CN112739986A - Compass calibration method, course measurement system and unmanned aerial vehicle - Google Patents
Compass calibration method, course measurement system and unmanned aerial vehicle Download PDFInfo
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- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
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- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
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Abstract
A method (100) of calibration of a compass (330), a heading measurement system (300,420) and a drone (400), the heading measurement system (300,420) including an RTK device (320) and the compass (330), the method (100) comprising: entering a calibration mode (S110); acquiring first heading data output by an RTK device (320) and second heading data output by a compass (330) (S120); a measurement error of the compass (330) is determined using the first and second heading data, the measurement error being used to calibrate the third heading data output by the compass (330) (S130). The method can automatically calibrate the compass (330) by adopting the output data of the RTK equipment (320), does not need the user to actively trigger calibration, improves the user experience and ensures the reliability of the system.
Description
Technical Field
The invention relates to the technical field of course measurement, in particular to a compass calibration method, a course measurement system and an unmanned aerial vehicle.
Background
The compass sensor can detect a geomagnetic signal, calculate a current heading angle according to a component of a geomagnetic vector under a triaxial coordinate System of the geomagnetic signal, and provide an error between an airplane coordinate System and a terrestrial coordinate System for unmanned aerial vehicle equipment building Global Positioning System (GPS) navigation. However, the unmanned aerial vehicle system itself and the external self-heating environment have various magnetic substances (iron, cobalt, nickel, etc.) and strong current interference, so that an interference magnetic field is generated. The presence of the interfering magnetic field causes the magnetic field measured by the compass to become the sum vector of the interfering magnetic field and the geomagnetic field, and further causes the heading angle calculated according to the magnetic field component to be inaccurate.
At present, a double-antenna RTK (Real-time kinematic) device is generally standard-matched on an unmanned aerial vehicle, and the device can acquire an accurate course angle while acquiring high-precision position and speed information based on a carrier phase difference technology, wherein the precision can reach within 1 degree. On the basis of the dual-antenna RTK equipment, the unmanned aerial vehicle system has low dependence on the accuracy of the compass, so that the problem that the compass is interfered is generally not considered. However, when the signal is blocked, for example, at the bottom of a bridge, between buildings, etc., the satellite signal received by the RTK device is limited, so that the correct heading information cannot be calculated, and the heading information output by the compass is required. If the course information output by the compass is inaccurate, the normal operation of the unmanned aerial vehicle is seriously influenced.
Disclosure of Invention
In this summary, concepts in a simplified form are introduced that are further described in the detailed description. This summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In view of the defects in the prior art, a first aspect of the embodiments of the present invention provides a method for calibrating a compass, which is applied to an unmanned aerial vehicle, where an RTK (real time kinematic) device and the compass are disposed, and the method includes:
entering a calibration mode;
acquiring first course data output by the RTK equipment and second course data output by the compass;
and determining a measurement error of the compass by using the first course data and the second course data, wherein the measurement error is used for calibrating third course data output by the compass.
The second aspect of the embodiments of the present invention provides a course measurement system, which is applied to an unmanned aerial vehicle, and the course measurement system includes:
the RTK equipment is used for outputting first course data;
the compass is used for outputting second course data;
a processor to: entering a calibration mode; acquiring the first course data and the second course data; and determining a measurement error of the compass by using the first course data and the second course data, wherein the measurement error is used for calibrating third course data output by the compass.
A third aspect of an embodiment of the present invention provides an unmanned aerial vehicle, including: the unmanned aerial vehicle body to and above-mentioned course measurement system, course measurement system set up in on the unmanned aerial vehicle body.
A fourth aspect of the embodiments of the present invention provides a computer storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the steps of the calibration method for a compass.
The compass calibration method, the course measurement system and the unmanned aerial vehicle can automatically calibrate the compass by adopting the output data of the RTK equipment, ensure the measurement precision of the compass, do not need a user to actively trigger calibration, and improve the user experience and the reliability of the system.
Drawings
The following drawings of the invention are included to provide a further understanding of the invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
In the drawings:
fig. 1 shows a flow chart of a method of calibrating a compass according to an embodiment of the invention;
FIG. 2 shows a more detailed flow chart of a method of calibrating a compass according to one embodiment of the present invention;
FIG. 3 shows a block diagram of a heading measurement system according to an embodiment of the invention;
fig. 4 shows a block diagram of a drone according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a subset of embodiments of the invention and not all embodiments of the invention, with the understanding that the invention is not limited to the example embodiments described herein. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention described herein without inventive step, shall fall within the scope of protection of the invention.
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.
It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.
In order to provide a thorough understanding of the present invention, detailed steps and detailed structures will be set forth in the following description in order to explain the present invention. The following detailed description of the preferred embodiments of the invention, however, the invention is capable of other embodiments in addition to those detailed.
The compass calibration method, the course measurement system, the drone and the computer-readable storage medium according to the present application will be described in detail below with reference to the accompanying drawings. The features of the following examples and embodiments may be combined with each other without conflict.
First, referring to fig. 1 and fig. 2, a method for calibrating a compass according to an embodiment of the present invention will be described. Fig. 1 shows a flow chart of a method 100 of calibrating a compass according to one embodiment of the present invention. As shown in fig. 1, the method 100 of the compass includes the following steps:
in step S110, enter a calibration mode;
in step S120, first heading data output by the RTK device and second heading data output by the compass are acquired;
in step S130, a measurement error of the compass is determined by using the first heading data and the second heading data, where the measurement error is used to calibrate third heading data output by the compass.
The scheme of the embodiment of the invention is suitable for the unmanned aerial vehicle provided with the RTK equipment and the compass. Two sites are required in RTK device based positioning schemes: a reference station and a rover, wherein the rover is mounted on the drone. The base station sends the obtained carrier phase to the rover station through a data communication link, the rover station receives data transmitted by the base station, the position of the rover station relative to the base station is determined in a dynamic differential positioning mode, the instantaneous absolute position of the rover station is determined according to the coordinates of the base station, and RTK positioning is completed. The communication link may comprise a radio station communication link or a wireless network communication link, among others. The RTK equipment capable of outputting the course information adopted in the embodiment of the invention is specifically double-antenna RTK equipment, and the precise course angle of the unmanned aerial vehicle is calculated by utilizing the relative positioning data between the positioning signals of the two antennas.
And the compass detects the geomagnetic field and calculates the current heading angle according to the components of the geomagnetic field vector under the triaxial coordinate system of the compass. Specifically, when the drone hovers in the horizontal direction, the compass measures X, Y, Z the component of the magnetic field on the axis and calculates based on the three-axis magnetic field components. When the compass is interfered, the magnetic field component is deviated, and further a course angle is subjected to error. When the deviation value of the magnetic field component is too large relative to the magnetic field component, the error of the heading angle is significantly increased, and therefore the calibration method 100 is adopted in the embodiment of the present invention to calibrate the deviation value.
Because the precision of the RTK equipment is higher than that of the compass, under the general condition, the unmanned aerial vehicle adopts the course data output by the RTK equipment to navigate, and when the RTK equipment fails due to various reasons, the third course data output by the compass is adopted to navigate. The scheme of the embodiment of the invention can calibrate the compass by using the RTK equipment in real time so as to avoid adverse effects caused by overlarge errors when the third course data output by the compass is used for navigation under the condition that the RTK is invalid.
Specifically, in the calibration method 100 for a compass provided in the embodiment of the present application, the first heading data output by the dual-antenna RTK device is used as a reference, and the deviation between the first heading data and the second heading data output by the compass is calculated as a measurement error of the compass, and then when the third heading data output by the compass needs to be used as a data source due to a fault or other reasons of the dual-antenna RTK device, the measurement error can be used to compensate the third heading data output by the compass, so as to ensure the accuracy of the third heading data. According to the calibration method 100 provided by the embodiment of the invention, the calibration can be realized in a state that the user does not sense the compass without actively calibrating the compass, so that the error of the compass can be eliminated on line, and the stability and reliability of the product are ensured.
In the present embodiment, the execution subject of steps S110 to S130 may be a processor. The processor may specifically be a flight controller of the drone, or may also be another general-purpose or special-purpose processor.
In step S110, it may be determined whether to enter a calibration mode when the drone is in the air, so as to eliminate interference caused by a ground magnetic field. When the unmanned aerial vehicle is positioned in the air, whether the unmanned aerial vehicle enters a calibration mode or not can be judged when the unmanned aerial vehicle is in a hovering state or an included angle between the unmanned aerial vehicle and a horizontal plane is small, so that the coupling influence of a magnetic field component which is not used for calculating a course angle in a compass on the magnetic field component used for calculating the course angle can be avoided. In addition, also can judge whether to get into the calibration mode under the quiescent condition after unmanned aerial vehicle power-on starts to guarantee to all can judge whether it needs the calibration before unmanned aerial vehicle navigation at every turn.
Further, one or more calibrations may be performed during each voyage of the drone. For example, in one flight, the determination of whether to enter the calibration mode may be performed each time the unmanned aerial vehicle enters the hovering state or an included angle between the unmanned aerial vehicle and a horizontal plane is small, or the determination may be performed every predetermined time. Besides, when a calibration instruction of a user is received, the calibration mode can be directly entered.
For the judgment of whether to enter the calibration mode, whether the RTK equipment is effective or not and whether the compass needs to be calibrated or not can be respectively judged. If the RTK equipment is effective and the compass needs to be calibrated, a calibration mode is entered. And if the RTK equipment is invalid and/or the compass does not need to be calibrated, not entering a calibration mode and ending the calibration judgment process.
Wherein, whether the compass needs to be calibrated and whether the RTK equipment is effective can be sequentially judged. For example, it may be determined whether the compass needs to be calibrated first, and if the compass does not need to be calibrated, the compass does not enter the calibration mode, and the process is directly ended; and if the compass needs to be calibrated, then judging whether the RTK equipment is effective, if the RTK equipment is effective, entering a calibration mode, otherwise, not entering the calibration mode and ending the process.
Similarly, as shown in fig. 2, it may also be determined whether the RTK device is valid, and if the RTK device is invalid, the process is ended; and on the premise that the RTK equipment is effective, judging whether the compass needs to be calibrated or not, if the compass needs to be calibrated, entering a calibration mode, otherwise, not entering the calibration mode and ending the process.
In other examples, the determination of whether the compass needs to be calibrated and the determination of whether the RTK device is valid may be performed in parallel, and the order of the compass and the RTK device is not limited in the embodiments of the present invention.
Specifically, determining whether the compass needs to be calibrated may include: and acquiring second magnetic field data output by the compass, and comparing the second magnetic field data with the real geomagnetic field data. The real geomagnetic field data is geomagnetic field data of an area where the unmanned aerial vehicle is located currently. If the deviation between the second magnetic field data and the real geomagnetic field data exceeds a preset threshold, the compass is determined to need to be calibrated; on the contrary, if the deviation between the second magnetic field data and the real geomagnetic field data does not exceed the preset threshold, the compass is considered not to be required to be calibrated.
Since the compass may have been calibrated before the current calibration, and the memory stores the measurement error determined at the previous calibration, the measurement error determined at the previous calibration stored in the memory may be used to compensate the triaxial magnetic field component output by the compass, and the second magnetic field data may be determined according to the compensated triaxial magnetic field component. The previous calibration may be calibration performed before factory shipment, or may be calibration performed during last flight of the unmanned aerial vehicle. The measurement error determined at the previous calibration may include a measurement error of a compass tri-axial magnetic field component.
The calculating of the second magnetic field data according to the compensated triaxial magnetic field component includes calculating to obtain the total magnetic field strength according to the triaxial magnetic field component output by the compass, and the real geomagnetic field data may be a numerical range of the geomagnetic field strength determined according to the current position of the unmanned aerial vehicle. Comparing the second magnetic field data with the real earth magnetic field data may be realized as comparing the total magnetic field strength with a numerical range of earth magnetic field strengths. In one example, it may be determined that the compass needs calibration when the total magnetic field strength is outside the numerical range and that the compass does not need calibration when the total magnetic field strength is not outside the numerical range. In another example, it may be determined that the compass needs to be calibrated when the total magnetic field strength deviates from the range of values by more than a predetermined threshold, whereas it is determined that the compass does not need to be calibrated.
Optionally, when determining whether the compass needs to be calibrated, the compass can also be determined by two-axis magnetic field components used for calculating the heading angle, instead of the three-axis magnetic field components.
Optionally, when it is determined whether the compass needs to be calibrated, the magnetic field components of the respective axes may be compared, and when one or more of the three-axis magnetic field components corresponding to the second magnetic field data exceed the numerical range of the corresponding real magnetic field component, it may be determined that the compass needs to be calibrated.
The inefficiency of an RTK device may be due to interference when the signal is received by the base station or rover from the satellite, the base station being too far from the rover, the data transmission link between the base station and the rover being interrupted, etc. When the communication link is interrupted or signal delay is large, so that the base station and the rover station cannot communicate, only the rover station outputs data, namely single-point solution occurs, and at the moment, the RTK equipment can be judged to be invalid. In some embodiments, when the RTK device exhibits differential decomposition due to signal occlusion or the like, the RTK device may also be determined to be invalid due to too low precision. Specifically, whether the RTK device is currently valid may be determined by the processor based on an identification bit in the RTK data.
In one embodiment, when the RTK device is determined to be invalid, if the unmanned aerial vehicle is in the air, the third heading data output by the compass is switched in time for navigation. If the unmanned aerial vehicle is in a static state after being powered on and started, prompt information is generated to a user in time, and for example, the user can determine whether to take off the unmanned aerial vehicle according to the prompt information.
According to the embodiment of the invention, whether the calibration condition is met can be automatically judged, and the calibration mode is automatically entered when the calibration condition is met, without the need of actively triggering calibration by a user, so that the influence on user experience caused by frequent prompt or inquiry of user calibration is avoided.
After entering the calibration mode, step S120 is executed to acquire the first heading data output by the RTK device and the second heading data output by the compass. Thereafter, in step S130, a measurement error of the compass is determined using the first and second heading data acquired in step S120. Here, steps S120 and S130 are performed automatically, that is, without prompting the user, when the conditions described below are satisfied, data is acquired and calibration is performed automatically.
The first course data output by the RTK equipment comprises a course angle output by the RTK equipment. Specifically, carrier phase double difference processing is carried out on a reference station measured value and carrier phase measured values of two antennas fixed on the unmanned aerial vehicle respectively to obtain two double difference observation equations, then baseline vectors between the reference station and the two antennas are obtained respectively, and the baseline vectors between the antennas can be obtained finally through vector operation; coordinate conversion is carried out on the baseline vector, so that the course angle theta of the unmanned aerial vehicle can be obtainedr。
The second heading data output by the compass is determined based on the first magnetic field data output by the compass. The first magnetic field data comprises X, Y, Z three-axis magnetic field data m in three coordinate axesx、my、mzWith X, Y, Z axes being perpendicular to each other, X, Y axis being in the horizontal direction and the Z axis being in the vertical direction. When the unmanned aerial vehicle hovers in the horizontal direction or the included angle between the unmanned aerial vehicle and the horizontal direction is small, the magnetic field data m on the X, Y axis can be directly usedx、myCalculating to obtain a heading angle theta which is arctan (-m)y/mx) 180/pi. Considering the errors bx, by of the X, Y-axis magnetic field data, the true heading angle should be arctan (- (m)y–by)/(mx-bx)) 180/pi. If the included angle between the unmanned aerial vehicle and the horizontal direction is largerIf the magnetic field data is large, firstly filtering the Z-axis coupling component in the X-axis magnetic field data and the Y-axis magnetic field data, and calculating the course angle by using the X-axis magnetic field data and the Y-axis magnetic field data after the Z-axis coupling component is filtered so as to eliminate the influence of the Z-axis coupling component on the calculation result.
In the embodiment of the invention, the course angle output by the RTK equipment is used as the real course angle to determine the measurement error of the first magnetic field data, so that after the measurement error of the first magnetic field data is used for compensating the first magnetic field data, the course angle calculated based on the compensated first magnetic field data is equal to the course angle output by the RTK equipment.
That is, the course angle θ of the RTK device output is establishedrRelation to the first magnetic field data and its measurement error: thetar＝arctan(-(my–by)/(mxBx)) 180/pi, and calculating two measurement error parameters bx and by.
It will be appreciated that at least two sets of first and second heading data are required to solve for bx and by. However, in one embodiment, in order to accurately calculate the measurement error of the compass, three or more sets of first heading data and second heading data that are synchronously output may be acquired at different angles during the rotation of the drone. In order to avoid the influence of the coupling component of the Z axis on the calculation of the heading angle, the first heading data and the second heading data are collected when the unmanned aerial vehicle is preferentially selected to be in the horizontal direction or have a small included angle with the horizontal direction in the rotation process of the unmanned aerial vehicle. However, if the included angle between the unmanned aerial vehicle and the horizontal direction is larger when the first heading data and the second heading data are collected, the data of the Z-axis coupling can be filtered after the first heading data and the second heading data are collected.
For example, any 10 points can be selected in the course of traversing the course angle of the unmanned aerial vehicle by-180 degrees to-180 degrees, a group of first course data and second course data are collected at each point, and 10 groups of first course data and second course data are collected together. Illustratively, in order to ensure the accuracy of the data, in the process of acquiring the first course data and the second course data, it is required to ensure that the rotating speed of the unmanned aerial vehicle is not greater than a preset value.
With continued reference to fig. 2, because multiple sets of first and second heading data at multiple angles need to be acquired to ensure accuracy of the measurement error, if enough data is not collected, the calibration can be terminated to avoid performing inaccurate calibration.
Specifically, a time period may be preset, and if sufficient first heading data and sufficient second heading data cannot be acquired within the preset time period after the calibration is started, the calibration is stopped and the calibration process is ended. The reason for failing to collect enough first and second heading data may be due to the inability of the heading angle of the drone to traverse a sufficiently large angle within a preset time period after the calibration is started. After the calibration is finished, whether the unmanned aerial vehicle enters the calibration mode can be judged again in a static state after the unmanned aerial vehicle is hovered or powered on and started next time.
After enough first course data and second course data are collected, a plurality of groups of the first course data and the second course data which are collected synchronously can be fitted according to a least square method to calculate errors bx and by of the first magnetic field data output by the compass on an X, Y axis, and the errors are stored in an internal memory as measurement errors of the compass.
The memory may be various nonvolatile memories, and may include a FLASH memory (FLASH), for example. The measurement error stored in the memory is updatable, with each calibration being performed, i.e., the measurement error stored in the memory at the time of the last calibration is replaced with the measurement error obtained from the current calibration. And subsequently, when the RTK equipment fails and the third course data output by the compass needs to be used as a data source, the latest updated measurement error stored in the memory can be called to calibrate the third course data, the measurement error is calculated by taking the first course data output by the RTK equipment as a real course angle, and the measurement error is used for calibrating the third course data, so that the calibrated data can be ensured to be consistent with the output data of the RTK equipment.
The third heading data output by the compass comprises third magnetic field data, and particularly comprises third magnetic field data on an X, Y, Z axis. Calibrating the third magnetic field data with the measurement errors may include compensating the third magnetic field data in the X-axis and the Y-axis with the measurement errors bx, by in the X-axis and the Y-axis. Bx and by are solved by using the course angle output by the RTK device as a true value, and after the bx and by are used for compensating the third magnetic field data on the X axis and the Y axis, the course angle obtained by using the compensated third magnetic field data can be equal to the course angle output by the RTK device.
The above exemplary steps included in the calibration method of the compass according to the embodiment of the present invention are exemplarily described. The calibration method of the compass provided by the embodiment of the invention automatically adopts the output data of the RTK equipment to calibrate the compass on the basis of the existing hardware, so that the effective utilization of the RTK data is realized, the measurement precision of the compass is ensured, the user does not need to actively trigger calibration, and the user experience and the reliability of the system are improved.
In another aspect of the present invention, a heading measurement system is provided, and fig. 3 is a schematic block diagram of a heading measurement system 300 according to an embodiment of the present invention. As shown in fig. 3, the heading measurement system 300 includes a processor 310, an RTK device 320 and a compass 330, the RTK device 320 and the compass 330 are communicatively connected to the processor 310, and only the main functions of the heading measurement system 300 will be described below, and some of the details that have been described above will be omitted.
Processor 310 may have any form of processing unit with data processing capabilities and/or instruction execution capabilities, among others. For example, the processor 310 may include a Micro Controller Unit (MCU) which appropriately reduces the frequency and specification of the cpu, and integrates a memory, a counter, a USB (universal serial bus), an a/D (analog/digital) converter, a UART (universal asynchronous receiver transmitter), a PLC (programmable logic controller), a DMA (direct memory access) and other peripheral interfaces, and an LCD (liquid crystal display) driving circuit on a single chip to form a chip-level processor, so as to perform different combination control for different applications. In addition to executing the calibration method of the embodiment of the present invention, the MCU may also control the stable operation of the drone through an algorithm according to the operation instruction of the user and the output data of the RTK device 320 or the compass 330.
The RTK device 320 and compass 330 are used to output first and second heading data, respectively. The RTK device 320 is specifically a dual-antenna RTK device, and the output first course data includes a course angle of the unmanned aerial vehicle calculated by using relative positioning data between positioning signals of two antennas. The compass 330 can detect the geomagnetic field, and the output second heading data is a heading angle calculated according to the component of the output first magnetic field data in the three-axis coordinate system.
In particular, the processor 310 is configured to perform the following steps:
entering a calibration mode;
acquiring the first course data and the second course data;
and determining a measurement error of the compass by using the first course data and the second course data, wherein the measurement error is used for calibrating third course data output by the compass.
In one embodiment, the measuring error of the compass comprises a measuring error of first magnetic field data output by the compass, and the determining the measuring error of the compass using the first heading data and the second heading data comprises:
and determining the measurement error of the first magnetic field data by using the first magnetic field data and the first course data, so that after the first magnetic field data is compensated by using the measurement error of the first magnetic field data, a course angle calculated based on the compensated first magnetic field data is equal to a course angle output by the RTK equipment.
In one embodiment, the first magnetic field data output by the compass includes three-axis magnetic field data, and determining the measurement error of the first magnetic field data specifically includes: and determining the measurement error of the two-axis magnetic field data used for calculating the heading angle in the three-axis magnetic field data.
In one embodiment, the acquiring the first heading data output by the RTK device and the second heading data output by the compass includes: and acquiring a plurality of groups of first course data and second course data which are synchronously output at different angles in the rotation process of the unmanned aerial vehicle.
In one embodiment, the determining a measurement error of the first magnetic field data comprises: and fitting multiple groups of the first course data and the second course data according to a least square method to calculate the measurement error of the first magnetic field data.
Further, the processor 310 is further configured to: and if the number of the first course data and the second course data collected within the preset time does not reach the preset number, exiting the calibration mode.
In one embodiment, heading measurement system 300 further includes a memory, and the processor is further configured to store the measurement error in the memory.
In one embodiment, the measurement error is updatable.
In one embodiment said entering a calibration mode comprises:
under the hovering state, second magnetic field data output by the compass is acquired;
and if the deviation between the second magnetic field data and the real geomagnetic field data exceeds a preset threshold value and the RTK equipment is currently effective, entering the calibration mode.
The main functions of the components of the heading measurement system 300 are described above, and further details can be found in the above description of the calibration method 100 for a compass, which is not repeated herein.
The course measuring system provided by the embodiment of the invention automatically adopts the output data of the RTK equipment to calibrate the compass on the basis of the existing hardware, so that the effective utilization of the RTK data is realized, the measuring precision of the compass is ensured, the user does not need to actively trigger calibration, and the user experience and the reliability of the system are improved.
In another embodiment, as shown in fig. 4, an embodiment of the present invention further provides a drone 400, where the drone 400 includes a drone body 410 and a heading measurement system 420, and the heading measurement system 420 is disposed on the drone body 410.
Wherein, the unmanned aerial vehicle body includes parts such as central organism, horn, power device, undercarriage. Illustratively, a plurality of horn and the fixed connection of center organism, a plurality of power device are located a plurality of horn respectively, power device can include the rotor. The undercarriage is arranged below the central machine body and is used for supporting a central body, a machine arm, a power device and the like of the machine.
A heading measurement system 420 is disposed in the center body. Heading measurement system 420 includes an RTK device, a compass, and a processor. The processor can be a flight control system of the unmanned aerial vehicle, the RTK equipment and the compass are in communication connection with the flight control system and provide course data for the flight control system, and the flight control system performs flight control according to the course data. The details of the heading measurement system 420 can be found above and will not be described herein.
In addition, the embodiment of the invention also provides a computer storage medium, and the computer storage medium is stored with the computer program. The steps of the calibration method 100 described above may be implemented when the computer program is executed by a processor.
For example, the computer storage medium is a computer-readable storage medium. The computer storage medium may include, for example, a memory card of a smart phone, a storage component of a tablet computer, a hard disk of a personal computer, a Read Only Memory (ROM), an Erasable Programmable Read Only Memory (EPROM), a portable compact disc read only memory (CD-ROM), a USB memory, or any combination of the above storage media. The computer-readable storage medium may be any combination of one or more computer-readable storage media.
In summary, the compass calibration method, the course measurement system, the unmanned aerial vehicle and the computer storage medium according to the embodiments of the present invention can automatically calibrate the compass by using the output data of the RTK device, thereby ensuring the measurement accuracy of the compass, and improving the user experience and the reliability of the system without actively triggering the calibration by the user.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Although the illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the foregoing illustrative embodiments are merely exemplary and are not intended to limit the scope of the invention thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as set forth in the appended claims.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another device, or some features may be omitted, or not executed.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the invention and aiding in the understanding of one or more of the various inventive aspects. However, the method of the present invention should not be construed to reflect the intent: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.
It will be understood by those skilled in the art that all of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.
The various component embodiments of the invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functionality of some of the modules according to embodiments of the present invention. The present invention may also be embodied as apparatus programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present invention may be stored on computer-readable media or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.
The above description is only for the specific embodiment of the present invention or the description thereof, and the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the changes or substitutions should be covered within the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (20)
1. A method for calibrating a compass, applied to an unmanned aerial vehicle, in which an RTK (real time kinematic) device and the compass are disposed, the method comprising:
entering a calibration mode;
acquiring first course data output by the RTK equipment and second course data output by the compass;
and determining a measurement error of the compass by using the first course data and the second course data, wherein the measurement error is used for calibrating third course data output by the compass.
2. The method of claim 1, wherein the first heading data comprises a heading angle output by the RTK device, the second heading data is determined based on first magnetic field data output by the compass, the measurement error of the compass comprises a measurement error of the first magnetic field data,
the determining the measurement error of the compass using the first heading data and the second heading data includes:
and determining the measurement error of the first magnetic field data by using the first magnetic field data and the first course data, so that after the first magnetic field data is compensated by using the measurement error of the first magnetic field data, a course angle calculated based on the compensated first magnetic field data is equal to a course angle output by the RTK equipment.
3. The method of claim 2, wherein the first magnetic field data output by the compass comprises three-axis magnetic field data, and wherein determining a measurement error of the first magnetic field data comprises:
and determining the measurement error of the two-axis magnetic field data used for calculating the heading angle in the three-axis magnetic field data.
4. The method of claim 2 or 3, wherein said acquiring first heading data output by said RTK device and second heading data output by said compass comprises:
and acquiring a plurality of groups of first course data and second course data which are synchronously output at different angles in the rotation process of the unmanned aerial vehicle.
5. The method of claim 4, wherein said determining a measurement error of said first magnetic field data comprises:
and fitting multiple groups of the first course data and the second course data according to a least square method to calculate the measurement error of the first magnetic field data.
6. The method of claim 4, further comprising:
and if the number of the first course data and the second course data collected within the preset time does not reach the preset number, exiting the calibration mode.
7. The method of any one of claims 1-4, wherein the method further comprises:
storing the measurement error in a memory.
8. Method according to one of claims 1 to 4, characterized in that the measurement error is updatable.
9. The method of claim 1, wherein the entering the calibration mode comprises:
under the hovering state, second magnetic field data output by the compass is acquired;
and if the deviation between the second magnetic field data and the real geomagnetic field data exceeds a preset threshold value and the RTK equipment is currently effective, entering the calibration mode.
10. The utility model provides a course measurement system, is applied to unmanned aerial vehicle which characterized in that, course measurement system includes:
the RTK equipment is used for outputting first course data;
the compass is used for outputting second course data;
a processor to:
entering a calibration mode;
acquiring the first course data and the second course data;
and determining a measurement error of the compass by using the first course data and the second course data, wherein the measurement error is used for calibrating third course data output by the compass.
11. The heading measurement system of claim 10, wherein the first heading data comprises a heading angle output by the RTK device, the second heading data is determined based on first magnetic field data output by the compass, a measurement error of the compass comprises a measurement error of the first magnetic field data,
the determining the measurement error of the compass using the first heading data and the second heading data includes:
and determining the measurement error of the first magnetic field data by using the first magnetic field data and the first course data, so that after the first magnetic field data is compensated by using the measurement error of the first magnetic field data, a course angle calculated based on the compensated first magnetic field data is equal to a course angle output by the RTK equipment.
12. The heading measurement system of claim 11, wherein the first magnetic field data output by the compass comprises three-axis magnetic field data, and wherein determining a measurement error of the first magnetic field data comprises:
and determining the measurement error of the two-axis magnetic field data used for calculating the heading angle in the three-axis magnetic field data.
13. The heading measurement system of claim 11 or 12, wherein the acquiring the first heading data output by the RTK device and the second heading data output by the compass comprises:
and acquiring a plurality of groups of first course data and second course data which are synchronously output at different angles in the rotation process of the unmanned aerial vehicle.
14. The heading measurement system of claim 13, wherein determining a measurement error of the first magnetic field data comprises:
and fitting multiple groups of the first course data and the second course data according to a least square method to calculate the measurement error of the first magnetic field data.
15. The heading measurement system of claim 12, wherein the processor is further configured to:
and if the number of the first course data and the second course data collected within the preset time does not reach the preset number, exiting the calibration mode.
16. The heading measurement system of any of claims 10-13, wherein the heading measurement system further comprises a memory, the processor further configured to:
storing the measurement error in the memory.
17. The heading measurement system of any of claims 10-13, wherein the measurement error is updatable.
18. The heading measurement system of claim 10, wherein the entering the calibration mode comprises:
under the hovering state, second magnetic field data output by the compass is acquired;
and if the deviation between the second magnetic field data and the real geomagnetic field data exceeds a preset threshold value and the RTK equipment is currently effective, entering the calibration mode.
19. An unmanned aerial vehicle, comprising:
an unmanned aerial vehicle body;
the heading measurement system of any of claims 10-18, disposed on the drone body.
20. A computer storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of calibrating a compass according to any one of claims 1 to 9.
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| PCT/CN2020/088287 WO2021217580A1 (en) | 2020-04-30 | 2020-04-30 | Compass calibration method, heading measurement system, and unmanned aerial vehicle |
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