Ultraviolet Non-Line-of-Sight Positioning Method Applicable to Non-Coplanar Geometric Transceiver Situations

Abstract

The present invention provides an ultraviolet non-line-of-sight positioning method for non-coplanar geometric transceiver scenarios, including: setting an ultraviolet optical communication system in a spherical coordinate system with the receiving end Rx as the origin; the azimuth angle of the transmitting end Tx is and the distance from the receiving end Rx is ; regarding the light beam emitted by the transmitting end Tx and the field of view of the receiving end Rx as a cone; obtaining the maximum received powers and at two receiving elevation angles; with the receiving elevation angles and and the corresponding azimuth angles azimuth angle and, the unit direction vectors and of the receiving field of view axis intersecting with the transmitting end beam can be obtained; solving to obtain the transceiver distance and the transmitting end elevation angle; obtaining the off-axis angle and elevation angle of the transmitting end Tx according to the solved, and the azimuth angle and geometric parameters where the transmitting end Tx is located; the method can estimate the azimuth where the ultraviolet emission source is located in the non-line-of-sight geometric scenario, and can also obtain the geometric configuration parameters related to the optimization of the ultraviolet non-line-of-sight link communication quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical communication, and particularly relates to an ultraviolet non-line-of-sight positioning method applicable to non-coplanar geometric transceiver situations. Background Art

[0002] Ultraviolet optical communication refers to a technology that uses the ultraviolet light band of 200 - 280 nm for communication. By means of the scattering effect of atmospheric particles on ultraviolet light, a non-line-of-sight link can be established when the receiving end is not within the visible range of the transmitting end. In the non-line-of-sight link, the ultraviolet light signal usually reaches the receiving end through one or more scatterings of atmospheric particles on ultraviolet light. Compared with multiple scatterings, the ultraviolet light signal that reaches the receiving end through one scattering has a higher signal intensity. Usually, in order to make the received ultraviolet light intensity within an acceptable range, the common scatterer formed by the transmitting end beam and the receiving field of view should be as large as possible to ensure that the transmitted ultraviolet light mainly reaches the receiving end through one scattering. Therefore, if the receiving end can know the geometric configuration adopted by the transmitting end and adjust its receiving field of view accordingly, the communication quality of the ultraviolet non-line-of-sight link will be further optimized. For this reason, it is necessary to estimate the geometric configuration of the transmitting end at the receiving end, and there are similar technical solutions in the prior art.

[0003] For example, the patent application document with the Chinese patent application number CN201810134056.4 discloses an ultraviolet light source positioning method. Among them, the method includes: when within the radiation range of the target ultraviolet light source, rotating periodically around its own central axis, and receiving and recording the light intensity information of each point on the circumference; determining the strongest light intensity point and the weakest light intensity point according to the light intensity information, and taking the direction from the weakest light intensity point to the strongest light intensity point as the direction information of the target ultraviolet light source.

[0004] In the actual application process, the above method has two limitations:

[0005] On the one hand, in the actual non-line-of-sight link, the transmitting end beam and the receiving end field of view are not necessarily in the same plane, and the azimuth of the ultraviolet light source measured by using this method is not necessarily the azimuth where the transmitting end is located;

[0006] On the other hand, only the azimuth of the transmitting end is estimated by this method, and the information obtained by the receiving end is not enough for optimizing and adjusting its own geometric configuration.

[0007] Based on the above technical problems existing in the prior art, the present invention proposes an ultraviolet non-line-of-sight positioning method applicable to non-coplanar geometric transceiver situations. Summary of the Invention

[0008] The purpose of the present invention is to provide an ultraviolet non-line-of-sight positioning method applicable to non-coplanar geometric transceiver situations in view of the deficiencies of the prior art.

[0009] The present invention adopts the following technical solutions:

[0010] An ultraviolet non-line-of-sight positioning method applicable to non-coplanar geometric transceiver scenarios, comprising:

[0011] Step 1: Set the ultraviolet optical communication system in a spherical coordinate system with the receiving end Rx as the origin.

[0012] Step 2: Let the azimuth angle of the transmitting end Tx be φ r and the distance from the receiving end Rx be r, then the coordinates of the transmitting end Tx are (rcosφ r , rsinφ r , 0);

[0013] Step 3: Consider the light beam emitted by the transmitting end Tx and the field of view of the receiving end Rx as a cone.

[0014] Step 4: Rotate the receiving end Rx around the z-axis at two receiving elevation angles θ R1 and θ R2 and measure the received power at each point to obtain the maximum received powers Pr1 and Pr2 at the two receiving elevation angles.

[0015] Step 5: When the received power is maximum, the non-line-of-sight link has the maximum common scatterer. At the two elevation angles θ R1 and θ R2 , the azimuth angles φ1 and φ2 where the receiving field-of-view axis is located when the power is maximum can be measured. With the receiving elevation angles and the corresponding azimuth angles, the unit direction vectors μ1 and μ2 of the receiving field-of-view axis intersecting with the light beam of the transmitting end Tx can be obtained.

[0016] Step 6: μ1 and μ2 intersect with the axis of the light beam of the transmitting end Tx. The transmitting end Tx is located in the plane A established by μ1 and μ2. The angle formed by the intersection of the plane A and the ground and the x-axis is the azimuth angle of the transmitting end Tx. On the plane A, with the two maximum received powers Pr1 and Pr2 measured at θ R1 and θ R2 , and the ultraviolet optical communication coplanar scattering path loss model, two equations related to the distance r between the transceiver and the elevation angle θ t of the transmitting end are obtained:

[0017]

[0018] where θ′ R1 and θ′ R2 are the angles formed by μ1 and μ2 with the line where the transceiver is located respectively. Solve to obtain the distance r between the transceiver and the elevation angle θ t ;

[0019] Step 7: According to the obtained θ′R1 and θ' R2 and the azimuth angle and geometric parameters of the transmitting end Tx to obtain the off-axis angle φ of the transmitting end Tx t and the elevation angle θ t .

[0020] Further, in step 5, the vectors μ1 and μ2 are expressed as:

[0021]

[0022] where φ1 and φ2 are the azimuth angles of the maximum power measured at the receiving elevation angles θ R1 and θ R2 respectively.

[0023] Further, in step 6, when μ1 and μ2 intersect with the beam axis of the transmitting end, and at this time the transmitting end Tx is located in the plane A established by μ1 and μ2, then there is:

[0024] A: ax + by + cz = 0...(3);

[0025]

[0026] The angle formed by the straight line formed by the intersection of the plane A and the ground and the x-axis is the azimuth angle of the transmitting end Tx:

[0027]

[0028] Further, in step 7, the off-axis angle φ t and the elevation angle θ t of the transmitting end Tx can be obtained by using the obtained θ' R1 , θ' R2 and φ r and expressed as:

[0029]

[0030] The beneficial effects of the present invention are:

[0031] The ultraviolet non-line-of-sight positioning method applicable to non-coplanar geometric transceiver situations of the present invention can not only estimate the azimuth of the ultraviolet emission source in the non-line-of-sight geometric situation, but also further obtain the geometric configuration parameters related to the optimization of the communication quality of the ultraviolet non-line-of-sight link. Description of the Drawings

[0032] Figure 1 is a schematic diagram of estimating the azimuth angle of the ultraviolet light transmitting end in the embodiment of the present invention;

[0033] Figure 2 is a schematic diagram of the geometric configuration of the transceiver in the plane A in the embodiment of the present invention. Detailed implementation manners

[0034] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0035] Embodiment

[0036] The ultraviolet non-line-of-sight positioning method applicable to non-coplanar geometric transceiver situations includes:

[0037] Step 1: Set the ultraviolet communication system in the spherical coordinate system with the receiving end Rx as the origin;

[0038] Step 2: Let the azimuth angle of the transmitting end Tx be φ r and the distance from the receiving end Rx be r, then the coordinates of the transmitting end Tx are (rcosφ r , rsinφ r , 0);

[0039] Step 3: Consider the light beam emitted by the transmitting end Tx and the field of view of the receiving end Rx as a cone respectively. The geometric body formed by the intersection of the two cones of the transmitting end beam and the receiving field of view is the common scatterer. When the axis of the receiving field of view intersects with the axis of the transmitting end beam, the common scatterer is the largest, and the received power is the largest at this time;

[0040] Step 4: Rotate the receiving end Rx around the z-axis at two receiving elevation angles θ R1 and θ R2 and measure the received power at each point to obtain the maximum received power and the azimuth angle φ i where the axis of the receiving end is located at this time (i = 1, 2);

[0041] The unit direction vectors μ1 and μ2 pointed by the axis;

[0042] Step 5: Fix the receiving elevation angle, make the axis of the receiving field of view intersect with the axis of the transmitting end, the non-line-of-sight link has the largest common scatterer, and obtain the maximum received power. According to the azimuth angles of the maximum power obtained respectively at the two receiving elevation angles θ R1 and θ R2 in Step 4, further obtain the direction vectors μ1 and μ2 of the receiving field of view axis when the received power is the largest;

[0043] Step 6: Since μ1 and μ2 intersect with the axis of the transmitting end beam, the transmitting end Tx is located in the plane A determined by μ1 and μ2. The angle formed by the straight line formed by the intersection of the plane A and the ground and the x-axis is the azimuth angle of the transmitting end Tx. On the plane A, with the help of θ R1and θ R2 From the two maximum received powers Pr1 and Pr2 measured below, and the co-planar scattering path loss model of ultraviolet optical communication, two equations related to the distance r between the transceiver and the elevation angle θ of the transmitter are obtained: t Equations related:

[0044]

[0045] where θ′ R1 and θ′ R2 are the angles formed by μ1 and μ2 with the line where the transceiver is located respectively. Solving for the distance r between the transceiver and the elevation angle θ of the transmitter is obtained; t ;

[0046] In the above embodiment, as Figure 1 shown, the ultraviolet optical communication system is located in a spherical coordinate system with the receiver Rx as the origin. Let the azimuth angle of the transmitter Tx be φ r and the distance from the receiver be r. Then the coordinates of the transmitter Tx are (r cosφ r , rsinφ r , 0); The light beam emitted by the transmitter Tx and the field of view of Rx can both be regarded as a cone. Rotate around the z-axis at two receiving elevation angles of Rx and measure the received power at each point, so that the unit direction vectors pointed to by the axes of the receivers with the maximum power are μ1 and μ2 respectively:

[0047]

[0048] where θ R1 and θ R2 represent the elevation angles taken by the receiver Rx during two rotations around the axis respectively, and the angular direction is from the positive direction of the z-axis to the axis; φ1 and φ2 are the azimuth angles of the maximum power points measured at the receiving elevation angles θ R1 and θ R2 respectively, and the angular direction is from the positive direction of the x-axis counterclockwise to the projection of the receiver's field of view axis in the xoy plane. The two direction vectors μ1 and μ2 can determine a plane passing through the transmitter Tx, denoted as plane A:

[0049] A: ax + by + cz = 0;

[0050] where the parameters a, b, and c of the plane equation are the direction vectors of the normal vector of plane A respectively, and can be obtained by taking the cross product of μ1 and μ2:

[0051]

[0052] The axis of the transmitter and the axes of the receivers corresponding to the two elevation angles θ R1 and θ R2 are all located in plane A. Specifically, as Figure 2As shown, the relationship between the received power and the transmit and receive geometry conforms to the coplanar scattering model:

[0053]

[0054] Among them, P T Indicates the transmission power; A r Indicates the aperture size of the receiver; k s represents the atmospheric scattering coefficient; k e represents the atmospheric extinction coefficient; β T and β R Respectively represent the beam divergence angle of the Tx beam and the field of view angle of the Rx receiving field of view; θ s represents the scattering deflection angle, defined as

[0055] Using the coplanar scattering model and two elevation angles θ R1 and θ R2 The maximum received powers Pr1 and Pr2 measured below can construct a set of equations:

[0056]

[0057] Among them, θ′ R1 and θ′ R2 are the angles formed by the projections of the two direction vectors μ1 and μ2 on plane A and the straight line passing through the transmitter Tx, θ′ R1 and θ′ R2 It can be obtained by geometric analysis:

[0058] θ′ R1 = cosθ R1 cosφ1cosφ r +cosθ R1 sinφ1sinφ r ;

[0059] θ′ R2 = cosθ R2 cosφ2cosφ r +cosθ R2 sinφ2sinφ r ;

[0060] The above equation has two unknowns, which can be solved by combining two equations. For the convenience of solving, the nonlinear equations can be converted into an optimization problem:

[0061]

[0062] This optimization problem can be solved by brute force search or Newton's method to find r and θ. T ;

[0063] Considering θ T which is not the elevation angle of the transmitter Tx in the general sense, the off-axis angle φ of the transmitter Tx is obtained according to the known geometric parameters t and the elevation angle θ t :

[0064]

[0065] wherein and are respectively the angles formed by the receiving field-of-view axis and the straight line passing through the transceiver when the elevation angles are and respectively.

[0066] The ultraviolet non-line-of-sight positioning method applicable to the geometric transceiver scenario described in the above embodiments can be applied to the integrated positioning and communication of military combat units in a strong electromagnetic interference combat scenario: under the condition of strong electromagnetic interference implemented by the enemy, ultraviolet communication can quickly establish temporary communication under the battlefield by virtue of its anti-electromagnetic interference ability. However, in the combat environment, each combat unit does not know the positions of each other in advance. At this time, it is necessary to use the ultraviolet non-line-of-sight positioning method to establish a communication link between the nodes of each combat unit. In addition, ultraviolet positioning can estimate the position where the combat unit is located and upload it to the command center through the data link, which can further improve the battlefield situation awareness ability of the military in a strong electromagnetic interference environment.

[0067] The ultraviolet non-line-of-sight positioning method applicable to the geometric transceiver scenario described in the above embodiments can also be applied to disaster relief and rescue communication in scenarios such as earthquakes and nuclear accidents: in natural disaster scenarios with high destructive power such as earthquakes, due to the occlusion of the transmitted signal by the collapsed buildings after the disaster, it is difficult to form a strong signal coverage at each disaster relief point. By virtue of the non-line-of-sight communication ability of ultraviolet communication, "obstacle avoidance" communication at the disaster relief site can be realized, providing strong support for disaster relief and rescue work. However, each disaster relief unit does not know the positions of each other during the disaster relief and rescue process and cannot establish a reliable communication link. Therefore, it is necessary to use the ultraviolet non-line-of-sight positioning method to establish a preliminary communication link and further optimize the communication quality according to the parameters obtained by the positioning estimation, so as to improve the robustness of the communication system during the disaster relief process.

[0068] The present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims.

Claims

1. An ultraviolet non-line-of-sight positioning method for non-coplanar geometric transceiver scenarios, characterized in that, Including: Step 1: Set the ultraviolet communication system in the spherical coordinate system with the receiving end Rx as the origin. Step 2, let the azimuth angle where the transmitter Tx is located be φ r and the distance from the receiver Rx be r. Then the coordinates of the transmitter Tx are (r cos φ r , r sin φ r , 0); Step 3: Consider the light beam emitted by the transmitting end Tx and the field of view of the receiving end Rx as a cone. Step 4, rotate the two receiving elevation angles θ R1 and θ R2 at the receiving end Rx downward around the z-axis and measure the received power at each point to obtain the maximum received powers Pr1 and Pr2 at the two receiving elevation angles; Step 5. When the received power is the maximum, the non-line-of-sight link has the maximum common scatterer. At two elevation angles θ R1 and θ R2 the azimuth angles φ1 and φ2 where the receiving field-of-view axis is located when the power is the maximum can be measured. With the receiving elevation angles and the corresponding azimuth angles, the unit direction vectors μ1 and μ2 of the receiving field-of-view axes intersecting with the transmitting-end light beam can be obtained; Step 6, μ1 and μ2 intersect with the beam axis at the transmitter, the transmitter Tx is located in the plane A established by μ1 and μ2, and the angle formed by the straight line formed by the intersection of the plane A and the ground and the x-axis is the azimuth angle where the transmitter Tx is located. On the plane A, with the help of θ R1 and θ R2 The two maximum received powers Pr1 and Pr2 measured under, and the ultraviolet optical communication coplanar scattering path loss model, two equations related to the distance r between the transceiver and the elevation angle θ t are obtained: where, θ′ R1 and θ′ R2 are the angles formed by μ1 and μ2 with the straight line where the transceiver is located respectively, and the transceiver distance r and the elevation angle θ of the transmitter t ; Step 7, according to the solved θ′ R1 , θ′ R2 and the azimuth angle and geometric parameters where the transmitter Tx is located, obtain the off-axis angle φ t and elevation angle θ t .

2. The ultraviolet non-line-of-sight positioning method for non-coplanar geometric transceiver scenarios according to claim 1, wherein In Step 5, the vectors μ1 and μ2 are expressed as: where φ1 and φ2 are the azimuth angles of the maximum power measured at the receiving elevation angles θ R1 and θ R2 respectively.

3. The ultraviolet non-line-of-sight positioning method for non-coplanar geometric transceiver scenarios according to claim 2, wherein In Step 6, when μ1 and μ2 intersect with the axis of the transmitting end beam, and at this time the transmitting end Tx is located in the plane A determined by μ1 and μ2, then there is: A: ax + by + cz = 0......(3); The angle formed by the straight line formed by the intersection of the plane A and the ground and the x-axis is the azimuth angle where the transmitting end Tx is located:

4. The ultraviolet non-line-of-sight positioning method for non-coplanar geometric transceiver scenarios according to claim 3, wherein In step 7, the off-axis angle φ of the transmitting end Tx t and the elevation angle θ t can be expressed using the obtained θ′ R1 、θ′ R2 and φ r as follows:

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