CN109739263B - Submarine detecting navigation method based on magnetic signal continuation algorithm for submarine detection - Google Patents

Abstract

The invention provides a submarine detection navigation method based on a magnetic signal continuation algorithm for submarine detection, and belongs to the field of submarine detection or submarine detection and a submarine detector. Firstly, equivalent magnetized submarines into magnetic dipoles to obtain submarine signals on the current complete route represented by the combination of orthogonal basis functions; the method comprises the following steps that three unidirectional vector magnetic field measuring probes are orthogonally arranged on a submarine detecting machine to form a submarine detecting instrument; on the current route, a submarine detection signal is obtained by using a submarine detection instrument, the submarine detection signal is extended to obtain a submarine signal of the extended current complete route, the orientation of the submarine is calculated, and then the current route of the submarine detection instrument is updated; and repeating the process until the submarine detecting machine is positioned right above the submarine, and ending navigation. The invention can make the submarine detecting machine position the submarine in real time, thereby continuously correcting the course and directly flying to the submarine.

Description

A Submarine Exploration Aircraft Navigation Method Based on Magnetic Signal Continuation Algorithm for Submarine Detection

technical field

The invention relates to the fields of submarine detection or submarine detection aircraft and submarine detection devices, in particular to a submarine detection aircraft navigation method based on a magnetic signal extension algorithm for submarine detection.

Background technique

In order to strike a submarine, the submarine must be effectively located. The currently used sonar method can detect the sonar emitted or reflected by the submarine through the sonar measurement equipment located in the water, so as to judge whether there is a submarine around and locate the submarine. This method has a long detection distance and mature technology. But since the sonar method detects signals in water, it is appropriate to install it on a ship, but not on an attack aircraft.

The magnetic submarine detection method is to use the principle of magnetic anomaly detection technology for magnetic submarine detection, that is, due to the magnetization of the steel structure of the submarine hull by the geomagnetic field, an additional induced magnetic field is generated, which makes the earth's magnetic field in the surrounding area of the submarine abnormal. Signals to detect and locate submarines. Since the propagation of the magnetic signal does not depend on the water medium and can be detected in the air, the equipment based on magnetic detection can be placed on the aircraft to realize airborne diving and navigation. In order to enable the submarine detection aircraft, especially the carrier-based submarine detection aircraft, to realize submarine detection and aircraft navigation after taking off, so that the submarine detection aircraft can quickly approach the submarine to carry out strikes, a submarine detection aircraft navigation technology suitable for submarine detection is required.

In an existing document called "Magnetic Anomaly Detection Using a Three-Axis Magnetometer", a magnetic detection method for ferromagnetic targets is described, which uses a three-axis magnetometer to move along a straight line to measure the magnetic field signal, which must be obtained. A signal that increases first and then decreases can locate the detection target. That is to say, it is necessary to make the magnetometer approach and then move away from the ferromagnetic target to obtain the detection signal on the complete motion trajectory in order to achieve target positioning. If this method is applied to submarine detection and aircraft navigation, it means that the aircraft needs to fly multiple "Z" round-trip paths to approach the submarine. This process increases the flight distance and diving time, which is obviously a big drawback.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to propose a navigation method for submarine detection based on a magnetic signal extension algorithm for submarine detection. The method enables the submarine exploration aircraft to locate the submarine in real time, so as to continuously correct the course and fly directly to the submarine, that is, the submarine exploration aircraft can perform the positioning and navigation of the submarine while flying. This overcomes the disadvantage of using the previous magnetic target detection method to navigate the submarine, which must wait for the aircraft to fly away from the submarine to obtain a complete signal before positioning the submarine. The navigation method of the invention can greatly reduce the flight distance of the submersible exploration aircraft and shorten the submersible exploration time.

The present invention proposes a navigation method for submarine detection based on a magnetic signal continuation algorithm, characterized in that the method comprises the following steps:

1) Equivalent the magnetized submarine as a magnetic dipole, and obtain the expression generated by the submarine signal on the current complete route of the submarine; rewrite the expression into the combined representation of the orthonormal basis function, as the current complete The submarine signal on the route is denoted as Q _C (u);

2) Orthogonally install three unidirectional vector magnetic field measurement probes on the submersible aircraft to form a submersible detection instrument, wherein the measurement direction of the first probe is consistent with the heading of the submersible aircraft, and is set as the x direction; the measurement direction of the second probe is the vertical sea level direction. The downward direction is set as the z direction; the measurement direction of the third probe is the y direction, which is determined by the orthogonality of the z direction and the x direction;

3) After the submersible aircraft takes off, make the submersible aircraft fly along the set route and use the submersible instrument to measure the magnetic field, and use the route as the current route;

4) Take the sum of the squares of the magnetic field measurement values of the three probes of the diving instrument at each position of the traveled segment on the current route minus the earth's magnetic field component in the corresponding direction as the submarine detection signal, denoted as Q _T ( u);

5) Extend the submarine detection signal obtained from the flight segment on the current route to obtain the extended submarine signal of the current complete route, denoted as Q _W (u); the extension method is to use the submarine detection signal Q _T (u ) and the orthonormal basis function combined with the submarine signal Q _C (u) to perform matching operation in the interval of the measurement signal, so as to obtain the coefficients of each basis function, and substitute the coefficients into Q _C (u) and measure the traveled segments. The obtained submarine detection signal Q _T (u) is extended to the submarine signal Q _W (u) of the current complete route;

6) Calculate the azimuth of the submarine using the extended submarine signal Q _W (u) of the current complete route;

7) according to the azimuth of the submarine that step 6) obtains, update the current route of the submarine, and the updated current route is the azimuth that the current submarine position points to the submarine;

8) Repeat step 4) to step 7), on the current route after the update of the submersible aircraft, re-acquire the submarine detection signal and carry out the extension to obtain the submarine signal of the current complete route after the extension, recalculate the position of the submarine and update it. The current route of the submersible aircraft, until the submersible aircraft is directly above the submarine, and the navigation ends.

The characteristics and beneficial effects of the present invention are:

The invention proposes a navigation method for submarine detection based on a magnetic signal extension algorithm for submarine detection. By extending a section of submarine detection signals at a long distance, the flight section that originally requires the aircraft to approach and then get away from the submarine can be obtained. Submarine positioning can be easily achieved after signal extension, because it is easy to calculate the submarine position when the complete signal is known, especially when the peak point of the signal is known. The invention can avoid the disadvantage that the aircraft needs to fly over the submarine to determine the position of the submarine when there is no signal extension method, and the aircraft needs to fly multiple "Z"-shaped round trips to approach the submarine. The invention has the advantages that the submarine exploration aircraft can quickly fly to the submarine, the method is simple to implement, etc.; the continuous real-time navigation of the submarine exploration aircraft can be realized, and the rapid and precise strike on the submarine is facilitated.

Description of drawings

1 is a schematic diagram of the distribution characteristics of the submarine signal Q _C (u) on the complete route of the submarine exploration aircraft in the present invention.

FIG. 2 is a schematic diagram of the extension of the submarine detection signal in the present invention.

Detailed ways

The present invention proposes a method for navigating a submarine for submarine detection based on a magnetic signal continuation algorithm, which is further described in detail below with reference to the accompanying drawings and specific embodiments.

The present invention proposes a method for navigating a submarine for submarine detection based on a magnetic signal continuation algorithm, comprising the following steps:

1) The magnetized submarine is equivalent to a magnetic dipole, and the signal expression generated by the submarine on any current complete straight line of the submarine is obtained, and the expression is organized into a combined representation of orthonormal basis functions, as The submarine signal on the current full course is denoted as Q _C (u).

2) Three unidirectional vector magnetic field measurement probes are installed orthogonally on the submersible aircraft to form a submersible detection instrument, and the probes can use the existing fluxgate magnetic field measurement probe products. The measurement direction of the first probe is the same as the heading of the submersible aircraft, which is set as the x direction; the measurement direction of the second probe is the downward direction perpendicular to the sea level, which is set as the z direction; the third probe measurement direction is the y direction, which is determined by the z direction and the z direction. Orthogonal determination of the x direction;

3) After the submersible plane takes off, make the submersible plane fly straight along the route and use the submersible instrument to measure the magnetic field, and use the route as the current route;

4) Take the sum of the squares of the magnetic field measurement values of the three probes of the diving instrument at each position of the traveled segment on the current route minus the earth's magnetic field component in the corresponding direction as the submarine detection signal, denoted as Q _T ( u).

5) Extend the submarine detection signal obtained from the flight segment on the current route to obtain the extended submarine signal of the current complete route, denoted as Q _W (u). The continuation method is that the submarine signal Q _C (u) represented by the combination of the submarine detection signal Q _T (u) and the orthogonal basis function performs matching operations in the interval of the measurement signal, thereby obtaining the coefficients of each basis function, and substituting the coefficients into Q In _C (u), the submarine detection signal Q _T (u) measured in the traveled segment is extended to the submarine signal Q _W (u) of the current complete route.

6) Calculate the azimuth of the submarine using the extended submarine signal Q _W (u) of the current complete route.

7) Update the current route of the submarine exploration aircraft according to the position of the submarine obtained in step 6), so that the submarine exploration aircraft flies to the submarine.

8) Repeat step 4) to step 7), on the current route after the update of the submersible aircraft, re-acquire the submarine detection signal and carry out continuation to obtain the submarine signal of the current complete route after the continuation, recalculate the position of the submarine and combine it. Update the current route of the submersible aircraft to realize the navigation of the submersible aircraft, until the submersible aircraft is located directly above the submarine, and the submarine signal at this time is at the peak of the waveform corresponding to Q _W (u) on the current route, and the navigation ends.

The step 1) specifically includes:

The submarine is equivalent to a magnetic dipole after being magnetized by the earth's magnetism, and the three components of the dipole moment of the magnetic dipole in the Cartesian coordinate system are m _x , m _y , and m _z . The square of the modulus of the magnetic field strength vector generated by the magnetic dipole is defined as the submarine signal, and the vertical distance from the submarine to the current route of the submersible aircraft is R ₀ , the expression of the submarine signal on the current complete route of the submersible aircraft can be deduced The formula is:

In the formula, u is the position coordinate of the current route. In theory, a complete route refers to a straight line from negative infinity to positive infinity.

Orthogonal decomposition of equation (1) is performed, that is, equation (1) is expressed as a linear combination of three orthogonal bases, and the submarine signal Q _C (u) on the current complete route is obtained:

The three orthogonal bases are:

The corresponding coefficients are:

Formulas (2)-(4) are equivalent to formula (1).

The waveform of the submarine signal Q _C (u) along the current complete route of the submarine is similar to the Gaussian pulse waveform. The schematic diagram of the distribution characteristics is shown in Figure 1, that is, the waveform reaches the maximum value at the position closest to the submarine, and decays monotonically on both sides. . Its maximum value and attenuation depend on the equivalent dipole moment of the submarine and the relative position of the route and the submarine.

The step 4) specifically includes:

Record the measurement values of the three probes at each position of the traveled segment on the current route, and take the squares of the differences between the measurement values of the three probes at each position and the components in the corresponding direction of the earth's magnetic field, and record it as the submarine Probe signal Q _T (u), namely:

Q _T (u)=|H _Tx (u)-H _Ex | ² +|H _Ty (u)-H _Ey | ² +|H _Tz (u)-H _Ez | ² (5)

In the formula, H _Tx (u), H _Ty (u), H _Tz (u) represent the measured values of the three magnetic field measuring probes at each position u respectively; H _Ex , H _Ey , H _Ez represent the earth's magnetic field in components in three directions.

Described step 5) specifically includes:

The submarine detection signal Q _T (u) obtained by the aircraft on the current route is extended to obtain the extended submarine signal of the current complete route, denoted as Q _W (u). Q _W (u) is the extension of Q _T (u) to the untraveled segment along the current route, and the extended signal has the same shape as the submarine signal Q _C (u) of the current complete route. Figure 2 shows A schematic diagram of extending the submarine detection signal (that is, the signal between the interval u _T1 to u _T2 ) into a complete signal, and the complete signal is a function of the entire u value.

The continuation method is to use the measured submarine detection signal Q _T (u) and the submarine signal Q _C (u) represented by the combination of the orthogonal basis functions on the current complete route to perform a matching operation to determine the equation (2). Four coefficients λ ₁ , λ ₂ , λ ₃ and R ₀ . The matching operation makes Q _T (u) and Q _C (u) satisfy the following relationship:

Q _C (u)-Q _T (u)=0 or Q _C (u)=Q _T (u)<in the interval u _T1 to u _T2 > (6)

In the formula, u _T1 and u _T2 are the channel coordinates corresponding to the submarine detection signal measured in the traveled segment, u _T1 is the position of the submarine when the signal reaches a noise value greater than the magnetic field probe, and u _T2 is the current position of the submarine .

For formula (6), the idea of the method of moments is used to formulate the equation system for solving the four coefficients. The specific content is as follows: select three basis functions g _1-3 (u) (or multiple functions in other forms) as the weight function, and perform the inner product of formula (6) respectively, and the integration interval is [u _T1 , u _T2 ], get:

Equation (7) constitutes a system of equations containing four unknowns λ ₁ , λ ₂ , λ ₃ and R ₀ . In order to solve these four unknowns, any one of the following two methods can be used: the first method is to calculate λ ₁ , λ ₂ , λ ₃ by setting a series of R ₀ , and choose the formula (6) The set of solutions with the smallest error; the setting of R ₀ can be: in the range of 0 meters to 3000 meters, a value is taken every 10 meters as the value of R ₀ , and the range of 3000 meters is taken into account when the submarine signal is greater than this distance. It is very weak and cannot be detected. Taking the interval of 10 meters is considered to meet the practical requirements when the submarine positioning accuracy reaches this value. The second solution method is to use the existing optimization algorithm to optimize the nonlinear function of equation system (7) to obtain four unknowns.

Substitute the obtained four unknowns into equation (2) to obtain the extended submarine signal of the current complete route:

The value range of u in formula (8) is from negative infinity to positive infinity.

The step 6) specifically includes:

Use the extended submarine signal Q _W (u) of the current complete route to calculate the orientation of the submarine. The calculation method is: obtain the foot of the submarine and the current route by the maximum value of Q _W (u), and set the route coordinates of the foot. is u _max (as shown in FIG. 2 ), and the hypotenuse of the triangle formed by the current route coordinate interval [u _T2 -u _max ] and the vertical line R ₀ from the submarine to the current route is the azimuth of the submarine.

The step 7) specifically includes:

According to the azimuth of the submarine obtained in step 6), the current route of the submersible aircraft is updated, and the updated current route is the azimuth where the current position of the submersible aircraft points to the submarine.

The step 8) specifically includes:

Due to the interference or error of the measurement signal and the error generated by the submarine positioning algorithm, the position of the submarine obtained when the submarine is far away from the submarine is not accurate. Therefore, the submarine detection aircraft should repeat the submarine detection method in steps 4) to 7) while flying, and adjust the direction of the submarine detection aircraft accordingly, so as to realize the submarine detection aircraft navigation during the submarine detection process. In the process of gradually approaching the submarine, due to the decreasing distance from the submarine, a stronger submarine detection signal can be obtained, thereby continuously improving the accuracy of the azimuth detection of the submarine, which is conducive to the implementation of accurate military strikes.

Claims (5)

1. A submarine detection navigation method based on a magnetic signal continuation algorithm for submarine detection is characterized by comprising the following steps:

1) the magnetized submarine is equivalent to a magnetic dipole, and an expression generated by submarine signals on the current complete route of the submarine detecting machine is obtained; the expression is rewritten into a combined expression form of orthogonal basis functions, and the signal is recorded as Q as a submarine signal on the current complete route_C(u)；

2) The method comprises the following steps that three unidirectional vector magnetic field measuring probes are orthogonally arranged on a submarine detecting machine to form a submarine detecting instrument, wherein the measuring direction of a first probe is consistent with the course of the submarine detecting machine and is set as the x direction; the measuring direction of the second probe is vertical to the sea level and downward, and is set as the z direction; the measurement direction of the third probe is the y direction and is determined by the orthogonality of the z direction and the x direction;

3) after the diving machine takes off, the diving machine flies along a set flight path and uses a diving instrument to measure a magnetic field, and the flight path is used as a current flight path;

4) subtracting earth magnetic field components in corresponding directions from magnetic field measurement values of three probes of the diving instrument at each position of a traveled route section on a current routeThe sum of the squares is taken as a submarine detection signal and is recorded as Q_T(u)；

5) Extending the submarine detection signal obtained from the current flight path in the run section to obtain the extended submarine signal of the current complete flight path, and recording as Q_W(u); the continuation method is to detect the signal Q by the submarine_T(u) submarine Signal Q represented in combination with orthogonal basis functions_C(u) performing a matching operation within the interval of the measurement signal to obtain coefficients of each basis function, substituting the coefficients into Q_C(u) and detecting the submarine detection signal Q from the travelled flight_T(u) submarine Signal Q extended to Current complete route_W(u)；

6) Submarine signal Q using extended current complete flight path_W(u) calculating the orientation of the submarine;

7) updating the current route of the submarine detection machine according to the position of the submarine obtained in the step 6), wherein the updated current route is the position of the submarine detection machine pointing to the submarine;

8) and (4) repeating the steps from 4) to 7), on the current route after the submarine detecting machine is updated, acquiring submarine detection signals again, extending to obtain submarine signals of the extended current complete route, recalculating the azimuth of the submarine, updating the current route of the submarine detecting machine until the submarine detecting machine is positioned right above the submarine, and ending navigation.

2. The method according to claim 1, wherein the step 1) specifically comprises:

the submarine is equivalent to a magnetic dipole after being magnetized by the earth magnetism, and three components of dipole moment of the magnetic dipole in a rectangular coordinate system are set as m_x，m_y，m_z(ii) a Defining the square of the modulus of the magnetic field intensity vector generated by the magnetic dipole as a submarine signal, and setting the vertical distance from the submarine to the current route of the submarine detecting machine as R₀And obtaining a submarine signal expression of the submarine detecting machine on the current complete route as follows:

in the formula, u is the position coordinate of the current air route;

carrying out orthogonal decomposition on the formula (1), namely expressing the formula (1) as a linear combination of three orthogonal bases to obtain a submarine signal Q on the current complete flight path_C(u)：

Wherein the three orthogonal bases are respectively:

the corresponding coefficients are respectively:

3. the method according to claim 2, wherein the step 4) comprises in particular:

recording the measured values of three probes at each position of the traveled flight section on the current flight line, taking the difference between the measured values of the three probes at each position and the components in the corresponding direction of the earth magnetic field, then taking the square sum, and recording as a submarine detection signal Q_T(u)：

Q_T(u)＝|H_Tx(u)-H_Ex|²+|H_Ty(u)-H_Ey|²+|H_Tz(u)-H_Ez|²(5)

In the formula, H_Tx(u)，H_Ty(u)，H_Tz(u) represents the measurements of the three magnetic field measurement probes at each position u, respectively; h_Ex，H_Ey，H_EzRepresenting components of the earth's magnetic field in three directions, respectively.

4. The method as claimed in claim 3, wherein the step 5) is specifically as follows:

detecting signal Q by submarine_T(u) submarine signal Q_C(u) performing matching operation to determine four coefficients lambda in the formula (2)₁，λ₂，λ₃And R₀(ii) a Matching operation makes Q_T(u) and Q_C(u) satisfies the following relationship:

Q_C(u)-Q_T(u) 0 or Q_C(u)＝Q_T(u) < in u_T1To u_T2Interval inner > (6)

In the formula u_T1And u_T2Channel coordinates u corresponding to a section of submarine detection signal measured for a section of traveled_T1The position u of the submersible vehicle is detected when the signal reaches a value larger than the noise value of the magnetic field probe_T2The current position of the submersible vehicle is detected;

selecting three basis functions g₁(u)，g₂(u)，g₃(u) as a weight function, and separately performing inner products on the formula (6) with an integration interval of [ u [ [ u ]_T1,u_T2]Obtaining:

solving equation (7) to obtain lambda₁，λ₂，λ₃And R₀A value of (d);

substituting the solving result of the formula (7) into the formula (2) to obtain the extended submarine signal of the current finish route:

the value range of u in the formula (8) is from negative infinity to positive infinity.

5. The method as claimed in claim 1, wherein the step 6) is specifically as follows: by Q_W(u) obtaining the vertical foot of the submarine and the current flight path by the maximum value of (u), and setting the flight path coordinate of the vertical foot as u_maxCurrent course coordinate interval u_T2-u_max]Perpendicular line R from submarine to current route₀The hypotenuse of the triangle is the orientation of the submarine, wherein u_T2The current position of the submersible vehicle is detected.

Images