A method and system for individual calibration of channel coefficients used by a radiosonde

Abstract

This invention relates to a method and system for individually calibrating channel coefficients used in a radiosonde. The method includes: S1, sending a command to the radiosonde; S2, if the radiosonde does not respond, returning to S1; if the radiosonde responds, proceeding to S3; S3, outputting a known standard resistance value to the radiosonde, calibrating the actual ADC sampling value according to the known standard resistance value, obtaining calibration result parameters, calculating a target resistance value based on the calibration result parameters, and returning to S1 to store the calibration result parameters; S4, establishing a resistance-ADC mapping model based on the calibrated actual ADC sampling value and the target resistance value, and obtaining the actual resistance value corresponding to the ADC value based on the resistance-ADC mapping model. This invention can effectively improve calibration accuracy.

Description

Technical Field

[0001] This invention relates to the field of radiosonde calibration technology, and in particular to a method and system for individually calibrating channel coefficients used in radiosondes. Background Technology

[0002] Temperature measurement in radiosondes typically uses platinum resistance thermometers (PTTs), whose resistance changes with temperature. PTTs are widely used in atmospheric monitoring, industrial control, medical applications, and food processing. The internal measurement circuit of a radiosonde generally employs an ADC (analog-to-digital converter) for data acquisition combined with a resistor voltage divider method. The resistance value of the platinum resistor is calculated by measuring the voltage after the voltage divider is applied, and then converted to temperature based on the temperature-resistance characteristic of the platinum resistor. However, due to the nonlinear characteristics of the resistor voltage divider circuit, the relationship between the ADC value and the platinum resistor resistance value is not strictly linear. Therefore, channel coefficient calibration is required to optimize measurement accuracy and make the mapping relationship from the ADC value to the resistance value more precise.

[0003] Existing methods for calibrating channel coefficients in radiosondes primarily rely on manual operation. This typically involves manually switching different calibration resistors, reading ADC measurements from a host computer, and then writing data from multiple calibration points into the radiosonde for linear calibration. However, this approach has several drawbacks: First, the calibration process is cumbersome and inefficient due to its manual operation, making it unsuitable for mass production. Second, the limited number of selectable calibration points due to the manual resistor switching method may result in insufficient fitting accuracy, affecting measurement precision. Furthermore, the reference resistor may drift due to ambient temperature, further increasing calibration errors. Therefore, those skilled in the art have developed a method and system for individually calibrating channel coefficients in radiosondes to address the problems described in the background section. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for individually calibrating the channel coefficients of a radiosonde, which adopts a multi-point calibration approach to effectively improve calibration accuracy.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A method for individually calibrating the channel coefficients used in a radiosonde includes:

[0007] S1. Send commands to the radiosonde;

[0008] S2. If the radiosonde does not respond, return to S1; if the radiosonde responds, proceed to S3.

[0009] S3. Output a known standard resistance value to the radiosonde, calibrate the actual ADC sampling value according to the known standard resistance value, and obtain calibration result parameters. Calculate the target resistance value according to the calibration result parameters, and return to S1 to store the calibration result parameters. The calibration result parameters are voltage offset factor, estimated resistance, proportional correction factor, and ADC offset.

[0010] S4. Based on the actual ADC sampling value and the target resistance value, establish a resistance-ADC mapping model, and obtain the actual resistance value corresponding to the ADC value according to the resistance-ADC mapping model.

[0011] Optionally, in S3, the actual ADC sampled value is calibrated according to the known standard resistance value, including:

[0012] Calculate the theoretical ADC value based on the known standard resistance value;

[0013] Based on the theoretical ADC value, obtain the voltage offset factor;

[0014] The theoretical ADC value is corrected according to the voltage offset factor to obtain the corrected ADC value;

[0015] Based on the corrected ADC value, the estimated resistance is calculated using interpolation.

[0016] Calculate the proportional correction factor based on the estimated resistance;

[0017] Calculate the ADC offset based on the aforementioned proportional correction factor;

[0018] The actual ADC sample value is calibrated based on the ADC offset to obtain the calibrated actual ADC sample value.

[0019] Optionally, calculating the theoretical ADC value includes:

[0020]

[0021] in, Given the standard resistance value R x The theoretical ADC value, R pullup R is the resistance value of the voltage divider resistor in the ground section. ref This is the total value of the reference voltage divider resistors.

[0022] Optionally, obtaining the voltage offset factor includes:

[0023]

[0024] Among them, v adc This is the voltage offset factor. These are the theoretical ADC values ​​for the known standard resistances R2, R3, and R4, respectively.

[0025] Optionally, calculating and estimating the resistance includes:

[0026]

[0027] Among them, res a To estimate the resistance, and The ADC value is the corrected value after considering the known standard resistance values ​​R2 and R3.

[0028] Optionally, the calculation of the scaling correction factor includes:

[0029]

[0030] Among them, res k This is the scaling correction factor.

[0031] Optionally, calculating the ADC offset includes:

[0032]

[0033] Among them, del adc R1 is the ADC offset, R1 is the known standard resistance value R1, and R1′ is the uncalibrated measured resistance value R1′.

[0034] Optionally, calculating the target resistance value based on the calibration result parameters includes:

[0035] When the actual ADC sample value is greater than the preset value, calculate the target resistance value:

[0036]

[0037] Calculate the target resistance value when the actual ADC sample value is not greater than the preset value:

[0038]

[0039] Among them, ADC measured For the actual ADC sampled value, res adj This represents the target resistance value.

[0040] The present invention also provides a channel coefficient separate calibration system for radiosondes, comprising: a host computer control module, a response judgment module, a resistance output module, and a feedback module;

[0041] The host computer control module is used to send commands to the radiosonde;

[0042] The response judgment module is used to resend the command by the host computer control module if the radiosonde does not respond, and to enter the resistance output module if the radiosonde responds.

[0043] The resistance output module is used to output a known standard resistance value to the radiosonde, calibrate the actual ADC sampling value according to the known standard resistance value, obtain calibration result parameters, calculate the target resistance value according to the calibration result parameters, establish a resistance-ADC mapping model according to the calibrated actual ADC sampling value and the target resistance value, and obtain the actual resistance value corresponding to the ADC value according to the resistance-ADC mapping model. The calibration result parameters are voltage offset factor, estimated resistance, proportional correction factor, and ADC offset.

[0044] The feedback module is used to return the calibration result parameters to the host computer control module for storage.

[0045] The beneficial effects of this invention are as follows: This invention adopts a multi-point calibration method, which includes several standard resistors, and accurately constructs the resistance-ADC mapping relationship through a fitting formula, wherein a voltage offset factor (v) is introduced. adc ), estimating resistance (res) a ), proportional correction factor (res) k ) and ADC offset (del adc Algorithms such as [list of algorithms] can effectively improve calibration accuracy. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a flowchart illustrating a method for individually calibrating the channel coefficients of a radiosonde according to an embodiment of the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1:

[0051] like Figure 1 As shown, this embodiment provides a method for individually calibrating the channel coefficients used in a radiosonde, including:

[0052] S1. Send commands to the radiosonde;

[0053] S2. If the radiosonde does not respond, return to S1; if the radiosonde responds, proceed to S3.

[0054] S3. The known standard resistance value is output by the radiosonde. The actual ADC sampling value is calibrated according to the known standard resistance value, and the calibration result parameters are obtained. The target resistance value is calculated according to the calibration result parameters, and the calibration result parameters are returned to S1 to store the calibration result parameters. The calibration result parameters are voltage offset factor, estimated resistance, proportional correction factor, and ADC offset.

[0055] S4. Based on the actual ADC sampling value and the target resistance value, establish a resistance-ADC mapping model, and obtain the actual resistance value corresponding to the ADC value according to the resistance-ADC mapping model.

[0056] Furthermore, in S3, the actual ADC sampled value is calibrated based on the known standard resistance value, including:

[0057] Calculate the theoretical ADC value based on the known standard resistance value;

[0058] The voltage offset factor is obtained based on the theoretical ADC value;

[0059] The theoretical ADC value is corrected based on the voltage offset factor to obtain the corrected ADC value;

[0060] Based on the corrected ADC value, the estimated resistance is calculated using interpolation.

[0061] Calculate the proportional correction factor based on the estimated resistance;

[0062] Calculate the ADC offset based on the scaling correction factor;

[0063] The actual ADC sample value is calibrated based on the ADC offset to obtain the calibrated actual ADC sample.

[0064] Furthermore, the calculation of the theoretical ADC value includes:

[0065]

[0066] in, Given the standard resistance value R x The theoretical ADC value, R pullupR is the resistance value of the voltage divider resistor in the ground section. ref This is the total value of the reference voltage divider resistors.

[0067] Furthermore, obtaining the voltage offset factor includes:

[0068]

[0069] Among them, v adc This is the voltage offset factor. These are the theoretical ADC values ​​for the known standard resistances R2, R3, and R4, respectively.

[0070] Furthermore, the calculation and estimation of resistance includes:

[0071]

[0072] Among them, res a To estimate the resistance, and Given the standard resistance values ​​R2 and R3, the corrected ADC value is given. R2 is the known standard resistance value. AD' = AD + v adc .

[0073] Furthermore, the calculation of the scaling correction factor includes:

[0074]

[0075] Among them, res k This is the scaling correction factor.

[0076] Furthermore, calculating the ADC offset includes:

[0077]

[0078] Among them, del adc R1 is the ADC offset, R1 is the known standard resistance value R1, and R1′ is the uncalibrated measured resistance value R1′.

[0079] Furthermore, based on the calibration result parameters, the target resistance value is calculated as follows:

[0080] When the actual ADC sample value is greater than the preset value, calculate the target resistance value:

[0081]

[0082] Calculate the target resistance value when the actual ADC sample value is not greater than the preset value:

[0083]

[0084] Among them, ADC measured For the actual ADC sampled value, resadj This represents the target resistance value.

[0085] The following section uses actual calibration resistance values ​​of 10K, 100K, 300K, and 500K as examples to further illustrate the calibration method for the actual ADC sampled values ​​in this embodiment:

[0086] Step 1: Voltage offset factor v adc Calculation:

[0087] First, the theoretical ADC value is calculated using the actual values ​​of three sets of precision resistors: 100kΩ, 300kΩ, and 500kΩ.

[0088]

[0089] Among them, the voltage divider resistor R of the site pullup =150kΩ, total value of reference voltage divider resistor R ref =172kΩ, R x The actual measured value for each precision resistor.

[0090] Furthermore, the following empirical offset correction expression is constructed:

[0091]

[0092] Among them, v adc This is the voltage offset factor.

[0093] AD 100 AD 300 AD 500 These are the theoretical ADC values ​​for known standard resistances of 100kΩ, 300kΩ, and 500kΩ, respectively. This correction value exhibits good numerical symmetry, and its geometric meaning is: the ADC value at the midpoint (300kΩ). Due to resistance errors, the value may deviate from the true nonlinear fitting curve. This is achieved through v... adc The correction aligns the curve trend, making subsequent fitting more accurate.

[0094] Step 2: Estimate the resistance res a Calculation:

[0095] In obtaining v adc Then, add them to AD respectively. 100 With AD 300 The corrected ADC value AD' is constructed above. 100 With AD' 300 Then, an approximate estimate of the resistance to be measured is calculated using interpolation.

[0096]

[0097] Among them, AD' 100and AD' 300 Given the corrected ADC values ​​for standard resistances of 100kΩ and 300kΩ, AD' = AD + v adc .

[0098] This value provides an initial estimate of the resistance for subsequent scaling adjustments.

[0099] Step 3: Scale Correction Factor res k Calculation:

[0100] Considering the nonlinearity of the ADC-resistance response curve, a proportional correction factor res is further introduced. k Its expression is as follows:

[0101]

[0102] This step can be understood as: at the corrected voltage level, the resistance response at the target point is linearly scaled to the entire dynamic range of the ADC to construct a dynamic calibration factor for the nonlinear response.

[0103] Step 4: ADC offset del adc Calculation:

[0104] Using a 10kΩ precision resistor as a reference, the difference between its theoretical ADC value and the back-calculated ADC value is used, and then superimposed with v adc Finally, the ADC offset del required to obtain the actual measured value adc .

[0105] The specific expression is as follows:

[0106]

[0107] This value is directly used for calibration of the actual ADC sampled values:

[0108] ADC corrected =ADC measured +del adc

[0109] Among them, ADC corrected For calibrated ADC values, ADC measured This represents the actual ADC sample value.

[0110] Finally, the target resistance is accurately determined by using the voltage divider inverse calculation formula.

[0111] Calculate v adc ,res a ,res k del adc After obtaining the four coefficients, the target resistance value res can be determined based on these four coefficients. adjPerform a reverse calculation.

[0112] When the actual ADC sample value is ≥37000, linear slope compensation is used:

[0113]

[0114] When using the actual ADC sample value, use basic compensation:

[0115]

[0116] Based on the actual ADC sampling value and the target resistance value, a resistance-ADC mapping model is established, and the actual resistance value corresponding to the ADC value is obtained according to the resistance-ADC mapping model.

[0117] Example 2:

[0118] A channel coefficient independent calibration system for a radiosonde includes: a host computer control module, a response judgment module, a resistance output module, and a feedback module;

[0119] The host computer control module is used to send commands to the radiosonde;

[0120] The response judgment module is used to resend the command by the host computer control module if the radiosonde does not respond, and to enter the resistance output module if the radiosonde responds.

[0121] The resistance output module is used to output a known standard resistance value to the radiosonde, calibrate the actual ADC sampling value according to the known standard resistance value, obtain calibration result parameters, calculate the target resistance value according to the calibration result parameters, establish a resistance-ADC mapping model according to the calibrated actual ADC sampling value and the target resistance value, and obtain the actual resistance value corresponding to the ADC value according to the resistance-ADC mapping model. The calibration result parameters include voltage offset factor, estimated resistance, proportional correction factor, and ADC offset.

[0122] The feedback module is used to return to the resistance output module if all calibration points (10K, 100K, 300K, 500K) have not been output. If all calibration points have been output, the module obtains the calibration result parameters and returns them to the host computer control module to store the calibration result parameters.

[0123] Specifically, the workflow of the system in this embodiment includes:

[0124] Start-up phase: The calibration system enters the initial state after being powered on or receiving an external trigger signal.

[0125] Send query command: The host computer control module sends a standard query command to the radiosonde main controller to establish a communication connection and confirm the online status of the equipment.

[0126] Determine the radiosonde response: The system checks whether the radiosonde is responding normally. If there is no response, the system resends the command and enters a waiting loop; if the radiosonde responds normally, the system proceeds to the next step.

[0127] Output calibration resistance values: The system control terminal outputs multiple known standard resistance values, such as 10kΩ, 100kΩ, 300kΩ, and 500kΩ, sequentially to the radiosonde via a multi-channel resistor switching module or preset values ​​in the program. These values ​​are used to construct the ADC mapping relationship. The mapping relationship is the ADC value corresponding to the actual resistance value. For example, a 12-bit ADC mapped to a theoretical ADC value of 54012 at a 10K resistance might actually map to a value of 54020. Therefore, if the measured ADC value is 54020, the corresponding resistance is 10K. After calibration, the mapping relationship between the ADC and the resistance becomes more accurate and realistic.

[0128] Waiting for the radiosonde to transmit the measured resistance value: The radiosonde completes the voltage division sampling internally and sends the acquired raw ADC value back to the host computer or calibration control module through the communication interface.

[0129] Determine if resistance value output is complete: The system determines whether all calibration points (10K, 100K, 300K, 500K) have been output. If not, it returns to continue outputting the next standard resistance value until all are completed.

[0130] Calculate and transmit calibration coefficients: After receiving the ADC data corresponding to all resistance points, the system uses the multi-point fitting and error compensation algorithms provided by this invention (such as voltage offset calculation, linear estimation, and scaling factor calculation) to calculate the complete resistance-ADC mapping model coefficients, i.e., v. adc ,res a ,res k del adc The calibration result parameters are written to the radiosonde or host computer storage via the communication interface for accurate correction of subsequent measurement data.

[0131] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for individually calibrating the channel coefficients of a radiosonde, characterized in that, include: S1. Send commands to the radiosonde; S2. If the radiosonde does not respond, return to S1; if the radiosonde responds, proceed to S3. S3. The known standard resistance value is output to the radiosonde. The actual ADC sampling value is calibrated according to the known standard resistance value, and the calibration result parameters are obtained. The target resistance value is calculated according to the calibration result parameters, and the calibration result parameters are returned to the host computer control module for storage. The calibration result parameters are voltage offset factor, estimated resistance, proportional correction factor, and ADC offset. S4. Based on the actual ADC sampling value and the target resistance value, establish a resistance-ADC mapping model, and obtain the actual resistance value corresponding to the ADC value according to the resistance-ADC mapping model; In S3, the actual ADC sampled value is calibrated according to the known standard resistance value, including: Calculate the theoretical ADC value based on the known standard resistance value; Based on the theoretical ADC value, obtain the voltage offset factor; The theoretical ADC value is corrected according to the voltage offset factor to obtain the corrected ADC value; Based on the corrected ADC value, the estimated resistance is calculated using interpolation. Calculate the proportional correction factor based on the estimated resistance; Calculate the ADC offset based on the aforementioned proportional correction factor; The actual ADC sample value is calibrated based on the ADC offset to obtain the calibrated actual ADC sample value; Obtaining the voltage offset factor includes: ； in, This is the voltage offset factor. , , These are the theoretical ADC values ​​for the known standard resistances R2, R3, and R4, respectively.

2. The method for individual calibration of the channel coefficients used by a radiosonde according to claim 1, characterized in that, The calculation of the theoretical ADC value includes: ； wherein, is a known standard resistance value is a theoretical ADC value, is a plot resistance value, is a reference resistance value.

3. The method of individual calibration of the channel coefficients used by a radiosonde according to claim 1, characterized in that, The calculation and estimation of resistance includes: ； wherein, To estimate the resistance, and ADC values corrected by known standard resistance values R2, R3.

4. The method of individual calibration of the channel coefficients used by a radiosonde according to claim 3, characterized in that, The calculation of the scaling correction factor includes: ； wherein, is a proportional correction factor.

5. The method for individually calibrating the channel coefficient of a radiosonde according to claim 4, characterized in that, Calculating the ADC offset includes: ； in, This is the ADC offset. Given the standard resistance value, This is an uncalibrated measured resistance value.

6. The method for individually calibrating the channel coefficient of a radiosonde according to claim 5, characterized in that, Calculating the target resistance value based on the calibration result parameters includes: When the actual ADC sample value is greater than the preset value, calculate the target resistance value: ； Calculate the target resistance value when the actual ADC sample value is not greater than the preset value: ； wherein, is the actual ADC sample value, res adj is the target resistance value.

7. A channel coefficient separate calibration system for a radiosonde, characterized in that, include: The system includes a host computer control module, a response judgment module, a resistance output module, and a feedback module. The host computer control module is used to send commands to the radiosonde; The response judgment module is used to resend the command by the host computer control module if the radiosonde does not respond, and to enter the resistance output module if the radiosonde responds. The resistance output module is used to output a known standard resistance value to the radiosonde, calibrate the actual ADC sampling value according to the known standard resistance value, obtain calibration result parameters, calculate the target resistance value according to the calibration result parameters, establish a resistance-ADC mapping model according to the calibrated actual ADC sampling value and the target resistance value, and obtain the actual resistance value corresponding to the ADC value according to the resistance-ADC mapping model. The calibration result parameters are voltage offset factor, estimated resistance, proportional correction factor, and ADC offset. The actual ADC sampled value is calibrated based on the known standard resistance value, including: Calculate the theoretical ADC value based on the known standard resistance value; Based on the theoretical ADC value, obtain the voltage offset factor; The theoretical ADC value is corrected according to the voltage offset factor to obtain the corrected ADC value; Based on the corrected ADC value, the estimated resistance is calculated using interpolation. Calculate the proportional correction factor based on the estimated resistance; Calculate the ADC offset based on the aforementioned proportional correction factor; The actual ADC sample value is calibrated based on the ADC offset to obtain the calibrated actual ADC sample value; Obtaining the voltage offset factor includes: ； in, This is the voltage offset factor. , , These are the theoretical ADC values ​​for the known standard resistances R2, R3, and R4, respectively. The feedback module is used to return the calibration result parameters to the host computer control module for storage.

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