A method for measuring the attitude of a rotating projectile by a single antenna satellite receiver

Abstract

The application discloses a method for measuring the attitude of a rotating projectile by a single-antenna satellite receiver, which comprises the following steps: capturing and tracking a satellite signal by using a single antenna; acquiring the electric text of the satellite after capturing the satellite signal; using the original observation and the electric text information to solve, which comprises the preprocessing of the observation, the calculation of the satellite position and speed, the correction of the observation, the solution of the position, and the solution of the speed; building a software loop to track the rotating speed of the carrier, and determining the rotating speed information and the phase information of the carrier at each time point; combining the speed information of the carrier to calculate the pitch angle and the azimuth angle of the carrier; and obtaining the rolling angle information of the carrier in a preset time period by the pitch angle and the azimuth angle information of the carrier, the satellite position information, the rotating speed information, the phase information, and the rolling angle information of the phase 0. The single-antenna satellite receiver can realize the attitude measurement and the position measurement of the rotating projectile, and compared with the traditional scheme, has the advantages of low cost, small installation volume, and strong maintainability.

Description

Technical Field

[0001] This application relates to the field of projectile attitude measurement technology, specifically to a method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver. Background Technology

[0002] With the development of modern warfare, the demand for small, low-cost munitions has shifted from saturation attacks to precision-guided strikes. Precision guidance typically employs a flight control system + satellite guidance + sensors + servos. The satellite guidance system provides the flight control system with position and velocity information, while the sensors provide the flight control system with the missile's roll angle information. The flight control system compares the current position and velocity information with the target point and adjusts the servos to move the missile toward the target point, thereby achieving the purpose of precision strike. Sensors generally use geomagnetism or gyroscopes to measure the missile's roll angle. Gyroscopes generally have a lower range due to their cost-effectiveness, typically less than 5 r / s, while geomagnetism has a high sampling rate and requires a separate external AD acquisition channel, which increases the size and power consumption of the missile.

[0003] Existing technology uses geomagnetic or gyroscope + satellite receiver + flight control + rudder mechanism to form a flight control system, such as Figure 1 As shown: Geomagnetism or gyroscopes are used to measure the current roll angle information. Geomagnetism, by cutting through the Earth's magnetic field, determines the current roll angle and rotational speed of the projectile based on the magnitude and direction of the magnetic field distributed at different latitudes. This method can calculate the roll angle information in most scenarios, but in strong magnetic environments, it may cause measurement inaccuracies. This is because the sensor is sensitive to magnetic fields, and the servo motor contains coils that also generate magnetic fields during operation.

[0004] A gyroscope is a sensor that measures rotational speed, but low-cost gyroscopes generally have a small measurement range (less than 5 r / s). For high-speed projectiles, such as grenades with a maximum rotational speed of 300 r / s, low-cost gyroscopes cannot measure this speed. Furthermore, gyroscopes require calibration before use, further increasing costs. Therefore, using geomagnetism or gyroscopes to measure the current roll angle has the advantage of good versatility, but it also brings disadvantages such as high cost, large size, and the need for pre-calibration. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, this application proposes the following technical solution:

[0006] In a first aspect, embodiments of this application provide a method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver. The method includes: acquiring and tracking satellite signals using a single antenna; acquiring satellite messages after acquiring satellite signals; performing calculations using raw observation data and message information, the calculations including preprocessing of observations, satellite position and velocity calculations, observation corrections, position calculations, and velocity calculations; establishing a software loop to track the rotational speed of the carrier, determining the rotational speed and phase information of the carrier at various time points; calculating the elevation and azimuth angles of the carrier by combining the azimuth angle information of the carrier; and obtaining the roll angle information of the carrier within a preset time period using the elevation and azimuth angle information of the carrier, satellite position information, rotational speed information, phase information, and roll angle information of phase 0.

[0007] Using the above implementation method, the attitude and position measurement of the rotating projectile can be realized with a single antenna satellite receiver. Compared with the traditional solution, it has the advantages of low cost, small installation size and strong maintainability.

[0008] In conjunction with the first aspect, in the first possible implementation of the first aspect, the method of acquiring and tracking satellite signals using a single antenna includes: using a hardware loop to track satellite signals, wherein the channel tracking loop generates a ms integral quantity every 1ms, the ms integral quantity reflecting the energy magnitude of the channel tracking signal within 1ms; and the tracking loop generates raw observations at 10Hz.

[0009] In conjunction with the first possible implementation of the first aspect, in the second possible implementation of the first aspect, the acquisition of the satellite message after capturing the satellite signal includes: obtaining the satellite message in the sky using a ms integral.

[0010] In conjunction with the first possible implementation of the first aspect, in the third possible implementation of the first aspect, the step of building a software loop to track the carrier rotation speed and determine the rotation speed and phase information of the carrier at each time point includes: building a software loop using the original millisecond integral, the software loop including either a frequency-locked loop or a phase-locked loop; under single antenna rotation conditions, the millisecond integral of the received signal exhibits a period, and the reciprocal of the period is the rotation speed; performing spectral analysis on the signal, through time-domain sampling, applying Discrete Fourier Transform (DFT) for approximate spectral analysis to obtain the initial rotation speed and phase with large errors; substituting the initial rotation speed and phase into the software loop to make the loop converge quickly, thereby obtaining the rotation speed and phase information of the carrier at each time point.

[0011] In conjunction with the third possible implementation of the first aspect, in the fourth possible implementation of the first aspect, the basic process of the software loop includes: DC removal, calculation of initial speed value, and tracking loop based on signal amplitude.

[0012] In conjunction with the fourth possible implementation of the first aspect, in the fifth possible implementation of the first aspect, the DC removal in the basic process of the software loop includes: recording the millisecond integral values ​​reported by the hardware as I(n) and Q(n), and calculating the modulus: Calculate the mean of the M-point modulus sequence: The preprocessed output sequence is:

[0013] In conjunction with the fifth possible implementation of the first aspect, in the sixth possible implementation of the first aspect, the calculation of the initial value of the rotational speed includes: performing an N-point FFT transformation on M B(n) signals to find the signal frequency f. sig Initial rotational speed f0 = f sig The unit is r / s, with values ​​M = N = 1024, and the corresponding frequency search precision is: The corresponding initial speed value accuracy is 1 r / s. The FFT is performed only once, and a phase-locked loop is used for speed tracking afterwards.

[0014] In conjunction with the sixth possible implementation of the first aspect, in the seventh possible implementation of the first aspect, the step of tracking the signal amplitude loop includes: approximating the sequence B(n) using a cosine model: B(n) = cos[Φ i [n]; The local carrier is a complex signal, and its expression is: sequence Phase detection is performed on the sequence C(n), and after passing it through a loop filter, the phase error is obtained: Finally, the software loop obtains the rotational speed and phase information at each time point.

[0015] In the eighth possible implementation of the first aspect, in combination with the first aspect or any of the first to seventh possible implementations of the first aspect, the calculation of the pitch angle and azimuth angle of the carrier based on the carrier's velocity information includes: when the carrier is moving at high speed, the xyz velocity in the geocentric coordinate system is obtained by the calculation module; combined with the current position, the east velocity, north velocity, sky velocity and ground velocity can be obtained; the azimuth angle information of the carrier is obtained through the east velocity and north velocity; and the pitch angle information of the carrier is obtained through the sky velocity and ground velocity.

[0016] Combining the eighth possible implementation of the first aspect, in the ninth possible implementation of the first aspect, each channel can obtain a rotational speed and roll angle information. By weighting the elevation angle of the satellite relative to the antenna surface, the accurate rotational speed and roll angle information of the carrier can be fitted. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a traditional flight control system;

[0018] Figure 2This is a schematic diagram illustrating the attitude measurement principle of a single-antenna satellite receiver provided in an embodiment of this application.

[0019] Figure 3 A flowchart illustrating a method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver, provided in an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the loop working principle provided in the embodiments of this application. Detailed Implementation

[0021] The present solution will now be described in conjunction with the accompanying drawings and specific embodiments.

[0022] This application's embodiment uses a single-antenna satellite to measure position, velocity, roll angle, and rotational speed, retaining the traditional satellite receiver's positioning and velocity measurement functions while adding the measurement functions of rotational speed and roll angle. The principle of this scheme is as follows: Figure 2 As shown.

[0023] Figure 3 A flowchart illustrating a method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver, as provided in this application embodiment, is shown below. Figure 3 Methods for measuring the attitude of a rotating projectile using a single-antenna satellite receiver include:

[0024] S101 uses a single antenna to acquire and track satellite signals.

[0025] A single antenna is used to acquire and track the satellite. A hardware loop is used to track the satellite signal. The channel tracking loop generates an integral value every 1 ms. The integral value reflects the energy of the channel tracking signal within 1 ms. When rotating, the energy of the integral value will also alternate due to the rotation of the antenna relative to the satellite. At the same time, the tracking loop generates raw observations (satellite signal time, carrier, and Doppler) at 10 Hz.

[0026] S102, after capturing satellite signals, acquires the satellite's messages.

[0027] The message from the satellite in space is obtained by using the ms integral. In practical applications, the message can be injected from an external source.

[0028] S103 uses raw observations and message information for calculation. The calculation includes preprocessing of observations, satellite position and velocity calculation, observation correction, position calculation, and velocity calculation.

[0029] Using the original observations and message information, calculations are performed. The calculations include preprocessing of the observations, calculation of satellite position and velocity, correction of observations, position calculation, and velocity calculation. This yields the satellite position and velocity, carrier position, carrier velocity, and local clock error at a given moment. The local clock error can be used to correct the module time, ensuring that the carrier's local time is basically consistent with the clock in space.

[0030] S104, build a software loop to track the carrier rotation speed and determine the rotation speed and phase information of the carrier at each time point.

[0031] A software loop is built using the original millisecond integral (ms). This loop can be either a frequency-locked loop (FLL) or a phase-locked loop (PLL). Under single-antenna rotation conditions, the energy of the received signal (i.e., the ms integral) will change periodically, and the reciprocal of the period is the rotational speed. To determine the rotational speed of the signal, spectral analysis can be performed. By sampling in the time domain and applying the Discrete Fourier Transform (DFT) for approximate spectral analysis, an initial rotational speed and phase with significant errors can be obtained. Substituting these initial rotational speed and phase into the software loop will allow the loop to converge quickly.

[0032] The basic process of software loop mainly includes the following points:

[0033] 1. DC removal

[0034] Let I(n) and Q(n) be the integral values ​​in milliseconds reported by the hardware. First, calculate the modulus:

[0035]

[0036] Since the modulus sequence consists entirely of positive values, directly performing an FFT transformation would introduce a DC component, which would affect the extraction of the rotational speed. Therefore, the DC component of the modulus sequence must be removed.

[0037] Calculate the mean of the M-point modulus sequence:

[0038]

[0039] The preprocessed output sequence is

[0040]

[0041] 2. Calculate the initial value of the rotational speed.

[0042] Perform an N-point FFT on M B(n) signals to find the signal frequency f. sig .

[0043] Rotational speed f0 = f sig The unit is r / s.

[0044] In engineering practice, the values ​​M = N = 1024 are used, corresponding to a frequency search precision of...

[0045]

[0046] The corresponding initial rotational speed accuracy is 1 r / s.

[0047] The FFT is performed only once, and a phase-locked loop is used for speed tracking afterwards.

[0048] 3. Signal amplitude tracking loop

[0049] The signal amplitude tracking loop is a phase-locked loop (PLL). Its input sequence comes from the sequence B(n) output by the integral preprocessing unit. B(n) contains satellite signal amplitude modulation information. The initial rotational speed value f0 output by the integral preprocessing unit is used to initialize the local carrier frequency. The loop's working principle is as follows: Figure 4 As shown.

[0050] The sequence B(n) is approximated using a cosine model:

[0051] B(n) = cos[Φ i (n)]

[0052] The local carrier is a complex signal, and its expression is:

[0053]

[0054] then:

[0055]

[0056] Phase detection is performed on the sequence C(n), and the phase error is obtained after passing it through a loop filter.

[0057]

[0058] Finally, the software loop can obtain the rotational speed and phase information at each time point.

[0059] S105, calculates the pitch and azimuth angles of the carrier by combining the carrier's speed information.

[0060] To calculate the pitch and azimuth angles, when the carrier is moving at high speed, the solution module obtains the xyz velocity in the geocentric coordinate system. Combined with the current position, the speed of the sky (northeast) can be obtained. The azimuth information of the carrier can be obtained through the east speed and the north speed. The pitch angle information of the carrier can be obtained through the sky speed and the ground speed.

[0061] S106, the carrier roll angle information within a preset time period is obtained through the carrier's pitch and azimuth angle information, satellite position information, rotation speed information, phase information, and roll angle information of phase 0.

[0062] The carrier elevation and azimuth angles calculated in step S105, the position and satellite position information obtained in step S103, and the rotational speed and phase information obtained in step S104, can be used to obtain the roll angle information at each time point throughout the entire process if the roll angle information at phase 0 is known. When using a single antenna, the signal energy is considered to be at its maximum when the antenna surface is at 90 degrees to the satellite incident surface. At this time, the phase of the phase-locked loop should be 0. Since the satellite position and the carrier position are known, the roll angle information when the current software loop phase is 0 can be calculated, and thus the roll angle information within the time period can be derived.

[0063] Each channel can obtain a rotational speed and roll angle information. By weighting the satellite's elevation angle relative to the antenna surface (the higher the elevation angle, the more reliable the information), accurate rotational speed and roll angle information can be fitted.

[0064] Compared with traditional solutions, the embodiments of this application save a dedicated device for calculating roll angle and rotational speed information, which not only saves hardware costs but also reserves space for a device, and significantly reduces subsequent maintenance costs.

[0065] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] Of course, the above description is not limited to the examples above. Technical features not described in this application can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solutions of this application and are not intended to limit this application. If any substitution is required, this application has only been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this application do not depart from the spirit of this application and should also fall within the scope of protection of the claims of this application.

Claims

1. A method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver, characterized in that, The method includes: A single antenna is used to acquire and track satellite signals; After capturing satellite signals, the satellite's messages are acquired; The calculation is performed using raw observations and message information. The calculation includes preprocessing of observations, calculation of satellite position and velocity, observation correction, position calculation, and velocity calculation. A software loop is constructed to track the rotational speed of the carrier and determine the rotational speed and phase information of the carrier at various time points. The software loop includes either a frequency-locked loop or a phase-locked loop. The pitch and azimuth angles of the carrier are calculated by combining the carrier's velocity information; The carrier roll angle information within a preset time period is obtained by using the carrier's pitch and azimuth angle information, satellite position information, rotation speed information, phase information, and roll angle information with a phase of 0, including: When using a single antenna, the phase of the phase-locked loop is 0 when the antenna surface is at 90 degrees to the satellite incident surface. With the satellite position and the carrier position known, the roll angle information when the current software loop phase is 0 can be calculated, and thus the roll angle information within the time period can be derived.

2. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to claim 1, characterized in that, The method of acquiring and tracking satellite signals using a single antenna includes: The system employs a hardware loop to track satellite signals. The channel tracking loop generates an integral value every 1 ms, which reflects the energy level of the channel tracking signal within 1 ms. The tracking loop generates raw observations at 10 Hz.

3. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to claim 2, characterized in that, The acquisition of satellite messages after capturing satellite signals includes: obtaining the satellite messages in space using millisecond integrals.

4. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to claim 3, characterized in that, The software loop is constructed to track the carrier rotation speed and determine the rotation speed and phase information of the carrier at various time points, including: A software loop is built using the original ms integral. The software loop includes either a frequency-locked loop or a phase-locked loop. Under the condition of single antenna rotation, the integral of the received signal in milliseconds has a period, and the reciprocal of the period is the rotational speed; Spectral analysis of the signal is performed by sampling in the time domain and applying discrete Fourier transform for approximate spectral analysis to obtain the initial rotational speed and phase with large errors. The initial rotational speed and phase are substituted into the software loop to enable rapid loop convergence, thereby obtaining the rotational speed and phase information of the carrier at various time points.

5. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to claim 4, characterized in that, The basic process of the software loop includes: DC removal, calculation of initial speed value, and tracking loop based on signal amplitude.

6. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to claim 5, characterized in that, The DC removal process in the basic software loop includes: Record the integral values ​​in milliseconds reported by the hardware as I(n) and Q(n). Calculate the modulus: ; Calculate the mean of the M-point modulus sequence: ; The preprocessed output sequence is: .

7. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to claim 6, characterized in that, The calculation of the initial value of the rotational speed includes: Perform an N-point FFT on M B(n) signals to find the signal frequency. initial rotational speed The unit is r / s, with values ​​M=N=1024, and the corresponding frequency search precision is: The corresponding initial speed value accuracy is 1 r / s. The FFT is performed only once, and a phase-locked loop is used for speed tracking afterwards.

8. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to claim 7, characterized in that, The signal amplitude tracking loop includes: The sequence B(n) is approximated using a cosine model: ; The local carrier is a complex signal, and its expression is: ; sequence ; Phase detection is performed on the sequence C(n), and after passing it through a loop filter, the phase error is obtained: ； Finally, the software loop obtains the rotational speed and phase information at each time point.

9. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to any one of claims 1-8, characterized in that, The calculation of the vehicle's pitch and azimuth angles based on the vehicle's velocity information includes: When the carrier moves at high speed, the xyz velocity in the geocentric coordinate system is obtained by the solution module; By combining the current location, the east velocity, north velocity, sky velocity, and ground velocity can be calculated. The azimuth information of the carrier is obtained through the east and north speeds, and the pitch information of the carrier is obtained through the sky speed and ground speed.

10. The method for measuring the attitude of a rotating projectile using a single-antenna satellite receiver according to claim 9, characterized in that, Each channel can obtain a rotational speed and roll angle information. By weighting the satellite's elevation angle relative to the antenna surface, the accurate rotational speed and roll angle information of the carrier can be fitted.

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