Method for constructing and evaluating eVTOL takeoff and landing field network in urban environment

Abstract

The invention discloses a method for constructing and evaluating an eVTOL takeoff and landing field network in an urban environment. The method comprises the following steps: 1, evaluating the feasibility of an eVTOL takeoff and landing field construction technology, and screening out all takeoff and landing fields which do not meet the constraint conditions of the eVTOL takeoff and landing field construction technology; 2, evaluating the riding demand density of the eVTOL, and deleting the riding demand density if the riding demand density does not meet the standard limit; and 3, measuring the feasibility of the take-off and landing field from the perspective of transfer convenience of the take-off and landing field, and deleting any one of which the walking time exceeds the standard from the surrounding transportation hub. And 4, calculating the partial rank correlation coefficient, and deleting all the partial rank correlation coefficients which do not meet the standard of the partial rank correlation coefficient. And 5, constructing an eVTOL takeoff and landing field network. And 6, calculating the total degree value of the eVTOL take-off and landing field. And according to the total degree value of the takeoff and landing fields, evaluating the takeoff and landing fields which play a key role in the whole eVTOL takeoff and landing field network. According to the invention, comprehensive processing of urban landforms and traffic conditions is realized, and the method can be used for measuring the feasibility of limiting the position of the take-off and landing field by various factors.

Description

Technical Field

[0001] The present invention relates to a method for constructing and evaluating an eVTOL takeoff and landing site network from the perspectives of technology and demand, and particularly to a method for constructing and evaluating an eVTOL takeoff and landing site network in an urban environment. Background Art

[0002] The concept of Urban Air Mobility (UAM) has received extensive attention from countries around the world since it was proposed. As a new type of transportation mode, UAM has advantages such as environmental protection, high speed, and low noise, and has a strong ability to relieve ground traffic pressure. In order to enable UAM to fully relieve ground traffic pressure, evaluating the location of takeoff and landing sites from both technical standards and passenger demands is a key link in UAM construction.

[0003] In an urban environment, the location of eVTOL (electric vertical takeoff and landing aircraft) takeoff and landing sites is restricted by various factors such as obstacles, airspace, infrastructure conditions, and passenger demands. Among them, obstacles and airspace directly affect the operation safety of eVTOL takeoff and landing sites; the surrounding infrastructure will affect the daily operation of takeoff and landing sites; passenger demands directly determine the service capacity and profitability level of the UAM system.

[0004] Existing evaluation standards and regulations mainly restrict the location of takeoff and landing sites from the perspectives of obstacles and airspace, ignoring infrastructure conditions. However, eVTOL necessarily needs to be charged, maintained, and repaired at the takeoff and landing site and consumes a large amount of electricity, which poses certain requirements for the capacity of the regional power grid. At the same time, existing standards do not consider passenger demands. Ignoring passenger demands will not be able to fully exert the service capacity of the system, and thus will not be able to generate income to support the daily operation of the system. Summary of the Invention

[0005] To make up for the deficiencies of existing evaluation standards, the present invention provides a method for constructing and evaluating an eVTOL takeoff and landing site network in an urban environment.

[0006] The technical solution adopted by the present invention is as follows: A method for constructing and evaluating an eVTOL takeoff and landing site network in an urban environment, the steps are as follows: I. Extracting geographical data of the pre-construction area of the takeoff and landing site.

[0007] II. Screening the pre-construction areas that meet the technical constraint conditions for takeoff and landing site construction.

[0008] III. Determining the passenger flow attraction factor of the pre-construction area.

[0009] IV. Calculating the riding demand Calculate the riding demand according to the traffic passenger flow, the number of business office population, the road congestion coefficient, the tourist flow of scenic spots, and the passenger flow attraction factor of the takeoff and landing site in the pre-construction area.

[0010] V. Riding Demand Density Assessment Solve the riding demand density based on the riding demand volume, and the riding demand density shall meet the riding demand density assessment criteria 。

[0011] VI. Analysis of the Transfer Convenience of the Takeoff and Landing Sites Introduce the walking time from the pre-construction area of the takeoff and landing site to the surrounding traffic, and the walking time shall not exceed the maximum acceptable walking time surveyed

[0012] VII. Construction of the Takeoff and Landing Site Network Calculate the simple correlation coefficient and the partial rank correlation coefficient between any two pre-construction areas; at the pre-construction areas where the partial rank correlation coefficient is greater than or equal to the correlation coefficient test criteria, set up takeoff and landing sites and construct the takeoff and landing site network

[0013] VIII. Evaluation of the Traffic Characteristics of the Takeoff and Landing Site Network Calculate the total degree value of each takeoff and landing site according to the takeoff and landing site network; the greater the total degree value of a takeoff and landing site, the greater its impact on the overall eVTOL takeoff and landing site network

[0014] In step 2, the technical constraints for the construction of the takeoff and landing site include: the terrain constraint of the takeoff and landing site, the airspace restriction range of the takeoff and landing site, the noise constraint of the takeoff and landing site, the power grid capacity constraint of the takeoff and landing site, and the signal strength constraint of the communication, navigation and surveillance system of the takeoff and landing site

[0015] The terrain constraint of the takeoff and landing site in the technical constraints for the construction of the takeoff and landing site is based on the takeoff and landing site construction standards issued by EASA and FAA, and the available area within the pre-construction area of the takeoff and landing site As i shall be set to at least L × L , L being the side length of the apron of the takeoff and landing site

[0016] Meanwhile, the height of the obstacles around the pre-construction area of the takeoff and landing site Oh i shall not exceed the total height of the apron of the takeoff and landing site H + H 1 , H being the height of the eVTOL vertical takeoff H 1 being the height for the eVTOL to exceed the obstacles within 100 m during the climb phase after vertical takeoff; the expressions are respectively As i ≥ L × L (1); Oh i ≤ H +H 1 (2).

[0017] The restricted airspace of the takeoff and landing field in the technical constraints for the construction of the takeoff and landing field does not overlap with the publicly released restricted airspace and no-go zone locations.

[0018] The noise constraint of the takeoff and landing field in the technical constraints for the construction of the takeoff and landing field is: the actual perceived noise level in the pre-construction area of the takeoff and landing field L 1 is not higher than the noise emission standard St noise , and the expression is: L 1 ≤ St noise (3).

[0019] The power grid capacity constraint of the takeoff and landing field in the technical constraints for the construction of the takeoff and landing field is: the available power grid capacity in the pre-construction area of the takeoff and landing field i available power grid capacity P i ag is greater than or equal to the charging power of a single eVTOL P 1 , and the expression is: P i ag ≥ P 1 (4); In the formula, the available power grid capacity in the pre-construction area of the takeoff and landing field i available power grid capacity P i ag The calculation formula is: P i ag = (1 - K ) × P L - P u (5); P L = P G - P u (6); In the formula, P L is the remaining power grid capacity; P G is the total power grid capacity; P u is the used power grid capacity;K is the percentage of the reserved grid capacity in the remaining grid capacity.

[0020] The signal strength constraint of the landing and take-off field communication, navigation and surveillance system in the technical constraints for the construction of the landing and take-off field is: obtain the daily received signal strength at the pre-construction area of the landing and take-off field Sr i minimum value, and compare it with the received signal strength standard of the landing and take-off field communication, navigation and surveillance system St signal The daily received signal strength at the pre-construction area of the landing and take-off field is greater than or equal to the received signal strength standard of the landing and take-off field communication, navigation and surveillance system St signal , and the expression is: Sr i ≥ St signal (7).

[0021] In step four, the commuting demand of the business office area in the pre-construction area that meets the technical constraints for the construction of the landing and take-off field is based on the passenger flow attraction factor of the pre-construction area Atr i and the number of business office population W i , calculate the commuting demand of the business office area A i , and then obtain the total commuting demand of the business office area Cd i : A i = W i × Atr i (8); Cd i =∑ A i (9).

[0022] The scenic spot tourism demand in the pre-construction area that meets the technical constraints for the construction of the landing and take-off field is based on the passenger flow attraction factor of the pre-construction area Atr i and the number of people in the scenic spot VP i calculate the scenic spot tourism demand B i , and then obtain the total tourism demand of the scenic spot Td i : B i = VP i ×Atr i (10); Td i = ∑ B i (11).

[0023] The travel demand of traffic within the pre - construction area that meets the technical constraints of the take - off and landing field construction is calculated based on the passenger flow attraction factor of the pre - construction area Atr i and the traffic volume F i , and the travel demand of traffic C i is calculated, and then the total travel demand of traffic T i is obtained: C i = F i × Atr i (12); T i = ∑ C i (13).

[0024] The road traffic congestion condition within the pre - construction area that meets the technical constraints of the take - off and landing field construction is obtained by using the congestion coefficient of each road section to calculate the average congestion coefficient Aver i , and the expression is as follows: (14); In the formula, Cg i is the road congestion coefficient of road section i ; n is the total number of road sections within the pre - construction area; then the average congestion coefficient Aver i is multiplied by the unimpeded travel time Ub i obtained from the map software to obtain the road traffic congestion condition within the pre - construction area At i : At i = Aver i × Ub i (15).

[0025] The beneficial effects produced by the present invention are: 1. The present invention calculates the available grid capacity by obtaining grid-related data, thereby ensuring the daily operation of the eVTOL takeoff and landing site; it makes up for the deficiencies in infrastructure considerations in the field of siting evaluation criteria for takeoff and landing sites.

[0026] 2. The present invention takes into account the constraints of transfer convenience, which helps to enhance multimodal transportation and improve the convenience of passenger travel.

[0027] 3. The present invention systematically analyzes the eVTOL passenger demand in the pre-construction area of the takeoff and landing site, enabling the takeoff and landing site to fully serve the passenger demand and relieve the ground traffic pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a flowchart of a method for constructing and evaluating an eVTOL takeoff and landing site network in an urban environment according to the present invention; Figure 2 is a network diagram of an eVTOL takeoff and landing site constructed according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Refer to Figure 1 : Step 1: Extraction of geographical data of the pre-construction area of the takeoff and landing site Extract the geographical data of the pre-construction area of the takeoff and landing site from various public data and geographical information service platforms; the geographical data of the pre-construction area of the takeoff and landing site includes: the location of buildings in the pre-construction area of the takeoff and landing site, the height of buildings in the pre-construction area of the takeoff and landing site, the scope of airspace restricted areas in the pre-construction area of the takeoff and landing site, the infrastructure conditions in the pre-construction area of the takeoff and landing site, the traffic passenger flow in the pre-construction area of the takeoff and landing site, the number of business office population in the pre-construction area of the takeoff and landing site, the road congestion coefficient in the pre-construction area of the takeoff and landing site, and the tourist flow in scenic spots in the pre-construction area of the takeoff and landing site.

[0031] In this embodiment, the traffic passenger flow, the number of business office population, the tourist flow in scenic spots, and the road congestion coefficient in the pre-construction area of the takeoff and landing site at 21 locations are extracted, as shown in Table 1: Table 1 Numerical table of various original data .

[0032] Step 2: Screen the pre-construction areas that meet the technical constraints for the construction of the takeoff and landing site According to the extracted geographical data of the pre-construction area of the takeoff and landing site, analyze the technical feasibility of the eVTOL takeoff and landing site construction, and screen the pre-construction areas of the takeoff and landing site that meet the technical constraints of the takeoff and landing site construction; the technical constraints of the takeoff and landing site construction include: the terrain constraint of the takeoff and landing site, the restricted airspace range of the takeoff and landing site, the noise constraint of the takeoff and landing site, the grid capacity constraint of the takeoff and landing site, and the signal strength constraint of the communication, navigation and surveillance system of the takeoff and landing site.

[0033] The terrain constraint of the takeoff and landing site in the technical constraints of the takeoff and landing site construction is based on the takeoff and landing site construction standards issued by EASA and FAA, and the available area within the pre-construction area of the takeoff and landing site As i should be set to at least L × L , L where Oh i is the side length of the apron of the takeoff and landing site; at the same time, the height of the obstacles around the pre-construction area of the takeoff and landing site H + H 1 , H is the vertical takeoff height of the eVTOL, H 1 is the height of the eVTOL exceeding the obstacles within 100 m during the climbing stage after vertical takeoff; the expressions are respectively: As i ≥ L × L (1); Oh i ≤ H + H 1 (2).

[0034] For example: In this embodiment, one of the side lengths of the takeoff and landing site is screened L to be 30 m; the vertical takeoff and landing height H is 30.5 m; the height of the eVTOL exceeding the obstacles within 100 m during the climbing stage after vertical takeoff H 1 is 12.5 m. Therefore, the available area of the pre-construction area of the takeoff and landing site within the pre-construction area of the takeoff and landing site As i should be at least 900 m 2 , and the height of the obstacles around the pre-construction area of the takeoff and landing site Oh i should not exceed 43 m of the apron of the takeoff and landing site.

[0035] According to formula (1) and formula (2), those that do not meet the available area of the pre-construction area of the takeoff and landing site As iand the heights of obstacles around the pre-construction area of the takeoff and landing site Oh i Exclusion of the required area.

[0036] The airspace restriction range in the technical constraints for the construction of the takeoff and landing site does not overlap with the positions of the publicly released airspace restriction areas and restricted areas. In this embodiment, the positions of the airspace restriction areas and restricted areas released by the Civil Aviation Administration of China are obtained, and the corresponding areas are excluded.

[0037] The noise constraint for the construction of the takeoff and landing site in the technical constraints is: the actual perceived noise level in the pre-construction area of the takeoff and landing site L 1 not higher than the noise emission standard St noise , and the expression is: L 1 ≤ St noise (3).

[0038] In this embodiment, the Joby S4 type electric vertical takeoff and landing aircraft is selected to conduct the noise constraint assessment of the takeoff and landing site. The wingspan of the electric vertical takeoff and landing aircraft d 2 = 11.6 m, the noise generated by the electric vertical takeoff and landing aircraft is L max = 54 dB, the distance between the noise-sensitive facility and the pre-construction area of the takeoff and landing site is d 1 。 Substitute d 1 、L max 、d 2 into the formula L max - 20log 10 ( d 2 / d 1 ), and solve for the noise level at the noise-sensitive facility. Compare the obtained noise level at the noise-sensitive facility with the ambient noise L en to obtain the actual perceived noise level L 1 : L 1 = max{ L max - 20log 10 ( d 2 / d1 ) L en}. According to formula (3), if the actual perceived noise level L 1 is higher than the noise emission standard St noise , then the landing and takeoff site should be abandoned.

[0039] The landing and takeoff site grid capacity constraint in the landing and takeoff site construction technical constraints is: the available grid capacity of the landing and takeoff site pre-construction area i available grid capacity P i ag should be greater than or equal to the charging power of a single eVTOL P 1 , and the expression is: P i ag ≥ P 1 (4); The available grid capacity of the landing and takeoff site pre-construction area i of P i ag is calculated as: P i ag = (1 - K ) × P L - P u (5); P L = P G - P u (6); In the formula, P L is the remaining grid capacity; P G is the total grid capacity; P u is the used grid capacity; K is the percentage of the reserved grid capacity in the remaining grid capacity.

[0040] To ensure the safe load of the power grid, 5% of the remaining grid capacity should be reserved P L , then from formula (5) we get: P i ag = 0.95 P L -P u 。

[0041] The remaining available grid capacity in the pre-construction area of the takeoff and landing site should supply at least 1 eVTOL for charging. Given the charging power of a single eVTOL P 1 is 300 kW, then from formula (4), we get: P i ag ≥300.

[0042] The signal strength constraint of the communication, navigation, and surveillance system at the takeoff and landing site in the technical constraints for the construction of the takeoff and landing site is as follows: Obtain the minimum daily received signal strength at the pre-construction area of the takeoff and landing site Sr i and compare it with the received signal strength standard of the communication, navigation, and surveillance system at the takeoff and landing site St signal The daily received signal strength at the pre-construction area of the takeoff and landing site is greater than or equal to the received signal strength standard of the communication, navigation, and surveillance system at the takeoff and landing site St signal , and the expression is: Sr i ≥ St signal (7).

[0043] In this embodiment, the minimum daily received signal strength at the pre-construction area of the takeoff and landing site Sr i is compared with the received signal strength standard. According to the existing standard, the known received signal strength standard of the communication, navigation, and surveillance system is St signal = 33 dBm. If the minimum daily received signal strength St signal is lower than the received signal strength standard Sr i , that is St signal , is less than 33 dBm, then according to formula (7), this takeoff and landing site should be excluded. Sr i is less than 33 dBm, then according to formula (7), this takeoff and landing site should be excluded.

[0044] Step 3. Determine the passenger flow attraction factor in the pre-construction area Based on the distance from the high-passenger-flow area to the pre-construction area that meets the technical constraints for the construction of the takeoff and landing site Ed kc , determine the passenger flow attraction factor of the pre-construction area in the high-passenger-flow area Atr i : (16).

[0045] Step 4: Calculation of Riding Demand Calculate the riding demand based on the traffic passenger flow, the number of business office workers, the road congestion situation, the tourist flow in scenic areas, and the passenger flow attraction factor within the pre-construction area that meets the technical constraints of the takeoff and landing field construction; the riding demand includes: the total commuting demand of business office areas within the pre-construction area that meets the technical constraints of the takeoff and landing field construction, the total tourism demand of scenic areas, the total travel demand of transportation, and the road traffic congestion situation.

[0046] The total commuting demand of business office areas within the pre-construction area that meets the technical constraints of the takeoff and landing field construction, based on the passenger flow attraction factor Atr i and the number of business office workers W i , calculate the commuting demand of business office areas A i , and then obtain the total commuting demand of business office areas Cd i : A i = W i × Atr i (8); Cd i =∑ A i (9).

[0047] The total tourism demand of scenic areas within the pre-construction area that meets the technical constraints of the takeoff and landing field construction, based on the passenger flow attraction factor Atr i and the tourist flow in scenic areas VP i calculate the tourism demand of scenic areas B i , and then obtain the total tourism demand of scenic areas Td i : B i = VP i × Atr i (10); Td i =∑ B i (11).

[0048] The total travel demand of the traffic within the pre-construction area that meets the technical constraints of the landing and take-off site construction is based on the passenger flow attraction factor of the pre-construction area Atr i and the traffic passenger volume F i , calculate the travel demand of the traffic C i , and then obtain the total travel demand of the traffic T i : C i = F i × Atr i (12); T i =∑ C i (13).

[0049] The road traffic congestion condition within the pre-construction area of the landing and take-off site that meets the technical constraints of the landing and take-off site construction is to calculate the average congestion coefficient using the congestion coefficient of each road section Aver i , and the expression is as follows: (14); In the formula, Cg i is the road congestion coefficient of road section i ; n is the total number of road sections within the pre-construction area; then multiply the average congestion coefficient Aver i by the unimpeded travel time Ub i obtained from the map software to obtain the road traffic congestion condition within the pre-construction area At i : At i = Aver i × Ub i (15).

[0050] The various demand quantities of eVTOL rides obtained after calculating the original data in Table 1 are shown in Table 2: Table 2 Various Demand Quantities of eVTOL Rides .

[0051] Step Five. Ride Demand Density Assessment According to the ride demand, solve the ride demand density to evaluate whether the pre-construction area that meets the technical constraints of the takeoff and landing field construction meets the demand density constraint; use the analytic hierarchy process to obtain the weight of each ride demand. γ ; Furthermore, establish the ride demand density D i Calculation formula: (17); In the formula, Td i is the total tourism demand of the scenic area; T i is the total travel demand of transportation; Cd i is the total commuting demand of the business office area; At i is the road traffic congestion condition; γ Td is the weight of the total tourism demand of the scenic area in the ride demand; γ T is the weight of the total travel demand of transportation in the ride demand; γ Cd is the weight of the total commuting demand of the business office area in the ride demand; γ At is the weight of the road traffic congestion condition in the ride demand; S is the area of the pre-construction area that meets the technical constraints of the takeoff and landing field construction.

[0052] eVTOL ride demand density D i should meet the ride demand density evaluation standard St demand , and the expression is: D i ≥ St demand (18).

[0053] Given the ride demand density evaluation standard St demand = 1000, in this embodiment, according to formula (18), the ride demand density D i is greater than or equal to 1000.

[0054] The ride demand densities of the 21 pre-construction areas of eVTOL takeoff and landing fields in this embodiment are shown in Table 3.

[0055] Table 3 Ride Demand Densities of the Pre-construction Areas of the Takeoff and Landing Fields .

[0056] Step 6. Analysis of the convenience of transfer at the takeoff and landing site The pre-construction area that meets the technical constraints for the construction of the takeoff and landing site should satisfy the convenience of transfer at the takeoff and landing site; the walking time from the pre-construction area of the takeoff and landing site to the surrounding traffic is introduced as Wt i , and the walking time does not exceed the maximum acceptable walking time obtained from the survey St time , and the expression is: Wt i ≤ St time (19).

[0057] The walking time from the pre-construction area of the takeoff and landing site in this embodiment to the surrounding traffic Wt i does not exceed the maximum acceptable walking time obtained from the survey St time is 10 min, and the walking time from the pre-construction area of the takeoff and landing site to the surrounding traffic Wti is shown in Table 4. The pre-construction areas of the takeoff and landing site except P1, P4, P8, P18, and P19 all satisfy formula (19).

[0058] Table 4 Walking time from the pre-construction area of each eVTOL takeoff and landing site to other traffic .

[0059] Step 7. Construct a takeoff and landing site network Evaluate the risk values of all pre-construction areas that meet the convenience of transfer at the takeoff and landing site, the technical constraints for the construction of the takeoff and landing site, and the density constraints of eVTOL passenger demand X , and for the pre-construction area i and the pre-construction area j bring the risk values X i and X j into the following formula to calculate the simple correlation coefficient between any two pre-construction areas of the takeoff and landing site r ij : (20); In the formula, Cov ( X i , X j ) is the covariance between the pre-construction area i and the pre-construction area j ; are respectively the risk values of the pre-construction area i and the pre-construction area j X ​i The standard deviation of X j ; the pre-construction area i The partial rank correlation coefficient between the pre-construction area j and the pre-construction area r ij,h is: (21); In the formula, r ij,h represents the partial rank correlation coefficient of the pre-construction area i and the pre-construction area j after controlling the pre-construction area h ; r ij represents the simple correlation coefficient between the pre-construction area i and the pre-construction area j ; r ih and r jh respectively represent the simple correlation coefficients between the pre-construction area i and the pre-construction area h , the pre-construction area j and the pre-construction area h .

[0060] At the pre-construction area of the takeoff and landing site where the partial rank correlation coefficient r ij,h is greater than or equal to the Pearson correlation coefficient test standard St p , a takeoff and landing site is set up and a takeoff and landing site network is constructed. The expression is: r ij,h ≥ St p (22).

[0061] Given that the Pearson correlation coefficient test standard St p is 0.05, the partial rank correlation coefficients r ij,h of all the pre-construction areas of the takeoff and landing sites that make up the takeoff and landing site network in this embodiment all satisfy formula (22).

[0062] In this embodiment, the partial rank correlation coefficients of all the pre-construction areas are compared with the Pearson correlation coefficient test standard. Finally, eVTOL takeoff and landing sites are respectively set up at the pre-construction areas P2, P5, P9, P13, P14, and P17. The longitude and latitude coordinates of the eVTOL takeoff and landing sites are shown in Table 5. The locations of each eVTOL takeoff and landing site and the formed takeoff and landing site network are shown in Figure 2 .

[0063] Table 5 Latitude and Longitude Coordinates of eVTOL Landing Sites

[0064] Step Eight: Evaluate the Network Traffic Characteristics of Landing Sites Calculate the total degree value of each eVTOL landing site based on the landing site network deg ; The total degree value refers to the total number of edges connected to the landing site, where the number of edges pointing to the eVTOL landing site is the in-degree indeg , and the number of edges emitted from the eVTOL landing site is the out-degree outdeg , and the total degree value is equal to the in-degree indeg and the out-degree outdeg The sum is as follows: deg = indeg + outdeg (23).

[0065] Based on the total degree value of each eVTOL landing site, the landing site with a larger total degree value has a greater impact on the overall eVTOL landing site network

[0066] The total degree values of each eVTOL landing site in this embodiment are shown in Table 6

[0067] Table 6 Total Degree Values of eVTOL Landing Sites .

[0068] Based on the total degree value of each eVTOL landing site, evaluate the eVTOL landing sites that play a key role in the overall eVTOL landing site network. The larger the total degree value, the greater the impact of the landing site on the overall eVTOL landing site network. As can be seen from Table 6, the eVTOL landing site P13 plays the most crucial role in the overall landing site network; the role of the eVTOL landing site P17 in the overall landing site network is not obvious

[0069] In the process of constructing and evaluating the takeoff and landing site network, takeoff and landing sites that meet the technical constraints for takeoff and landing site construction and the standard of passenger demand density should be selected first. 1. Evaluate the technical feasibility of takeoff and landing site construction, and all takeoff and landing sites that do not meet the technical constraints for takeoff and landing site construction should be screened out. 2. The passenger demand density should be evaluated from the perspective of passenger demand. If the calculated passenger demand density does not meet the limit of the passenger demand density standard, the takeoff and landing site should be deleted. 3. Measure the feasibility of takeoff and landing sites from the perspective of the convenience of transfer at takeoff and landing sites. Any takeoff and landing site with a walking time to the surrounding transportation hub exceeding the maximum acceptable walking time should be deleted. 4. Calculate the partial rank correlation coefficient of takeoff and landing sites that meet the technical constraints for takeoff and landing site construction and the standard of passenger demand quantity. All takeoff and landing sites that do not meet the partial rank correlation coefficient standard should be deleted. 5. Use takeoff and landing sites that simultaneously meet the technical constraint standard for takeoff and landing site construction, the passenger demand density standard, and the partial rank correlation coefficient standard to construct the takeoff and landing site network. 6. Calculate the total degree value of each takeoff and landing site in the takeoff and landing site network according to the constructed takeoff and landing site network. Evaluate the takeoff and landing sites that play a key role in the overall takeoff and landing site network based on the total degree value of each takeoff and landing site. The greater the total degree value of a takeoff and landing site, the greater its impact on the overall takeoff and landing site network.

Claims

1. A method for constructing and evaluating an eVTOL take-off and landing site network in an urban environment, characterized in that: Here are the steps:

1. Extraction of geographic data of the pre-construction area of ​​the take-off and landing field; 2. Select the pre-construction area that meets the technical constraints of the take-off and landing field construction; 3. Determine the passenger flow attraction factors in the pre-construction area; 4. Calculation of Ride Demand Calculate the demand for rides based on the passenger flow in the pre-construction area, the number of business office population, the road congestion coefficient, the passenger flow in the scenic area, and the passenger flow attraction factor in the pre-construction area; 5. Ride Demand Density Assessment Solve the riding demand density based on the riding demand, and the riding demand density should meet the riding demand density assessment standard; VI. Analysis of Transfer Convenience at Take-off and Landing Airports Introduce walking time from the pre-construction area of ​​the landing field to surrounding traffic, and the walking time does not exceed the maximum acceptable walking time surveyed; 7. Build a take-off and landing field network Calculate the simple correlation coefficient and partial rank correlation coefficient of any two pre-construction areas; establish a take-off and landing field and construct a take-off and landing field network in the pre-construction area where the partial rank correlation coefficient is greater than or equal to the correlation coefficient test standard; 8. Evaluating the traffic characteristics of the take-off and landing network The total degree value of each landing field is calculated based on the landing field network; the landing field with a larger total degree value has a greater impact on the overall eVTOL landing field network.

2. The method for constructing and evaluating an eVTOL take-off and landing site network in an urban environment according to claim 1, characterized in that: In step 2, the technical constraints for the construction of the take-off and landing field include: take-off and landing field terrain constraints, take-off and landing field airspace restrictions, take-off and landing field noise constraints, take-off and landing field power grid capacity constraints, and take-off and landing field communication, navigation and monitoring system signal strength constraints; The landing field terrain constraint in the landing field construction technical constraint condition is based on the landing field construction standards issued by EASA and FAA, and the available area in the landing field pre-construction area is As i At least L × L , L is the side length of the take-off and landing field apron; At the same time, the obstacle height around the pre-construction area of ​​the take-off and landing field Oh i Cannot exceed the total height of the take-off and landing apron H + H 1 , H is the vertical take-off height of the eVTOL, H 1 It is the height of the obstacle within 100m that the eVTOL surpasses during the climbing phase after vertical takeoff; the expressions are: As i ≥ L × L （1）； Oh i ≤ H + H 1 （2）； The restricted airspace range of the take-off and landing field in the technical constraints of the take-off and landing field construction does not overlap with the publicly released airspace restricted area and restricted area location; The landing field noise constraint in the landing field construction technical constraint condition is: the actual perceived noise level in the landing field pre-construction area L 1 No higher than the noise emission standard St noise , the expression is: L 1 ≤ St noise （3）； The grid capacity constraint of the take-off and landing field in the technical constraint conditions of the take-off and landing field construction is: i Available grid capacity P i ag Greater than or equal to the charging power of a single eVTOL P 1 , the expression is: P i ag ≥ P 1 （4）； In the formula, the take-off and landing field pre-construction area i Available grid capacity P i ag The calculation formula is: P i ag = (1- K ) × P L - P u （5）； P L = P G - P u （6）； In the formula, P L is the remaining grid capacity; P G is the total capacity of the power grid; P u is the used grid capacity; K The percentage of reserved grid capacity to remaining grid capacity; The signal strength constraint of the communication, navigation and monitoring system of the take-off and landing field in the technical constraint conditions of the take-off and landing field construction is: obtain the daily received signal strength at the pre-construction area of ​​the take-off and landing field Sr i minimum value, and the receiving signal strength standard of the communication, navigation and monitoring system of the take-off and landing field St signal By comparison, the daily received signal strength at the take-off and landing field pre-construction area is greater than or equal to the received signal strength standard of the communication, navigation and monitoring system of the take-off and landing field. St signal , the expression is: Sr i ≥ St signal （7）。 3. The method for constructing and evaluating an eVTOL take-off and landing site network in an urban environment according to claim 1, characterized in that: The commuting demand of the business office area in the pre-construction area of ​​the take-off and landing field that meets the technical constraints of the take-off and landing field construction is based on the passenger flow attraction factor of the pre-construction area. Atr i Number of business office population W i , calculate the commuting demand of business office areas A i , and then find the total commuting demand of the business office area in the pre-construction area that meets the technical constraints of the take-off and landing field construction Cd i : A i = W i × Atr i （8）； Cd i =∑ A i （9）； The tourism demand for scenic spots in the pre-construction area of ​​the take-off and landing field that meets the technical constraints of the take-off and landing field construction is calculated based on the passenger flow attraction factor of the pre-construction area. Atr i The flow of tourists to scenic spots VP i Calculate the tourism demand of scenic spots B i , and then obtain the total tourism demand of scenic spots in the pre-construction area that meets the technical constraints of the take-off and landing field construction Td i : B i = VP i × Atr i （10）； Td i =∑ B i （11）； The travel demand in the pre-construction area of ​​the take-off and landing field that meets the technical constraints of the take-off and landing field construction is calculated based on the passenger flow attraction factor of the take-off and landing field. Atr i Traffic flow F i , calculate the travel demand of traffic C i , and then obtain the total travel demand of the traffic in the pre-construction area that meets the technical constraints of the take-off and landing field construction T i : C i = F i × Atr i （12）； T i =∑ C i （13）； The traffic congestion condition of roads in the pre-construction area that meets the technical constraints of the take-off and landing field construction, and the average congestion coefficient is calculated using the congestion coefficient of each road section Aver i , the expression is as follows: （14）； In the formula, C i For road section i The road congestion coefficient; n is the total number of road sections in the pre-construction area; Then the average congestion coefficient Aver i Compare with the smooth travel time obtained from the map software Ub i Multiply them to get the road traffic congestion situation in the pre-construction area. At i : At i = Ave i × Ub i （15）。

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