A processing method for enhancing robustness of two-excess radio altitude signals

Abstract

This invention patent belongs to the field of fly-by-wire flight control law design for large firefighting amphibious aircraft, and relates to a processing method for enhancing the robustness of dual-redundant radio altitude signals. First, a "validity" check is performed, followed by a "availability" check. When the signal is valid and available, if the left-right deviation exceeds a threshold, the effective radio altitude voting signal from the previous moment is used, and after climb / fall rate correction, an approximately equivalent ground-free altitude signal is obtained. This effectively solves the short-term voting deviation problem of dual-redundant radio altitude signals and improves the robustness of the radio altitude signal.

Description

Technical Field

[0001] This invention patent belongs to the field of fly-by-wire flight control law design for large firefighting amphibious aircraft, and relates to a processing method to enhance the robustness of dual-redundant radio altitude signals. Background Technology

[0002] Radio altitude signals work by transmitting radio waves to the ground and measuring the time required to receive the reflected waves, thereby calculating the aircraft's altitude. Due to limitations in the principle of radio altitude measurement, radio altitude signals are easily affected by reflections from complex terrain or other clutter.

[0003] Civilian transport aircraft typically have two sets of radio altimeters, providing dual-redundant altitude signals for determining the aircraft's altitude. For traditional mechanical aircraft, radio altimeters are primarily used by the pilot to determine altitude; if the left and right altimeters are inconsistent, the pilot can visually determine which side's altitude signal value to display. However, for fly-by-wire (FBB) aircraft, in addition to determining altitude, the radio altimeter signal plays a crucial role in the automatic switching of the flight control system's control law modes. When the dual-redundant signals are inconsistent, the system cannot automatically determine which signal is correct and which is incorrect, reducing signal availability. The general voting logic for FBB systems is that when the dual-redundant radio altimeter signal exceeds the limit, the primary flight control system considers the signal unreliable and latches it, no longer using it. For civil transport aircraft, low-altitude flight primarily occurs during airport takeoffs and landings. The terrain near airports is relatively flat, and the radio altimeter signal is relatively stable, making altitude latch-up less likely. For firefighting aircraft that frequently operate at low altitudes and in mountainous areas, radio altitude signals are susceptible to interference from complex terrain, necessitating a special processing method to enhance their robustness. In some cases, improving the measurement accuracy and anti-interference capabilities of the radio altitude signal itself, or increasing its redundancy (e.g., using triple redundancy), can improve robustness to some extent. However, the inherent anti-interference capabilities of radio altitude signals cannot completely eliminate interference from complex terrain, and using higher redundancy radio altitude signals would significantly increase the aircraft's cost. Summary of the Invention

[0004] Purpose of the invention

[0005] This method improves the signal robustness of two sets of radio altimeter signals by applying a specific voting process to the two sets of radio altimeter signals, when the product itself cannot be improved and the radio altimeter margin cannot be increased.

[0006] Technical solution

[0007] A processing method to enhance the robustness of dual-redundant radio altitude signals first performs a "validity" check, then a "availability" check. When the signal is valid and available, if the left and right deviations exceed the threshold, the effective radio altitude voting signal from the previous moment is used, and after correction of the ascent and descent speeds, an approximately equivalent ground-free altitude signal is obtained to compensate for the short-term radio altitude signal deviation.

[0008] Further steps include the following:

[0009] Step 1: Validity Check. Check the status signals RA1_STATE and RA2_STATE of the dual-redundancy radio altitudes RA1 and RA2. When the radio altitude is valid, the signal is marked as "valid". For example, if the status signal RA1_STATE = 1, then the radio altitude RA1 is marked as "valid"; otherwise, RA1 is marked as "invalid".

[0010] Step 2: Availability Check. Monitor the numerical change of signals marked as "valid" in real time. For example, if a radio signal is highly valid and its numerical change rate Δt exceeds 30 m / s within a given time period, the signal is marked as "unavailable"; otherwise, it is marked as "available".

[0011] Step 3: When a radio altitude is marked as "invalid", the radio altitude is determined using another radio altitude signal as the radio voting value RA_VOTE;

[0012] Step 4: If both radio altitudes are marked as "invalid", then the radio altitude signal is invalid;

[0013] Step 5: Compare and monitor the two radio altitude signals to obtain the difference ΔH between the two radio altitudes.

[0014] Step 6: When both radio altitude signals are "valid" and "available" and the "altitude difference ΔH does not exceed the threshold value", the average of the two signals is taken as the radio altitude voting value RA_VOTE.

[0015] Step 7: When both radio altitude signals are "valid" and "available" and the "altitude difference ΔH exceeds the threshold value",

[0016] 1) Determination of the virtual signal RA3. The radio altitude voting value RA_VOTE from the previous moment is used and corrected by the ascent and descent rate Vz to obtain the third reconstructed radio altitude virtual signal RA3. RA3 is then used as the output radio altitude voting value RA_VOTE.

[0017] 2) Recovery of RA1 and RA2. If the comparison and monitoring of RA1 and RA2 do not exceed the threshold for 5 consecutive seconds, the average value of RA1 and RA2 is taken as the radio altitude voting value RA_VOTE.

[0018] 3) If the “RA1 and RA2 comparison exceeds the threshold” continues for more than 1 minute, the radio altitude signal will fail.

[0019] Furthermore, in step 8: if both radio altitude signals are "valid" but one of them is marked as "unavailable", then the other radio altitude signal is used as the radio altitude signal voting value RA_VOTE.

[0020] Further, step 9: Clear the "Unavailable" flag. Clear the "Unavailable" flag if the altitude difference ΔH between the two radios does not exceed the threshold for 5 seconds.

[0021] Furthermore, in step 2, the given time interval is Δt = 1s.

[0022] Furthermore, in step 2, additional processing logic is applied based on the characteristics of the radio altitude signal. For large transport aircraft, unlike fighter jets which pursue high maneuverability, their maximum climb and fall speed capabilities are limited. A threshold value is set that is impossible to occur under normal aircraft operating conditions. This effectively eliminates situations where a signal fails due to abrupt changes in radio altitude caused by complex terrain or high-altitude errors, resulting in inconsistencies between two radio altitude signals.

[0023] Furthermore, in step 7(1), the expression for the virtual signal RA3 is as follows:

[0024] RA3=RA_VOTE(Step 1)+Vz*ts…………………………………….(2)

[0025] In the formula, Vz is the acceleration / deceleration speed, and ts is the sampling period.

[0026] Furthermore, in step 9, if a radio altitude signal is already marked as "unavailable" and a second radio altitude signal is marked as "unavailable" before the "unavailable" status is cleared, then the radio altitude signal becomes invalid.

[0027] Furthermore, a computer signal processing unit stores computer execution instructions, characterized in that the computer instructions are used to execute the processing method for enhancing the robustness of dual-redundant radio altitude signals.

[0028] Furthermore, a computer module employing the computer signal processing unit.

[0029] Furthermore, a computer whose software utilizes the computer module.

[0030] Furthermore, a large amphibious firefighting aircraft is provided, wherein the computer is installed on the large amphibious firefighting aircraft.

[0031] The beneficial effects of this application are as follows:

[0032] This invention, without adding additional radio altitude redundancy, effectively solves the problem of short-term voting errors in dual-redundancy radio altitude signals by using only the elevation and descent speeds measured by airborne sensors and a special signal voting processing method, thereby improving the robustness of radio altitude signals. Attached Figure Description

[0033] Figure 1 This is the execution logic diagram of this processing method;

[0034] Figure 2 It is a flight test data chart;

[0035] Figure 3 Correction error diagram;

[0036] Figure 4 This is a diagram illustrating a temporary inconsistency in height. Detailed Implementation

[0037] The present invention will be further described below with reference to embodiments. The following description represents only a portion of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] This invention discloses a processing method for enhancing the robustness of dual-redundant radio altitude signals of large firefighting amphibious aircraft. The main principle is to first perform an "validity" check, and then a "availability" check. When the signal is valid and available, if the left and right deviation exceeds the threshold, the effective radio altitude voting signal from the previous moment is used, and after correction by the climb rate, an approximately equivalent altitude signal is obtained to compensate for the short-term radio altitude signal deviation.

[0039] A method for enhancing the robustness of dual-redundant radio altitude signals includes the following steps:

[0040] Step 1: Validity Check. Check the status signals RA1_STATE and RA2_STATE of the dual-redundancy radio altitudes RA1 and RA2. When a radio altitude is valid, the signal is marked as "valid". For example, if the status signal RA1_STATE = 1, then radio altitude RA1 is marked as "valid"; otherwise, RA1 is marked as "invalid". This ensures that if a signal fails due to its own malfunction, it is removed from the signal voting process, thereby improving signal reliability.

[0041] Step 2: Availability Check. Monitor the numerical change of signals marked as "valid" in real time. For example, if a radio altitude signal is valid, and its rate of change exceeds 30 m / s within a given time (Δt = 1 s), the signal is marked as "unavailable"; otherwise, it is marked as "available." The purpose of the availability check is to implement additional processing logic based on the characteristics of the radio altitude signal. For large transport aircraft, unlike fighter jets which prioritize high maneuverability, their maximum climb and fall speed capabilities are limited. Setting a threshold value (30 m / s, derived from extensive flight test data) that is impossible under normal aircraft operating conditions can effectively eliminate situations where a signal fails due to drastic changes in altitude caused by complex terrain or high-altitude errors leading to inconsistent altitudes between two signals. This further improves signal reliability after the availability check.

[0042] Step 3: When a radio altitude is marked as "invalid", the radio altitude is determined using another radio altitude signal as the radio voting value RA_VOTE;

[0043] Step 4: If both radio altitudes are marked as "invalid", then the radio altitude signal is invalid;

[0044] Step 5: Compare and monitor the two radio altitude signals to obtain the difference ΔH between the two radio altitudes.

[0045] Step 6: When both radio altitude signals are "valid" and "available" and the "altitude difference ΔH does not exceed the threshold value", the average of the two signals is taken as the radio altitude voting value RA_VOTE.

[0046] Step 7: When both radio altitude signals are "valid" and "available" and the "altitude difference ΔH exceeds the threshold value",

[0047] 1) Determination of the virtual signal RA3. The previous radio altitude voting value RA_VOTE (step 1) is used as the basis for correction using the ascent / descent rate Vz to obtain the third reconstructed virtual radio altitude signal RA3. RA3 is then output as the radio altitude voting value RA_VOTE. The expression for the virtual signal RA3 is as follows:

[0048] RA3=RA_VOTE(Step 1)+Vz*ts…………………………………….(3)

[0049] In the formula, Vz is the acceleration / deceleration speed, and ts is the sampling period.

[0050] 2) Recovery of RA1 and RA2. If the comparison and monitoring of RA1 and RA2 do not exceed the threshold for 5 consecutive seconds, the average value of RA1 and RA2 is taken as the radio altitude voting value RA_VOTE.

[0051] 3) If the “RA1 and RA2 comparison exceeds the threshold” continues for more than 1 minute, the radio altitude signal will fail.

[0052] Step 8: If both radio altitude signals are "valid" but one of them is marked as "unavailable", then the other radio altitude signal is used as the radio altitude signal voting value RA_VOTE.

[0053] Step 9: Clear the "Unavailable" flag. Clear the "Unavailable" flag if the difference between two radio altitudes ΔH does not exceed the threshold for 5 consecutive seconds. If a second radio altitude is marked "Unavailable" before the first one is cleared, the radio altitude signal is considered invalid.

[0054] The addition of the virtual signal RA3 effectively resolves temporary altitude discrepancies caused by brief terrain changes, where one radio altimeter measures a low-lying target while another measures a high-lying target. A specific illustration is provided below. Figure 4 As shown.

[0055] Depend on Figure 4As shown, when both radio altitude signals are "valid" and "available," when the aircraft flies over irregular terrain, the actual measured ground clearance value of the radio altitude RA1 on the "low terrain" side will be greater than the measured ground clearance value of the radio altitude RA2 on the "high terrain" side. This is because the actual ground clearance values ​​on the left and right sides of the aircraft are not the same. When the difference between the two values ​​continuously exceeds the voting threshold, the control system cannot determine the accuracy of the signal, causing the 1:1 voting to fail. This step, using the virtual signal RA3, effectively solves the radio altitude signal failure in this scenario. For amphibious aircraft that frequently navigate complex low-altitude terrain, it can effectively improve the robustness of the radio altitude signal.

[0056] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein. The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A processing method for enhancing the robustness of dual-redundant radio altitude signals, characterized in that, First, a validity check is performed, followed by an availability check. When the signal is valid and available, if the left-right deviation exceeds the threshold, an approximately equivalent ground-free altitude signal is obtained by using the valid radio altitude voting signal from the previous moment, after correction for ascent and descent speeds, to compensate for the short-term radio altitude signal deviation. This process includes the following steps: Step 1: Validity check; check the status signals RA1_STATE and RA2_STATE of the dual-redundancy radio altitudes RA1 and RA2; if the radio altitude is valid, mark the signal as valid; if the status signal RA1_STATE=1, mark the radio altitude RA1 as valid; otherwise, mark RA1 as invalid. Step 2: Availability check; real-time monitoring of the numerical change of signals marked as valid; when a radio altitude is valid, if the rate of change of its value Δt exceeds 30m / s within a given time period, the signal is marked as unavailable; otherwise, it is marked as available. Step 3: If a radio altitude identifier is invalid, the radio altitude is adopted as the radio voting value RA_VOTE using another radio altitude signal; Step 4: If both radio altitudes are marked as invalid, the radio altitude signal is invalid; Step 5: Compare and monitor the two radio altitude signals, and provide the difference ΔH between the two radio altitudes; Step 6: When both radio altitude signals are valid and available and the altitude difference ΔH does not exceed the threshold, the average of the two signals is taken as the radio altitude voting value RA_VOTE. Step 7: When both radio altitude signals are valid and available, and the altitude difference ΔH exceeds the threshold value, 1) Determination of the virtual signal RA3: The radio altitude voting value RA_VOTE from the previous moment is corrected using the ascent / descent rate Vz to obtain the third reconstructed radio altitude virtual signal RA3. RA3 is then output as the radio altitude voting value RA_VOTE. The expression for the virtual signal RA3 is as follows: RA3 = RA_VOTE + Vz*ts……………………(1) In the formula, Vz is the acceleration / deceleration speed, and ts is the sampling period; 2) Recovery of RA1 and RA2; if the altitude difference ΔH does not exceed the threshold for 5 consecutive seconds, the average of RA1 and RA2 is taken as the radio altitude voting value RA_VOTE; 3) If the altitude difference ΔH exceeds the threshold for more than 1 minute, the radio altitude signal will fail.

2. The processing method as described in claim 1, characterized in that, It also includes step 8: when both radio altitude signals are valid but one of the radio altitude signals is marked as unavailable, the other radio altitude signal is used as the radio altitude signal voting value RA_VOTE.

3. The processing method as described in claim 2, characterized in that, It also includes step 9: Clear the unavailable flag; if the height difference ΔH between the two radios does not exceed the threshold for 5 seconds, the unavailable flag is cleared.

4. The processing method as described in claim 1, characterized in that, In step 2, the given time interval is Δt = 1s.

5. The processing method as described in claim 1, characterized in that, In step 2, additional processing logic is performed based on the characteristics of the radio altitude signal. For large transport aircraft, unlike fighter jets that pursue high maneuverability, their maximum climb and fall speed capabilities are limited. A threshold value is set that is impossible to occur under normal aircraft operating conditions. This effectively eliminates the situation where a certain signal fails due to a sudden change in the radio altitude signal caused by a small altitude failure caused by complex terrain or high-altitude errors, resulting in inconsistency between two radio altitude signals and exceeding the tolerance.

6. The processing method as described in claim 3, characterized in that, In step 9, if a radio altitude signal is marked as unavailable and a second radio altitude signal is marked as unavailable before the unavailable status is cleared, then the radio altitude signal becomes invalid.

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