An aircraft self-organizing network cooperative positioning method

Abstract

This invention discloses a cooperative localization method for aircraft in ad hoc networks, relating to the field of aircraft cooperative localization. It utilizes the relative distance and angle measurements between aircraft within a two-hop link and the positions of observable anchor nodes within that two-hop link to construct a multi-hop link joint observation. A weight matrix is ​​constructed by combining the influence of ranging and angle measurement errors on the localization error. Cooperative localization of the aircraft in the ad hoc network is then achieved based on a weighted linear least squares algorithm. Compared to conventional cooperative localization methods, this method does not require aggregating all link measurement results to a central computing node for position calculation. It only needs to collect measurement results within a two-hop link to autonomously calculate the position of its own nodes, resulting in low communication overhead and low localization latency between aircraft.

Description

Technical Field

[0001] This invention relates to the field of aircraft cooperative localization, and more specifically to a method for cooperative localization of aircraft using self-organizing networks. Background Technology

[0002] Cooperative positioning enables aircraft to obtain relative position information with other aircraft via inter-aircraft data links in GNSS-denied environments, representing an important direction in aircraft positioning technology development. However, in scenarios with few anchor nodes, the aircraft to be positioned cannot rely solely on ranging information for positioning calculations. Cooperative positioning, which jointly utilizes ranging and angle measurement information, refers to a method where an aircraft simultaneously obtains relative distance and angle information with other aircraft via data links for positioning calculations. This approach can be applied to positioning scenarios with few anchor nodes and has significant research value.

[0003] Conventional cooperative localization methods require aggregating all measurement information from the network to a designated central computing device and simultaneously performing localization calculations for all nodes. This results in high communication overhead and high localization latency, making it unsuitable for self-organizing aircraft networks without a central node. Some joint ranging and angle measurement cooperative localization methods can achieve distributed localization of nodes in a two-dimensional network by constructing multi-hop link linear least squares equations in a two-dimensional environment. However, these methods are not applicable to the localization of aircraft maneuvering in three-dimensional space.

[0004] Compared to linear least squares positioning methods, weighted least squares positioning methods offer higher positioning accuracy. However, some weighted least squares positioning methods only consider the impact of ranging errors on positioning accuracy, neglecting to account for angle measurement errors. Summary of the Invention

[0005] In view of this, the present invention provides a cooperative localization method for aircraft in an ad hoc network. This method constructs a weighted linear least squares observation equation in a three-dimensional environment based on the position information of anchor nodes within a two-hop range and the ranging and angular measurement information from the data link. The geometric model considers the influence of ranging and angular measurement errors on the localization error and designs a weight calculation method to ultimately achieve aircraft localization in the ad hoc network. Compared with conventional cooperative localization methods that aggregate the measurement information of all nodes to a central computing node, this method has lower communication overhead and lower localization latency.

[0006] To achieve the above objectives, the technical solution of this invention is as follows: During the cooperative positioning process of aircraft, the set of visible anchor nodes within the two-hop range of the aircraft to be positioned is: , where a i The anchor node with number i is represented; the set of one-hop neighbor nodes of the aircraft s to be located is... , where u jThis represents a one-hop neighbor node numbered j; the spacecraft s to be located uses the position p of anchor node a. a =[x a ,y a ,z a ] T The distance measurement result d between the one-hop neighbor node u and the anchor node a au Horizontal angle measurement result θ au φ, the result of elevation angle measurement au The distance measurement result between itself and its one-hop neighbor nodes d us Horizontal angle measurement result θ us φ, the result of elevation angle measurement us And the distance measurement results d between itself and the anchor node as Horizontal angle measurement result θ as φ, the result of elevation angle measurement as Determine your own position p s =[x s ,y s ,z s ] T .

[0007] The following steps are performed using a relative distance measurement module, a relative angle measurement module, a communication data demodulation module, a multi-hop link joint observation construction module, a weight calculation module, and a position calculation module;

[0008] (1) The relative distance measurement module measures the relative distance d between the node to be located s and the directly visible anchor node a through the received communication signal. as The relative distance d between the node to be located s and its one-hop neighbor node u us After obtaining the ranging results, the ranging results are passed to the multi-hop link joint observation construction module and the weight calculation module.

[0009] (2) The relative angle measurement module measures the relative horizontal angle θ between the node to be located s and the directly visible anchor node a through the received communication signal. as The relative elevation angle φ between the node to be located (s) and the directly visible anchor node (a) as The relative horizontal angle θ between the node to be located s and its one-hop neighbor node u us The relative elevation angle φ between the node to be located s and its one-hop neighbor node u us The angular relationship between any node i and node j is as follows: Figure 2 As shown. After obtaining the angle measurement results, the angle measurement results are passed to the multi-hop link joint observation construction module and the weight calculation module.

[0010] (3) The communication data demodulation module demodulates the position p of the modulated anchor node a in the communication signal. a =[x a ,ya ,z a ] T The distance measurement result d between the one-hop neighbor node u and the anchor node a au Horizontal angle measurement result θ au φ, the result of elevation angle measurement au The demodulated information is then passed to the multi-hop link joint observation construction module and the weight calculation module.

[0011] (4) The multi-hop link joint observation construction module constructs the anchor node based on the input anchor node position and the ranging and angle measurement results of each link. Two-hop internal link set to the node to be located s Among them l i This represents the link numbered i, where i is an integer in the range [1, L]; the link set It includes a single-hop link from anchor node a to node s to be located, and a two-hop link from anchor node a to node s via a one-hop neighbor node u.

[0012] After completing the link set Based on the construction, for the i-th link l in the set i Construct joint observations b along its x-axis, y-axis, and z-axis respectively. x,i b y,i b z,i ;

[0013] After obtaining the joint observations of each link, they are combined into a joint observation vector b = [b x,1 ,b x,2 ,...,b x,L ,b y,1 ,b y,2 ,...,b y,L ,b z,1 ,b z,2 ,...,b z,L ] T The joint observation vector is sent to the location calculation module, and the link set is sent to the weight calculation module.

[0014] (5) The weight calculation module calculates the link l based on the input anchor node position and the ranging and angle measurement results of each link. i Positioning error caused by ranging error Positioning error caused by angle measurement error

[0015] Compute link l i The weight w i The calculation method is as follows

[0016]

[0017] After calculating the weights of all links, the weight matrix W is calculated using the following method:

[0018] W = diag([w1,...,w L ,w1,...,w L ,w1,...,w L (12)

[0019] After obtaining the weight matrix W, the weight matrix is ​​passed to the position calculation unit;

[0020] (6) The position calculation unit first calculates the coefficient matrix Q, and the calculation method is as follows:

[0021]

[0022] Among them 1 L×1 It is a column matrix consisting of L 1s, 0 L×1 It is a column matrix consisting of L zeros.

[0023] After obtaining the coefficient matrix, the position p of the node to be located, s, is calculated based on the input joint observation vector and weight matrix. s =[x s ,y s ,z s ] T The calculation method is as follows

[0024] p s =(Q T W T WQ) -1 Q T W T Wb (14).

[0025] Furthermore, for the i-th link l in the set i Construct joint observations b along its x-axis, y-axis, and z-axis respectively. x,i b y,i b z,i Specifically:

[0026] If the i-th link l i For a single-hop link from anchor node a to node s to be located, the joint observation b along the x-axis, y-axis, and z-axis is... x,i b y,i b z,i The calculation methods are as follows:

[0027] b x,i =x a +d as cosθ as cosφ as (1)

[0028] b y,i =y a +d as sinθ as cosφ as (2)

[0029] b z,i =z a +d as sinφ as (3)

[0030] If link l i Given a two-hop link from anchor node a to the node to be located via a one-hop neighbor node u, then the joint observations b along the x, y, and z axes are... x,i b y,i b z,i The calculation methods are respectively

[0031] b x,i =x a +d au cosθ au cosφ au +d us cosθ us cosφ us (4)

[0032] b y,i =y a +d au sinθ au cosφ au +d us sinθ us cosφ us (5)

[0033] b z,i =z a +d au sinφ au +d us sinφ us (6).

[0034] Furthermore, calculate link l i Positioning error caused by ranging error Positioning error caused by angle measurement error Specifically:

[0035] If link l i For a single-hop link from anchor node a to node s to be located, the positioning error caused by the ranging error... Positioning error caused by angle measurement error They are respectively

[0036]

[0037]

[0038] Where, σ distance and σ angle These are the standard deviations of distance measurement and angle measurement, respectively.

[0039] If link l i If the anchor node a is a two-hop link relayed to the node s to be located via a one-hop neighbor node u, then the positioning error caused by the ranging error is... Positioning error caused by angle measurement error They are respectively

[0040]

[0041]

[0042] Where e au =[cosθ au cosφ au sinθ au cosφ au ,sinφ au ] T Let e ​​be the direction vector from node a to node u. us =[cosθ us cosφ us sinθ us cosφ us ,sinφ us ] T Let be the direction vector from node u to node s.

[0043] Beneficial effects:

[0044] This invention utilizes the relative distance and angle measurements between aircraft within a two-hop link and the positions of observable anchor nodes within the two-hop link to construct a multi-hop link joint observation measurement. A weight matrix is ​​constructed by combining the influence of ranging and angle measurement errors on the positioning error. Based on a weighted linear least squares algorithm, cooperative positioning of aircraft in an ad hoc network is achieved. Compared to conventional cooperative positioning methods, this method does not require aggregating all link measurement results to a central computing node for position calculation. It only needs to collect the measurement results within the two-hop link to autonomously calculate the position of its own nodes, resulting in low communication overhead and low positioning latency between aircraft. Attached Figure Description

[0045] Figure 1 A block diagram of the self-organizing network cooperative localization method for aircraft provided by the present invention;

[0046] Figure 2A schematic diagram of the angular relationship between any nodes. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] The structural block diagram of this invention is as follows: Figure 1 As shown, it includes a relative distance measurement module, a relative angle measurement module, a communication data demodulation module, a multi-hop link joint observation construction module, a weight calculation module, and a position calculation module.

[0049] The specific steps of this invention are as follows:

[0050] Without loss of generality, cooperative localization of aircraft is described as follows: Assume that the set of visible anchor nodes within two hops of an aircraft s to be localized is . Where a i This represents the anchor node with node number i. The set of one-hop neighbor nodes for the aircraft s to be located is: Where u j This represents a one-hop neighbor node with node number j. The spacecraft s to be located uses the position p of anchor node a. a =[x a ,y a ,z a ] T The distance measurement result d between the one-hop neighbor node u and the anchor node a au Horizontal angle measurement result θ au φ, the result of elevation angle measurement au The distance measurement result between itself and its one-hop neighbor nodes d us Horizontal angle measurement result θ us φ, the result of elevation angle measurement us And the distance measurement results d between itself and the anchor node as Horizontal angle measurement result θ as φ, the result of elevation angle measurement as Determine your own position p s =[x s ,y s ,z s ] T .

[0051] (1) The relative distance measurement module measures the relative distance d between the node to be located s and the directly visible anchor node a through the received communication signal. as The relative distance d between the node to be located s and its one-hop neighbor node u us After obtaining the ranging results, the ranging results are passed to the multi-hop link joint observation construction module and the weight calculation module.

[0052] (2) The relative angle measurement module measures the relative horizontal angle θ between the node to be located s and the directly visible anchor node a through the received communication signal. as The relative elevation angle φ between the node to be located (s) and the directly visible anchor node (a) as The relative horizontal angle θ between the node to be located s and its one-hop neighbor node u us The relative elevation angle φ between the node to be located s and its one-hop neighbor node u us The angular relationship between any node i and node j is as follows: Figure 2 As shown. After obtaining the angle measurement results, the angle measurement results are passed to the multi-hop link joint observation construction module and the weight calculation module.

[0053] (3) The communication data demodulation module demodulates the position p of the modulated anchor node a in the communication signal. a =[x a ,y a ,z a ] T The distance measurement result d between the one-hop neighbor node u and the anchor node a au Horizontal angle measurement result θ au φ, the result of elevation angle measurement au The demodulated information is then passed to the multi-hop link joint observation construction module and the weight calculation module.

[0054] (4) The multi-hop link joint observation construction module constructs the anchor node based on the input anchor node position and the ranging and angle measurement results of each link. Two-hop internal link set to the node to be located s Among them l i This represents the link numbered i. Link set It includes a single-hop link from anchor node a to node s to be located, and a two-hop link from anchor node a to node s via a one-hop neighbor node u.

[0055] After completing the link set Based on the construction, for each link in the set l i Construct joint observations b along its x-axis, y-axis, and z-axis respectively. x,i b y,i b z,i .

[0056] If link l i For a single-hop link from anchor node a to node s to be located, the joint observation b along the x-axis, y-axis, and z-axis is... x,i b y,i b z,i The calculation methods are respectively

[0057] b x,i =x a +das cosθ as cosφ as (1)

[0058] b y,i =y a +d as sinθ as cosφ as (2)

[0059] b z,i =z a +d as sinφ as (3)

[0060] If link l i Given a two-hop link from anchor node a to the node to be located via a one-hop neighbor node u, then the joint observations b along the x, y, and z axes are... x,i b y,i b z,i The calculation methods are respectively

[0061] b x,i =x a +d au cosθ au cosφ au +d us cosθ us cosφ us (4)

[0062] b y,i =y a +d au sinθ au cosφ au +d us sinθ us cosφ us (5)

[0063] b z,i =z a +d au sinφ au +d us sinφ us (6)

[0064] After obtaining the joint observations of each link, they are combined into a joint observation vector b = [b x,1 ,b x,2 ,...,b x,L ,b y,1 ,b y,2 ,...,b y,L ,b z,1 ,b z,2,...,b z,L ] T The joint observation vector is sent to the location calculation module, and the link set is sent to the weight calculation module.

[0065] (5) The weight calculation module calculates the link l based on the input anchor node position and the ranging and angle measurement results of each link. i Positioning error caused by ranging error Positioning error caused by angle measurement error

[0066] If link l i For a single-hop link from anchor node a to node s to be located, the positioning error caused by the ranging error... Positioning error caused by angle measurement error They are respectively

[0067]

[0068]

[0069] Where, σ distance and σ angle These are the standard deviations for distance measurement and angle measurement, respectively.

[0070] If link l i If the anchor node a is a two-hop link relayed to the node s to be located via a one-hop neighbor node u, then the positioning error caused by the ranging error is... Positioning error caused by angle measurement error They are respectively

[0071]

[0072]

[0073] Where e au =[cosθ au cosφ au sinθ au cosφ au ,sinφ au ] T Let e ​​be the direction vector from node a to node u. us =[cosθ us cosφ us sinθ us cosφ us ,sinφ us ] T Let be the direction vector from node u to node s.

[0074] Compute link l i The weight wi The calculation method is as follows

[0075]

[0076] After calculating the weights of all links, the weight matrix W is calculated using the following method:

[0077] W = diag([w1,...,w L ,w1,...,w L ,w1,...,w L (12)

[0078] After obtaining the weight matrix W, the weight matrix is ​​passed to the position calculation unit.

[0079] (6) The position calculation unit first calculates the coefficient matrix Q, and the calculation method is as follows:

[0080]

[0081] Among them 1 L×1 It is a column matrix consisting of L 1s, 0 L×1 It is a column matrix consisting of L zeros.

[0082] After obtaining the coefficient matrix, the position p of the node to be located, s, is calculated based on the input joint observation vector and weight matrix. s =[x s ,y s ,z s ] T The calculation method is as follows

[0083] p s =(Q T W T WQ) -1 Q T W T Wb (14)

[0084] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cooperative localization method for self-organizing networks of aircraft, characterized in that, During the collaborative positioning process of aircraft, the node to be positioned s The set of visible anchor nodes within the two-hop range is ,in This represents the anchor nodes numbered 1 to A; the set of one-hop neighbor nodes of the node to be located, is... ,in Indicates the number is 1~ N One-hop neighbor node; Node to be located s Using anchor nodes a Location One-hop neighbor node u With anchor node a Distance measurement results Horizontal angle measurement results Elevation angle measurement results Distance measurement results between itself and its one-hop neighbor nodes Horizontal angle measurement results Elevation angle measurement results and the distance measurement results between itself and the anchor node. Horizontal angle measurement results Elevation angle measurement results Determine your own position ; The following steps are performed using a relative distance measurement module, a relative angle measurement module, a communication data demodulation module, a multi-hop link joint observation construction module, a weight calculation module, and a position calculation module; (1) The relative distance measurement module measures the node to be located by receiving the communication signal. s With anchor node relative distance Node to be located s with one-hop neighbor nodes u relative distance After obtaining the ranging results, the ranging results are passed to the multi-hop link joint observation construction module and the weight calculation module; (2) The relative angle measurement module measures the node to be located by receiving the communication signal. s With anchor node relative horizontal angle Node to be located s With anchor node a Relative elevation angle Node to be located s with one-hop neighbor nodes u relative horizontal angle Node to be located s with one-hop neighbor nodes u relative elevation angle After obtaining the angle measurement results, the angle measurement results are passed to the multi-hop link joint observation construction module and the weight calculation module; (3) The communication data demodulation module demodulates the modulated anchor node in the communication signal. a Location One-hop neighbor node u With anchor node a Distance measurement results Horizontal angle measurement results Elevation angle measurement results The demodulated information is then transmitted to the multi-hop link joint observation construction module and the weight calculation module. (4) The multi-hop link joint observation construction module constructs the anchor node based on the input anchor node position and the ranging and angular measurement results of each link. To the node to be located s Two-hop internal link set ,in Indicates the number is i The links, where i takes the value of an integer in the range [1, L]; the link set Includes anchor nodes a To the node to be located s Single-hop links and anchor nodes a via one-hop neighbor node u Relay to the node to be located s Two-hop link; After completing the link set Based on the construction, for the i-th link in the set ， Construct them separately x axis 、y axis 、z Joint observation of the shaft , , ; After obtaining the joint observations of each link, they are combined into a joint observation vector. The joint observation vector is sent to the location calculation module, and the link set is sent to the weight calculation module. (5) The weight calculation module calculates the link weight based on the input anchor node position and the distance and angle measurement results of each link. Positioning error caused by ranging error Positioning error caused by angle measurement error ; Computational Link Weight The calculation method is as follows （11） After calculating the weights of all links, calculate the weight matrix. The calculation method is as follows （12） Obtain the weight matrix Then, the weight matrix is ​​passed to the position calculation module; (6) The position calculation module first calculates the coefficient matrix. The calculation method is as follows （13） in for L A column matrix consisting of 1s for L A column matrix consisting of zeros; After obtaining the coefficient matrix, the node to be located is calculated based on the input joint observation vector and weight matrix. s Location The calculation method is as follows （14）。 2. The aircraft self-organizing network cooperative localization method as described in claim 1, characterized in that, The i-th link in the set ， Construct them separately x axis 、y axis 、z Joint observation of the shaft , , Specifically: If the i-th link For anchor nodes a To the node to be located s For single-hop links, x axis 、y axis 、z Joint observation of the shaft , , The calculation methods are as follows: （1） （2） （3） If link For anchor nodes a via one-hop neighbor node u Relay to the node to be located s The two-hop link, then x axis 、y axis 、z Joint observation of the shaft , , The calculation methods are respectively （4） （5） （6）。 3. The aircraft self-organizing network cooperative localization method as described in claim 1, characterized in that, The computing link Positioning error caused by ranging error Positioning error caused by angle measurement error Specifically: If link For anchor nodes a To the node to be located s In a single-hop link, the ranging error leads to the positioning error. Positioning error caused by angle measurement error They are respectively （7） （8） in, and These are the standard deviations of distance measurement and angle measurement, respectively. If link For anchor nodes a via one-hop neighbor node u If the two-hop link from the relay to the node s to be located results in a positioning error due to the ranging error... Positioning error caused by angle measurement error They are respectively （9） （10） in For nodes a Pointing to node u directional vector, For nodes u Pointing to node s The direction vector.

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