A method for monitoring and alerting fuel levels in civil aircraft based on ACARS and ADS-B

Abstract

This invention relates to the field of aviation technology, specifically to a fuel level monitoring and alarm method for civil aircraft based on ACARS and ADS-B. This method extracts the master flight path from historical ADS-B data, obtains real-time remaining fuel and historical fuel consumption for each flight phase using ACARS data, and calculates the estimated flight time by matching the current flight position with the master flight path. This allows for accurate estimation of remaining fuel at the destination airport, triggering an alarm when the remaining fuel falls below a set threshold. This invention eliminates reliance on airline computer plans and air traffic control flight plans, improves fuel level prediction accuracy by fusing historical and real-time data, reduces false alarms and missed alarms, and supports airports in developing ground support plans in advance. It is applicable to fuel level safety monitoring during civil aircraft flight.

Description

Technical Field

[0001] This invention relates to the field of aviation technology, specifically to a method for monitoring and alerting fuel levels in civil aircraft based on ACARS and ADS-B. Background Technology

[0002] According to the "AC-121-FS-2019-133 Implementation Guidelines for Air Carrier Operation Monitoring" issued by the Civil Aviation Administration of China, it is clearly stipulated that an alert should be issued regarding the remaining fuel level on board a flight.

[0003] Monitoring an aircraft's remaining fuel primarily relies on ACARS information, which is transmitted wirelessly during flight. Users can set up ground-based base stations to receive and analyze this information. Ideally, a single ACARS base station has a range of up to 240 nautical miles. For aircraft position monitoring, ADS-B information is mainly used. Aircraft transmit ADS-B information wirelessly during flight. Users can set up ground-based base stations to receive and analyze this information. Ideally, a single ADS-B base station has a range of up to 200 nautical miles.

[0004] In practical use, existing technologies generally rely on pre-prepared computer flight plans by airlines. These plans specify core parameters such as preset fuel consumption rates, planned flight routes, and cruising altitudes. These parameters are determined during the planning stage before flight takeoff and do not fully consider the dynamic changes during actual flight.

[0005] However, in actual flight, due to multiple factors, the actual flight status deviates significantly from the preset plan. On the one hand, air traffic control instructions (such as temporary route diversions and holding in the air during takeoff and landing) and fluctuations in weather conditions (such as strong crosswinds and altitude adjustments caused by turbulence) can cause the actual flight path to deviate from the planned route, and the flight altitude also needs to be dynamically adapted to ensure safety. On the other hand, in key stages such as the altitude increase during the climb phase, the timing of the transitional altitude layer switching, and the altitude decrease during the descent phase and the adjustment of the approach procedure, the actual stage characteristics differ more significantly from the preset stage duration and altitude change patterns. This comprehensive deviation between the actual flight status and the preset plan directly results in the static fuel consumption rate in the plan failing to match the actual fuel consumption patterns during dynamic flight, ultimately causing a significant discrepancy between the planned estimated fuel consumption and the total fuel consumption during actual flight, thus affecting the accuracy of the remaining fuel estimate. Summary of the Invention

[0006] The purpose of this invention is to provide a fuel level monitoring and alarm method for civil aircraft based on ACARS and ADS-B, in order to solve the problem that the actual flight status deviates significantly from the preset plan due to multiple factors, which in turn affects the accuracy of remaining fuel level estimation.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for monitoring and alarming fuel levels in civil aircraft based on ACARS and ADS-B, comprising the following steps:

[0008] S1. Extracting the main operating trajectory based on ADS-B historical data: For a specified pair of take-off and landing airports, the historical flight trajectories of multiple aircraft are obtained from the ADS-B database. An algorithm based on spatial density clustering plus time series traversal is used to perform cluster analysis on the trajectory points of each trajectory, identify the main operating trajectory of the aircraft for the pair of take-off and landing airports, and represent the main operating trajectory with several key points arranged in chronological order.

[0009] S2. Obtain current remaining fuel and location: Obtain the aircraft's fuel information through the ACARS receiving base station and the aircraft's location information through the ADS-B receiving base station. Associate the fuel information and location information according to the timestamp and ICAO address code, and integrate them into a real-time track with timestamp.

[0010] S3. Extracting fuel consumption for each stage based on ACARS historical data: Extract historical flight track data of the target aircraft from the ADS-B database and onboard fuel data of the target aircraft corresponding to the historical flight track from the ACARS database. Form an associated dataset using time and ICAO address code as matching fields. In the associated dataset, analyze the flight track altitude data using a sliding time window based on the change in altitude over time to divide the flight into flight stages such as climb, cruise, and descent. Calculate the change in onboard fuel in each flight stage and combine it with the corresponding time length to obtain the fuel consumption rate of the target aircraft in each flight stage.

[0011] S4. Calculate the expected flight path and remaining time to reach the landing airport: Based on the current geographical coordinates of the target aircraft obtained in step S2, calculate the spatial distance between the coordinates and each key point in the main operating path extracted in step S1, select the key point with the smallest distance as the matching key point, extract all key points after the matching key point to form the remaining path set, and based on the altitude and time information in the remaining path set, identify each flight stage included in the remaining path according to the flight stage determination rules in step S3, and calculate the remaining flight time corresponding to each flight stage;

[0012] S5. Calculate the remaining fuel amount upon arrival at the destination airport based on fuel consumption: Multiply the remaining time of each flight phase obtained in step S4 by the corresponding fuel consumption rate calculated in step S3 to obtain the estimated fuel consumption; Subtract the estimated fuel consumption from the aircraft's fuel information extracted in step S2 to obtain the aircraft's estimated remaining fuel amount upon arrival at the destination airport.

[0013] S6. Fuel Remaining Alarm: When the remaining fuel at the destination airport calculated in step S5 is less than a preset alarm threshold, a fuel remaining alarm message is output.

[0014] Preferably, the specific steps for extracting the main flight track in step S1 are as follows:

[0015] S1.1 Extract all flight trajectory information between the specified take-off and landing airport pairs from the ADS-B database. Each flight trajectory consists of multiple trajectory points. Each trajectory point contains the recording time, aircraft ICAO address code, longitude, latitude, and altitude information, and marks all trajectory points as unvisited.

[0016] S1.2 Determine if there is a track containing unvisited trajectory points. If not, proceed to step S1.7; if so, select a track containing unvisited trajectory points and proceed to step S1.3.

[0017] S1.3. Filter out the earliest track point P in the selected track and the track point P whose status is unvisited, and update the status of track point P to visited; if all track points of the track have been visited, return to step S1.2.

[0018] S1.4. With trajectory point P as the center, construct a cubic space interval with length, width and height of (X,Y,Z), extract the trajectory points of all flight trajectories in the interval, form a trajectory point set Q, and count the number of elements in set Q as Np.

[0019] S1.5 Determine if Np is greater than the preset threshold G: If it is greater, mark trajectory point P as a key point and add trajectory point P to the key point set K, then proceed to step S1.6; if it is not greater, return to step S1.2.

[0020] S1.6. Filter out the trajectory point P1 in the trajectory point set Q that is unvisited, update the status of trajectory point P1 to visited, and use trajectory point P1 as the new trajectory point P. Repeat step S1.4. If there are no unvisited trajectory points in set Q, return to step S1.3.

[0021] S1.7 Output the set of key points K. The trajectory corresponding to the set of key points K is the main flight path of the aircraft. The clustering process ends.

[0022] Preferably, the specific steps for obtaining the current remaining oil quantity and location in step S2 are as follows:

[0023] S2.1 Receive the original ACARS message transmitted by the aircraft, decode the original ACARS message according to the ARINC 724B international standard, and extract the current remaining fuel and destination airport code from the decoded information.

[0024] S2.2 Receive the original ADS-B message transmitted by the aircraft, decode the original ADS-B message according to the RTCA DO-260B international standard, and extract the current longitude, current latitude, current altitude and aircraft ICAO address code from the decoded information;

[0025] S2.3 Using the timestamp and aircraft ICAO address code as associated fields, the current remaining fuel and destination airport code extracted in step S2.1 are associated and integrated with the current longitude, current latitude and current altitude extracted in step S2.2 to form a real-time track; the real-time track contains at least 7 types of information, including time, longitude, latitude, altitude, ICAO address code, remaining fuel, and destination airport code.

[0026] Preferably, the specific steps for extracting fuel consumption at each stage in step S3 are as follows:

[0027] S3.1 Extract all historical flight track data of the target aircraft from the ADS-B database. The historical flight track data includes the time, ICAO address code, and altitude information of each flight track. Extract the time and remaining fuel data of the target aircraft corresponding to the historical flight track from the ACARS database. Use the time and ICAO address code as matching fields to align the remaining fuel data and the matching fields in time to form a related dataset.

[0028] S3.2 Determine whether there are any uncalculated fuel consumption rates in the associated dataset. If not, proceed to step S3.8; if so, select an uncalculated fuel consumption rate and proceed to step S3.3.

[0029] S3.3 Analyze the altitude data of the selected track using a sliding time window: The duration of the sliding time window is T. If the cumulative climb altitude within any sliding time window is greater than H1, and the climb altitude per minute within the sliding time window is not negative, then it is determined that the aircraft is in a climb state during the continuous time period corresponding to the sliding time window, and step S3.7 is executed; if not, step S3.4 is executed.

[0030] S3.4 Analyze the altitude data within the same sliding time window: If the cumulative descent altitude within the sliding time window is greater than H2, and the descent altitude per minute within the sliding time window is not negative, then it is determined that the aircraft is in a descent state during the continuous time period corresponding to the sliding time window, and step S3.7 is executed; if not, step S3.5 is executed.

[0031] S3.5 Analyze the altitude data within the same sliding time window: If the average altitude of the aircraft within the sliding time window is greater than H3, it is determined that the aircraft is in cruise mode during the continuous time period corresponding to the sliding time window, and step S3.7 is executed; if not, step S3.6 is executed.

[0032] S3.6. If it is determined that the aircraft flight phase cannot be confirmed within the time period corresponding to the sliding time window, discard the fuel consumption data within the sliding time window and return to step S3.2.

[0033] S3.7. Based on the remaining fuel data on board the associated dataset in step S3.1, calculate the fuel consumption within the sliding time window, and combine it with the duration of the time period to obtain the fuel consumption rate of the aircraft in the current flight phase, and return to step S3.2.

[0034] S3.8 Summarize the fuel consumption rate data of the target aircraft in the three phases of climb, cruise and descent, and complete the extraction of fuel consumption for each phase.

[0035] Preferably, the specific steps in step S4 for calculating the expected flight path and remaining time to reach the landing airport are as follows:

[0036] S4.1 Obtain the current geographical coordinates (X,Y,Z) of the aircraft, calculate the spatial distance between the current geographical coordinates and each key point in the main operating track extracted in step S1; filter out the key point with the smallest spatial distance and record it as the matching key point; extract all key points after the matching key point in the main operating track to form the remaining track set M, wherein the remaining track set M contains the altitude and time information of each key point;

[0037] S4.2. According to the flight phase determination rules in steps S3.3 to S3.6, analyze the altitude and time information in the remaining track set M, identify the flight phases included in the remaining track, and calculate the remaining flight time corresponding to each flight phase.

[0038] Preferably, the specific steps in step S5 for calculating the remaining fuel amount upon arrival at the destination airport, based on fuel consumption, are as follows:

[0039] S5.1 After completing the flight phase classification and time calculation in S4, the estimated fuel consumption of the aircraft is obtained by multiplying the remaining flight time of each flight phase of the remaining flight segment by the corresponding fuel consumption rate.

[0040] S5.2. Subtract the aircraft's estimated fuel consumption from the current remaining fuel on board to obtain the remaining fuel amount at the aircraft's expected destination airport.

[0041] Preferably, in step S5:

[0042] The formula for calculating the estimated fuel consumption is:

[0043] Estimated fuel consumption = (Remaining time of climb phase × Climb phase fuel consumption rate) + (Remaining time of cruise phase × Cruise phase fuel consumption rate) + (Remaining time of descent phase × Descent phase fuel consumption rate).

[0044] The formula for calculating the remaining fuel at the destination airport is: Remaining fuel at the destination airport = Current remaining fuel on board - Estimated fuel consumption.

[0045] Compared with the prior art, the beneficial effects of the present invention are:

[0046] This invention, by extracting historical data such as aircraft main flight paths, takeoff and landing information, and fuel consumption, eliminates reliance on airline computer plans and air traffic control flight plans. It enables low fuel warnings for aircraft under complex conditions using only historical civil aviation data and a single ADS-B and ACARS integrated receiver. Because it uses historical data for main flight path and fuel consumption analysis, it more closely reflects actual operations, resulting in fuel consumption rates, future projected flight routes, and altitudes that are highly consistent with reality, leading to more accurate predicted fuel consumption. This invention can be used by airports to develop ground support plans in advance based on the current remaining fuel levels of flights. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the main flight track extraction and clustering algorithm of the civil aircraft fuel level monitoring and alarm method based on ACARS and ADS-B of the present invention.

[0048] Figure 2 This is a schematic diagram of the Tianjin-Wuhan flight trajectory and extraction of the main operating track for the civil aircraft fuel level monitoring and alarm method based on ACARS and ADS-B of this invention.

[0049] Figure 3 This is a schematic diagram illustrating the fuel consumption information of an aircraft at different operating stages, obtained through historical data analysis according to the present invention.

[0050] Figure 4 This is a schematic diagram illustrating the display of aviation operation status based on received ADS-B and ACARS information according to the present invention;

[0051] Figure 5 This is a schematic diagram showing the ICAO address, call sign, and remaining fuel information received by the integrated receiver of the present invention. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Please see Figure 1-5This invention provides a technical solution: a method for monitoring and alerting fuel levels in civil aircraft based on ACARS and ADS-B, comprising the following steps:

[0054] S1. Extracting Master Operating Tracks from ADS-B Historical Data: A time-series-based clustering algorithm is used to obtain the aircraft's master operating tracks from the ADS-B database. See details... Figure 1 The specific steps are as follows:

[0055] S1.1 Extract all flight trajectory information between the specified take-off and landing airport pairs from the ADS-B database. Each flight trajectory consists of multiple trajectory points. Each trajectory point contains the recording time, aircraft ICAO address code, longitude, latitude, and altitude information, and marks all trajectory points as "unvisited".

[0056] S1.2 Determine if there is a track containing "unvisited" trajectory points. If not, proceed to step S1.7; if so, select a track containing "unvisited" trajectory points and proceed to step S1.3.

[0057] S1.3. Filter out the earliest track point P in the selected track and the status is "unvisited", and update the status of P to "visited"; if all track points of the track have been "visited", return to step S1.2;

[0058] S1.4. With trajectory point P as the center, construct a cubic space interval with length, width and height of (1000, 1000, 1200), extract the trajectory points of all flight trajectories in the interval, form a trajectory point set Q, and count the number of elements in set Q as Np.

[0059] S1.5 Determine if Np is greater than the preset threshold G: If it is greater, mark P as a "key point" and add P to the key point set K, then proceed to step S1.6; if it is not greater, return to step S1.2.

[0060] S1.6. Filter out the trajectory point P1 with the status "unvisited" from the trajectory point set Q, update the status of P1 to "visited", and repeat step S1.4 with P1 as the new trajectory point P; if there is no "unvisited" trajectory point in set Q, return to step S1.3.

[0061] S1.7 Output the set of key points K. The trajectory corresponding to this set is the main flight path of the aircraft. The clustering process ends.

[0062] like Figure 2 As shown in the figure, the blue line represents the historical trajectory of various flights from Tianjin to Wuhan, and the red line represents the main operating trajectory of the route obtained using a time-series-based clustering algorithm. The data in the figure includes longitude, latitude, and flight altitude.

[0063] S2. Obtain the current remaining fuel level and location: e.g. Figure 3 As shown, the aircraft's fuel level information is obtained through an ACARS receiving base station, and the aircraft's location information is obtained through an ADS-B receiving base station. These two types of information are then integrated into a real-time tracking point with a timestamp. The specific steps are as follows:

[0064] S2.1 Receive the original ACARS message transmitted by the aircraft, decode the original ACARS message according to the RTCAO-620 international standard, and extract the "current remaining fuel" and "destination airport code" from the decoded information.

[0065] S2.2 Receive the original ADS-B message transmitted by the aircraft, decode the original ADS-B message according to the RTCADO-260B international standard, and extract the "current longitude", "current latitude", "current altitude" and "aircraft ICAO address code" from the decoded information;

[0066] S2.3 Using "timestamp" and "aircraft ICAO address code" as associated fields, the "current remaining fuel" and "destination airport code" extracted in step S2.1 are associated and integrated with the "current longitude", "current latitude" and "current altitude" extracted in step S2.2 to form a real-time tracking point; the real-time tracking point contains at least 7 types of information, including time, longitude, latitude, altitude, ICAO address code, remaining fuel, and destination airport code;

[0067] Figure 4 To display the aviation operation status based on the received ADS-B and ACARS information, information such as the aircraft's ICAO address, call sign, flight altitude, longitude, and latitude can be observed;

[0068] S3. Extracting fuel consumption for each stage based on ACARS historical data: Combining ADS-B information to divide the aircraft's flight stages, statistically analyzing the fuel consumption data for each flight stage in the ACARS historical data, and calculating the aircraft's fuel consumption rate for each stage. The specific steps are as follows:

[0069] S3.1 Extract all historical flight track data of the target aircraft from the ADS-B database. The historical flight track data includes the time, ICAO address code, and altitude information of each flight track. Extract the time and remaining fuel data of the target aircraft corresponding to the historical flight track from the ACARS database. Use "time" and "ICAO address code" as matching fields to align the two types of data by time to form a related dataset.

[0070] S3.2 Determine whether there are any uncalculated fuel consumption rates in the associated dataset. If not, proceed to step S3.8; if so, select an uncalculated fuel consumption rate and proceed to step S3.3.

[0071] S3.3 Analyze the altitude data of the selected flight path using a sliding time window: The duration of the sliding time window is 3 minutes. If the cumulative climb altitude within a certain sliding time window is greater than 1500 feet, and the climb altitude per minute within the time window is not negative, then it is determined that the aircraft is in a climb state during the continuous time period corresponding to the time window, and step S3.7 is executed; if not, step S3.4 is executed.

[0072] S3.4 Analyze the altitude data within the 3-minute sliding time window. If the cumulative descent altitude within the time window is greater than 1500 feet, and the descent altitude per minute within the time window is not negative, then it is determined that the aircraft is in a descent state during the continuous time period corresponding to the time window, and step S3.7 is executed; if not, step S3.5 is executed.

[0073] S3.5 Analyze the altitude data within the same sliding time window: If the average altitude of the aircraft within the time window is greater than 6,000 feet, it is determined that the aircraft is in cruise mode during the continuous time period corresponding to the time window, and step S3.7 is executed; if not, step S3.6 is executed.

[0074] S3.6. If it is determined that the aircraft flight phase cannot be confirmed within the time period corresponding to the sliding time window, discard the fuel consumption data within that time period and return to step S3.2.

[0075] S3.7. Based on the "remaining fuel on board" data in the associated dataset in step S3.1, calculate the fuel consumption during this time period. Combined with the duration of the time period, determine the fuel consumption rate (kg / hour) of the aircraft in the current flight phase, and return to step S3.2.

[0076] S3.8 Summarize the fuel consumption rate data of the target aircraft in the three phases of climb, cruise and descent, and complete the fuel consumption extraction for each phase;

[0077] Each phase includes climb, cruise, and descent. The current operational phase of the aircraft is determined using the following method:

[0078] The aircraft's average climb rate was calculated using a sliding time window method with a sliding window width of 3 minutes.

[0079] If the climb rate is greater than 500 feet per minute within the time window, the aircraft is determined to be in a climb state during that continuous time period.

[0080] If the rate of climb is less than -500 feet / minute within the time window, the aircraft is determined to be in a descent state during that continuous time period.

[0081] If the aircraft's altitude is greater than 6,000 feet within the time window and the aircraft is not in the climb or descent phase, then the aircraft is considered to be in cruise mode during that time period.

[0082] S4. Calculate the estimated flight path and remaining time to reach the landing airport: Match the aircraft's current position with the main operating path to determine the path information for the remaining flight segments. Based on the flight phase division rules, identify each flight phase and its corresponding duration for the remaining flight segments. The specific steps are as follows:

[0083] S4.1 Obtain the current geographical coordinates (X, Y, Z) of the aircraft (X is longitude, Y is latitude, and Z is altitude), calculate the spatial distance between these coordinates and each key point in the main operating track extracted in step S1; filter out the key point with the smallest spatial distance and denot it as the "matching key point"; extract all key points after the "matching key point" in the main operating track to form the remaining track set M, wherein the remaining track set M contains the altitude and time information of each key point;

[0084] S4.2. According to the flight phase determination rules in steps S3.3 to S3.6, analyze the altitude and time information in the remaining track set M, identify the flight phases (climb, cruise, descent) included in the remaining track, and calculate the flight duration corresponding to each flight phase.

[0085] S5. Calculate the remaining fuel amount upon arrival at the destination airport based on fuel consumption: Multiply the remaining flight time for each flight phase obtained in step S4 by the corresponding fuel consumption rate calculated in step S3 to obtain the estimated fuel consumption; subtract the estimated fuel consumption from the aircraft fuel information extracted in step S2 to obtain the aircraft's estimated remaining fuel amount upon arrival at the destination airport. The specific steps are as follows:

[0086] S5.1 After completing the flight phase classification and time calculation in S4, the estimated fuel consumption of the aircraft is obtained by multiplying the remaining flight time of each flight phase of the remaining flight segment by the corresponding fuel consumption rate.

[0087] S5.2. Subtract the aircraft's estimated fuel consumption from the current remaining fuel on board to obtain the remaining fuel amount at the aircraft's expected destination airport;

[0088] like Figure 5 As shown, the list specifies the aircraft's ICAO address, call sign, and remaining fuel.

[0089] S6. Fuel Remaining Alarm: When the remaining fuel at the destination airport calculated in step S5 is less than the preset alarm threshold, a fuel remaining alarm message is output.

[0090] The formula for calculating the estimated fuel consumption is as follows:

[0091] Estimated fuel consumption = (Remaining time of climb phase × Climb phase fuel consumption rate) + (Remaining time of cruise phase × Cruise phase fuel consumption rate) + (Remaining time of descent phase × Descent phase fuel consumption rate).

[0092] The formula for calculating the remaining fuel at the destination airport is: Remaining fuel at the destination airport = Current remaining fuel on board - Estimated fuel consumption.

[0093] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for monitoring and alarming fuel levels in civil aircraft based on ACARS and ADS-B, characterized in that: Includes the following steps: S1. Extracting the main operating track based on ADS-B historical data: Using a time-series-based clustering algorithm, the main operating track of the aircraft is obtained from the ADS-B database; S2. Obtain current remaining fuel and location: Obtain the aircraft's fuel information through the ACARS receiving base station and the aircraft's location information through the ADS-B receiving base station. Associate the fuel information and location information according to the timestamp and ICAO address code, and integrate them into a real-time track with timestamp. S3. Extract fuel consumption for each stage based on ACARS historical data: Extract historical flight track data of the target aircraft from the ADS-B database, extract onboard fuel data of the target aircraft corresponding to the historical flight track from the ACARS database, form a related dataset with time and ICAO address code as matching fields, and calculate the fuel consumption rate of the target aircraft in each flight stage. S4. Calculate the expected flight path and remaining time to reach the landing airport: Based on the current geographical coordinates of the target aircraft obtained in step S2, calculate the spatial distance between the coordinates and the key points in the main operating path extracted in step S1, determine the flight path information of the remaining flight segment, and identify the remaining flight time corresponding to each flight stage of the remaining flight segment. S5. Calculate the remaining fuel amount upon arrival at the destination airport based on fuel consumption: Multiply the remaining time of each flight phase obtained in step S4 by the corresponding fuel consumption rate calculated in step S3 to obtain the estimated fuel consumption; Subtract the estimated fuel consumption from the aircraft's fuel information extracted in step S2 to obtain the aircraft's estimated remaining fuel amount upon arrival at the destination airport. S6. Fuel Remaining Alarm: When the remaining fuel at the destination airport calculated in step S5 is less than a preset alarm threshold, a fuel remaining alarm message is output.

2. The civil aircraft fuel level monitoring and alarm method based on ACARS and ADS-B according to claim 1, characterized in that: The specific steps for extracting the main operating track in step S1 are as follows: S1.1 Extract all flight trajectory information between the specified take-off and landing airport pairs from the ADS-B database. Each flight trajectory consists of multiple trajectory points. Each trajectory point contains the recording time, aircraft ICAO address code, longitude, latitude, and altitude information, and marks all trajectory points as unvisited. S1.2 Determine if there is a track containing unvisited trajectory points. If not, proceed to step S1.7; if so, select a track containing unvisited trajectory points and proceed to step S1.

3. S1.

3. Filter out the earliest track point P in the selected track and the track point P whose status is unvisited, and update the status of track point P to visited; if all track points of the track have been visited, return to step S1.

2. S1.

4. With trajectory point P as the center, construct a cubic space interval with length, width and height of (X,Y,Z), extract the trajectory points of all flight trajectories in the interval, form a trajectory point set Q, and count the number of elements in set Q as Np. S1.5 Determine whether Np is greater than the preset threshold G: If it is greater, mark the trajectory point P as a key point and add the trajectory point P to the key point set K, and execute step S1.6; If it is not greater than, return to step S1.2; S1.

6. Filter out the trajectory point P1 in the trajectory point set Q that is unvisited, update the status of trajectory point P1 to visited, and use trajectory point P1 as the new trajectory point P. Repeat step S1.

4. If there are no unvisited trajectory points in set Q, return to step S1.

3. S1.7 Output the set of key points K. The trajectory corresponding to the set of key points K is the main flight path of the aircraft. The clustering process ends.

3. The civil aircraft fuel level monitoring and alarm method based on ACARS and ADS-B according to claim 1, characterized in that: The specific steps for obtaining the current remaining fuel quantity and location in step S2 are as follows: S2.1 Receive the original ACARS message transmitted by the aircraft, decode the original ACARS message according to the ARINC 724B international standard, and extract the current remaining fuel and destination airport code from the decoded information. S2.2 Receive the original ADS-B message transmitted by the aircraft, decode the original ADS-B message according to the RTCA DO-260B international standard, and extract the current longitude, current latitude, current altitude and aircraft ICAO address code from the decoded information; S2.3 Using the timestamp and aircraft ICAO address code as associated fields, the current remaining fuel and destination airport code extracted in step S2.1 are associated and integrated with the current longitude, current latitude and current altitude extracted in step S2.2 to form a real-time tracking point; The real-time tracking data includes at least seven types of information: time, longitude, latitude, altitude, ICAO address code, remaining fuel, and destination airport code.

4. The civil aircraft fuel level monitoring and alarm method based on ACARS and ADS-B according to claim 1, characterized in that: The specific steps for extracting fuel consumption at each stage in step S3 are as follows: S3.1 Extract all historical flight track data of the target aircraft from the ADS-B database. The historical flight track data includes the time, ICAO address code, and altitude information of each flight track. Extract the time and remaining fuel data of the target aircraft corresponding to the historical flight track from the ACARS database. Use the time and ICAO address code as matching fields to align the remaining fuel data and the matching fields in time to form a related dataset. S3.2 Determine whether there are any uncalculated fuel consumption rates in the associated dataset. If not, proceed to step S3.8; if so, select an uncalculated fuel consumption rate and proceed to step S3.

3. S3.3 Analyze the altitude data of the selected track using a sliding time window: The duration of the sliding time window is T. If the cumulative climb altitude within any sliding time window is greater than H1, and the climb altitude per minute within the sliding time window is not negative, then it is determined that the aircraft is in a climb state during the continuous time period corresponding to the sliding time window, and step S3.7 is executed; if not, step S3.4 is executed. S3.4 Analyze the altitude data within the same sliding time window: If the cumulative descent altitude within the sliding time window is greater than H2, and the descent altitude per minute within the sliding time window is not negative, then it is determined that the aircraft is in a descent state during the continuous time period corresponding to the sliding time window, and step S3.7 is executed; if not, step S3.5 is executed. S3.5 Analyze the altitude data within the same sliding time window: If the average altitude of the aircraft within the sliding time window is greater than H3, it is determined that the aircraft is in cruise mode during the continuous time period corresponding to the sliding time window, and step S3.7 is executed; if not, step S3.6 is executed. S3.

6. If it is determined that the aircraft flight phase cannot be confirmed within the time period corresponding to the sliding time window, discard the fuel consumption data within the sliding time window and return to step S3.

2. S3.

7. Based on the remaining fuel data on board the associated dataset in step S3.1, calculate the fuel consumption within the sliding time window, and combine it with the duration of the time period to obtain the fuel consumption rate of the aircraft in the current flight phase, and return to step S3.

2. S3.8 Summarize the fuel consumption rate data of the target aircraft in the three phases of climb, cruise and descent, and complete the extraction of fuel consumption for each phase.

5. The civil aircraft fuel level monitoring and alarm method based on ACARS and ADS-B according to claim 4, characterized in that: The specific steps in step S4 for calculating the expected flight path and remaining time to reach the landing airport are as follows: S4.1 Obtain the current geographical coordinates (X,Y,Z) of the aircraft, calculate the spatial distance between the current geographical coordinates and each key point in the main flight path extracted in step S1; filter out the key point with the smallest spatial distance and record it as the matching key point; Extract all key points after matching key points in the main running track to form a set of remaining tracks M, wherein the set of remaining tracks M contains the altitude and time information of each key point; S4.2 and S3.3 to S3.6 are flight phase determination rules. The altitude and time information in the remaining track set M are analyzed to identify the flight phases contained in the remaining track and to calculate the remaining flight time corresponding to each flight phase.

6. The civil aircraft fuel level monitoring and alarm method based on ACARS and ADS-B according to claim 1, characterized in that: The specific steps in step S5 for calculating the remaining fuel upon arrival at the destination airport, based on fuel consumption, are as follows: S5.1 After completing the flight phase classification and time calculation in S4, the estimated fuel consumption of the aircraft is obtained by multiplying the remaining flight time of each flight phase of the remaining flight segment by the corresponding fuel consumption rate. S5.

2. Subtract the aircraft's estimated fuel consumption from the current remaining fuel on board to obtain the remaining fuel amount at the aircraft's expected destination airport.

7. The civil aircraft fuel level monitoring and alarm method based on ACARS and ADS-B according to claim 1, characterized in that: In step S5: The formula for calculating the estimated fuel consumption is: Estimated fuel consumption = (Remaining time of climb phase × Climb phase fuel consumption rate) + (Remaining time of cruise phase × Cruise phase fuel consumption rate) + (Remaining time of descent phase × Descent phase fuel consumption rate). The formula for calculating the remaining fuel at the destination airport is: Remaining fuel at the destination airport = Current remaining fuel on board - Estimated fuel consumption.

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