Radar angle measurement error real-time correction method based on communication target object backhaul information

Abstract

The radar angle measurement error real-time correction method based on communication target echo information of the application comprises: obtaining three-direction position information (dx1, dy1, dz1) of the communication target echo, and obtaining three-direction position information (dx2, dy2, dz2) of the radar through inertial navigation calculation; determining azimuth and elevation angle information (θ Az (n),θ El (n)) of the communication target in the radar system, determining the mean value of the radar angle measurement error of the communication target to obtain angle information (Φ′ Az ,Φ′ El ) of the target, and the angle information (Φ′ Az ,Φ′ El ) is used to improve the stability of the non-communication target tracking, and the method can improve the use performance of the radar.

Description

Technical Field

[0001] This invention belongs to the technical field of airborne fire control radar, and particularly relates to a method for real-time correction of radar angle measurement error based on information transmitted back from the target object. Background Technology

[0002] Many factors affect the accuracy of angle measurement. Traditional error correction methods are based on amplitude and phase comparison, which are inherently flawed. According to the nature of the error, radar angle measurement errors are divided into systematic errors and random errors. Systematic errors include receiver amplitude-phase inconsistency errors, target calibration errors, and aircraft deformation caused by large maneuvers. Random errors include errors caused by thermal noise, target amplitude fluctuation noise, target angle noise, and other factors.

[0003] Existing methods only consider a single influencing factor to correct angle measurement errors. However, in reality, radar angle measurement errors are caused by the combined effects of various factors. Correction methods that only consider a single factor are one-sided, have a large computational load, require significant modifications to the original system, and are difficult to implement in engineering. Therefore, traditional methods have low real-time error correction and are more complex to operate, thus reducing the performance of the radar.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a real-time radar angle measurement error correction method based on the feedback information from the communication target, thereby solving the technical problem of reduced radar performance caused by existing methods. The technical solution of this invention has many beneficial effects, as described below:

[0006] A method for real-time correction of radar angle measurement errors based on information transmitted back from communication targets is provided. The method includes:

[0007] A method for real-time correction of radar angle measurement errors based on information transmitted back from a communication target, characterized in that the method includes:

[0008] After the nth communication between the radar and the target object, the radar obtains the three-dimensional position information (dx1, dy1, dz1) returned by the target object, and obtains the three-dimensional position information (dx2, dy2, dz2) output by the radar after calculation by the inertial navigation system.

[0009] Based on the three-dimensional position information (dx2, dy2, dz2), the azimuth and elevation angle information (α) of the communication target is calculated in the inertial frame. Az (n),α El (n)), where n is a natural integer, and α Az α represents the orientation of the communication target in the inertial frame. El The elevation of the communication target in the inertial frame; the azimuth and elevation angle information (α)Az (n),α El (n) performs coordinate transformation to determine the azimuth and elevation angle information (θ) of the communication target under the radar system. Az (n),θ El (n)), θ Az θ represents the azimuth of the communication target in the radar system. El Elevation of the target object in the radar system;

[0010] The radar sends a name signal to the communication target. After receiving the name signal, the communication target sends a feedback signal to obtain the radar system angle of the communication target.

[0011] According to the radar system angle and azimuth and elevation information (θ) Az (n),θ El (n) Determine the mean value of the radar angle measurement error

[0012] When the radar tracks a non-communication target, the azimuth and elevation angles (Φ) of the non-communication target measured by the radar are obtained under the radar system. Az ,Φ El The azimuth and elevation angle (Φ) is corrected based on the mean (Az, El). Az ,Φ El ), to obtain the target's angle information (Φ′) Az ,Φ′ El The angle information (Φ′) Az ,Φ′ El It is used to improve the stability of tracking non-communication targets.

[0013] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0014] The method of this invention obtains the radar angle measurement error by adding a dedicated angle measurement window for the communication target during normal radar communication with the target. Considering the resistance of secondary radar to interference, the angle measurement window utilizes the principle of secondary radar for angle measurement. An angle measurement error is estimated each time communication with the target is conducted, and averaging multiple measurements further improves the accuracy of the angle measurement error estimate. This angle measurement error is removed during target tracking or communication with the target, thereby improving target tracking stability and the probability of the communication target hitting the target. Compared with existing methods, after agreeing on the relevant transmit and receive parameters, only one angle measurement window needs to be added at the end of the communication illumination window with the target to achieve angle error estimation. The method is simple and computationally inefficient. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the method of the present invention;

[0017] Figure 2 A schematic diagram illustrating radar tracking of a communication target.

[0018] Figure 3 A schematic diagram showing the addition of an angle measurement window in the communication timing sequence with the target object;

[0019] Figure 4 The signal-to-noise ratio difference between the two angle measurement methods varies with distance;

[0020] Figure 5 A simulation diagram of the angle measurement effect. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] The real-time radar angle measurement error correction method based on communication target feedback information provided by this invention is described in [reference needed]. Figures 1 to 5 The methods include:

[0023] S101: After the nth communication with the target object is completed, the radar receives the three-dimensional position information (dx1, dy1, dz1) returned by the target object (e.g., an aircraft). The radar determines its own three-dimensional position information (dx2, dy2, dz2) through inertial navigation.

[0024] S102: Based on the three-dimensional position information (dx2, dy2, dz2), calculate the azimuth and elevation angle information (α) of the communication target in the inertial frame. Az (n),α El(n)), where n is a natural integer, and α Az α represents the orientation of the communication target in the inertial frame. El The elevation of the communication target in the inertial frame; the azimuth and elevation angle information (α) Az (n),α El (n) performs coordinate transformation to determine the azimuth and elevation angle information (θ) of the communication target under the radar system. Az (n),θ El (n)), θ Az θ represents the azimuth of the communication target in the radar system. El For the elevation of the target object in the radar system, specifically:

[0025] The azimuth and elevation angle information of the communication target in the inertial frame (α) Az (n),α El (n)), its expression is:

[0026]

[0027] Determine the azimuth and elevation angle information (θ) of the target object in the radar system. Az (n),θ El (n));

[0028] Assuming the radar and the aircraft are coaxial in azimuth and elevation, the expression for the normalized three-dimensional position of the target in the inertial frame is given by, for example, if the radar installation angle is θ. Weapon =0°, the expression is:

[0029]

[0030] We obtain the expressions for the three-dimensional positions of the target communication object's radar:

[0031]

[0032] Where, θ Roll θ Pitch θ Course These are the roll angle, climb angle, and heading angle of the aircraft at the current moment, respectively. If θ Weapon The angle is F, which is a measurable known value. All "0" in Formula 3 is in F.

[0033] According to the azimuth and elevation angle information (θ) described in formula (3) Az (n),θ El (n) is:

[0034]

[0035] Azimuth and elevation information (θ) Az (n),θ El(n) is used as the theoretical value.

[0036] S103: The radar sends a name-call signal to the communication target. After receiving the name-call signal, the communication target sends a feedback signal to determine the radar system angle of the communication target. Specifically:

[0037] The radar uses the received feedback signal to perform single-pulse angle measurement on the communication target, thus obtaining the radar system angle of the communication target.

[0038] Since the theoretical angle information calculated from the three-dimensional position is in the inertial frame, while the angle directly measured by the radar is in the radar frame, it is necessary to convert the theoretical inertial frame angles to the radar frame. Since the radar is mounted on the aircraft nose and coaxial with the fuselage, the conversion from the inertial frame to the radar frame only requires considering the aircraft's attitude angles (roll, climb, and yaw).

[0039] S104: According to the radar system angle and azimuth and elevation information (θ) Az (n),θ El (n) Determine the mean value of the radar angle measurement error Specifically:

[0040] Using the feedback signal received from the radar, a single-pulse angle measurement is performed on the communication target to obtain the radar system angle of the communication target.

[0041] Determine the mean value of radar angle measurement error include:

[0042] Radar system angle As measured values ​​and azimuth and elevation angle information (θ) Az (n),θ El By fusing the theoretical values ​​(n) together, the radar's angle measurement error (ΔAz(n), ΔEl(n)) can be obtained;

[0043] The current radar angle measurement error (ΔAz(n), ΔEl(n)) is expressed as:

[0044]

[0045] Under a preset period, the mean value of the radar angle measurement error is calculated by taking the weighted average of the angle measurement errors (ΔAz(n), ΔEl(n)) obtained from the first n calculations. Represented as:

[0046]

[0047] S105: When the radar tracks a non-communication target, acquire the azimuth and elevation angles (Φ) of the non-communication target as measured by the radar system. Az,Φ El According to the mean Corrected azimuth and elevation angle (Φ) Az ,Φ El ), to obtain the target's angle information (Φ′) Az ,Φ′ El ), angle information (Φ′) Az ,Φ′ El This is used to improve the stability of tracking non-communication targets, specifically:

[0048] When tracking a target, the radar measures the target's radar system azimuth and elevation angles (Φ). Az ,Φ El ), after average After correction, the target's angle information (Φ′) is obtained. Az ,Φ′ El ):

[0049]

[0050] Based on angle information (Φ′) Az ,Φ′ El ) Communicating with target tracking and communication targets can improve the stability of target tracking and the probability of the communication target hitting the target.

[0051] The correction method of this invention uses real-time GPS information of the target object for correction, and reduces the fluctuation of random errors by averaging multiple calculations. Compared with the prior art, it has the following advantages:

[0052] Compared with existing methods, this method utilizes the characteristic of the communication target and the carrier aircraft to exchange high-precision position information when communicating with the communication target to evaluate the radar angle measurement error in real time, which has strong real-time performance and high accuracy.

[0053] Compared with existing methods, the method of averaging through real-time evaluation can not only correct relatively fixed systematic errors, but also smooth out some random errors.

[0054] Compared with existing methods, after agreeing on the relevant transmission and reception parameters, at the end of the communication illumination window with the target object, only an angle measurement window needs to be added to achieve angle error estimation. The method is simple and has a small computational load.

[0055] Example

[0056] A schematic diagram of radar tracking and communication with targets is shown below. Figures 1 to 5 The overall flowchart for implementing this method is as follows: Figure 2 As shown, the implementation steps are as follows:

[0057] Step 1: After the nth communication with the target object, the target object's three-dimensional position information is received back, which is (dx1, dy1, dz1) in the order of North-East-South. The local machine's three-dimensional position information is known (dx2, dy2, dz2). The azimuth and elevation angles (α) of the target object in the inertial frame can be calculated. Az (n),α El (n)), then

[0058]

[0059] The formula for converting the angle from the inertial frame to the radar frame is (assuming the radar installation angle is θ). Weapon =0°), to obtain the azimuth and elevation angle information (θ) of the communication target under the radar system. Az (n),θ El (n)):

[0060] The expression for the normalized three-dimensional position of the communication target in the inertial frame is:

[0061]

[0062] Expressions for the three-dimensional position of the target communication object radar:

[0063]

[0064] We can obtain,

[0065]

[0066] Where, θ Roll θ Pitch θ Course These are the aircraft's roll angle, climb angle, and heading angle at the current moment, respectively.

[0067] Step 2: After completing Step 1, add a communication target angle measurement window immediately after the illumination window, as shown in the diagram. Figure 3 Given the signal-to-noise ratio advantage of secondary radar at long distances—as illustrated in Simulation Case 1—this method employs secondary radar angle measurement. The radar transmits a name signal to the target object at a predetermined frequency waveform. Upon receiving the name signal, the target object responds with a corresponding signal at the same frequency waveform. The radar then uses the received response signal to perform single-pulse angle measurement on the target object, thus obtaining the radar-based angle of the target object.

[0068] Step 3: Based on Step 1 and Step 2, the radar's current angle measurement error (ΔAz(n), ΔEl(n)) can be obtained:

[0069]

[0070] Step 4: If the shift handover is not completed, average the angle errors obtained from the previous n calculations to obtain the mean value of the radar angle measurement error.

[0071]

[0072] Step 5: During target tracking, the radar measures the target's radar system azimuth and elevation angles (Φ). Az ,Φ El After correcting the average angular error obtained in step 4, the target's angle information (Φ′) is obtained. Az ,Φ′ El ):

[0073]

[0074] Using this angle information for target tracking and communication with the target object can improve the stability of target tracking and the probability of the communication target hitting the target.

[0075] Simulation Case 1:

[0076] Assume the radar's peak transmitted power is: P t =10000W; Antenna transmit gain G t =25dB; Radar cross-section of communication target σ = 0.1m 2 ; Azimuth θ of the communication target (elevation angle) All angles are 0°. Assuming the external power of the target radiator ERP = 5W and atmospheric absorption loss La = 0.02dB / km; the target-missile distance ranges from 2km to 80km. The signal-to-noise ratio difference between the secondary radar method and the primary radar method for angle measurement is as follows: Figure 4 .

[0077] The simulation results show that when the distance between the radar and the communication target is greater than 15km, the signal-to-noise ratio of the secondary radar is nearly 10dB higher than that of the primary radar. Considering the current characteristics of air-to-air communication targets, such as their long range and the fact that the secondary radar is not easily interfered with, the angle measurement of the communication target adopts the principle of secondary radar.

[0078] Simulation Case 2:

[0079] Taking azimuth information as an example, assuming the target's true azimuth information is Az = 0°, the radar system's angle measurement error is stable at Δ1 = 0.5°, and the radar's random angle measurement error Δ2 follows a normal distribution with a mean of 0 and a standard deviation of 0.5°, and the number of communications with the target is N = 100, then the target angle information obtained using this method and without using this method is as follows: Figure 5 ,Depend on Figure 5As can be seen (in the correction method of this invention, after communicating with the target 10, the angle measured by the radar is almost consistent with the true value), the normal angle measurement oscillates on the side of the true angle under the influence of systematic error and random error, and the overall error is large. With the method in this paper, the angle measurement error converges quickly and the angle measurement information quickly approaches the true value, which is beneficial to improving the target tracking stability and the probability of the communicating target hitting the target.

[0080] The product provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the invention claims.

Claims

1. A method for real-time correction of radar angle measurement error based on information transmitted back from a communication target, characterized in that, The methods include: After the nth communication between the radar and the target object, the radar obtains the three-dimensional position information (dx1, dy1, dz1) returned by the target object, and obtains the three-dimensional position information (dx2, dy2, dz2) output by the radar after calculation by the inertial navigation system. Based on the three-dimensional position information (dx2, dy2, dz2), the azimuth and elevation angle information (α) of the communication target is calculated in the inertial frame. Az (n),α El (n)), where n is a natural integer, and α Az α represents the orientation of the communication target in the inertial frame. El The elevation of the communication target in the inertial frame; the azimuth and elevation angle information (α) Az (n),α El (n) performs coordinate transformation to determine the azimuth and elevation angle information (θ) of the communication target under the radar system. Az (n),θ El (n)); The radar sends a name signal to the communication target. After receiving the name signal, the communication target sends a feedback signal to obtain the radar system angle of the communication target. According to the radar system angle and azimuth and elevation information (θ) Az (n),θ El (n) Determine the mean value of the radar angle measurement error When the radar tracks a non-communication target, the azimuth and elevation angles (Φ) of the non-communication target measured by the radar are obtained under the radar system. Az ,Φ El According to the mean Correct the azimuth and elevation angle (Φ) Az ,Φ El ), to obtain the target's angle information (Φ′) Az ,Φ′ El The angle information (Φ′) Az ,Φ′ El It is used to improve the stability of tracking non-communication targets.

2. The real-time correction method for radar angle measurement error according to claim 1, characterized in that, The azimuth and elevation angle information of the communication target in the inertial frame (α) Az (n),α El (n)), the expression is:

3. The real-time correction method for radar angle measurement error according to claim 2, characterized in that, Determine the azimuth and elevation angle information (θ) of the target object in the radar system. Az (n),θ El (n)), including: Assuming the radar and the aircraft are coaxial in azimuth and elevation, the expression for the normalized three-dimensional position of the communication target in the inertial frame is: The expression for the three-dimensional position of the target communication object radar is: Where, θ Roll θ Pitch θ Course These are the aircraft's roll angle, climb angle, and heading angle at the current moment, respectively. According to the azimuth and elevation angle information (θ) described in formula (3) Az (n),θ El (n) is:

4. The real-time correction method for radar angle measurement error according to claim 1, characterized in that, The radar sends a name signal to the communication target. After receiving the name signal, the communication target feeds back to determine the radar system angle of the communication target. include: Using the feedback signal received from the radar, a single-pulse angle measurement is performed on the communication target to obtain the radar system angle of the communication target.

5. The real-time correction method for radar angle measurement error according to claim 4, characterized in that, According to the radar system angle and azimuth and elevation information (θ) Az (n),θ El (n) Determine the mean value of the radar angle measurement error include: Radar system angle As measured values ​​and azimuth and elevation angle information (θ) Az (n),θ El By fusing the theoretical values ​​(n) together, the radar's angle measurement error (ΔAz(n), ΔEl(n)) can be obtained; The current radar angle measurement error (ΔAz(n), ΔEl(n)) is expressed as: Under a preset period, the mean value of the radar angle measurement error is calculated by taking the weighted average of the angle measurement errors (ΔAz(n), ΔEl(n)) obtained from the first n calculations. Represented as: 。 6. The real-time correction method for radar angle measurement error according to claim 5, characterized in that, According to the mean Correct the azimuth and elevation angle (Φ) Az ,Φ El ), to obtain the target's angle information (Φ′) Az ,Φ′ El ),include: When tracking a target, the radar measures the target's radar system azimuth and elevation angles (Φ). Az ,Φ El ), based on the aforementioned mean After correction, the target's angle information (Φ′) is obtained. Az ,Φ′ El ): Based on angle information (Φ′) Az ,Φ′ El It can communicate with the target object for target tracking and communication.

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