A method for airspace collision risk assessment based on collision protection zone

Abstract

The present invention provides an airspace collision risk assessment method based on a collision protection zone, including: constructing a flight plan model and a risk airspace unit model; identifying the risk airspace unit, and using a double exponential distribution to establish an aircraft positioning error model under the premise that each flight strictly performs the flight mission according to the plan, respectively calculating the aircraft height and horizontal position positioning errors, and further deriving the actual position of the aircraft; establishing an aircraft collision protection zone according to the longitudinal, lateral, and height safety interval requirements of the aircraft; and sequentially quantifying the risk intensity of airspace units with collision risks to complete the airspace collision risk assessment. This method takes the flight plan as the data basis, fully considers the aircraft positioning performance limitations and control interval requirements, and realizes the objective quantification of the airspace collision risk value, which can provide a basis for flight plan formulation, airspace structure planning, and risk airspace identification.

Description

Technical Field

[0001] The invention relates to an airspace collision risk assessment method based on a collision protection zone. Background Art

[0002] With the continuous development of the aviation transportation industry, the complexity of air traffic operations and potential operational risks are increasing. Airspace operation risk assessment is a typical multivariate correlation analysis problem, which is related to many factors, including the arrangement of flight plans, airspace structure, special airspace distribution, etc. Therefore, how to conduct airspace operation risk assessment has become a hot and difficult issue at present. Objective and quantitative airspace operation risk assessment plays an important role in improving airspace operation safety and reducing the workload of controllers, and can effectively assist managers in making decisions such as flight plan adjustments, operation plan design, and airspace structure adjustments.

[0003] At present, commonly used airspace operation risk assessment methods include risk assessment methods based on the Reich model, risk assessment methods based on event models, and risk assessment methods based on accident trees. The above methods are often used to analyze the minimum interval between aircraft. On the premise that a large amount of historical operation data has been obtained, it is necessary to conduct post-hoc statistical review of the probability of aircraft violating safety interval regulations and the number of dangerous events. The number of selected samples and the uncertainty of the probability of basic events directly affect the reliability of the assessment results. The obtained assessment results represent the long-term operation risk of an airspace and cannot predict potential risks for typical operation scenarios. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide an airspace collision risk assessment method based on a collision protection zone in view of the deficiencies of the prior art. The present invention is based on flight plans, analyzes flight plans, identifies risky airspace units, analyzes aircraft positioning errors for each airspace unit with collision risks, establishes aircraft collision protection zones, and numerically quantifies collision risks, thereby providing a basis for flight plan formulation, airspace structure planning, and risky airspace identification.

[0005] The present invention specifically provides an airspace collision risk assessment method based on a collision protection zone, comprising the following steps:

[0006] Step 1: Construct flight plan and risk airspace unit model;

[0007] Step 2: Identify airspace units with collision risk;

[0008] Step 3, constructing an aircraft positioning error model;

[0009] Step 4: construct a quantitative model for the severity of operational conflicts;

[0010] Step 5: Calculate the collision risk assessment value.

[0011] Step 1: Build flight plan and risk airspace unit model

[0012] In a certain airspace to be evaluated, let the risk assessment period be T, and there is a flight plan set F in the period T. Let the flight plan set F = {f1,f2,...,f n}. Among them, f i , represents the flight plan numbered i, i = 1, 2, ..., n; flight plan f i It contains the following elements: flight number, waypoint sequence, route segment sequence, let the flight plan f i ={ID i ,PT i ,L i}, the information of each element is as follows:

[0013] ID i :Flight plan i The flight number, a unique identifier;

[0014] PT i :Flight plan i The sequence of waypoints to be passed For PT i An element numbered k in , i.e., a waypoint Contains elements with waypoint numbers Waypoint longitude Waypoint Latitude Waypoint altitude Flight i Occupancy time window at waypoint Respectively represent flights f i The start and end time of the time occupied at the waypoint. The longitude and latitude positions are projected onto the horizontal plane, with horizontal and vertical coordinates It means, the same below, so we can assume:

[0015] L i :Flight plan i Planned flight sequence For L i One of the items is numbered as k, i.e., the flight segment. The elements included are the flight segment number Segment starting point horizontal coordinate The vertical coordinate of the starting point of the flight segment Segment start point altitude The horizontal coordinate of the end point of the flight segment The vertical coordinate of the end point of the flight segment Segment end altitude course The flight's occupied time window for this segment Respectively represent flights f i The start and end time of the occupied time at the flight segment. Therefore, we can set:

[0016]

[0017] The airspace unit with collision risk includes risk waypoints and risk segments. Let the set of waypoints with collision risk be RT = {rt1, rt2, ..., rt n}, for the item rt with number i i , which contains the elements of waypoint number, conflicting flight, and conflicting time range, i.e. The information of each element is as follows:

[0018] N i : waypoint number;

[0019] f i r , Two flight plans with a risk of collision;

[0020] T rstart :Flight f i r , The starting time of the collision risk;

[0021] T rend :Flight f i r , End time when there is a risk of collision.

[0022] Assume that the set of flight segments with collision risk is RL = {rl1, rl2, ..., rl n}, for the element item rl numbered i i , including the elements: conflicting flight number, conflicting flight, conflicting time range, that is:

[0023] The information of each element is as follows:

[0024] The numbers of the two flight segments that are at risk of collision.

[0025] Step 2: Identification of airspace units with collision risk

[0026] The identification of airspace units with collision risks includes two parts: the identification of waypoints with collision risks and the identification of flight segments with collision risks.

[0027] Step 2-1, identification of waypoints with collision risk:

[0028] Assume that the risk assessment period is T. In the airspace to be assessed, if multiple flights pass through the same waypoint in a short period of time, there may be a collision risk at the waypoint. n}, n represents the number of flight plans, let the flight plan index be i, and let the initial value of i be 1, and execute step 2-1-1.

[0029] Step 2-1-1, get flight f with index i i , let f i ={ID i ,PT i ,L i The waypoint sequence of} is Where p represents the number of waypoints, and the waypoint index is k, with an initial value of 1. Pick Waypoint number Flight i At waypoint The occupied time window at Follow step 2-1-2;

[0030] Step 2-1-2, traverse the flight plan set F′={f1,f2,...,f n}-{f i}, let the flight plan index be j, the initial value is j=i+1, take the flight plan f j , let the waypoint index m = 1, and traverse the waypoint sequence in the plan If there is a waypoint Same as the waypoint in step 2-1-1 For the same waypoint, take flight f j At waypoint The occupied time window at Execute step 2-1-3, otherwise continue to traverse the flight plan set F′, set j=j+1, and repeat step 2-1-2 until all flights in F′ are traversed, and then execute step 2-1-4;

[0031] Step 2-1-3, if flight f j In the number The occupied time window at the waypoint The time window in step 2-1-1 If there is overlap, then flight f i With flight f j There is a risk of collision, and the conflict time range is T range for:

[0032] make And rt i Add to the set of waypoints with collision risk RT. Return to step 2-1-2;

[0033] Step 2-1-4, set the waypoint index k = k + 1, pointing to the next waypoint. If k ≤ p, return to step 2-1-1; if k> p, flight f i The identification of waypoints with collision risks is completed, and the flight index i=i+1 is set, and the process returns to step 2-1-1 until i≥n, and the identification of risk waypoints for all flights is completed.

[0034] Step 2-2: Identification of flight segments with collision risk

[0035] Assume that the risk assessment period is T. In the airspace to be assessed, if the distance between a flight segment and other segments is less than a certain safety value D s If the flight schedules overlap, there is a risk of collision between flights on adjacent segments. n}, n represents the number of flight plans, let the flight plan index be i, and let the initial value of i be 1, and execute step 2-2-1.

[0036] Step 2-2-1, get flight f with index i i , let f i ={ID i ,PT i ,L i The segment sequence of} is Where p represents the number of flight segments. Let the flight segment index be k, with an initial value of 1. Pick Waypoint number Flight i In the flight segment The occupied time window at Follow step 2-2-2;

[0037] Step 2-2-2, traverse the flight plan set F′={f1,f2,...,f n}-{f i}, let the flight plan index be j, the initial value is j=i+1, take the flight plan f j , let the segment index be m=1, and traverse the segment sequence in the plan If a flight segment exists Same as the segment in step 2-2-1 The minimum separation distance is less than D s , then take flight fj In the flight segment The occupied time window at Execute step 2-2-3, otherwise continue to traverse the flight plan set F′, set j=j+1, repeat step 2-2-2 until all flights in F′ are traversed, and execute step 2-2-4;

[0038] Step 2-2-3, if flight f j In the flight segment Occupancy time window The time window in step 2-2-1 If there is overlap, then flight f i With flight f j There is a potential risk of conflict, and the conflict time range is:

[0039] make And rl i Add it to the flight segment set RL with security risks. Return to step 2-2-2;

[0040] Step 2-2-4, let the waypoint index k = k + 1, pointing to the next waypoint, if k ≤ p, return to step 2-2-1; if k> p, then flight f i The identification of flight segments with potential operational risks is completed, and the flight index i=i+1 is set, and the process returns to step 2-2-1 until i≥n, and the identification of potential risk segments of all flights is completed.

[0041] Step 3: Build an aircraft positioning error model

[0042] In the actual operation of the aircraft, due to the performance limitation of the positioning equipment, there is often an error between the actual position and the nominal position. The present invention uses a positioning error model to describe the relationship between the nominal position and the actual position of the aircraft.

[0043] The aircraft is assumed to strictly follow the flight plan, that is, during the flight mission, its nominal position is consistent with the flight plan position, and the horizontal position positioning error of the aircraft is subject to the position parameter μ L , the scale parameter is λ L The double exponential distribution of the height position positioning error follows the position parameter μ H , the scale parameter is λ H The double exponential distribution of L , L , μ H , H The value of can be inferred based on historical samples of positioning devices using methods such as the maximum likelihood method.

[0044] Assume aircraft f iThe nominal position at time t is Heading Execute steps 3-1 to 3-2.

[0045] Step 3-1, determine the actual altitude of the aircraft, including:

[0046] Step 3-1-1, use uniform distribution to generate a random number u between (0,1);

[0047] Step 3-1-2, let the height positioning error value ΔH = μ H -λ H sgn(u-0.5)ln(1-2|u-0.5|); where sgn(x) is a step function, and

[0048] Step 3-1-3, Aircraft f i The actual height at time t for:

[0049] Step 3-2, determining the actual horizontal position of the aircraft, includes:

[0050] Step 3-2-1, use uniform distribution to generate a random number u between (0,1);

[0051] Step 3-2-2, let the horizontal positioning error value ΔL = μ L -λ L sgn(u-0.5)ln(1-2|u-0.5|), where sgn(x) is a step function, which is consistent with the definition in step 3-1-2;

[0052] Step 3-2-3, aircraft f i The actual horizontal coordinate position at time t is set to The actual ordinate position is At this point, we can get the aircraft f i The actual position at time t

[0053] Step 4: Construct a quantitative model of conflict severity, including:

[0054] Step 4-1, construct the aircraft collision protection zone:

[0055] In the "Signs of Civil Aircraft Flight Accidents", there are regulations such as "During the en route (route) flight phase, the longitudinal separation between aircraft is less than 3000m, the lateral separation is less than 3000m, and the vertical separation is less than 1000m, which is considered a dangerous approach; in general aviation flight, the height difference between two aircraft is less than 50m, and at the same time the longitudinal separation is less than 200m, and the lateral separation is less than 100m, which is considered a dangerous approach". Therefore, in combination with the regulations, a rectangular protection zone model can be established for aircraft of different types and in different flight phases, with the aircraft as the center and based on the safety separation requirements.

[0056] Step 4-1-1, suppose the aircraft f i r , There is a risk of collision, and f i r The actual position at time t is Heading The actual position at time t is Heading The longitudinal safety interval DV s , lateral safety interval DC s , height interval DH s Model a rectangular protection zone for length, width, and height;

[0057] Step 4-1-2: During operation, if the protected areas overlap, it is not a safety risk between aircraft. i r and The actual position satisfies:

[0058]

[0059] Then aircraft f i r and There is a risk of collision, and the volume of the overlapping parts of the protection zone for:

[0060] and The larger the value, the greater the severity of the corresponding conflict.

[0061] Step 4-2, calculate the severity of the operation conflict:

[0062] The artificial potential field method is a commonly used path planning algorithm. It establishes a virtual force field and measures the magnitude of the gravitational and repulsive forces exerted on an intelligent entity based on the distance from the force field source.

[0063] Step 4-2-1, referring to the idea of ​​artificial potential field method, quantify the severity of conflict by the size of the overlap volume of the aircraft protection area, and define the severity of aircraft conflict Fx as:

[0064] in Indicates the size of the space occupied by the two aircraft protection zones, V i r , Aircraft f i 、f j The collision protection zone volume, and is the overlapping volume of the two aircraft, ρ0 represents the size of the protected area when there is no collision risk between the two flights, and η is the proportional gain coefficient;

[0065] Step 4-2-2, determine the proportional gain coefficient η value:

[0066] The unit of measurement for conflict severity is defined as the number of fatal accidents. Since airspace risk is often described as "number of fatal accidents / unit time", the airspace risk can be regarded as the integral of conflict severity over time. Perform the following steps:

[0067] Step 4-2-2-1 Set the aircraft f i r , A collision occurs at time t, that is, a fatal accident occurs, indicating that the severity of the conflict Fx = 1, and the aircraft f i r and The actual positions overlap.

[0068] Step 4-2-2-2 Set Fx=1, Substituting into the calculation formula of aircraft conflict severity, we can get the proportional gain coefficient η=2·(V i r ) 3 .

[0069] On the basis of obtaining the proportional gain coefficient η value, according to the aircraft f i r , The actual conflict severity Fx of the aircraft can be obtained by the formula in step 4-2-1 based on the overlapping volume of the actual position and the protected area.

[0070] Step 5-1, calculate the waypoint operation risk:

[0071] Based on the airspace units with collision risk obtained in step 2, RT = {rt1, rt2, ..., rt n}、RL={rl1,rl2,...,rl n}Calculate the operational risk value within the time period T, then the operational risk of the airspace to be assessed is the sum of the waypoint operational risk and the segment operational risk.

[0072] Step 5-1, calculate the waypoint operation risk:

[0073] The set of waypoints with collision risk RT = {rt1, rt2, ..., rt n}, let the element index be i, the initial value be 1, and let the unit time for quantifying the degree of running conflict be T unit , that is, T unit is the time step length rt i The operational conflict degree of the aircraft with collision risk is calculated, and the initial value of the unit time operation risk of the waypoints in the period T is set to R = 0. Perform the following steps:

[0074] Step 5-1-1, according to the index i value, take RT = {rt1, rt2, ..., rt n Airspace units at risk in Suppose there is a time variable t, and its initial value is t = T rstart , execute step 5-1-2;

[0075] Step 5-1-2, according to the flight plan, take the aircraft f i r The nominal position at time t is Heading Aircraft The nominal position at time t is course Execute step 3 to obtain the aircraft f i r , The actual location is Execute step 5-1-3;

[0076] Step 5-1-3, after obtaining the aircraft f i r , Based on the actual position, execute step 4 to obtain the aircraft f i r , The degree of operational conflict at time t is Fx. According to the definition of operational risk value and integral, let the length of time period T be T len , then the unit time operation risk value of the waypoint in time period T is R = R + (Fx·T unit ) / T len , execute step 5-1-4;

[0077] Step 5-1-4, let t = t + T unit , if t≤Trend , then continue to step 5-1-2; if t>T rend , the airspace unit rt where there is a collision risk i After the operation safety risk calculation in time period T is completed, let the element index i of set RT = i + 1. If i ≤ n, the next airspace unit rt with collision risk in set RT is i Calculate the risk value and execute step 5-1-1; if i>n, the calculation of the waypoint operation risk value within time period T is completed.

[0078] Step 5-2, calculate the flight segment operation risk:

[0079] Assume that the initial value of the flight segment operation risk in time period T is R′=0, and the unit time for quantifying the flight segment operation conflict degree is set as T′ unit , for the set of flight segments with collision risk RL = {rl1, rl2, ..., rl n} Calculate the operation risk value, and set the initial value of the unit time operation risk of the flight segment in time period T to R′=0. Perform the following steps:

[0080] Step 5-2-1, according to the index i value, take RL = {rl1, rl2, ..., rl n Airspace units at risk in Suppose there is a time variable t, and its initial value is t = T rstart , execute step 5-2-2;

[0081] Step 5-2-2, according to the flight plan, take the aircraft f i r The nominal position at time t is Heading Aircraft The nominal position at time t is course Execute step 3 to obtain the aircraft f i r , The actual locations are Execute step 5-2-3;

[0082] Step 5-2-3, after obtaining the aircraft f i r , Based on the actual position, execute step 4 to obtain the aircraft f i r , The degree of operational conflict at time t is Fx. According to the definition of operational risk value and integral, let the length of time period T be T len , then the unit time operation risk value of the waypoint in time period T is R′=R′+(Fx·T′unit ) / T len , execute step 5-2-4;

[0083] Step 5-2-4, let t = t + T' unit , if t≤T rend , then continue to step 5-2-2; if t>T rend , the airspace unit rl where there is a collision risk i After the operation safety risk calculation in time period T is completed, let the element index i of set RL = i + 1. If i ≤ n, the next airspace unit rl with collision risk in set RL is i Calculate the risk value and execute step 5-2-1; if i>n, the calculation of the risk value of the flight segment operation in period T is completed. Step 5-3, calculate the airspace operation risk:

[0084] After completing the waypoint and segment operation risk calculations in steps 5-1 and 5-2, the airspace operation risk value R in time period T can be obtained. v is the sum of the waypoint collision risk and the segment collision risk, that is, R v =R+R′.

[0085] Beneficial effects: The present invention uses flight plans as data basis, analyzes flight plans in the airspace to be evaluated, identifies risky airspace units, analyzes aircraft positioning errors for each airspace unit with potential collision risks, establishes aircraft collision protection zones, and numerically quantifies operational risks. The operational risk assessment values ​​obtained are objective and effective, and can provide a basis for flight plan formulation, airspace structure planning, and risky airspace identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0087] Figure 1 It is a schematic diagram of the airspace operation risk assessment algorithm;

[0088] Figure 2 It is a statistical chart of the number of flights in the terminal area of ​​a certain airport and the identification results of airspace units with collision risks;

[0089] Figure 3 It is a comparative statistical chart of the operational risk assessment value and the overlap time of the collision protection zone in a terminal area of ​​a certain airport;

[0090] Figure 4 It is a schematic diagram of a method for identifying airspace units with collision risks. DETAILED DESCRIPTION

[0091] like Figure 1As shown, the present invention provides a risk assessment method, which specifically includes the following steps.

[0092] Step 1: Build flight plan and risk airspace unit model

[0093] In a certain airspace to be evaluated, let the risk assessment period be T, and there is a flight plan set F in the period T. Let the flight plan set F = {f1,f2,...,f n}. Among them, f i , (i=1,2,...,n) represents the flight plan numbered i. Flight plan f i The elements that should be included are: flight number, waypoint sequence, route segment sequence, let the flight plan f i ={ID i ,PT i ,L i}, the information of each element is as follows:

[0094] ID i :Flight plan i The flight number, a unique identifier;

[0095] PT i :Flight plan i The sequence of waypoints to be passed For PT i An element numbered k in , i.e., a waypoint Contains elements with waypoint numbers Waypoint longitude Waypoint Latitude Waypoint altitude Flight i Occupancy time window at waypoint Respectively represent flights f i The start and end time of the time occupied at the waypoint. The longitude and latitude positions are projected onto the horizontal plane, with horizontal and vertical coordinates It means, the same below, so we can assume:

[0096] L i :Flight plan i Planned flight sequence For L i One of the items is numbered as k, i.e., the flight segment. The elements included are the flight segment number Segment starting point horizontal coordinate The vertical coordinate of the starting point of the flight segment Segment start point altitude The horizontal coordinate of the end point of the flight segment The vertical coordinate of the end point of the flight segment Segment end altitude course The flight's occupied time window for this segment Respectively represent flights f i The start and end time of the occupied time at the flight segment. Therefore, we can set:

[0097]

[0098] The airspace unit with collision risk includes risk waypoints and risk segments. Let the set of waypoints with collision risk be RT = {rt1, rt2, ..., rt n}, for the item rt with number i i , the elements that should be included are waypoint number, conflicting flight, and conflicting time range, that is, The information of each element is as follows:

[0099] N i : waypoint number;

[0100] f i r , Flight plans that present a risk of collision;

[0101] T rstart :Flight f i r , The starting time of the collision risk;

[0102] T rend :Flight f i r , End time when there is a risk of collision.

[0103] Assume that the set of flight segments with collision risk is RL = {rl1, rl2, ..., rl n}, for the element item rl numbered i i The elements that should be included are: conflicting flight segment number, conflicting flight, conflicting time range, that is,

[0104] The information of each element is as follows:

[0105] The number of the flight segment where there is a risk of collision;

[0106] f i r , Flight plans that present a risk of collision;

[0107] T rstart:Flight f i r , The starting time of the collision risk;

[0108] T rend :Flight f i r , End time when there is a risk of collision.

[0109] Step 2: Identification of airspace units with collision risk

[0110] The identification of airspace units with collision risks includes two parts: the identification of waypoints with collision risks and the identification of flight segments with collision risks.

[0111] Step 2-1: Identification of waypoints with collision risk

[0112] Assume that the risk assessment period is T. In the airspace to be assessed, if multiple flights pass through the same waypoint in a short period of time, there may be a collision risk at the waypoint. n}, n represents the number of flight plans, let the flight plan index be i, and let the initial value of i be 1, and execute step 2-1-1.

[0113] Step 2-1-1, get flight f with index i i , let f i ={ID i ,PT i ,L i The waypoint sequence of} is Where p represents the number of waypoints, and the waypoint index is k, with an initial value of 1. Pick Waypoint number Flight i At waypoint The occupied time window at Follow step 2-1-2;

[0114] Step 2-1-2, traverse the flight plan set F′={f1,f2,...,f n}-{f i}, let the flight plan index be j, the initial value is j=i+1, take the flight plan f j , let the waypoint index m = 1, and traverse the waypoint sequence in the plan If there is a waypoint Same as the waypoint in step 2-1-1 For the same waypoint, take flight f j At waypoint The occupied time window at Execute step 2-1-3, otherwise continue to traverse the flight plan set F′, set j=j+1, and repeat step 2-1-2 until all flights in F′ are traversed, and then execute step 2-1-4;

[0115] Step 2-1-3, if flight f j In the number The occupied time window at the waypoint The time window in step 2-1-1 If there is overlap, then flight f i With flight f j There is a risk of collision, and the conflict time range is:

[0116] make And rt i Add to the set of waypoints with collision risk RT. Return to step 2-1-2;

[0117] Step 2-1-4, set the waypoint index k = k + 1, pointing to the next waypoint. If k ≤ p, return to step 2-1-1; if k> p, flight f i The identification of waypoints with collision risks is completed, and the flight index i=i+1 is set, and the process returns to step 2-1-1 until i≥n, and the identification of risk waypoints for all flights is completed.

[0118] Step 2-2: Identification of flight segments with collision risk

[0119] Assume that the risk assessment period is T. In the airspace to be assessed, if the distance between a flight segment and other segments is less than a certain safety value D s If the flight schedules overlap, there is a risk of collision between flights on adjacent segments. n}, n represents the number of flight plans, let the flight plan index be i, and let the initial value of i be 1, and execute step 2-2-1.

[0120] Step 2-2-1, get flight f with index i i , let f i ={ID i ,PT i ,L i The segment sequence of} is Where p represents the number of flight segments. Let the flight segment index be k, with an initial value of 1. Pick Waypoint number Flight i In the flight segment The occupied time window at Follow step 2-2-2;

[0121] Step 2-2-2, traverse the flight plan set F′={f1,f2,...,f n}-{f i}, let the flight plan index be j, the initial value is j=i+1, take the flight plan f j , let the segment index be m=1, and traverse the segment sequence in the plan If a flight segment exists Same as the segment in step 2-2-1 The minimum separation distance is less than D s , then take flight f j In the flight segment The occupied time window at Execute step 2-2-3, otherwise continue to traverse the flight plan set F′, set j=j+1, repeat step 2-2-2 until all flights in F′ are traversed, and execute step 2-2-4;

[0122] Step 2-2-3, if flight f j In the flight segment Occupancy time window The time window in step 2-2-1 If there is overlap, then flight f i With flight f j There is a potential risk of conflict, and the conflict time range is:

[0123] make And rl i Add it to the flight segment set RL with security risks. Return to step 2-2-2;

[0124] Step 2-2-4, set the waypoint index k = k + 1, pointing to the next waypoint. If k ≤ p, return to step 2-2-1; if k> p, flight f i The identification of flight segments with potential operational risks is completed, and the flight index i=i+1 is set, and the process returns to step 2-2-1 until i≥n, and the identification of potential risk segments of all flights is completed.

[0125] Step 3: Build an aircraft positioning error model

[0126] In the actual operation of the aircraft, due to the performance limitation of the positioning equipment, there is often an error between the actual position and the nominal position. The present invention uses a positioning error model to describe the relationship between the nominal position and the actual position of the aircraft.

[0127] The aircraft is assumed to strictly follow the flight plan, that is, during the flight mission, its nominal position is consistent with the flight plan position, and the horizontal position positioning error of the aircraft is subject to the position parameter μ L , the scale parameter is λ L The double exponential distribution of the height position positioning error follows the position parameter μ H , the scale parameter is λ H The double exponential distribution of L , L , μ H , H The value of can be inferred based on historical samples of positioning devices using methods such as the maximum likelihood method.

[0128] Assume aircraft f i The nominal position at time t is Heading Execute steps 3-1 to 3-2.

[0129] Step 3-1: Determine the actual altitude of the aircraft

[0130] Step 3-1-1, use uniform distribution to generate a random number u between (0,1);

[0131] Step 3-1-2, let the height positioning error value ΔH = μ H -λ H sgn(u-0.5)ln(1-2|u-0.5|); where sgn(x) is a step function, and

[0132] Step 3-1-3, Aircraft f i The actual height at time t:

[0133] Step 3-2, determine the actual horizontal position of the aircraft

[0134] Step 3-2-1, use uniform distribution to generate a random number u between (0,1);

[0135] Step 3-2-2, let the horizontal positioning error value ΔL = μ L -λ L sgn(u-0.5)ln(1-2|u-0.5|), where sgn(x) is a step function, which is consistent with the definition in step 3-1-2;

[0136] Step 3-2-3, aircraft f i The actual horizontal coordinate position at time t is set to The actual ordinate position is At this point, we can get the aircraft f iThe actual position at time t

[0137] Step 4: Build a quantitative model of conflict severity

[0138] Step 4-1: Constructing the aircraft collision protection zone

[0139] In the "Signs of Civil Aircraft Flight Accidents", there are regulations such as "During the en route (route) flight phase, the longitudinal separation between aircraft is less than 3000m, the lateral separation is less than 3000m, and the vertical separation is less than 1000m, which is considered a dangerous approach; in general aviation flight, the height difference between two aircraft is less than 50m, and at the same time the longitudinal separation is less than 200m, and the lateral separation is less than 100m, which is considered a dangerous approach". Therefore, in combination with the regulations, a rectangular protection zone model can be established for aircraft of different types and in different flight phases, with the aircraft as the center and based on the safety separation requirements.

[0140] Step 4-1-1, suppose the aircraft f i r , There is a risk of collision, and f i r The actual position at time t is Heading The actual position at time t is Heading The longitudinal safety interval DV s , lateral safety interval DC s , height interval DH s Model a rectangular protection zone for length, width, and height;

[0141] Step 4-1-2: During the operation, if the protection zones overlap, it means that there is an operation conflict between the aircraft. i r and The actual position satisfies:

[0142]

[0143] Then aircraft f i r and There is a risk of collision, and the overlapping volume of the protection zone is:

[0144] and The larger the value, the greater the severity of the corresponding conflict.

[0145] Step 4-2, run the conflict severity calculation

[0146] The artificial potential field method is a commonly used path planning algorithm. It establishes a virtual force field and measures the magnitude of the gravitational and repulsive forces exerted on an intelligent entity based on the distance from the force field source.

[0147] Step 4-2-1, drawing on the idea of ​​artificial potential field method, quantifies the severity of the conflict by the size of the overlap volume of the aircraft protection zone, and defines the severity of the aircraft conflict as:

[0148] in Indicates the size of the space occupied by the two aircraft protection zones, V i r , Aircraft f i 、f j The collision protection zone volume, and is the overlapping volume of the two aircraft, It represents the size of the protected area when there is no collision risk between two flights, and η is the proportional gain coefficient;

[0149] Step 4-2-2, determine the proportional gain coefficient η value

[0150] The unit of measurement for defining conflict severity is the number of fatal accidents. Since airspace risk is often described as “number of fatal accidents / unit time”, the airspace risk can be considered as the integral of conflict severity over time.

[0151] Step 4-2-2-1 Set the aircraft f i r , A collision occurs at time t, that is, a fatal accident occurs, which means that the severity of the conflict Fx = 1, and the aircraft f i r and The actual positions overlap.

[0152] Step 4-2-2-2 Set Fx=1, Substituting into the calculation formula of aircraft conflict severity, we can get the proportional gain coefficient η=2·(V i r ) 3 .

[0153] On the basis of obtaining the proportional gain coefficient η value, according to the aircraft f i r , The actual conflict severity Fx of the aircraft can be obtained by the formula in step 4-2-1 based on the overlapping volume of the actual position and the protected area.

[0154] Step 5: Calculate the airspace operation risk assessment value:

[0155] Based on the airspace units with collision risk obtained in step 2, RT = {rt1, rt2, ..., rt n}、RL={rl1,rl2,...,rl n}Calculate the operational risk value within the time period T, then the operational risk of the airspace to be assessed is the sum of the waypoint operational risk and the segment operational risk.

[0156] Step 5-1, Waypoint Operation Risk Calculation

[0157] The set of waypoints with collision risk RT = {rt1, rt2, ..., rt n}, let the element index be i, the initial value be 1, and let the unit time for quantifying the degree of running conflict be T unit , that is, T unit is the time step length rt i The operational conflict degree of aircraft with collision risk is calculated, and the initial value of the unit time operation risk of the waypoints in time period T is set to R = 0.

[0158] Step 5-1-1, according to the index i value, take RT = {rt1, rt2, ..., rt n Airspace units at risk in Suppose there is a time variable t, and its initial value is t = T rstart , execute step 5-1-2;

[0159] Step 5-1-2, according to the flight plan, take the aircraft f i r The nominal position at time t is Heading Aircraft The nominal position at time t is course Execute step 3 to obtain the aircraft f i r , The actual location is Execute step 5-1-3;

[0160] Step 5-1-3, after obtaining the aircraft f i r , Based on the actual position, execute step 4 to obtain the aircraft f i r , The degree of operational conflict at time t is Fx. According to the definition of operational risk value and integral, let the length of time period T be T len, then the unit time operation risk value of the waypoint in time period T is R = R + (Fx·T unit ) / T len , execute step 5-1-4;

[0161] Step 5-1-4, let t = t + T unit , if at this time t≤T rend , then continue to step 5-1-2; if t>T rend , the airspace unit rt where there is a collision risk i The operation safety risk calculation in time period T is completed, and the element index of set RT is set to i=i+1. If i≤n, the next airspace unit rt with collision risk in set RT is i To calculate the risk value, execute step 5-1-1; if i>n, the calculation of the risk value of the waypoint operation within time period T is completed.

[0162] Step 5-2, flight segment operation risk calculation

[0163] Assume that the initial value of the flight segment operation risk in time period T is R′=0, and the unit time for quantifying the flight segment operation conflict degree is set as T′ unit , for the set of flight segments with collision risk RL = {rl1, rl2, ..., rl n} Calculate the operational risk value. The initial value of the unit time operational risk of the flight segment in time period T is set to R′=0. Perform the following steps:

[0164] Step 5-2-1, according to the index i value, take RL = {rl1, rl2, ..., rl n Airspace units at risk in Suppose there is a time variable t, and its initial value is t = T rstart , execute step 5-2-2;

[0165] Step 5-2-2, according to the flight plan, take the aircraft f i r The nominal position at time t is Heading Aircraft The nominal position at time t is course Execute step 3 to obtain the aircraft f i r , The actual location is Execute step 5-2-3;

[0166] Step 5-2-3, after obtaining the aircraft f i r , Based on the actual position, execute step 4 to obtain the aircraft f i r , The degree of operational conflict at time t is Fx. According to the definition of operational risk value and integral, let the length of time period T be T len , then the unit time operation risk value of the waypoint in time period T is R′=R′+(Fx·T u ' nit ) / T len , execute step 5-2-4;

[0167] Step 5-2-4, let t = t + T' unit , if t≤T rend , then continue to step 5-2-2; if t>T rend , the airspace unit rl where there is a collision risk i After the operation safety risk calculation in time period T is completed, let the element index i of set RL = i + 1. If i ≤ n, the next airspace unit rl with collision risk in set RL is i To calculate the risk value, execute step 5-2-1; if i>n, the calculation of the risk value of the flight segment operation within time period T is completed.

[0168] Step 5-3, Airspace Operation Risk Calculation

[0169] After completing the waypoint and segment operation risk calculations in steps 5-1 and 5-2, the airspace operation risk value in time period T can be obtained as the sum of the waypoint collision risk and the segment collision risk, that is, R v =R+R′.

[0170] The above method is used to conduct collision risk assessment on incoming and outgoing flights in the terminal area of ​​an airport. The verification process is as follows:

[0171] Identification of risky airspace units:

[0172] During the time period of 7:00 to 22:00, the arrival and departure flights in the terminal area of ​​the airport are randomly generated using probability distribution with "hours (h)" as the unit time, and each flight is assigned a route, take-off and landing time, and waypoint / segment occupancy time. The above flight plans are traversed and compared in sequence, and the airspace units with possible collision risks are identified and counted. The statistical results of the number of flights and airspace units with collision risks in each time period are as follows: Figure 2 shown.

[0173] Parameter configuration:

[0174] Assume that the horizontal positioning error of the aircraft obeys the position parameter μ L = 0km, scale parameter λ L=0.017km double exponential distribution, the height position positioning error obeys the position parameter μ H = 0km, scale parameter λ H =0.005km double exponential distribution. The Civil Aircraft Flight Accident Signs stipulates that during the approach flight phase, when the longitudinal separation is less than 2000m, the lateral separation is less than 1000m, and the vertical separation is less than 100m, it is considered a dangerous approach. Therefore, the longitudinal safety separation DV of the aircraft collision protection zone is set. s =2km, lateral safety distance DC s =1km, height interval DH s =0.1km,ρ0=0.4km 3 When two aircraft collide, that is, when the collision risk intensity Fx = 1, the space occupied by the two aircraft is ρ = 0.2 km 3 , according to the formula Calculation shows that the proportional gain coefficient η = 0.016.

[0175] Collision risk assessment value calculation:

[0176] Let the unit time T that quantifies the intensity of risk be unit = 1s = 1 / 3600h, and the conflict severity is estimated for the airspace units with collision risk in different time periods. unit The conflict severity is quantified and integrated for the step length to obtain the collision risk assessment value, and the duration of the overlap time of the collision protection zone is recorded. The results are as follows Figure 3 shown.

[0177] from Figure 2 , Figure 3 , Figure 4 It can be seen that the total length of the overlap time of the collision protection zone, the number of airspace units with collision risk and the risk assessment value are positively correlated. So far, the algorithm has completed the objective quantification of the collision risk value of the flight plan in the terminal area of ​​the airport.

[0178] The present invention provides an airspace collision risk assessment method based on a collision protection zone. There are many methods and ways to implement the technical solution. The above is only a preferred implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for airspace collision risk assessment based on a collision protection zone, characterized in that: The following steps are involved: Step 1: Construct flight plan and risk airspace unit model; Step 2: Identify airspace units with collision risk; Step 3, constructing an aircraft positioning error model; Step 4: construct a quantitative model of conflict severity; Step 5, calculating the collision risk assessment value; Step 1 includes: In the airspace to be evaluated, let the risk assessment period be T, and there is a flight plan set F in the period T, let the flight plan set F = {f1,f2,...,f n }, where f i represents the flight plan numbered i, i = 1, 2, ..., n; flight plan f i It contains the following elements: flight number, waypoint sequence, route segment sequence, let the flight plan f i ={ID i ,PT i ,L i }, the information of each element is as follows: ID i :Flight plan i The flight number, a unique identifier; PT i :Flight plan i The sequence of waypoints to be passed For PT i The element numbered k is the waypoint Contains elements with waypoint numbers Waypoint longitude Waypoint Latitude Waypoint altitude Flight i Occupancy time window at waypoint Respectively represent flights f i The start and end time of the time occupied at the waypoint; Waypoint The longitude and latitude positions are projected onto the horizontal plane, with horizontal and vertical coordinates Indicates that: L i :Flight plan i Planned flight sequence For L i The first number is the k element, i.e. the flight segment The elements included are the flight segment number Segment starting point horizontal coordinate The vertical coordinate of the starting point of the flight segment Segment start point altitude The horizontal coordinate of the end point of the flight segment The vertical coordinate of the end point of the flight segment Segment end altitude course The flight's occupied time window for this segment Respectively represent flights f i The start and end time of the occupied time at the flight segment; set up: The airspace units with collision risk include risk waypoints and risk segments. Let the set of waypoints with collision risk be RT = {rt1, rt2, ..., rt n }, for the item rt with number i i , which contains the elements of waypoint number, conflicting flight, and conflicting time range, i.e. The information of each element is as follows: N i : waypoint number; f i r , Two flight plans with a risk of collision; T rstart :Flight f i r , The starting time of the collision risk; T rend :Flight f i r , The end time of the risk of collision; Assume that the set of flight segments with collision risk is RL = {rl1, rl2, ..., rl n }, for the element item rl numbered i i , including the elements: conflicting flight number, conflicting flight, conflicting time range, that is: The information of each element is as follows: The numbers of the two flight segments that are at risk of collision.

2. The method according to claim 1, characterized in that: Step 2 includes: Step 2-1, identifying waypoints with collision risk; Step 2-2, identifying flight segments with collision risks.

3. The method according to claim 2, characterized in that Step 2-1 includes: assuming that the risk assessment period is T, in the flight plan set F = {f1,f2,...,f n }, n represents the number of flight plans, set the flight plan index to i, and set the initial value of i to 1, and execute step 2-1-1; Step 2-1-1, get flight f with index i i , let f i ={ID i ,PT i ,L i The waypoint sequence of} is Where p represents the number of waypoints, let the waypoint index be k, and the initial value be 1; for waypoints Pick Waypoint number Flight i At waypoint The occupied time window at Follow step 2-1-2; Step 2-1-2, traverse the flight plan set F′={f1,f2,...,f n }-{f i }, let the flight plan index be j, the initial value is j=i+1, take the flight plan f j , let the waypoint index m = 1, and traverse the waypoint sequence in the plan If there is a waypoint Same as the waypoint in step 2-1-1 For the same waypoint, take flight f j At waypoint The occupied time window at Execute step 2-1-3, otherwise continue to traverse the flight plan set F′, set j=j+1, and repeat step 2-1-2 until all flights in F′ are traversed, and then execute step 2-1-4; Step 2-1-3, if flight f j In the number The occupied time window at the waypoint The time window in step 2-1-1 If there is overlap, then flight f i With flight f j There is a risk of collision, and the conflict time range is T range for: make And rt i Add it to the set of waypoints RT with collision risk, and return to step 2-1-2; Step 2-1-4, let the waypoint index k = k + 1, pointing to the next waypoint, if k ≤ p, return to step 2-1-1; if k> p, then flight f i The identification of waypoints with collision risks is completed, and the flight index i=i+1 is set, and the process returns to step 2-1-1 until i≥n, and the identification of risk waypoints for all flights is completed.

4. The method according to claim 3, characterized in that Step 2-2 includes: Assume that the risk assessment period is T. In the airspace to be assessed, if the distance between a flight segment and other segments is less than the safety value D s If the flight schedules overlap, there is a risk of collision between flights on adjacent segments. n }, n represents the number of flight plans, set the flight plan index to i, and set the initial value of i to 1, and execute step 2-2-1; Step 2-2-1, get flight f with index i i , let f i ={ID i ,PT i ,L i The segment sequence of} is Where p represents the number of flight segments; let the flight segment index be k, with an initial value of 1; for the flight segment Pick Waypoint number Flight i In the flight segment The occupied time window at Follow step 2-2-2; Step 2-2-2, traverse the flight plan set F′={f1,f2,...,f n }-{f i }, let the flight plan index be j, the initial value is j=i+1, take the flight plan f j , let the segment index be m=1, and traverse the segment sequence in the plan If there is a flight segment Same as the segment in step 2-2-1 The minimum separation distance is less than D s , then take flight f j In the flight segment The occupied time window at Execute step 2-2-3, otherwise continue to traverse the flight plan set F′, set j=j+1, repeat step 2-2-2 until all flights in F′ are traversed, and execute step 2-2-4; Step 2-2-3, if flight f j In the flight segment Occupancy time window The time window in step 2-2-1 If there is overlap, then flight f i With flight f j There is a potential risk of conflict, and the conflict time range is: make And rl i Add the flight segments to the set RL of flight segments with safety risks; return to step 2-2-2; Step 2-2-4, let the waypoint index k = k + 1, pointing to the next waypoint, if k ≤ p, return to step 2-2-1; if k> p, then flight f i The identification of flight segments with potential operational risks is completed, and the flight index i=i+1 is set, and the process returns to step 2-2-1 until i≥n, and the identification of potential risk segments of all flights is completed.

5. The method according to claim 4, characterized in that Step 3 includes: setting the nominal position of the aircraft to be consistent with the flight plan position during the flight mission, and the horizontal position positioning error of the aircraft is subject to the position parameter μ L , the scale parameter is λ L The double exponential distribution of the height position positioning error follows the position parameter μ H , the scale parameter is λ H Double exponential distribution; let aircraft f i The nominal position at time t is Heading Execute steps 3-1 to 3-2: Step 3-1, determine the actual altitude of the aircraft; Step 3-2, determine the actual horizontal position of the aircraft.

6. The method according to claim 5, characterized in that Step 3-1 includes: Step 3-1-1, use uniform distribution to generate a random number u between (0,1); Step 3-1-2, let the height positioning error value ΔH = μ H -λ H sgn(u-0.5)ln(1-2|u-0.5|); where sgn(x) is a step function, and Step 3-1-3, aircraft f i The actual height at time t for:

7. The method according to claim 6, characterized in that Step 3-2 includes: Step 3-2-1, use uniform distribution to generate a random number u between (0,1); Step 3-2-2, let the horizontal positioning error value ΔL = μ L -λ L sgn(u-0.5)ln(1-2|u-0.5|); Step 3-2-3, aircraft f i The actual horizontal coordinate position at time t is set to The actual ordinate position is Get aircraftf i The actual position at time t 8. The method according to claim 7, characterized in that Step 4 includes: Step 4-1, constructing an aircraft collision protection zone; Step 4-2, calculating the severity of the operation conflict; Step 4-1 includes: Step 4-1-1, suppose the aircraft f i r , There is a risk of collision, and f i r The actual position at time t is Heading The actual position at time t is Heading The longitudinal safety interval DV s , lateral safety interval DC s , height interval DH s Model a rectangular protection zone for length, width, and height; Step 4-1-2: During operation, if the protected areas overlap, it is not a safety risk between aircraft. i r and The actual position satisfies: Then aircraft f i r and There is a risk of collision, and the volume of the overlapping parts of the protection zone for: and The larger the value of , the greater the corresponding collision risk intensity; Step 4-2 includes: Step 4-2-1, define the aircraft conflict severity Fx as: in Indicates the size of the space occupied by the two aircraft protection zones, V i r , Aircraft f i 、f j The collision protection zone volume, and is the overlapping volume of the two aircraft, ρ0 represents the size of the protected area when there is no collision risk between the two flights, and η is the proportional gain coefficient; Step 4-2-2, determine the proportional gain coefficient η value: To define the unit of measurement for conflict severity as the number of fatal accidents, perform the following steps: Step 4-2-2-1 Set the aircraft f i r , A collision occurs at time t, that is, a fatal accident occurs, indicating that the severity of the conflict Fx = 1, and the aircraft f i r and The actual positions overlap. Step 4-2-2-2 Set Fx=1, Substituting into the calculation formula of aircraft conflict severity, we can get the proportional gain coefficient η=2·(V i r ) 3 ; On the basis of obtaining the proportional gain coefficient η value, according to the aircraft f i r , The volume of the overlap between the actual position and the protected area is used to obtain the actual severity of the aircraft conflict Fx using the formula in step 4-2-1.

9. The method according to claim 8, characterized in that Step 5 includes: Step 5-1, calculate the waypoint operation risk: The set of waypoints with collision risk RT = {rt1, rt2, ..., rt n }, let the element index be i, the initial value be 1, and let the unit time for quantifying the intensity of risk be T unit , that is, T unit is the time step length rt i The risk intensity of the aircraft with collision risk is calculated. The initial value of the collision risk per unit time of the waypoints in the time period T is set to R = 0, and the following steps are performed: Step 5-1-1, according to the index i value, take RT = {rt1, rt2, ..., rt n Airspace units at risk in Assume that the risk intensity quantification time is t, and the initial value is t = T rstart , execute step 5-1-2; Step 5-1-2, according to the flight plan, take the aircraft f i r The nominal position at time t is Heading Aircraft The nominal position at time t is course Execute step 3 to obtain the aircraft f i r , The actual location is Execute step 5-1-3; Step 5-1-3, after obtaining the aircraft f i r , Based on the actual position, execute step 4 to obtain the aircraft f i r , The collision risk intensity at time t is Fx; according to the definition of collision risk and integral, let the length of time period T be T len , then the collision risk per unit time of the waypoint in time period T is R = R + (Fx·T unit ) / T len , execute step 5-1-4; Step 5-1-4, let the risk intensity be quantified at time t = t + T unit , if t≤T rend , then continue to step 5-1-2; if t>T rend , the airspace unit rt where there is a collision risk i After the operation safety risk calculation in time period T is completed, let the element index i of set RT = i + 1. If i ≤ n, the next airspace unit rt with collision risk in set RT is i Calculate the risk value and execute step 5-1-1; if i>n, the calculation of the collision risk value of the waypoints within the time period T is completed; Step 5-2, calculate the flight segment operation risk: Assume that the initial value of the collision risk of the flight segment in the time period T is R′=0, and set the unit time T′ for quantifying the risk intensity of the flight segment unit , for the set of flight segments with collision risk RL = {rl1, rl2, ..., rl n } Calculate the risk intensity, set the initial value of the unit time operation risk of the flight segment in time period T to R′=0, and perform the following steps: Step 5-2-1, according to the index i value, take RL = {rl1, rl2, ..., rl n Airspace units at risk in Suppose there is a time variable t, and its initial value is t = T rstart , execute step 5-2-2; Step 5-2-2, according to the flight plan, take the aircraft f i r The nominal position at time t is Heading Aircraft The nominal position at time t is course Execute step 3 to obtain the aircraft f i r , The actual locations are Execute step 5-2-3; Step 5-2-3, after obtaining the aircraft f i r , Based on the actual position, execute step 4 to obtain the aircraft f i r , The degree of operation conflict at time t is Fx; according to the definition of operation risk value and integral, let the length of time period T be T len , then the unit time operation risk value of the waypoint in time period T is R′=R′+(Fx·T′ unit ) / T len , execute step 5-2-4; Step 5-2-4, let t = t + T' unit , if t≤T rend , then continue to step 5-2-2; if t>T rend , the airspace unit rl where there is a collision risk i After the operation safety risk calculation in time period T is completed, let the element index i of set RL = i + 1. If i ≤ n, the next airspace unit rl with collision risk in set RL is i Calculate the risk value and execute step 5-2-1; if i>n, the calculation of the risk value of the flight segment operation in period T is completed; Step 5-3, calculate airspace operation risk: Obtain the airspace operation risk value R within the period T v is the sum of the waypoint collision risk and the segment collision risk, that is, R v =R+R′.

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