A sea level altitude correction method for forward-looking terrain avoidance warning

Abstract

The present invention discloses a method for correcting sea level altitude for a forward-looking terrain avoidance warning, comprising the following steps: obtaining current onboard parameter information of an aircraft, wherein the onboard parameter information includes at least the current altitude above the ground, the current speed, the current standard pressure altitude, and the current terrain altitude of the aircraft; determining whether the aircraft is currently on the ground based on the current altitude above the ground and the current speed; if the aircraft is currently on the ground, determining a reference plane deviation based on the current standard pressure altitude and the current terrain altitude; and, if the absolute value of the reference plane deviation is less than a deviation increment threshold, correcting the sea level altitude value based on the current standard pressure altitude and the reference plane deviation. The advantages of the present invention are that the deviation between the measured altitude and the reference plane of the terrain database caused by temperature is corrected to obtain a corrected altitude, thereby reducing false alarms and missed alarms in the forward-looking terrain avoidance warning.

Description

Technical Field

[0001] The present invention relates to the field of forward-looking terrain avoidance warning, and in particular to a sea level altitude correction method for forward-looking terrain avoidance warning. Background Art

[0002] Forward Terrain Avoidance Alert (FTA) is a key component of the enhanced ground proximity warning system (EPGWS). This function primarily collects flight parameters input from external onboard detection equipment and, based on the product's built-in terrain database, uses a pre-set warning algorithm to determine whether the aircraft is in danger of a ground collision, thereby preventing controlled ground collisions.

[0003] Currently, aircraft avionics equipment cannot provide reliable corrected sea altitude, or the corrected sea altitude provided is heavily dependent on the corrected sea level deviation input by the crew. Therefore, conventional warning modes typically use a downgraded solution to corrected sea altitude—pressure altitude—for warning calculations. This solution introduces a temperature-dependent deviation between the measured pressure altitude and the reference level in the terrain database, resulting in false ground proximity warnings in winter and missed ground proximity warnings in summer. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem in the prior art that it is impossible to reliably obtain the corrected sea level deviation, and to provide a novel sea level altitude correction method for forward-looking terrain avoidance warning.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: a sea level altitude correction method for forward-looking terrain avoidance warning comprises the following steps:

[0006] Obtain the current onboard parameter information of the aircraft, wherein the onboard parameter information includes at least a current altitude H0, a current speed V0, a ​​current standard pressure altitude H p and the current terrain height H m ;

[0007] Determining whether the aircraft is currently on the ground based on the current height above the ground H0 and the current speed V0;

[0008] If the aircraft is currently on the ground, then the current standard pressure altitude H p and the current terrain height H m Determine the reference surface deviation H err : as well as,

[0009] Provide a deviation increment threshold H k , if the reference plane deviation H err The absolute value of the deviation increment threshold H is less than k, then according to the current standard air pressure altitude H p And the reference surface deviation H err Corrected sea level height value H: H = H p -H err .

[0010] As a preferred solution for the sea level altitude correction method for forward terrain avoidance warning, if the current altitude H0 and the current speed V0 are both less than the altitude threshold H 限值 and speed threshold V 限值 , it is determined that the aircraft is currently on the ground.

[0011] As a preferred solution for sea level altitude correction method for forward terrain avoidance warning, the altitude threshold H 限值 =min{H 飞机 +ΔH,10}, where H 飞机 Depending on the installation height of the aircraft radio altimeter, ΔH is the altitude deviation, and ΔH is 1-3 meters.

[0012] As a preferred solution for sea level altitude correction method for forward terrain avoidance warning, the speed threshold V 限值 =V lf , where V lf is the aircraft's takeoff speed.

[0013] As a preferred solution for the sea level altitude correction method for forward terrain avoidance warning, the deviation increment threshold H k Depends on the incremental deviation of the pressure altitude measurement.

[0014] As a preferred solution for the sea level altitude correction method for forward terrain avoidance warning, the deviation increment threshold H k It is 250 meters.

[0015] Compared to existing technologies, the present invention offers the following advantages: it is applicable to any aircraft equipped with an air data system. By acquiring onboard parameter information from a positioning system and onboard sensors, it can automatically derive an accurate sea level altitude value (H), independent of human intervention. Furthermore, it corrects for temperature-related deviations between the measured altitude and the reference plane of the terrain database, reducing false and missed alerts in forward-looking terrain avoidance warnings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the implementation process of an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of vacant land status determination in one embodiment of the present invention. DETAILED DESCRIPTION

[0018] See Figure 1 The figure shows a sea level altitude correction method for forward terrain avoidance warning, which is embedded in the airborne control system in the form of a computer program. It includes the following steps:

[0019] Step 1: Use the aircraft's positioning system to obtain the aircraft's current longitude and latitude. Read the aircraft's current terrain altitude from the terrain database. Use onboard sensors to obtain the aircraft's current standard pressure altitude, altitude above the ground, and speed. After completing Step 1, proceed to Step 2.

[0020] Step 2: According to the current altitude and speed of the aircraft, Figure 2 Determine whether the aircraft is on the ground: If the current altitude and current speed are both less than the altitude threshold and speed threshold, respectively, the aircraft is determined to be on the ground. If so, proceed to step 3; otherwise, repeat step 1.

[0021] Step 3: Substitute the current terrain height and the current standard pressure altitude into the deviation calculator to calculate the reference plane deviation H err The deviation calculator is:

[0022]

[0023] Where: H p H is the current standard pressure altitude of the aircraft. m The current terrain height of the aircraft is read. After completing step 3, proceed to step 4.

[0024] Step 4: Determine the reference surface deviation H err Is it valid? In this embodiment, the comparison reference plane deviation H err Is it between -250 meters and 250 meters (the comparison range is the deviation increment of the reference pressure altitude measurement, and in other embodiments may not be limited to -250 meters to 250 meters). If yes, proceed to step 5, otherwise, repeat step 1.

[0025] Step 5: According to the effective reference surface deviation H err Complete the calculation of the sea level height value H: H = H p -H err. The precise sea level height value H thus obtained corrects the deviation between the measured height and the reference plane of the terrain database caused by temperature reasons, and reduces the false alarms and missed alarms of the forward-looking terrain avoidance warning. The above only expresses the implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the attached claims.

Claims

1. A method for correcting sea level altitude for forward-looking terrain avoidance warning, characterized in that: It includes the following steps: Obtain the current onboard parameter information of the aircraft, wherein the onboard parameter information includes at least a current altitude H0, a current speed V0, a ​​current standard pressure altitude H p and the current terrain height H m ; Determine whether the aircraft is currently on the ground by the current height above the ground H0 and the current speed V0; If the aircraft is currently on the ground, then the current standard pressure altitude H p and the current terrain height H m Determine the reference plane deviation Herr: as well as, Provide a deviation increment threshold Hk. If the absolute value of the reference plane deviation Herr is less than the deviation increment threshold Hk, then according to the current standard pressure altitude H p And the reference plane deviation Herr corrects the sea level height value H: H = H p -H err The sea level value H is used to correct the deviation between the measured height and the reference plane of the terrain database caused by temperature, thereby reducing false alarms and missed alarms of the forward-looking terrain avoidance warning.

2. The method for correcting sea level altitude for forward terrain avoidance warning according to claim 1, characterized in that: If the current ground clearance H0 and the current driving speed V0 are both less than the height threshold H 限值 and speed threshold V 限值 , it is determined that the aircraft is currently on the ground.

3. The method for correcting sea level altitude for forward-looking terrain avoidance warning according to claim 2, characterized in that: The height threshold H 限值 =min{H 飞机 +ΔH,10}, where H 飞机 Depending on the installation height of the aircraft radio altimeter, ΔH is the altitude deviation, and ΔH is 1-3 meters.

4. The method for correcting sea level altitude for forward-looking terrain avoidance warning according to claim 2, characterized in that: The speed threshold V 限值 =V lf , where V lf is the aircraft's takeoff speed.

5. The method for correcting sea level altitude for forward-looking terrain avoidance warning according to claim 1, characterized in that: The deviation increment threshold Hk depends on the deviation increment of the barometric altitude measurement.

6. A method for correcting sea level altitude for forward-looking terrain avoidance warning according to claim 1 or 5, characterized in that: The deviation increment threshold Hk is 250 meters.

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