Ultrasonic sensor gain compensation method

Abstract

The invention provides an ultrasonic sensor gain compensation method. The method comprises the following steps: constructing a gain-temperature curve of an ultrasonic sensor; the ultrasonic sensor is an ultrasonic sensor mounted on an automobile; the current temperature T of the ultrasonic sensor is collected, and a gain compensation variable delta Gain (T) corresponding to the current temperature T is inquired according to the current temperature T and the gain-temperature curve; and calculating the compensation gain value Gain (T) of the ultrasonic sensor at the current temperature T according to the gain Gain (at) 25 DEG C of the ultrasonic sensor at the temperature of 25 DEG C and the gain compensation variable delta Gain (T) corresponding to the current temperature T. According to the method, the measurement precision of the obstacle at high temperature and low temperature can be improved; and the stability of the other-transmitting and other-receiving working mode between different ultrasonic sensors is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic sensors, and in particular to a gain compensation method for ultrasonic sensors. Background Art

[0002] The ultrasonic radar parking system consists of 1 host and 12 ultrasonic sensors.

[0003] Obstacle measurement distance is a parameter indicator of ultrasonic radar parking system: at normal temperature, the ultrasonic sensor obstacle echo information is generally very stable, and the host measurement distance is also stable; however, at high and low temperatures, the individual ultrasonic sensor obstacle echo information is unstable, and the host measurement distance is also unstable. Therefore, improving the stability of ultrasonic sensor obstacle measurement distance is an important development parameter indicator of ultrasonic sensors.

[0004] The current strategy to improve the stability of obstacle measurement distance is: 1) During production, the production measuring tool confirms the resonance frequency of the single ultrasonic sensor. 2) The host software determines the obstacle.

[0005] However, all of the above have obvious disadvantages: 1) The production measuring tool can only improve the obstacle information of the ultrasonic sensor at normal temperature, and cannot change the obstacle information changes at high and low temperatures. 2) After the host software collects the body temperature information at high and low temperatures, it uniformly compensates the obstacle information for 12 ultrasonic sensors according to the gain change characteristic curve provided by the ultrasonic sensor. Due to individual differences in ultrasonic sensors, the individual distance information of ultrasonic sensors is very unstable. Summary of the invention

[0006] The object of the present invention is to provide a gain compensation method for an ultrasonic sensor to improve the above-mentioned problem.

[0007] In order to achieve the above objectives, the present application provides the following technical solutions:

[0008] A gain compensation method for an ultrasonic sensor, comprising:

[0009] Constructing a gain-temperature curve of an ultrasonic sensor; the ultrasonic sensor is an ultrasonic sensor installed on a car;

[0010] Collect the current temperature T of the ultrasonic sensor, and obtain the gain compensation variable ΔGain(T) corresponding to the current temperature T according to the current temperature T and the gain-temperature curve;

[0011] The ultrasonic sensor compensation gain value Ga(T) at the current temperature T is calculated based on the ultrasonic sensor gain Gain@25°C at 25°C and the gain compensation variable ΔGain(T) corresponding to the current temperature T.

[0012] Optionally, construct a gain-temperature curve for the ultrasonic sensor, including:

[0013] For each ultrasonic sensor, the gain of the ultrasonic sensor at different temperatures is subtracted from the gain Gain@25°C of the ultrasonic sensor at 25°C to obtain the gain compensation variable at each temperature;

[0014] The gain compensation variables of multiple identical ultrasonic sensors at each temperature are analyzed, wherein for any temperature, the maximum value of the gain compensation variable, the minimum value of the gain compensation variable and the mean value of the gain compensation variable among all the gain compensation variables at this temperature are calculated; a gain-temperature curve is constructed according to the corresponding maximum value of the gain compensation variable, the minimum value of the gain compensation variable and the mean value of the gain compensation variable at different temperatures, and the gain-temperature curve contains three curves, namely, the maximum value of the gain compensation variable-temperature curve, the minimum value of the gain compensation variable-temperature curve and the mean value of the gain compensation variable-temperature curve.

[0015] Optionally, the current temperature T of the ultrasonic sensor is collected, including:

[0016] Collect the body temperature T2 of the ultrasonic sensor;

[0017] The collection results are analyzed, wherein if the body temperature T2 is successfully collected, the transducer temperature T3 is obtained, and the current temperature T of the ultrasonic sensor is calculated based on the transducer temperature T3 and the body temperature T2; if the body temperature T2 is not successfully collected, the outdoor temperature T1 of the car is obtained, and the current temperature T of the ultrasonic sensor is calculated based on the transducer temperature T3 and the outdoor temperature T1 of the car.

[0018] Optionally, the body temperature T2 of the ultrasonic sensor is collected, including:

[0019] The temperature data inside the application-specific integrated circuit ASIC in the ultrasonic sensor or the temperature data of the PCBA board is collected as the body temperature T2 of the ultrasonic sensor, wherein an NTC temperature sensor is installed on the application-specific integrated circuit ASIC or the PCBA board to collect the temperature data.

[0020] Optionally, analyzing the collection results includes:

[0021] During the acquisition, if there is a numerical value output, the acquired temperature data is used as the main body temperature T2 of the ultrasonic sensor and proves that the main body temperature T2 is successfully acquired; otherwise, it proves that the main body temperature T2 is not successfully acquired.

[0022] Optionally, obtaining the transducer temperature T3 includes:

[0023] Calculate the change in resonant frequency between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer at 25°C; calculate the change in resonant frequency between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer at 0°C; calculate the change in resonant frequency between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer at -40°C;

[0024] A temperature-resonance frequency change curve is constructed with temperature as the horizontal coordinate and the resonant frequency change as the vertical coordinate; the resonant frequency change corresponding to the current transducer is input into the temperature-resonance frequency change curve to obtain the transducer temperature T3.

[0025] Optionally, the current temperature T of the ultrasonic sensor is calculated according to the transducer temperature T3 and the body temperature T2, including:

[0026] The transducer temperature T3 and the body temperature T2 are analyzed. If

[0027] |T3-T2|>5°C and T2<25°C and T3<25°C, the body temperature T3 is taken as the final temperature of the ultrasonic sensor, otherwise the transducer temperature T2 is taken as the final temperature of the ultrasonic sensor.

[0028] Optionally, the current temperature T of the ultrasonic sensor is calculated according to the transducer temperature T3 and the outdoor temperature T1 of the vehicle, including:

[0029] The transducer temperature T3 and the vehicle outdoor temperature T1 are analyzed.

[0030] |T3-T1|>5°C and T1<25°C and T3<25°C, the body temperature T3 is taken as the final temperature of the ultrasonic sensor, otherwise the transducer temperature T1 is taken as the final temperature of the ultrasonic sensor.

[0031] Optionally, obtaining a gain compensation variable ΔGain(T) corresponding to the current temperature T according to the current temperature T and the gain-temperature curve query includes:

[0032] The state of the ultrasonic sensor is analyzed, wherein, if the echo signal received by the ultrasonic sensor is attenuated to a preset value, the maximum value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the maximum value of the gain compensation variable-temperature curve and the current temperature T; if the echo signal received by the ultrasonic sensor exceeds the preset upper limit value, the minimum value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the minimum value of the gain compensation variable-temperature curve and the current temperature T; otherwise, the mean value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the mean value of the gain compensation variable-temperature curve and the current temperature T.

[0033] Optionally, the ultrasonic sensor compensation gain value Gain(T) at the current temperature T is calculated according to the gain Gain@25°C of the ultrasonic sensor at 25°C and the gain compensation variable ΔGain(T) corresponding to the current temperature T, including:

[0034] The ultrasonic sensor compensation gain value Gain(T) at the current temperature T is calculated using the formula Gain(T)=Gain@25°C+ΔGain(T).

[0035] The beneficial effects of the present invention are:

[0036] 1. Improvement of the overall performance of sensors: A car is generally equipped with 12 ultrasonic sensors. Through the method of the present invention, each ultrasonic sensor has its own compensation gain, and there will be no significant difference in the measurement of the same obstacle at room temperature due to the individual differences of the 12 sensors; there will also be no significant difference in the measurement of the same obstacle at high and low temperatures due to the individual differences of the 12 sensors. Therefore, the measurement accuracy of obstacles is improved at high and low temperatures.

[0037] 2. The host ECU software no longer performs gain compensation, which is executed by the ultrasonic sensor, increasing the flexibility of detection: it used to be a curve of the host ECU, and 12 sensors were uniformly supplemented, and the ultrasonic sensor passively received compensation; after changing to the ultrasonic sensor's own compensation gain, gain compensation can be performed more flexibly according to its own differences; the stability of the transmitting and receiving working modes between different ultrasonic sensors is enhanced; and under high and low temperature conditions, the signal-to-noise ratio is improved and the anti-disturbance performance is enhanced.

[0038] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or be understood by implementing the embodiments of the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 It is a schematic flow chart of a method for gain compensation of an ultrasonic sensor in an embodiment of the present invention;

[0041] Figure 2 is a gain-temperature curve in an embodiment of the present invention;

[0042] Figure 3 is a diagram of the first simulation result of the transducer in an embodiment of the present invention;

[0043] Figure 4 is a temperature-resonance frequency variation curve diagram in an embodiment of the present invention;

[0044] Figure 5 4 is a diagram of the second simulation result of the transducer in the embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] It should be noted that similar reference numerals or letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0047] Example 1

[0048] like Figure 1 As shown, a method for gain compensation of an ultrasonic sensor includes:

[0049] Step S1, constructing a gain-temperature curve of an ultrasonic sensor; the ultrasonic sensor is an ultrasonic sensor installed on a car;

[0050] The specific implementation steps of this step include step S11;

[0051] Step S11, for each ultrasonic sensor, subtract the gain Gain@25°C of the ultrasonic sensor at 25°C from the measured gain of the ultrasonic sensor at different temperatures to obtain a gain compensation variable at each temperature;

[0052] Step S12, analyzing the gain compensation variables of multiple identical ultrasonic sensors at each temperature, wherein, for any temperature, calculating the maximum value of the gain compensation variable, the minimum value of the gain compensation variable and the mean value of the gain compensation variable among all the gain compensation variables at this temperature; constructing a gain-temperature curve according to the corresponding maximum value of the gain compensation variable, the minimum value of the gain compensation variable and the mean value of the gain compensation variable at different temperatures, wherein the gain-temperature curve contains three curves, namely, a maximum value of the gain compensation variable-temperature curve, a minimum value of the gain compensation variable-temperature curve and a mean value of the gain compensation variable-temperature curve.

[0053] In this step, the gain compensation variables corresponding to each temperature can be collected when 50 or more identical ultrasonic sensors (for example, the same model) are measured; in this way, multiple gain compensation variables corresponding to different temperatures can be collected, and then the maximum and minimum values ​​can be screened out and the mean can be calculated to construct Figure 2 The three curves in Figure 2 The red curve in the figure corresponds to the maximum value of the gain compensation variable - temperature curve, the gray curve corresponds to the minimum value of the gain compensation variable - temperature curve, and the blue curve corresponds to the mean value of the gain compensation variable - temperature curve;

[0054] Step S2, collecting the current temperature T of the ultrasonic sensor, and obtaining the gain compensation variable ΔGain(T) corresponding to the current temperature T according to the current temperature T and the gain-temperature curve;

[0055] In this step, the specific implementation steps of collecting the current temperature T of the ultrasonic sensor include step S21 and step S22;

[0056] Step S21, collecting the body temperature T2 of the ultrasonic sensor;

[0057] In this step, the position of the ultrasonic sensor is not specifically limited. Meanwhile, the specific implementation steps of this step include step S211;

[0058] Step S211, collecting the temperature data inside the application-specific integrated circuit ASIC in the ultrasonic sensor or the temperature data of the PCBA board as the body temperature T2 of the ultrasonic sensor, wherein an NTC temperature sensor is installed on the application-specific integrated circuit ASIC or the PCBA board for collection.

[0059] Step S22, analyzing the acquisition results, wherein if the body temperature T2 is successfully acquired, the transducer temperature T3 is acquired, and the current temperature T of the ultrasonic sensor is calculated based on the transducer temperature T3 and the body temperature T2; if the body temperature T2 is not successfully acquired, the outdoor temperature T1 of the car is acquired, and the current temperature T of the ultrasonic sensor is calculated based on the transducer temperature T3 and the outdoor temperature T1 of the car.

[0060] In step S22, the outdoor temperature T1 of the automobile can be collected by a conventional collection method, and this step is not specifically limited; the specific implementation steps of analyzing the collection result include step S221;

[0061] Step S221, when collecting, if there is a numerical output, the obtained temperature data is used as the main body temperature T2 of the ultrasonic sensor and proves that the main body temperature T2 is successfully collected, otherwise, it proves that the main body temperature T2 is not successfully collected.

[0062] Meanwhile, in step S22, the specific implementation steps of obtaining the transducer temperature T3 include step S222 and step S223;

[0063] Step S222, calculating the resonant frequency change between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer under the condition of 25°C; calculating the resonant frequency change between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer under the condition of 0°C; calculating the resonant frequency change between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer under the condition of -40°C;

[0064] Before confirming this step, a simulation was performed, taking the murata (model: MAX-22-0079) transducer simulation as an example:

[0065] Figure 3 This is the first simulation result of the transducer. Figure 3In the figure, the first group of three curves are AC scanning curves of the transmitting frequency of the transducer at 25℃, 0℃ and -40℃, and the second group are AC scanning curves of the receiving circuit at 25℃, 0℃ and -40℃. From the comparison of the curves, it can be seen that at the same temperature, the resonant frequency fp of the transmitting circuit is inconsistent with the resonant frequency fp of the receiving circuit. The temperature T3 of the transducer can be inferred by monitoring the change Δfp between the resonant frequency fp of the transmitting circuit and the resonant frequency fp of the receiving circuit (subtracting the resonant frequency fp of the receiving circuit from the resonant frequency fp of the transmitting circuit).

[0066] At the same time, in this step, the resonant frequency change Δfp (kHz) corresponding to 25°C is 0; the resonant frequency change Δfp (kHz) corresponding to 0°C is 1.52; the resonant frequency change Δfp (kHz) corresponding to -40°C is 2.49; these three sets of data are reflected in the coordinate axis, and the temperature-resonant frequency change curve can be constructed by fitting according to these three sets of data, as shown in FIG. Figure 4 shown.

[0067] Step S223, constructing a temperature-resonance frequency change curve with temperature as the horizontal coordinate and the resonant frequency change as the vertical coordinate; inputting the resonant frequency change corresponding to the current transducer into the temperature-resonance frequency change curve to obtain the transducer temperature T3.

[0068] Meanwhile, in step S22, the specific implementation steps of calculating the final temperature of the ultrasonic sensor according to the transducer temperature T3 and the body temperature T2 include step S224;

[0069] Step S224, analyzing the transducer temperature T3 and the body temperature T2, if |T3-T2|>5°C and T2<25°C and T3<25°C, then the body temperature T3 is used as the final temperature of the ultrasonic sensor, otherwise, the transducer temperature T2 is used as the final temperature of the ultrasonic sensor.

[0070] Meanwhile, in step S22, the specific implementation steps of calculating the final temperature of the ultrasonic sensor according to the transducer temperature T3 and the outdoor temperature T1 of the vehicle include step S225;

[0071] Step S225, analyzing the transducer temperature T3 and the outdoor temperature T1 of the automobile, if |T3-T1|>5°C and T1<25°C and T3<25°C, then the body temperature T3 is used as the final temperature of the ultrasonic sensor, otherwise, the transducer temperature T1 is used as the final temperature of the ultrasonic sensor.

[0072] Before confirming step S224 and step S225, a simulation is performed, taking the simulation of the murata (model: MAX-22-0079) transducer as an example:

[0073] Figure 5 This is the result of the second simulation of the transducer. Figure 5 In the figure, the first group of three curves are respectively the AC scanning curves of the transmitting frequency of the transducer at 85℃, 25℃ and -40℃, and the second group are the AC scanning curves of the receiving resistance impedance at 85℃, 25℃ and -40℃. From the simulation data, it can be obtained that when the temperature is >25℃, the transducer is not very sensitive to temperature, but when the temperature is <25℃, the transducer is very sensitive to temperature changes. Therefore, different comparative analysis methods are used in step S224 and step S225 to confirm the current temperature T of the ultrasonic sensor.

[0074] In step S2, the specific implementation steps of obtaining the gain compensation variable ΔGain(T) corresponding to the current temperature T according to the current temperature T and the gain-temperature curve include step S23;

[0075] Step S23, analyzing the state of the ultrasonic sensor, wherein if the echo signal received by the ultrasonic sensor is attenuated to a preset value, the maximum value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the maximum value of the gain compensation variable-temperature curve and the current temperature T; if the echo signal received by the ultrasonic sensor exceeds the preset upper limit value, the minimum value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the minimum value of the gain compensation variable-temperature curve and the current temperature T; otherwise, the mean value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the mean value of the gain compensation variable-temperature curve and the current temperature T.

[0076] In this step, the preset value is 20%; the upper limit is a user-defined setting;

[0077] Step S3, calculating the ultrasonic sensor compensation gain value Gain(T) at the current temperature T according to the ultrasonic sensor gain Gain@25°C at 25°C and the gain compensation variable ΔGain(T) corresponding to the current temperature T.

[0078] The specific implementation steps of this step include step S31;

[0079] Step S31 , using the formula Gain(T)=Gain@25°C+ΔGain(T) to calculate the ultrasonic sensor compensation gain value Gain(T) at the current temperature T.

[0080] In this embodiment, since the main parameter of gain compensation is gain, gain compensation is mainly obtained by compensating gain; and in this embodiment, each ultrasonic sensor processes gain compensation separately, thereby reducing errors.

[0081] At the same time, in this embodiment, 12 ultrasonic sensors are generally installed on the car. Through the method in this embodiment, each ultrasonic sensor compensates for its gain, and the individual differences of the 12 sensors will not cause a large difference in the measurement of the same obstacle at normal temperature; nor will the individual differences of the 12 sensors cause a large difference in the measurement of the same obstacle at high and low temperatures. Therefore, the measurement accuracy of the obstacle is increased at high and low temperatures.

[0082] In addition, through the method in this embodiment, the host ECU software no longer performs gain compensation, which is executed by the ultrasonic sensor, thereby increasing the flexibility of detection: originally it was a curve of the host ECU, and 12 sensors were uniformly supplemented, and the ultrasonic sensor passively received compensation; after changing to the ultrasonic sensor's own compensation gain, gain compensation can be performed more flexibly according to its own differences; the stability of the transmitting and receiving working modes between different ultrasonic sensors is enhanced; and under high and low temperature conditions, the signal-to-noise ratio is improved and the anti-disturbance performance is enhanced.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for gain compensation of an ultrasonic sensor, characterized in that: include: Constructing a gain-temperature curve of an ultrasonic sensor; the ultrasonic sensor is an ultrasonic sensor installed on a car; Collect the current temperature T of the ultrasonic sensor, and obtain the gain compensation variable ΔGain(T) corresponding to the current temperature T according to the current temperature T and the gain-temperature curve; The ultrasonic sensor compensation gain value Ga(T) at the current temperature T is calculated based on the ultrasonic sensor gain Gain@25°C at 25°C and the gain compensation variable ΔGain(T) corresponding to the current temperature T.

2. The ultrasonic sensor gain compensation method according to claim 1, characterized in that: Construct a gain-temperature curve for an ultrasonic sensor, including: For each ultrasonic sensor, the gain of the ultrasonic sensor at different temperatures is subtracted from the gain Gain@25°C of the ultrasonic sensor at 25°C to obtain the gain compensation variable at each temperature; The gain compensation variables of multiple identical ultrasonic sensors at each temperature are analyzed, wherein for any temperature, the maximum value of the gain compensation variable, the minimum value of the gain compensation variable and the mean value of the gain compensation variable among all the gain compensation variables at this temperature are calculated; a gain-temperature curve is constructed according to the corresponding maximum value of the gain compensation variable, the minimum value of the gain compensation variable and the mean value of the gain compensation variable at different temperatures, and the gain-temperature curve contains three curves, namely, the maximum value of the gain compensation variable-temperature curve, the minimum value of the gain compensation variable-temperature curve and the mean value of the gain compensation variable-temperature curve.

3. The ultrasonic sensor gain compensation method according to claim 1, characterized in that: Collect the current temperature T of the ultrasonic sensor, including: Collect the body temperature T2 of the ultrasonic sensor; The collection results are analyzed, wherein if the body temperature T2 is successfully collected, the transducer temperature T3 is obtained, and the current temperature T of the ultrasonic sensor is calculated based on the transducer temperature T3 and the body temperature T2; if the body temperature T2 is not successfully collected, the outdoor temperature T1 of the car is obtained, and the current temperature T of the ultrasonic sensor is calculated based on the transducer temperature T3 and the outdoor temperature T1 of the car.

4. The ultrasonic sensor gain compensation according to claim 3, characterized in that: The body temperature T2 of the ultrasonic sensor is collected, including: The temperature data inside the application-specific integrated circuit ASIC in the ultrasonic sensor or the temperature data of the PCBA board is collected as the body temperature T2 of the ultrasonic sensor, wherein an NTC temperature sensor is installed on the application-specific integrated circuit ASIC or the PCBA board to collect the temperature data.

5. The ultrasonic sensor gain compensation according to claim 3, characterized in that: Analyzing the collection results includes: During the acquisition, if there is a numerical value output, the acquired temperature data is used as the main body temperature T2 of the ultrasonic sensor and proves that the main body temperature T2 is successfully acquired; otherwise, it proves that the main body temperature T2 is not successfully acquired.

6. The ultrasonic sensor gain compensation according to claim 3, characterized in that: Obtaining the transducer temperature T3 includes: Calculate the change in resonant frequency between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer at 25°C; calculate the change in resonant frequency between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer at 0°C; calculate the change in resonant frequency between the resonant frequency of the transmitting circuit and the resonant frequency of the receiving circuit in the transducer at -40°C; A temperature-resonance frequency change curve is constructed with temperature as the horizontal coordinate and the resonant frequency change as the vertical coordinate; the resonant frequency change corresponding to the current transducer is input into the temperature-resonance frequency change curve to obtain the transducer temperature T3.

7. The ultrasonic sensor gain compensation according to claim 3, characterized in that: The current temperature T of the ultrasonic sensor is calculated according to the transducer temperature T3 and the body temperature T2, including: The transducer temperature T3 and the body temperature T2 are analyzed. If |T3-T2|>5°C and T2<25°C and T3<25°C, the body temperature T3 is used as the final temperature of the ultrasonic sensor. Otherwise, the transducer temperature T2 is used as the final temperature of the ultrasonic sensor.

8. The ultrasonic sensor gain compensation according to claim 3, characterized in that: The current temperature T of the ultrasonic sensor is calculated according to the transducer temperature T3 and the outdoor temperature T1 of the vehicle, including: The transducer temperature T3 and the automobile outdoor temperature T1 are analyzed. If |T3-T1|>5°C and T1<25°C and T3<25°C, the body temperature T3 is used as the final temperature of the ultrasonic sensor. Otherwise, the transducer temperature T1 is used as the final temperature of the ultrasonic sensor.

9. The ultrasonic sensor gain compensation according to claim 2, characterized in that: The gain compensation variable ΔGain(T) corresponding to the current temperature T is obtained according to the current temperature T and the gain-temperature curve, including: The state of the ultrasonic sensor is analyzed, wherein, if the echo signal received by the ultrasonic sensor is attenuated to a preset value, the maximum value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the maximum value of the gain compensation variable-temperature curve and the current temperature T; if the echo signal received by the ultrasonic sensor exceeds the preset upper limit value, the minimum value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the minimum value of the gain compensation variable-temperature curve and the current temperature T; otherwise, the mean value of the gain compensation variable-temperature curve is called, and the gain compensation variable ΔGain(T) corresponding to the current temperature T is calculated using the mean value of the gain compensation variable-temperature curve and the current temperature T.

10. The ultrasonic sensor gain compensation according to claim 1, characterized in that: The ultrasonic sensor compensation gain value Gain(T) at the current temperature T is calculated based on the gain Gain@25°C of the ultrasonic sensor at 25°C and the gain compensation variable ΔGain(T) corresponding to the current temperature T, including: The ultrasonic sensor compensation gain value Gain(T) at the current temperature T is calculated using the formula Gain(T)=Gain@25°C+ΔGain(T).

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