KR101252791B1 - Apparatus and method for correcting bias for digital sensor - Google Patents

Abstract

PURPOSE: A bias correction device for a digital sensor is provided to prevent accumulation of errors in various terminals provided with a digital sensor, thereby markedly improving performance and functions of the terminal. CONSTITUTION: A digital sensor(200) is a temperature-based digital sensor which outputs digital data having bias which varies on temperature changes. A data processor(100) includes multiple bias correction devices for estimating and compensating in real time the variation of bias depending on temperature changes. The multiple bias correction devices process smoothing or filtering using moving average method, on the digital data of X, Y, and Z axes received from the digital sensor. A processing unit(300) finds the angle of a platform using the detection values of the digital sensor which are corrected by the multiple bias correction devices. [Reference numerals] (200) Digital sensor; (300) Processing;

Description

Digital Sensor Bias Compensator and Method {APPARATUS AND METHOD FOR CORRECTING BIAS FOR DIGITAL SENSOR}

The present invention relates to a digital sensor bias correction technique, and more particularly to a bias correction technique required to use a digital type inertial sensor.

In general, the inertial sensor has been used a lot of analog methods, but circuits related to bias correction and digital conversion must be configured separately. In addition, when using multiple sensors, single axis sensors are adopted due to problems such as error between axes. We adopt type sensor. Digital sensors are easy to use because they already have a variety of circuits built-in, and even if multiple sensors are used, the error between axes is very small unless it is a problem in the semiconductor process.

However, since the digital sensor has a disadvantage in that the bias is sensitively changed with temperature, if it is not properly corrected, errors due to temperature change accumulate over time. It becomes a big stumbling block.

Unlike an analog sensor, a digital sensor exhibits a bias characteristic that changes sensitively with temperature changes, so that errors accumulate in the driving direction in vehicle dead reckoning and errors in motion detection or attitude determination in a personal portable terminal. Occurs, causing the problem that the utility of the sensor falls.

If the change in the bias due to temperature change can be eliminated, the utility of the digital sensor can be improved drastically, and the effect of increasing the ratio of employing the digital sensor in a vehicle or a personal portable terminal will be brought. In addition, if existing analog sensors can be replaced by digital sensors based on MEMS (Micro Electro Mechanical System), more diverse application technologies will be developed or spread.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital sensor bias correction device that uses digital sensor data for tracking and correcting a bias that changes with temperature in real time in the process of processing a data signal of a digital sensor.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the present invention will be realized and attained by the structure particularly pointed out in the claims, as well as the following description and the annexed drawings.

The present invention eliminates the error accumulation phenomenon of various terminals employing the digital sensor by correcting the bias change of the digital sensor that is sensitive to temperature change in real time, which can drastically improve the operation performance and function of the terminal. A bias compensation device and method for a digital sensor are implemented. The bias correction method of the digital sensor according to the present invention can be used for dead reckoning and inertial navigation for vehicle navigation, and can be installed in a personal portable device and used for detecting posture, position, direction, and the like.

The bias correction device and method of the digital sensor according to the present invention can be mounted on a vehicle navigation device of an after market equipped with a digital sensor (eg, a gyro sensor) as well as a vehicle navigation device of a before market. It can be applied to the detection of pedestrian navigation devices (eg smartphones) and robots or game remote controllers (eg wii) and their applications.

1 is a conceptual diagram of a digital sensor bias correction in accordance with the present invention.
2 is a block diagram of a TBEC device block according to a first embodiment of the present invention;
3 is a block diagram of a TBEC device block according to a second embodiment of the present invention;
4 is a graph showing a pattern of a bias change and a temperature change of a gyro sensor.
5 is a graph illustrating a smoothing effect according to a smoothing error bug technique.
6 is a graph showing the estimation result of the gyro sensor.
Figure 7 a) is a graph showing the bias estimation result in accordance with the present invention.
7B is a graph showing a correction result of the gyro sensor detection value according to the present invention.

In order to achieve the above object, the digital sensor bias correction device according to the present invention is

A digital sensor for outputting digital data having a characteristic of changing bias according to temperature change, and a plurality of bias compensators for receiving and processing X, Y, and Z axis data received from the digital sensor (TBEC, Temperature- a data processing processor for estimating and correcting a bias change according to a temperature change, including based bias estimation & corrections, and a processor for calculating an angle (or posture) of the platform based on a detected value of a digital sensor corrected through the bias correctors. Including,

The data processing processor includes a first bias correction unit configured to estimate and correct a bias that changes according to a temperature change with respect to the X-axis data, and a second bias estimation unit that estimates and corrects a bias that changes according to a temperature change with respect to the Y-axis data. And a second bias correction unit for estimating and correcting a bias that changes with temperature change with respect to the Z-axis data.

The digital sensor bias correction technique according to the present invention may be mounted in the form of software in a terminal equipped with a digital sensor.

That is, in the past, the processor inside the terminal receives digital data generated from the digital sensor and corrects only the bias at that time. However, in the present invention, the bias that changes according to temperature in the process of receiving and processing the digital data generated from the digital sensor Track and correct in real time.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1 is a conceptual diagram of a digital sensor bias correction according to the present invention.

As shown in FIG. 1, the digital sensor bias correction apparatus according to the present invention includes a digital sensor 200, a data processing processor 100, an X-TBEC 110, or a first bias correction unit, and a Y-TBEC 120. Or a second bias correction unit), a Z-TBEC 130 (a third bias correction unit), and a processing unit 300.

The digital sensor 200 is a sensor that outputs digital data having a characteristic that the bias also changes with temperature changes.

The data processing processor 100 is directly connected to the digital sensor 200 so that the detected value of the sensor is I2C (I-square-C, also known as 'ice square') communication or SPI (Serial Peripheral Interface, peripheral device). It receives and processes directly through serial interface communication or UART (Universal Asynchronous Receiver / Transmitter) communication.

It is assumed that the detection value received by the data processing processor 100 includes data of three axes including the posture (for example, the X axis, the Y axis, and the Z axis), and the data processing processor 100 has a temperature for each axis. It is composed of devices (eg, X-TBEC 110, Y-TBEC 120, and Z-TBEC 130) that perform a bias-based bias estimation and correction function. Analog sensors only contain data from one axis (eg Z-axis), while digital sensors contain data from three axes (eg X-axis, Y-axis and Z-axis).

The X-TBEC 110 (first bias correction unit) is an apparatus block for estimating and correcting a bias that changes according to temperature change with respect to the X-axis data.

The Y-TBEC 120 (second bias correction unit) is an apparatus block for estimating and correcting a bias that changes according to temperature change with respect to Y-axis data.

The Z-TBEC 130 (first bias correction unit) is an apparatus block for estimating and correcting a bias that changes according to temperature change with respect to Z-axis data.

The processor 300 obtains an angle (or posture) of a platform (eg, a vehicle) based on the detected value of the digital sensor corrected through the TBEC device blocks 110, 120, and 130. When the calculation performed by the processing unit 300 is represented by a formula, it is as follows.

[Equation 1]

θ _t = θ _t-1 + δθ _t

Here, θ _t is the final angle and 'δθ _t ' is the angle change amount (corresponding to the detected value X _t of the digital sensor).

2 is a block diagram of a TBEC device block according to a first embodiment of the present invention. The TBEC device block (or bias correction device block) according to the present embodiment estimates and corrects the bias on the premise that the terminal equipped with the digital sensor is not operating, that is, the stopped state, and is used for general navigation or smartphone. do.

As shown in FIG. 2, each of the TBEC device blocks 110 to 130 according to the first embodiment of the present invention includes a temperature change detector 110A, a bias detector 110B, an operation detector 110C, and a bias bias for each temperature. The unit 110D includes a real time bias correction unit 110E.

The temperature change detector 110A detects a temperature change around the digital sensor 200. Since the digital sensor 200 is sensitive to temperature, it is necessary to accurately detect the temperature change to estimate the accurate bias.

The motion detector 110C may detect an operation of a platform (for example, a general navigation or a smart phone) on which the digital sensor 200 is mounted, and determine whether the platform is operated by using a threshold technique. Create a flag that can be used.

The bias detector 110B detects a bias of the digital sensor 200 that changes according to time and temperature, and transfers the detected data to a temperature-specific bias estimator 110D.

The bias estimation unit 110D for each temperature receives a flag from the motion detection unit 110C, and receives data detected from the temperature change detection unit 110A and the bias detection unit 110B.

The temperature bias estimation unit 110D may refer to data received from the temperature change detection unit 110A and the bias detection unit 110B when the flag of the operation detection unit 110C indicates that the platform is stopped. Calculate the bias according to the temperature change of (200).

The real-time bias correction unit 110E corrects the measured value 200 of the digital sensor in real time using the bias calculated by the temperature bias estimator 110D. By correcting the measured value of the digital sensor 200 and feeding the result back to the bias detector 110B, the bias detection function can be continuously updated and precise bias can be detected.

3 is a block diagram of a TBEC device block according to a second embodiment of the present invention. The TBEC device block according to the present embodiment estimates and corrects a bias on the premise that a terminal equipped with a digital sensor operates, and is used for navigation embedded in an automobile.

As shown in FIG. 3, the TBEC device blocks 110 to 130 according to the second embodiment of the present invention may include a temperature change detector 110A, a bias detector 110B, an operation detector 110C, and a bias estimation unit for each temperature. 110D, a real time bias correcting unit 110E, and a bias estimating unit 110F while driving.

The temperature change detector 110A detects a temperature change around the digital sensor 200. Since the digital sensor 200 is sensitive to temperature, it is necessary to accurately detect the temperature change to estimate the accurate bias.

The motion detector 110C may detect whether the vehicle is driven and generates a flag for determining whether the vehicle is driven or stopped by using a threshold technique. The motion detector 110C according to the first embodiment determines whether the platform is driven by using only the digital data output from the digital sensor 200, but the motion detector 110C according to the present embodiment uses the GPS (Global Positioning System). GPS signals and vehicle speed pulses are applied from external devices such as the vehicle speed sensor and the vehicle speed sensor to determine whether the vehicle is running and stopped more accurately.

The bias detector 110B detects a bias of the digital sensor 200 that changes with time and temperature, and transfers the detected data to a temperature-specific bias estimator 110D.

When the flag of the motion detector 110C indicates that the vehicle is in a driving state, the bias estimator 110F receives the GPS signal (or the vehicle speed pulse) from the GPS (or the vehicle speed sensor) while driving and the bias ( Estimate B2). The estimated bias value B2 is transferred to the real time bias correction unit 110E.

On the other hand, when the flag of the motion detector 110C indicates that the vehicle is stopped, the temperature bias estimator 110D receives the data detected by the temperature change detector 110A and the bias detector 110B. As in the first embodiment, the bias B1 is calculated according to the temperature change of the digital sensor 200. In addition, the bias value B1 according to the calculated temperature change is transmitted to the real-time bias correction unit 110E.

When the real-time bias correction unit 110E receives the bias value B1 calculated at the time of stopping the vehicle from the temperature bias estimation unit 110D, the bias estimation value received from the bias estimation unit 110F during the driving. Compare with (B2).

The real time bias correcting unit 110E compares the bias value B1 of the bias estimation unit 110D for each temperature with the bias estimation value B2 of the bias estimating unit 110F while driving, and determines an optimum bias in real time. To correct the measured value of the digital sensor.

When the correction of the real-time bias correction unit 110E is represented by a formula, Equation 2 below.

[Equation 2]

Calibration result of real-time bias compensator = ((B1 x 8) + (B2 x 1) / 9)

The bias correction is performed in real time, and the real-time bias correction unit 110E feeds back the corrected result value to the bias detection unit 110B to continuously update the bias detection function and enable precise bias detection.

This embodiment proposes a function that overcomes the limitation of bias estimation only when there is no operation in the first embodiment and estimates the bias while driving.

4 is a graph showing a pattern of a bias change and a temperature change of a gyro sensor.

As shown in FIG. 4, the bias change of the digital sensor 200 (hereinafter referred to as a gyro sensor) moves in the same pattern as the temperature change. The present invention takes advantage of the fact that the bias change of the gyro sensor 200 moves in the same pattern as the temperature change.

The data processing processor 100 according to the present invention sets an initial bias value by estimating an initial bias during an initial operation of the gyro sensor 200.

Thereafter, the data processing processor 100 performs smoothing or filtering on the detection value of the gyro sensor 200 by Equation 3 below. Since the detected value of the gyro sensor 200 is jagged due to noise, the gyro sensor 200 is subjected to smoothing or filtering according to a smoothing average technique. The detection cycle of the gyro sensor 200 according to the present invention is preferably performed at a 50 Hz sampling stage.

[Equation 3]

[Smoothing or Filtering]

Here, 'S' is a smoothed gyro sensor value, 'n' is a time index, and 'x' is an original gyro sensor value.

5 is a graph illustrating a smoothing effect according to a smoothing Everest technique.

The advantage of smoothing is that as shown in a) of FIG. 5, there is an advantage of eliminating the bouncing value. However, as shown in b) of FIG. 5, the smoothing value is biased because a time delay problem occurs. It is preferable to use only for estimation.

6 is a graph showing the estimation result of the gyro sensor.

Temperature bias estimation unit 110D according to the present invention calculates the bias change rate according to the temperature change using the calculated bias value.

The data processing processor 100 should also calculate the rate of change of the bias according to the temperature in the section for calculating the initial bias. This initial bias value and the rate of change of the bias are used to estimate the bias following the temperature change.

As shown in FIG. 6, the bias change rate is formed in the range of -6.4 to -7.2 per temperature change of approximately 1 degree.

7A is a graph showing a bias estimation result according to the present invention.

The present invention performs bias estimation while driving by using the secured bias change rate. In a) of FIG. 7, 'gyroBias' is an original bias value of the gyro sensor 200, 'estBias' is a bias value (first embodiment) estimated at driving stop, and 'EstBias' is a bias value estimated at driving. (Second embodiment).

7B is a graph showing a correction result of the gyro sensor detection value according to the present invention. The real-time bias correction unit 110E according to the present invention reflects the estimated bias values B1 and B2 to the detection values of the gyro sensor 200 to perform correction.

In FIG. 7B, 'RawGyroZ' is a detection value of the gyro sensor 200 before correction, and 'fbGyro' is a detection value of the gyro sensor 200 corrected by applying a bias estimated when the driving stops (first embodiment). For example, 'FBGyro' is a detection value (second embodiment) of the gyro sensor 200 corrected by applying a bias estimated during driving.

As in the first embodiment of the present invention, if it is determined that the driving stops immediately after the bias estimation is performed, the same operation as the initialization is performed. That is, after the initial bias estimation, the process of detecting the bias change rate is performed again. If driving starts again after stopping, the bias change rate estimation algorithm is out of the case of the first embodiment.

The digital sensor bias correction method described above may be implemented in hardware or in software.

According to an exemplary hardware implementation, the digital sensor bias correction method according to the present invention may include application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and FPGAs ( It may be implemented using at least one of field programmable gate arrays, processors, controllers, micro-controllers, microprocessors, and electrical units for performing other functions.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. May be constructed by selectively or in combination. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

The present invention eliminates the error accumulation phenomenon of various terminals employing the digital sensor by correcting the bias change of the digital sensor that is sensitive to temperature change in real time, which can drastically improve the operation performance and function of the terminal. A bias compensation device and method for a digital sensor are implemented. The bias correction method of the digital sensor according to the present invention can be used for dead reckoning and inertial navigation for vehicle navigation, and can be installed in a personal portable device and used for detecting posture, position, direction, and the like.

The bias correction device and method of the digital sensor according to the present invention can be mounted on a vehicle navigation device of an after market equipped with a digital sensor (eg, a gyro sensor) as well as a vehicle navigation device of a before market. It can be applied to the detection of pedestrian navigation devices (eg smartphones) and robots or game remote controllers (eg wii) and their applications.

100: data processing processor 110: X-TBEC
110A: temperature change detector 110B: bias detector
110C: motion detection unit 110D: temperature bias estimation unit
110E: real time bias correction unit 110F: bias estimation unit while driving
120: Y-TBEC 130: Z-TBEC
200: digital sensor 300: processing unit

Claims (7)

A digital sensor 200 for outputting a digital data value having a characteristic of changing a bias according to a temperature change;
Temperature change including a plurality of bias correction devices for smoothing or filtering according to a smoothing error technique by receiving digital data of X, Y, and Z axes received from the digital sensor A data processing processor (100) for estimating and correcting a bias change in real time;
Comprising a processing unit 300 for obtaining the angle of the platform by the detection value of the digital sensor corrected through the bias correction device,
The data processing processor 100,
A first bias correction unit (110) for estimating and correcting a bias that changes according to temperature change in real time with respect to the digital data of the X-axis;
A second bias correction unit (120) for estimating and correcting a bias that changes according to a temperature change in real time with respect to the digital data of the Y-axis;
Comprising a third bias correction unit 130 for estimating and correcting the bias in accordance with the temperature change in real time with respect to the digital data of the Z-axis,
The first to third bias correction device (110 to 130), respectively,
A temperature change detector (110A) for detecting a temperature change around the digital sensor;
A motion detector 110C for detecting a motion of the platform on which the digital sensor is mounted and generating a flag for determining whether to operate by using a threshold technique;
A bias detector (110B) for detecting a bias of the digital sensor that changes with time and temperature;
A temperature bias estimator 110D for calculating a bias according to a temperature change of the digital sensor by referring to the data detected by the temperature change detector 110A and the bias detector 110B;
And a real-time bias correction unit (110E) for correcting the detection value of the digital sensor in real time using the calculated bias. delete A digital sensor 200 for outputting a digital data value having a characteristic of changing a bias according to a temperature change;
Temperature change including a plurality of bias correction devices for smoothing or filtering according to a smoothing error technique by receiving digital data of X, Y, and Z axes received from the digital sensor A data processing processor (100) for estimating and correcting a bias change in real time;
Comprising a processing unit 300 for obtaining the angle of the platform by the detection value of the digital sensor corrected through the bias correction device,
The data processing processor 100,
A first bias correction unit (110) for estimating and correcting a bias that changes according to a temperature change in real time with respect to the digital data of the X-axis;
A second bias correction unit (120) for estimating and correcting a bias that changes according to a temperature change in real time with respect to the digital data of the Y-axis;
Comprising a third bias correction unit 130 for estimating and correcting the bias in accordance with the temperature change in real time with respect to the digital data of the Z-axis,
The first to third bias correction device (110 to 130), respectively,
A temperature change detector (110A) for detecting a temperature change around the digital sensor;
A motion detection unit (110C) for detecting whether the vehicle is driven or stopped by receiving a GPS signal and a vehicle speed pulse from an external device;
A bias detector 110B for detecting in real time a bias of a digital sensor that changes with time and temperature;
A bias estimating unit (110F) for estimating a bias according to the driving by receiving a GPS signal from the GPS when the detection information of the motion detecting unit indicates that the vehicle is traveling;
A temperature bias detector (110D) for calculating a bias according to a temperature change of the digital sensor by referring to the data detected by the temperature change detector and the bias detector when the detection information of the motion detector is in a vehicle stop state;
It includes a real-time bias correction unit 110E for performing correction by reflecting the bias value of the bias estimation unit 110D for each temperature and the bias estimation value of the bias estimation unit 110F during driving in real time to the detection value of the digital sensor. Digital sensor bias correction device, characterized in that configured to. The method of claim 1 or 3, wherein the real-time bias correction unit 110E
And feeding back the detected value of the corrected digital sensor to the bias detector so as to continuously update the bias detection function and detect a precise bias. delete delete The method of claim 1 or 3, wherein the smoothing ever
Digital sensor bias correction device, characterized in that calculated according to the following formula.

(Where 'S' is a smoothed gyro sensor value, 'n' is a time index and 'x' is the original gyro sensor value)

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