: 1) Since the satellite orbit altitude is 20,000-30,000 kilometers, the satellite signal incident on the array antenna is equivalent to a plane wave, and the unit direction vector of array element 1 pointing to the satellite is parallel to the unit direction vector of array element 2 pointing to the satellite, that is: ； and then: ； 2) The phase center position coordinates of the array antenna are recorded as , the same as above, using the satellite signal equivalent to a plane wave to rearrange the formula get: ； 3) For array elements 1 and 2 whose spacing does not exceed half the wavelength of the carrier, the paths of satellite signals propagating to the two elements are almost the same. By subtracting the carrier phase observations of the two elements, eliminating the ionosphere and troposphere delays, and ignoring the influence of multipath effects and receiver noise, we can obtain .

5. The method according to claim 4, characterized in that Calculating the double difference of the carrier phase between each array element and the reference array element includes: When array element 1 and array element 2 simultaneously observe the Satellites are used to further eliminate the receiver clock error by using the double difference of carrier phase. The double difference formula used is: 。 6. The method according to claim 5, characterized in that Multiple baseline vector solutions include: Substitute the carrier phase double difference, the coordinates of the phase center position of the array antenna, the five possible values ​​of the integer ambiguity, and the satellite coordinates into the carrier phase double difference calculation formula to solve the five candidate solutions of the baseline vector of each array element pointing to the reference array element; Using the constraint that the distance between each array element and the reference array element does not exceed half the wavelength of the carrier, the unique solution of each baseline vector is selected from the five candidate solutions; The derivation process of the five possible values ​​of the integer ambiguity includes: 1) Since the distance between array element 1 and array element 2 does not exceed half the wavelength of the carrier, the phase difference caused by the path difference in the carrier phase observation does not exceed half a cycle. and Either the same or adjacent, then It can only take three values: 0, -1 and 1; 2) Due to and can only take three values: 0, -1 and 1. It can only take five values: 0, -1, -2, 1 and 2; The carrier phase double difference, array antenna phase center position coordinates, , and satellite , Substituting the coordinates into the double difference formula , and get 5 vector solutions; From the five vector solutions, a solution is obtained that satisfies the constraint that the array element spacing does not exceed half the carrier wavelength. This solution is the baseline vector from array element 2 to array element 1, expressed as: ; The same method is used to obtain the baseline vectors of other array elements pointing to array element 1, which can be expressed as: ,in, .

7. The method according to claim 6, characterized in that The rough estimation of antenna array attitude includes: Substituting the unique solutions of the baseline vectors into the general equation of the plane where the antenna array face is located, a homogeneous equation group is obtained, and a rough estimate of the antenna array face attitude is obtained from the least square solution of the homogeneous equation group.

8. The method according to claim 7, characterized in that The general equation expression of the plane where the antenna array surface is located is: ； The expression of the homogeneous equation system is: ； in, ; The least squares solution of the homogeneous equations is the normal vector of the plane where the antenna array is located, that is, , which is a rough estimate of the antenna array attitude.

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