Flight test data course signal processing method

Abstract

The invention provides a flight test data course signal processing method, which comprises the following steps of: backward difference calculation: carrying out difference calculation on discrete course signals in pairs backwards, namely mapping the discrete course signals to a difference space; a conversion rule is defined, a difference space image curve rule is analyzed, and jump is converted into three sub-problems of signal invariant, signal low jump and signal high jump for representation; solving the sub-problems: respectively solving the three sub-problems obtained by transformation; the solutions of the sub-problems are merged, and jump signals in any form within the range of + / -180 degrees are converted into continuous signals within the range of + / -infinity. And the processed course signal in the + / -infinity range is correct and good in continuity. The method can be applied to flight state monitoring, flight accident analysis and D-level flight simulator objective testing.

Description

Technical Field

[0001] The invention belongs to an aircraft flight test data signal processing technology, and is used for flight status monitoring, flight accident analysis and objective testing of a Class D flight simulator. Background Art

[0002] The true heading signal of the aircraft's onboard navigation system generally has a data range of -180 degrees to +180 degrees, which is used for avionics instrument display, navigation, and flight parameter recording. This data range is particularly suitable for the indication of the flight heading of the circular mechanical dial pointer, and the aircraft and the ground navigation station also have a unified coordinate space for communication. At the same time, due to the small number of bits of data within this range, it is also particularly suitable for recording flight parameters, saving storage space and improving data storage accuracy. However, this display method is not conducive to flight parameter interpretation. When the data sampling rate is low, the drastic jump of the data will interfere with the judgment process, and the continuous characteristics of the heading will be disrupted.

[0003] In the process of flight accident analysis and objective testing of Class D flight simulators, virtual pilot inverse simulation technology is used. This technology uses an inverse simulation algorithm to solve the pilot's control variables based on the inertial position signals and heading signals in the north, east and ground directions recorded by the onboard flight parameters. By comparing the solved control variables with the control variable signals recorded by the onboard flight parameters, the cause of the flight accident and the compliance of the objective test of the Class D flight simulator can be evaluated. However, in the inverse simulation solution process, a continuous heading signal in the range of -∞ to +∞ is used. Therefore, reconstructing the ±180-degree airborne heading signal into a continuous signal of ±∞ is a technical problem that needs to be solved urgently in this application. At present, there is no relevant description of this signal processing method in domestic and foreign public information for reference. Summary of the invention

[0004] The purpose of the present invention is to provide a flight test data heading signal processing method, which provides a correct and reliable heading angle signal source for aircraft flight accident analysis and inverse simulation analysis in objective testing of a Class D flight simulator.

[0005] The technical solution to achieve the purpose of the present invention is:

[0006] A flight test data heading signal processing method, comprising:

[0007] Step 1: backward difference calculation, performing a pairwise difference operation on the discrete heading signals, i.e. mapping them into the difference space;

[0008] Step 2: Define the conversion rules, analyze the law of the differential space image curve, and transform the jump into three sub-problems: "signal unchanged", "signal jump low", and "signal jump high";

[0009] Step 3: Solve the sub-problems, respectively solve the three sub-problems obtained by the transformation;

[0010] Step 4: Combine the solutions of the sub-problems and convert any transition signal within the range of ±180 degrees into a continuous signal within the range of ±∞.

[0011] Compared with the prior art, the present invention has the following significant advantages:

[0012] (1) By analyzing the curve law in the differential space and decomposing the signal reconstruction into three sub-problems, it is possible to reconstruct any form of ±180-degree heading signal into the ±∞ range, providing a reliable continuous heading signal source for inverse simulation;

[0013] (2) By modifying the restriction parameter 360, the method can be extended to the processing of any discrete jump signal, including signals whose jump range is a random amount, providing a reference for the reconstruction of such signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of the method of the present invention.

[0015] Figure 2 This is an example of a discrete heading jump signal of flight test data before being processed by the present invention.

[0016] Figure 3 It is an example backward difference curve of discrete heading jump signal of flight test data before being processed by the present invention.

[0017] Figure 4 This is the definition of the differential space curve graph conversion rule in the present invention.

[0018] Figure 5 It is a comparison before and after the processing of the discrete heading jump signal example of flight test data by the present invention.

[0019] Figure 6 This is another example of the present invention's processing of discrete heading jump signals of flight test data. DETAILED DESCRIPTION

[0020] The present invention is further described below with reference to the accompanying drawings and specific implementation examples.

[0021] Combination Figure 1 A flight test data heading signal processing method of this embodiment comprises the following steps:

[0022] The first step is to perform a backward difference calculation to convert the discrete heading signal (such as Figure 2 The following are the steps to perform pairwise difference operations, i.e. map them to the difference space.

[0023] Step 1-1, take the heading signal value Psi(t) at time t, and take the heading signal value Psi(t-1) at time t-1;

[0024] Step 1-2, calculate the difference: Psi(t)-Psi(t-1).

[0025] The second step is to define the transformation rules and analyze the difference space image (such as Figure 3 According to the curve rule shown in Figure 1, the jump is transformed into: "signal unchanged", "signal jump low", "signal jump high", and three sub-problems are expressed. The detailed steps are as follows:

[0026] Step 2-1, draw the backward difference space curve of the heading signal obtained in the first step, such as Figure 3 shown.

[0027] Step 2-2: Analyze the law of the backward difference space curve in step 2-1. The curve is Figure 4 The three basic shapes shown are: "1" (representing unchanged signal), shape (representing a signal jump from unchanged to low) and shape (representing the signal jumps from unchanged to high), so it can be divided into these three sub-problems for solution.

[0028] The third step is to solve the sub-problems separately. Figure 4 The three sub-problems shown are solved as follows:

[0029] Step 3-1, sub-problem 1 is that the shape of the differential space curve is "1", such as Figure 2 The continuous change segment shown, such as Figure 3 The "straight line" segment with a curve value ≈ 0 indicates that the signal does not jump, and the heading signal is not processed;

[0030] Step 3-2, sub-problem 2 is the shape of the difference space curve Shape, such as Figure 2 The value near +180 degrees shown suddenly jumps to a value near -180 degrees, such as Figure 3 The descending section of the curve value ≈ -360 indicates that the signal jumps down from unchanged, so 360 degrees needs to be added when processing the heading signal;

[0031] Step 3-3, sub-problem 3 is the shape of the difference space curve Shape, such as Figure 2 The value near -180 degrees shown suddenly jumps to a value near +180 degrees, such as Figure 3 The rising section of the curve value ≈ +360 shown indicates that the signal jumps from a constant value to a high value, so 360 degrees needs to be subtracted when processing the heading signal.

[0032] The fourth step is to merge the solutions of the three sub-problems in the third step and generalize them to support any form of transition signal within the range of ±180 degrees (such as Figure 5 The solid line shown) is converted into a continuous signal in the range of ±∞ (such as Figure 5 The method of merging the solutions of the sub-problems is to refer to the third step, determine the sub-problem category to which the current differential space curve shape belongs, and process the current heading signal as appropriate:

[0033] (1) If it belongs to sub-problem 1, that is, the shape of the differential space curve in step 3-1 is "1", indicating that the signal remains unchanged, then the heading signal processing is plus / minus 360 degrees × n, where n ≥ 0 is the number of times 360 degrees has been added / subtracted (e.g. Figure 5 The dashed line shows a continuous change of true heading value from 0 to -700).

[0034] (2) If it belongs to sub-problem 2, that is, it satisfies step 3-2, the shape of the differential space curve is Shape, indicating that the signal jumps from unchanged to low. First, determine the situation of adding / subtracting 360 degrees × n in the unchanged segment before the jump:

[0035] ① If n == 0, the heading signal processing is increased by 360 degrees;

[0036] ② Otherwise:

[0037] i. If the unchanged section before the jump is reduced by 360 degrees × n, then the heading signal processing is reduced by 360 degrees × (n-1)

[0038] (like Figure 5 The dashed line descending segment between 6000 seconds and 10000 seconds on the time axis shown);

[0039] ii. If the unchanged section before the jump is increased by 360 degrees × n, then the heading signal processing is increased by 360 degrees × (n + 1)

[0040] (like Figure 5 The rising segment of the dotted line between 6000 seconds and 10000 seconds on the time axis is shown).

[0041] (3) If it belongs to sub-problem 3, that is, it satisfies step 3-3, the shape of the differential space curve is Shape, indicating that the signal jumps from unchanged to high. First, determine the situation of adding / subtracting 360 degrees × n in the unchanged segment before the jump:

[0042] ① If n == 0, the heading signal processing minus 360 degrees;

[0043] ② Otherwise:

[0044] i. If the unchanged section before the jump is increased by 360 degrees × n, then the heading signal processing is increased by 360 degrees × (n-1)

[0045] (like Figure 5 The rising section of the dotted line between 2500 seconds and 5000 seconds on the time axis shown);

[0046] ii. If the unchanged section before the jump is reduced by 360 degrees × n, then the heading signal processing is reduced by 360 degrees × (n + 1)

[0047] (like Figure 5 The dashed descending segment between 2500 seconds and 5000 seconds on the time axis is shown).

[0048] The pseudo code is as follows:

[0049] Let the number of additions / subtractions n be 0;

[0050] When a jump occurs {

[0051] If shape{

[0052] If n is 0, the heading signal is +360 degrees, and n is 1;

[0053] If the previous value is minus 360 degrees × n, the heading signal is -360 degrees × (n-1), n ​​= n-1;

[0054] If 360 degrees × n is added before, the heading signal + 360 degrees × (n + 1), n ​​= n + 1;

[0055] }

[0056] If shape{

[0057] If n is 0, the heading signal is -360 degrees, and n is 1;

[0058] If 360 degrees × n is added before, the heading signal + 360 degrees × (n-1), n ​​= n-1;

[0059] If the previous value is minus 360 degrees × n, the heading signal is -360 degrees × (n+1), n ​​= n+1;

[0060] }

[0061] }

[0062] Another discrete heading signal processing result is as follows Figure 6 shown.

Claims

1. A flight test data heading signal processing method, characterized in that: include: Step 1: backward difference calculation, performing a pairwise difference operation on the discrete heading signals, i.e. mapping them into the difference space; Step 2: Define the conversion rules, analyze the law of the differential space image curve, and transform the jump into three sub-problems: "signal unchanged", "signal jump low", and "signal jump high"; Step 3: Solve the sub-problems, respectively solve the three sub-problems obtained by the transformation; Step 4: Combine the solutions of the sub-problems and convert any transition signal within the range of ±180 degrees into a continuous signal within the range of ±∞.

2. The flight test data heading signal processing method according to claim 1, characterized in that: Step 2 specifically includes: Step 2-1, draw the backward difference space curve graph obtained in step 1; Step 2-2: Analyze the law of the backward difference space curve graph in step 2-1 and divide it into "one" shape, Shape and The shapes represent the three sub-problems of "signal unchanged", "signal jumps low" and "signal jumps high".

3. The flight test data heading signal processing method according to claim 1, characterized in that: The sub-problems to be solved include: For the "signal unchanged" sub-problem, the heading signal is not processed; For the "signal jump low" sub-problem, the heading signal processing is added 360 degrees; For the "signal jump height" sub-problem, the heading signal processing minus 360 degrees.

4. The flight test data heading signal processing method according to claim 3, characterized in that: Step 4 specifically includes: (1) If the differential space curve is in the shape of a "1", the heading signal processing is plus / minus 360 degrees × n, where n ≥ 0, which is the number of times 360 degrees have been added / minus; (2) For the difference space curve shape Shape, first determine the situation of adding / subtracting 360 degrees × n before jumping down: If n == 0, the heading signal processing adds 360 degrees; Otherwise: if the unchanged section before the low jump is reduced by 360 degrees × n, then the heading signal processing is reduced by 360 degrees × (n-1); if the unchanged section before the low jump is increased by 360 degrees × n, then the heading signal processing is increased by 360 degrees × (n+1); (3) For the difference space curve shape Shape, first determine the situation of adding / subtracting 360 degrees × n before the high jump: If n == 0, the heading signal processing minus 360 degrees; Otherwise: if the unchanged segment before the high jump is increased by 360 degrees × n, the heading signal processing is increased by 360 degrees × (n-1); if the unchanged segment before the low jump is decreased by 360 degrees × n, the heading signal processing is decreased by 360 degrees × (n+1).

5. The flight test data heading signal processing method according to claim 1, characterized in that: The specific process of backward difference calculation is: Take the heading signal value Psi(t) at time t and the heading signal value Psi(t-1) at time t-1; calculate the difference: Psi(t)-Psi(t-1).

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