A double-point real-time temperature correction method for barometer in extremely cold environment

Abstract

The application discloses a kind of barometer double-point real-time temperature correction method under extremely cold environment, microcontroller records reference point display height and standard temperature in offline stage, and obtains real-time environmental temperature synchronously when online running, and the same real-time temperature is used to correct respectively for current measuring point and starting reference point: current point correction height, reference point correction height and dynamic deviation ΔH are calculated, and finally output;While eliminating numerical oscillation through temperature filtering and temperature-height decoupling calculation.The application reduces elevation error from tens of meters to sub-meter under-30 ℃ extremely cold environment, completely eliminates the jagged fluctuation when temperature changes rapidly, is simple to calibrate, has high reliability, and is suitable for unmanned aerial vehicle autonomous navigation, polar scientific expedition, high-latitude pipeline inspection and other high-precision elevation measurement scenes.

Description

Technical Field

[0001] This invention relates to the field of barometric altimeter technology, specifically a method for significantly improving the measurement accuracy of a barometric altimeter and eliminating numerical oscillations caused by rapid temperature changes in extremely cold environments (-10℃ and below) through dual-point real-time temperature synchronization correction. Background Technology

[0002] With the increasing use of drones for autonomous navigation, polar scientific expeditions, high-latitude pipeline inspections, and winter flight missions, barometric altimeters, as a low-cost and highly reliable method of altitude measurement, are widely used on various motion platforms. Barometric altimeters operate based on the International Standard Atmosphere (ISA) model, and their pressure-to-elevation conversion formula assumes a sea-level standard temperature of 15°C and a temperature lapse rate of 6.5°C / km.

[0003] However, in actual extremely cold environments (such as Mohe in my country where winter temperatures can reach -30℃), the actual atmospheric temperature deviates significantly from the ISA standard value, leading to a systematic deviation in the pressure-altitude conversion relationship. Traditional temperature correction methods only compensate for the temperature at the current measurement point, while the initial reference point still uses a fixed calibration temperature (e.g., 15℃) to calculate the deviation ΔH, resulting in inconsistencies between the temperature references at both ends. When the ambient temperature changes rapidly, the correction slope at the current point mismatches with the correction slope at the starting point, producing periodic overshoot-rebound errors. This manifests as sawtooth fluctuations in the elevation output, severely degrading accuracy and failing to meet engineering measurement requirements.

[0004] Therefore, it is imperative to develop a barometric altimeter temperature correction method that can achieve high accuracy throughout the entire stroke and eliminate temperature-coupled oscillations in extremely cold environments. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a two-point real-time temperature correction method for barometric altimeters in extremely cold environments. By using two-point real-time temperature synchronous correction and temperature-altitude decoupling calculation, the method eliminates areas with poor hysteresis and achieves high-precision elevation output.

[0006] The technical solution provided by this invention to solve the above problems is: a method for real-time temperature correction of a barometric altimeter at two points in extremely cold environments, the method comprising: The current atmospheric pressure is collected by a barometric pressure sensor and converted into an altitude display. ; Real-time ambient temperature is collected via a temperature sensor. ; A microcontroller is used to execute a two-point real-time temperature synchronization correction algorithm, wherein the algorithm includes: Calculate the standard temperature at the current point ; Calculate the corrected height of the current point ; Calculate the reference point standard temperature ; Calculate the corrected height of the reference point ; Calculate dynamic benchmark deviation ; Output final elevation .

[0007] Preferably, the reference point correction height and the current point correction height use the same real-time ambient temperature. Ensure that the temperature correction slopes at both ends are consistent.

[0008] Preferably, the method further includes a temperature filtering step using a microcontroller: performing low-pass filtering on the real-time temperature sensor data, and using the filtered temperature for two-point correction calculation to suppress the jitter of the correction coefficient caused by sensor noise.

[0009] Preferably, the microcontroller performs a first-order low-pass filter on the raw data from the temperature sensor, with the filter coefficient α ranging from 0.05 to 0.2, and the filtered temperature is used for two-point correction calculation.

[0010] Preferably, the standard temperature The calculation uses a fixed reference height or the output height of the previous cycle to avoid forming a closed-loop feedback with the real-time displayed height, thereby eliminating numerical oscillations when the temperature changes rapidly.

[0011] Preferably, the method reduces the elevation measurement error from tens of meters to sub-meters in an extremely cold environment of -30℃, and outputs without sawtooth fluctuations when the temperature changes rapidly.

[0012] Preferably, the method only requires adding a real-time temperature correction step for the reference point to the original pressure-height conversion algorithm, and recording the displayed height of the reference point during offline calibration. No additional calibration equipment is required when running online.

[0013] Compared with the prior art, the advantages of the present invention are: by synchronously correcting the starting reference point and the current measurement point using the same real-time ambient temperature, the temperature-altitude coupling feedback is broken, numerical oscillations are eliminated, and the elevation measurement error in extremely cold environments is reduced from tens of meters to sub-meters. Attached Figure Description

[0014] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0015] Figure 1This is a principle block diagram of the dual-point real-time temperature correction method of the present invention; Figure 2 This is a comparison curve of the error between the present invention and three traditional methods: single-point correction and no correction. Figure 3 This is a comparison curve showing the impact of temperature changes on the errors of the three correction methods; Figure 4 This is a comparison chart of the absolute values ​​of the outbound and inbound errors grouped together; Figure 5 This is a comparison chart of statistical indicators for the three correction methods.

[0016] Figure 6 It is a software flowchart. Detailed Implementation

[0017] The following will describe in detail the implementation of the present invention with reference to the accompanying drawings and embodiments, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0018] In the description of this invention, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature, and in the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0020] In this invention, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0022] It should also be understood that the terminology used in this specification of embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of the invention. As used in this specification of embodiments of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. Example 1: Algorithm Implementation

[0023] A method for real-time temperature correction of a barometric altimeter at two points in extremely cold environments includes: 1. Signal Acquisition Unit The signal acquisition unit includes a barometric pressure sensor, a temperature sensor, and a microcontroller. The barometric pressure sensor is used to acquire the current atmospheric pressure and convert it into a display altimeter (H); the temperature sensor is used to acquire the real-time ambient temperature (T); and the microcontroller acquires the barometric pressure and temperature data in parallel via an I2C or SPI bus.

[0024] 2. Dual-point real-time correction unit The microcontroller internally executes a two-point real-time temperature correction algorithm: • Calculate the current standard temperature:

[0025] • Calculate the corrected height for the current point:

[0026] • Calculate the reference point standard temperature:

[0027] • Calculate the corrected height of the benchmark point:

[0028] • Calculate the dynamic baseline deviation:

[0029] • Output the final elevation:

[0030] 3. Temperature filtering unit

[0031] The microcontroller performs a first-order low-pass filter on the raw data from the temperature sensor: ,

[0032] Where α is the filtering coefficient, with a value of 0.05 to 0.2, used to suppress high jitter caused by temperature noise.

[0033] 4. Decoupled computing unit To avoid The calculation and real-time altitude form a closed-loop feedback. The calculation uses a fixed reference height (such as the initial height after power-on stabilization) or the output height of the previous cycle, rather than the current real-time displayed height, thereby eliminating numerical oscillations. Example 2: Algorithm Implementation

[0034] To verify the effectiveness of this invention in extremely cold environments, a sports car test was conducted in Mohe City, Heilongjiang Province during winter. Test conditions: ambient temperature -14.1℃ to -25.1℃, test route including outbound and return journeys, elevation difference of approximately 140m, data collected using an altimeter and BeiDou satellite, with BeiDou satellite measurements used as the baseline true value.

[0035] Table 1: Outbound test data (temperature dropped from -14.1℃ to -21.6℃): , Table 2: Return test data (temperature dropped from -21.8℃ to -25.1℃, passing through the same points): , Data Analysis: 1. Original error: Without temperature correction, the error range is -5.40m to +17.12m, which increases significantly with the increase of elevation difference. Moreover, during the return trip, the error at the same point increases significantly due to the further decrease in temperature.

[0036] 2. Single-point correction error (correction only at the current point, starting point fixed): The error was manageable on the outbound journey (maximum -8.63m), but as the temperature continued to decrease during the run (from -14.1℃ to -25.1℃), the return error deteriorated sharply to -16.70m, showing a clear systematic underreading trend. This is because the starting point is still locked at a higher temperature, while the current point is at a lower temperature, resulting in a mismatch in the temperature slopes at both ends, and the error amplifies linearly with the temperature difference.

[0037] 3. Dual-point error correction (in this invention, the starting point and the current point are corrected synchronously): The error is controlled within the range of 0 to -4.74m throughout the entire journey. The error distribution is consistent for both the outbound and return journeys, and there is no phenomenon of deterioration with temperature changes. In particular, at the same 467.57m reference point, the error is 0m when the outbound journey is the starting point, and the error is only -4.74m when the return journey passes through it, which is significantly better than the -16.70m of the single-point correction. Table 3: Statistical comparison: , Key findings: While single-point correction provides some improvement in the initial stage, when the temperature change exceeds 7°C (from -14.1°C to -21.8°C), the hysteresis error deteriorates from -8.63m to -16.70m, with an error amplification factor of 1.93 times. In contrast, the dual-point correction of this invention keeps the error within 5m at all times, and temperature changes do not cause error amplification.

[0038] Example 3: Comparison of temperature changes at the same location before and after

[0039] Table 4: Comparing the errors before and after temperature changes by selecting a reference point of 467.57m (starting point of the outbound journey and ending point of the return journey): , The data shows that:

[0040] After the temperature decreased by 10.4℃, the single-point correction error increased from 0m to -16.70m, while the double-point correction error was only -4.74m, verifying the strong robustness of the double-point synchronous correction to temperature changes.

[0041] The above description only illustrates the preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All modifications made within the scope of the independent claims of this invention are also within the scope of protection of this invention.

Claims

1. A method for real-time temperature correction of a barometric altimeter at two points in extremely cold environments, characterized in that, The method includes: The current atmospheric pressure is collected by a barometric pressure sensor and converted into an altitude display. ; Real-time ambient temperature is collected via a temperature sensor. ; A microcontroller is used to execute a two-point real-time temperature synchronization correction algorithm, wherein the algorithm includes: Calculate the standard temperature at the current point ; Calculate the corrected height of the current point ; Calculate the reference point standard temperature ; Calculate the corrected height of the reference point ; Calculate dynamic benchmark deviation ; Output final elevation .

2. The method for dual-point real-time temperature correction of a barometric altimeter in extremely cold environments according to claim 1, characterized in that, in, The reference point correction height and the current point correction height use the same real-time ambient temperature. Ensure that the temperature correction slopes at both ends are consistent.

3. The method for dual-point real-time temperature correction of a barometric altimeter in extremely cold environments according to claim 1, characterized in that, The method further includes a temperature filtering step using a microcontroller: low-pass filtering is performed on the real-time temperature sensor data, and the filtered temperature is used for two-point correction calculation to suppress the jitter of the correction coefficient caused by sensor noise.

4. The method for dual-point real-time temperature correction of a barometric altimeter in extremely cold environments according to claim 3, characterized in that, The microcontroller performs a first-order low-pass filter on the raw data from the temperature sensor, with the filter coefficient α ranging from 0.05 to 0.

2. The filtered temperature is then used for two-point correction calculations.

5. The method for dual-point real-time temperature correction of a barometric altimeter in extremely cold environments according to claim 1, characterized in that, The standard temperature The calculation uses a fixed reference height or the output height of the previous cycle to avoid forming a closed-loop feedback with the real-time displayed height, thereby eliminating numerical oscillations when the temperature changes rapidly.

6. The method for dual-point real-time temperature correction of a barometric altimeter in extremely cold environments according to claim 1, characterized in that, The method reduces elevation measurement error from tens of meters to sub-meters in extremely cold environments of -30℃, and outputs without sawtooth fluctuations when the temperature changes rapidly.

7. The method for real-time temperature correction of a barometric altimeter in extremely cold environments according to claim 1, characterized in that: The method only requires adding a real-time temperature correction step for the reference point to the original pressure-height conversion algorithm, and recording the displayed height of the reference point during offline calibration. No additional calibration equipment is required when running online.

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