CN110824470B

CN110824470B - Radio altitude data processing method of amphibious aircraft

Info

Publication number: CN110824470B
Application number: CN201910967943.4A
Authority: CN
Inventors: 蔡志勇; 李登登; 张宏志; 郭星灿
Original assignee: South China Aircraft Industry Co Ltd of China Aviation Industry General Aircraft Co Ltd
Current assignee: South China Aircraft Industry Co Ltd of China Aviation Industry General Aircraft Co Ltd
Priority date: 2019-10-12
Filing date: 2019-10-12
Publication date: 2024-04-16
Anticipated expiration: 2039-10-12
Also published as: CN110824470A

Abstract

The application provides a method for processing radio altitude data of an amphibious aircraft, which comprises the following steps: judging the take-off and landing positions of the aircraft according to the landing gear retraction state, wherein the take-off and landing positions of the aircraft comprise land take-off and landing and water take-off and landing; obtaining residual height information according to the taking-off and landing positions of the aircraft; obtaining a pitch angle value from an aircraft inertial navigation system; and correcting the measured radio height according to the residual height information, the pitch angle value and the height error corresponding to the pitch angle of 1 degree to obtain a corrected radio height.

Description

Radio altitude data processing method of amphibious aircraft

Technical Field

The invention relates to the technical field of aircraft navigation systems, in particular to a radio altitude data processing method of an amphibious aircraft.

Background

The radio altimeter is a ranging navigation device, which uses the working principle of a common radar, takes the ground/water surface as a reflector to emit electric waves on an aircraft, and receives echoes to determine the actual height from the aircraft to the ground/water surface. The device is an important device for ensuring flight safety in the approaching and landing processes, and can fly and pass through cloud to descend under complex meteorological conditions and land under the condition of low visibility by utilizing the radio altimeter to be matched with other navigation devices (such as an instrument landing system).

For most of the aircraft types, the aircraft only takes off and land, so that the radio altimeter antennas on the currently known aircraft types are almost arranged at the positions of the aircraft abdomen, and the radio altimeter antennas are displayed by taking the landing of the aircraft as a zero reference.

However, amphibious aircraft have the particularity of taking off and landing on land and on water, so that the radio altitude is required to be switched according to two different zero references of the amphibious aircraft in the two states of taking off and landing on land and taking off and landing on water; the particularity of the amphibious aircraft is also reflected in that the belly of the aircraft is of a ship body design, the antenna cannot be arranged because of the need of entering water, the altimeter antenna of the amphibious aircraft is arranged on the lower skins of the left and right horizontal tails of the aircraft, and the altitude difference is generated between the measured radio altitude and the actual altitude of the aircraft due to different pitching angles due to the change of the attitude of the aircraft in the landing and the landing processes of the aircraft on water.

Disclosure of Invention

The purpose of the invention is that: because of the particularity of the amphibious aircraft, the two states of water and land have the difference of residual heights due to the retraction and the extension of the landing gear, and the pitch angle of the aircraft has a large influence on the radio height value, the invention provides a data processing method capable of correcting the radio height.

The application provides a method for processing radio altitude data of an amphibious aircraft, which comprises the following steps:

judging the take-off and landing positions of the aircraft according to the landing gear retraction state, wherein the take-off and landing positions of the aircraft comprise land take-off and landing and water take-off and landing;

obtaining residual height information according to the taking-off and landing positions of the aircraft;

obtaining a pitch angle value from an aircraft inertial navigation system;

and correcting the measured radio height according to the residual height information, the pitch angle value and the height error corresponding to the pitch angle of 1 degree to obtain a corrected radio height.

Optionally, the obtaining the remaining altitude information according to the take-off and landing positions of the aircraft specifically includes:

if the airplane taking-off and landing position is the land taking-off and landing position, the residual height information is a first reference, and the first reference is the measured radio height of the airplane when the airplane lands;

if the airplane taking-off and landing position is the water taking-off and landing position, the residual height information is a second reference, and the second reference is the measured radio height of the airplane when the airplane is in water.

Optionally, the land zero reference comprises 38 feet and the water zero reference comprises 36 feet.

Alternatively, a 1 degree pitch angle corresponds to a height error of 1 foot.

Optionally, correcting the measured radio height according to the remaining height information, the pitch angle value and the height error corresponding to the pitch angle of 1 degree to obtain a corrected radio height, which specifically includes:

if the take-off and landing position of the airplane is land take-off and landing, the following formula is adopted:

corrected radio altitude = measured radio altitude-first reference +1 degree pitch angle-corresponding altitude error x pitch angle value, a corrected radio altitude is obtained.

if the take-off and landing position of the airplane is the take-off and landing on water, the following formula is adopted:

corrected radio altitude = measured radio altitude-second reference +1 degree pitch angle-corresponding altitude error x pitch angle value, a corrected radio altitude is obtained.

Optionally, the obtaining the pitch angle value from the inertial navigation system of the aircraft specifically includes:

if the range of pitch angle value theta is obtained from the inertial navigation system of the aircraft: and if the angle theta is more than or equal to 15 and less than or equal to 15, the pitch angle value is theta.

if the range of pitch angle value theta is obtained from the inertial navigation system of the aircraft: θ < -15, or θ >15, the pitch angle value is 0.

The invention has the advantages that: the aircraft landing gear is used for correcting measured data through the pitch angle of the aircraft, radio height display is more accurate in the take-off and landing process of the aircraft, the landing time of the aircraft is more consistent with the time when the height is displayed as 0, and when the aircraft takes off and lands on water, after the landing gear is retracted, the ship body at the lower part of the aircraft is submerged in water, the radio height displays a negative value, so that a crew can conveniently identify the water situation of the aircraft through the radio height.

Drawings

FIG. 1 is a schematic illustration of the effect of aircraft pitch angle on radio altitude values;

fig. 2 is a schematic diagram showing a negative value of the radio altitude in the water landing.

Detailed Description

The invention provides a radio altitude data processing method of an amphibious aircraft, which is characterized in that: the data processing method for correcting the radio height solves the problem that the residual height difference exists between the water state and the land state due to the fact that the landing gear is retracted and put down, and the problem that the pitch angle of the aircraft has a large influence on the radio height value, so that the radio height display is more real-time and accurate, and the negative value of the height can be displayed when the aircraft slides on water and takes off and land, and a crew can conveniently identify the water situation of the aircraft through the radio height.

The radio height data processing method adopted by the invention is as follows:

first, the two remaining heights of the land and water are analyzed and measured, and both the water and land conditions will have a difference in remaining height of about 2ft due to the retraction and extension of the landing gear.

Secondly, the influence of the pitch angle of the aircraft on the radio altitude value is analyzed: when the aircraft is parked on the ground in a static state, alpha in fig. 1 is 37 degrees (theoretical shape measurement value), the lowest point of the aircraft is taken as a base point, the pitch angle of the aircraft is theta, the altitude change quantity delta h=67 sin37-67sin (37-theta), the pitch angle change range is smaller in the multiple flying processes, the pitch angle theta is between-10 degrees and +10 degrees through flying parameter analysis, and when theta= (-10, -5, -1, 5, 10), delta h= (-8.7, -4.5, -0.93, 0.94, 4.8 and 9.9) are calculated. Therefore, in the take-off and landing stage where the pitch angle variation range is small, it can be approximated as corresponding to about 1ft height difference per 1 ° pitch angle.

In summary, the radio altitude data processing method includes: the radio altimeter keeps the original state when leaving the factory, does not process the measured altitude value, and corrects the measured altitude value at the EFIS end according to the following logic:

a=left main take-off in place lock or right main take-off in place lock, i.e. determining that the aircraft is taking off and landing on land:

h＝H-38+1×θ……………………………………………………(1)

if h is less than 0, h is set to 0;

in the case of non-A, namely, judging that the aircraft takes off and land on water:

h＝H-36+1×θ……………………………………………………(2)

in the formula (1) (2):

h—modify radio height, rounded in ft.

H—measured radio height in ft.

θ—the pitch angle value of the aircraft in degrees, θ being positive when pitched up and negative when pitched down; and theta is more than or equal to 15 degrees and less than or equal to 15 degrees, otherwise, theta is set to 0.

38—measured radio altitude when the aircraft is grounded.

36—measured radio altitude of the aircraft when it is in water.

1-in the taking-off and landing process of the aircraft, the pitch angle of 1 degree corresponds to the altitude error.

In particular, the effect of the present invention will be further described with reference to the drawings.

The method is implemented according to the invention, and comprises the following steps:

step one, the radio altimeter is restored to the original state when leaving the factory through software upgrading.

Step two, the EFIS system is updated by software, and a left main start down in-place locking signal, a right main start down in-place locking signal and aircraft pitch angle data are introduced to correct the radio height according to the logic in the invention content.

After implementation, the process that the radio altitude display value gradually drops to 0 in the land test flight process is nearly consistent with the process that the airplane gradually descends to the ground; the radio altitude during the water test flight may show negative values, see fig. 2.

Claims

1. A method of radio altitude data processing for an amphibious aircraft, the method comprising:

obtaining a pitch angle value from an aircraft inertial navigation system;

correcting the measured radio height according to the residual height information, the pitch angle value and the height error corresponding to the pitch angle of 1 degree to obtain a corrected radio height;

the obtaining the remaining height information according to the taking-off and landing positions of the aircraft specifically comprises the following steps:

2. The method of claim 1, wherein the first datum comprises 38 feet and the second datum comprises 36 feet.

3. The method of claim 1, wherein the 1 degree pitch angle corresponds to a height error of 1 foot.

4. The method according to claim 1, wherein the correcting the measured radio height according to the remaining height information, the pitch angle value and the height error corresponding to the pitch angle of 1 degree to obtain a corrected radio height specifically comprises:

5. The method according to claim 1, wherein the correcting the measured radio height according to the remaining height information, the pitch angle value and the height error corresponding to the pitch angle of 1 degree to obtain a corrected radio height specifically comprises:

6. The method according to claim 1, wherein said obtaining a pitch angle value from an inertial navigation system of an aircraft, in particular comprises:

7. The method according to claim 1, wherein said obtaining a pitch angle value from an inertial navigation system of an aircraft, in particular comprises: