A system and method for measuring gravity acceleration and positioning orientation

Abstract

The present invention proposes a measurement system and method for gravity acceleration and positioning orientation, the system includes a measurement module and a calculation control module, the calculation control module obtains the first signal output by a small-range three-axis accelerometer, the second signal output by a medium-range three-axis accelerometer, the third signal output by a three-axis fiber optic gyroscope and the vibration range of the vehicle engine and determines whether the range of the small-range three-axis accelerometer includes the vibration signal range of the vehicle engine. If it does, the calculation control module uses the third signal to correct the first signal and processes it and outputs the corrected gravity acceleration value and positioning orientation data at the same time; if it does not, the calculation control module uses the first signal and the third signal to correct the second signal and processes it and outputs the corrected positioning orientation data. Not only does it achieve the simultaneous measurement of the local gravity acceleration value and positioning orientation data, but it also has a high measurement accuracy.

Description

Technical Field

[0001] The present invention belongs to the field of geodetic measurement technology, and more specifically, relates to a system and method for measuring gravity acceleration and positioning orientation. Background Art

[0002] With the rapid development of science and technology, vehicle-mounted aircraft have received widespread attention. In order to enable the aircraft to land accurately, the data, environment and platform at the time of takeoff need to have extremely high requirements. When the vehicle-mounted aircraft takes off at a preset location, high-precision data is required to land accurately. When the vehicle moves to a non-preset location, the geographical location changes, and its gravity acceleration will also produce slight deviations with factors such as geographical location and time. At this time, if the gravity acceleration value, geographical location and other parameters of the take-off location cannot be accurately obtained, the landing will be inaccurate, which will bring many unpredictable consequences. In short, if the landing accuracy of the vehicle-mounted aircraft is to be improved, it is necessary not only to measure the gravity acceleration at the take-off location with high precision, but also to obtain more accurate take-off location information at the same time.

[0003] At present, the purpose of measuring gravity acceleration is simply to measure gravity acceleration. The measurement of gravity acceleration is not organically combined with the positioning and orientation functions, and it is impossible to achieve high-precision measurement of gravity acceleration values ​​and positioning and orientation data at the same time. Secondly, the measurement accuracy of gravity acceleration is not high, which cannot meet the actual needs in complex environments, making landing subject to unpredictable risks. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a system and method for measuring gravity acceleration and positioning orientation, which solves the problem of not being able to simultaneously measure local gravity acceleration and positioning orientation with high precision, and meets the actual needs in complex environments.

[0005] In order to achieve the above object, the present invention adopts the following technical solution.

[0006] A system for measuring gravitational acceleration and positioning orientation, the system comprising:

[0007] Measurement modules, including a small-range three-axis accelerometer with independent acquisition channels, a medium-range three-axis accelerometer, and a three-axis fiber optic gyroscope;

[0008] A calculation control module collects in real time the first signal output by the small-range three-axis accelerometer, the second signal output by the medium-range three-axis accelerometer, and the third signal output by the three-axis fiber optic gyroscope for fusion processing;

[0009] The fusion process is as follows:

[0010] The calculation control module determines whether the range of the small-range triaxial accelerometer includes the range of the vehicle engine vibration signal;

[0011] In the case of including, the calculation control module uses the third signal to correct the first signal and processes it, and then outputs the corrected gravity acceleration value and the positioning and orientation data simultaneously;

[0012] In the absence of inclusion, the calculation control module uses the first signal and the third signal to correct the second signal and outputs the corrected positioning and orientation data after processing.

[0013] Furthermore, the measurement module also includes a vehicle-mounted precision multi-channel odometer and / or a Beidou navigation receiver;

[0014] The calculation and control module also receives a fourth signal output by the vehicle-mounted precision multi-channel odometer and / or the Beidou navigation receiver, uses the fourth signal to correct the second signal to obtain a fifth signal, and then uses the first signal and the third signal to correct the fifth signal and output the corrected positioning and orientation data.

[0015] Furthermore, the measurement accuracy of the small-range three-axis accelerometer is ≤1mGal, and the measurement range is ±2g.

[0016] Furthermore, the measurement accuracy of the mid-range three-axis accelerometer is ≤20mGal, and the measurement range is ±10g; the measurement accuracy of the three-axis fiber optic gyroscope is ≤0.001° / h, and the measurement range is ±80° / s.

[0017] Furthermore, the vehicle-mounted precision multi-channel odometer includes at least two channels, which are respectively arranged on the left and right wheels of the vehicle, and the measurement accuracy is not less than 3600 lines / cycle.

[0018] According to another aspect of the present invention, a high-precision measurement method for vehicle-mounted gravity acceleration and positioning orientation is provided, the method comprising:

[0019] Obtaining a first signal output by a small-range three-axis accelerometer, a second signal output by a medium-range three-axis accelerometer, a third signal output by a three-axis fiber optic gyroscope, and a vibration range of a vehicle engine;

[0020] determining whether the measuring range of the short-range triaxial accelerometer includes the vehicle engine vibration range,

[0021] If included, the first signal is corrected by using the third signal and processed, and the corrected gravity acceleration value and the positioning and orientation data are output simultaneously;

[0022] If not included, the second signal is corrected using the first signal and the third signal, and the corrected positioning and orientation data is output after processing.

[0023] Furthermore, the second signal can also be fused with a fourth signal output by a vehicle-mounted precision multi-channel odometer and / or a Beidou navigation receiver;

[0024] The fourth signal is used to correct the second signal to obtain a fifth signal, and the first signal and the third signal are used to correct the fifth signal to output the corrected positioning and orientation data.

[0025] Furthermore, the measurement accuracy of the small-range three-axis accelerometer is ≤1mGal, and the measurement range is ±2g.

[0026] Furthermore, the measurement accuracy of the mid-range three-axis accelerometer is ≤20mGal, and the measurement range is ±10g; the measurement accuracy of the three-axis fiber optic gyroscope is ≤0.001° / h, and the measurement range is ±80° / s.

[0027] Furthermore, the vehicle-mounted precision multi-channel odometer includes at least two channels, which are respectively arranged on the left and right wheels of the vehicle, and the measurement accuracy is not less than 3600 lines / cycle.

[0028] In summary, compared with the prior art, the present invention provides a system and method for measuring gravity acceleration and positioning orientation, which has the following beneficial effects:

[0029] (1) The present invention provides a system and method for measuring gravity acceleration and positioning and orientation, which organically combines large and small range accelerometers with fiber optic gyroscopes, realizing both the function of measuring local gravity acceleration values ​​and the positioning and orientation functions. It is a comprehensive product that integrates positioning and orientation functions with gravity acceleration measurement technology. The two are not a simple combination, but constitute an integral whole with information fusion, cross-complementarity, and mutual fault tolerance, which is simpler and more practical, and reduces costs.

[0030] (2) The present invention provides a system and method for measuring gravity acceleration and positioning orientation, which adds a set of small-range three-axis accelerometers to accurately eliminate related errors, greatly improving the measurement accuracy and anti-interference performance. In complex environments, it provides the aircraft with high-precision information such as the gravity acceleration value and positioning orientation at the take-off point, improves the landing accuracy, and meets the actual needs of vehicle-mounted aircraft in dynamic environments.

[0031] (3) The gravity acceleration and positioning orientation measurement system and method of the present invention enable a vehicle-mounted aircraft to obtain high-precision gravity acceleration values ​​and positioning orientation data in any unknown and complex location, so that the aircraft can successfully achieve rapid, unpredictable and unsupported landing in complex environments such as tunnels, culverts, and deep mountain canyons. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 The diagram is a basic structure diagram of a system and method for measuring gravity acceleration and positioning orientation of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The present invention provides a system and method for measuring gravity acceleration and positioning orientation, which mainly installs inertial sensors, namely gyroscopes and accelerometers, in a three-axis indexing control system. The system collects signals output by the inertial sensors after self-calibration and self-alignment, calculates calibration parameters and alignment results, and finally obtains high-precision gravity acceleration values ​​and positioning orientation data after signal fusion processing.

[0036] Figure 1 The present invention provides a basic structural diagram of a system and method for measuring gravity acceleration and positioning and orientation, which can simultaneously measure high-precision gravity acceleration values ​​and positioning and orientation data in any unknown complex area. The system includes a measurement module and a control module.

[0037] The measurement module includes a small-range three-axis accelerometer, a medium-range three-axis accelerometer and a three-axis fiber optic gyroscope with independent acquisition channels. The better one includes three sets of inertial sensors: a high-precision small-range three-axis accelerometer, a high-precision medium-range three-axis accelerometer and a high-precision three-axis fiber optic gyroscope; specifically, gyroscopes and accelerometers are installed on three axes, the three axes are perpendicular to each other, and each axis has a high-precision small-range accelerometer, a high-precision medium-range accelerometer and a high-precision fiber optic gyroscope.

[0038] The computing control module can be a comprehensive computer that collects in real time the first signal output by the high-precision small-range three-axis accelerometer, the second signal output by the high-precision medium-range three-axis accelerometer, and the third signal output by the high-precision three-axis fiber optic gyroscope, performs fusion processing, and outputs high-precision data to the outside.

[0039] Preferably, the system also includes some auxiliary components such as an inner frame, an outer frame, a driving circuit, an outer shell, a mounting bracket, an interface circuit, a cable, a plug-in, and a landmark distance measurement to make the system more complete and comprehensive.

[0040] As an embodiment of the present invention, the computing control module first receives external instructions to enable the entire measurement system to complete self-calibration and self-alignment. Since the core of the entire measurement system is the gyroscope and accelerometer, the error of the entire measurement system also mainly comes from the gyroscope and accelerometer. Therefore, self-calibration and self-alignment are required before measurement, so that the verticality and parallelism measurement errors between the gyroscope and the accelerometer do not exceed 1", meeting the measurement requirements.

[0041] During the self-calibration process, the calibration of gravity acceleration value and positioning orientation data are carried out simultaneously, and the same set of inner and outer frames are used, which saves costs. It is worth noting that during self-calibration, the vehicle vibration is within the range of -1.5g to 1.5g. At this time, the first signal is mainly used, and the self-calibration is completed after it is corrected by using the remaining inertial sensors.

[0042] During the self-alignment process, the vehicle vibration is also within the range of -1.5g to 1.5g. At this time, the positioning and orientation data alignment is performed. This process is also based on the first signal, and the remaining inertial sensors are used to correct it to improve the self-alignment accuracy. In short, in the self-calibration and self-alignment process, the first signal is mainly used.

[0043] After the system completes self-calibration and self-alignment, the calculation control module determines whether the range of the small-range three-axis accelerometer includes the range of the vehicle engine vibration signal.

[0044] If included, the calculation control module uses the third signal to correct the first signal and processes it, and then outputs the corrected gravity acceleration value and positioning and orientation data. That is, the high-precision small-range three-axis accelerometer signal is used as the main signal, and the high-precision three-axis fiber optic gyroscope signal is used to correct it and process it to obtain the corrected high-precision gravity acceleration value and positioning and orientation data.

[0045] If not included, the calculation control module uses the first signal and the third signal to correct the second signal and output the corrected positioning and orientation data after processing. That is, the high-precision medium-range three-axis accelerometer signal is mainly used, and the signals of the high-precision small-range three-axis accelerometer and the high-precision three-axis fiber optic gyroscope are used to correct and process it to obtain the corrected high-precision positioning and orientation data.

[0046] After the vehicle has been driving for a period of time, the position and speed of the vehicle change too quickly, resulting in a gradually increasing error. In order to more accurately obtain the positioning and orientation data of the vehicle during driving, the measurement module also includes a vehicle-mounted precision multi-channel odometer and / or a Beidou navigation receiver, both of which are used to improve the positioning and orientation data during driving.

[0047] The calculation and control module also receives a fourth signal output by the vehicle-mounted precision multi-channel odometer and / or the Beidou navigation receiver, uses the fourth signal to correct the second signal to obtain a fifth signal, and then uses the first signal and the third signal to correct the fifth signal and output the corrected positioning and orientation data.

[0048] As an embodiment of the present invention, when the vehicle is in driving, the system is in a mode of inertial navigation and odometer navigation combination. Inertial navigation outputs a first signal, a second signal and a third signal; odometer navigation outputs a fourth signal. More preferably, the Beidou navigation receiver is turned on to correct the navigation speed and position in real time, and correct the position accuracy of the driving trajectory, calculate and eliminate the estimated error of the subsequent driving trajectory, so that the accurate position can still be obtained after the Beidou navigation receiver signal fails; when the Beidou navigation receiver cannot work normally, the vehicle can also go to the nearest landmark point and use the landmark to correct the position, so as to obtain the corrected real-time and high-precision positioning and orientation data through high-precision positioning and orientation data and real-time correction of position and trajectory.

[0049] When the road condition is bad during driving, and the measuring range of the high-precision small-range three-axis accelerometer does not include the vibration range of the vehicle engine, the high-precision medium-range three-axis accelerometer signal is used as the main signal, and the fourth signal is used to correct it to obtain the fifth signal, and then the signals of the high-precision small-range three-axis accelerometer and the high-precision three-axis fiber optic gyroscope are used to correct it and process it, and finally the corrected real-time high-precision positioning and orientation data is output.

[0050] When the road condition is relatively flat during driving and the measuring range of the high-precision small-range three-axis accelerometer includes the vibration range of the vehicle engine, the signal of the high-precision small-range three-axis accelerometer is used as the main signal, and the signal of the high-precision three-axis fiber optic gyroscope is used to correct it in order to improve the accuracy of the positioning and orientation solution.

[0051] It is worth noting that only by combining the accelerometer and the gyroscope can the positioning and orientation data be obtained. When the road conditions are relatively bad, the vehicle positioning and orientation data mainly comes from the high-precision medium-range three-axis accelerometer. When the road conditions are relatively flat, the vehicle is stable within the range of the high-precision small-range three-axis accelerometer for a long time, and the system will convert the high-precision medium-range three-axis accelerometer into a high-precision small-range three-axis accelerometer to improve the positioning and orientation accuracy of the inertial navigation.

[0052] When the vehicle stops at an unknown and complex location after driving for a period of time, the vehicle is in a stopped state. The measuring range of the high-precision small-range three-axis accelerometer includes the vibration range of the vehicle engine. The computer control module collects mainly the signal of the high-precision small-range three-axis accelerometer, and uses the signal of the high-precision three-axis fiber optic gyroscope to correct it and process it to obtain the corrected high-precision gravity acceleration value and positioning and orientation data.

[0053] Correction is to correct the higher precision value on the same axis to improve the accuracy. When the vehicle reaches an unknown complex location to measure gravity acceleration, the gravity component value in the direction perpendicular to the ground is generally large. At this time, it is necessary to correct the measurement results of the high-precision, small-range three-axis accelerometer in this direction; while the other two directions relative to the horizontal are still based on the measurement results of the high-precision, small-range three-axis accelerometer; at the same time, the high-precision three-axis fiber optic gyroscope is responsible for detecting the angular vibration changes of the vehicle, so that various complex vibration errors can be effectively eliminated. It should be noted that the measurement accuracy of the gravity acceleration value is not less than 5mGal.

[0054] When the vehicle reaches an unknown complex location and measures the positioning and orientation data, the system converts the high-precision medium-range three-axis accelerometer into a high-precision small-range three-axis accelerometer; at the same time, the high-precision three-axis fiber optic gyroscope is responsible for detecting the angular vibration changes of the vehicle, so that various complex vibration errors can be more effectively eliminated, thereby improving the positioning and orientation accuracy of inertial navigation. As an embodiment of the present invention, in order to effectively eliminate the measurement errors caused by vehicle-mounted vibration, a correlation filtering algorithm is used to eliminate them.

[0055] Better yet, the high-precision small-range three-axis accelerometer has a measurement accuracy of ≤1mGal and a measurement range of ±2g, to meet the local gravity acceleration measurement requirements when the vehicle is stopped but the engine is still running; the high-precision medium-range three-axis accelerometer has a measurement accuracy of ≤20mGal and a measurement range of ±10g, to meet the acceleration measurement requirements during vehicle driving; the high-precision three-axis fiber optic gyroscope has a measurement accuracy of ≤0.001° / h and a measurement range of ±80° / s, to meet the angular velocity measurement requirements during vehicle driving.

[0056] The vehicle-mounted precision multi-channel odometer includes at least two channels, which are respectively installed on the left and right wheels of the vehicle, ensuring that there is at least one channel on the left and right wheels, and the measurement accuracy is not less than 3600 lines / week. Among them, the passive wheels and driven wheels are preferred for installation, so that the wheels can combine the signal of the main module to achieve fault tolerance in the case of signal distortion such as sideslip and suspension.

[0057] More specifically, the antenna of the Beidou navigation receiver is fixed in a relatively open area on the top of the vehicle to facilitate the reception of navigation satellite signals. Landmarks refer to ground markers with known geographic location information, which can be boundary markers, road signs, marking lines, trees, etc. near the road surface in the vehicle activity area. When the navigation satellite signal can be received normally, the relative position measurement accuracy between the Beidou navigation receiver and the landmark is not less than 2mm, the global positioning accuracy is not less than 2m, and the speed measurement accuracy is not less than 5cm / s. Among them, the geographic location accuracy of the landmark is not less than 0.1m. When the vehicle drives next to the landmark, the relative position between the vehicle's measurement center and the landmark can be measured using a landmark distance measurement auxiliary device (such as a steel ruler, laser rangefinder, etc.), and the measurement accuracy is not less than 2mm.

[0058] It should be noted that after the vehicle arrives at an unknown complex location and stops steadily, the measurement of its gravity acceleration value and positioning and orientation data is carried out synchronously, and high-precision measurement is completed quickly within 2 minutes, providing the aircraft with high-precision gravity acceleration value and positioning and orientation data before takeoff.

[0059] As another aspect of the present invention, the present invention also provides a high-precision measurement method for vehicle-mounted gravity acceleration and positioning orientation, the method comprising:

[0060] Obtaining a first signal output by a small-range three-axis accelerometer, a second signal output by a medium-range three-axis accelerometer, a third signal output by a three-axis fiber optic gyroscope, and a vibration range of a vehicle engine;

[0061] determining whether the measuring range of the short-range triaxial accelerometer includes the vehicle engine vibration range,

[0062] If included, the first signal is corrected by using the third signal and processed, and the corrected gravity acceleration value and the positioning and orientation data are output simultaneously;

[0063] If not included, the second signal is corrected using the first signal and the third signal, and the corrected positioning and orientation data is output after processing.

[0064] As an embodiment of the present invention, when the vehicle stops at a preset location, high-precision information related to the preset location can be obtained, such as longitude, latitude, altitude and other positioning and orientation data and gravity acceleration value can be accurately obtained. After the vehicle is powered on, after the signals of the three groups of inertial sensors, namely, the high-precision small-range three-axis accelerometer, the high-precision medium-range three-axis accelerometer and the high-precision three-axis fiber optic gyroscope, are outputted stably, the high-precision gravity acceleration value and positioning and orientation data of the preset location will be obtained, so that the three groups of inertial sensors can complete self-calibration and self-alignment, so that the verticality and parallelism measurement errors between the gyroscope and the accelerometer do not exceed 1", meeting the measurement requirements.

[0065] Among them, during the self-calibration process, the calibration of gravity acceleration value and positioning orientation data are carried out simultaneously, and the same set of inner and outer frames are used, which saves costs. It is worth mentioning that during self-calibration, the vehicle vibration is within the range of -1.5g to 1.5g. At this time, the first signal is mainly used, and the self-calibration is completed after it is corrected by using the remaining inertial sensors.

[0066] During the self-alignment process, the vehicle vibration is also within the range of -1.5g to 1.5g. At this time, the positioning and orientation data alignment is performed. This process is also based on the first signal, and the remaining inertial sensors are used to correct it to improve the self-alignment accuracy. In short, in the self-calibration and self-alignment process, the first signal is mainly used.

[0067] After completing the self-calibration and self-alignment, the first signal, the second signal, the third signal and the vibration range of the vehicle engine are obtained, and it is determined whether the range of the small-range three-axis accelerometer includes the vibration range of the vehicle engine.

[0068] If included, the third signal is used to correct the first signal and then processed to output the corrected gravity acceleration value and positioning and orientation data. That is, the high-precision small-range three-axis accelerometer signal is used as the main signal, and the high-precision three-axis fiber optic gyroscope signal is used to correct it and process it to obtain the corrected high-precision gravity acceleration value and positioning and orientation data.

[0069] If not included, the first signal and the third signal are used to correct the second signal and process it to output the corrected positioning and orientation data. That is, the high-precision medium-range three-axis accelerometer signal is used as the main signal, and the high-precision small-range three-axis accelerometer and high-precision three-axis fiber optic gyroscope signals are used to correct them and process them to obtain the corrected high-precision positioning and orientation data.

[0070] After the vehicle has been driving for a period of time, the position and speed of the vehicle change too quickly, resulting in a gradually increasing error. In order to more accurately obtain the positioning and orientation data during the vehicle's driving process, the fourth signal output by the vehicle's precision multi-channel odometer and / or Beidou navigation receiver can also be collected at the same time to improve the positioning and orientation data during driving. The fourth signal is used to correct the second signal to obtain the fifth signal, and then the first signal and the third signal are used to correct the fifth signal and output the corrected positioning and orientation data.

[0071] As an embodiment of the present invention, when the vehicle is in driving, a combination of inertial navigation and odometer navigation can be used for measurement. Inertial navigation outputs a first signal, a second signal, and a third signal; odometer navigation outputs a fourth signal. More preferably, the Beidou navigation receiver is turned on to correct the navigation speed and position in real time, and the position accuracy of the driving trajectory is corrected, and the estimated error of the subsequent driving trajectory is calculated and eliminated, so that the accurate position can still be obtained after the Beidou navigation receiver signal fails; when the Beidou navigation receiver cannot work normally, the vehicle can also go to the nearest landmark point and use the landmark to correct the position, so as to obtain the corrected real-time and high-precision positioning and orientation data through high-precision positioning and orientation data and real-time correction of position and trajectory.

[0072] When the road conditions are relatively bad during driving, the range of the small-range three-axis accelerometer does not include the vibration range of the vehicle engine. The high-precision medium-range three-axis accelerometer signal is used as the main signal, and the fourth signal is used to correct it to obtain the fifth signal. The signals of the high-precision small-range three-axis accelerometer and the high-precision three-axis fiber optic gyroscope are then used to correct and process it, and finally the corrected real-time and high-precision positioning and orientation data is output.

[0073] When the road condition is relatively flat during driving, the measurement range of the small-range three-axis accelerometer does not include the vibration range of the vehicle engine. The high-precision small-range three-axis accelerometer signal is used as the main signal, and the signal of the high-precision three-axis fiber optic gyroscope is used to correct it to improve the accuracy of the positioning and orientation solution.

[0074] It is worth noting that only by combining the accelerometer and the gyroscope can the positioning and orientation data be obtained. When the road conditions are relatively bad, the vehicle-mounted positioning and orientation data mainly comes from the high-precision medium-range three-axis accelerometer. When the road conditions are relatively flat, the vehicle-mounted high-precision medium-range three-axis accelerometer is stable for a long time within the range of the high-precision small-range three-axis accelerometer, and the collected high-precision medium-range three-axis accelerometer signal will be converted into a high-precision small-range three-axis accelerometer signal, thereby improving the positioning and orientation accuracy of the inertial navigation.

[0075] When the vehicle stops at an unknown and complex location after driving for a period of time, the vehicle is in a stopped state. The measuring range of the small-range three-axis accelerometer includes the vibration range of the vehicle engine. The computer control module collects mainly the signal of the high-precision small-range three-axis accelerometer, and uses the signal of the high-precision three-axis fiber optic gyroscope to correct it and process it to obtain the corrected high-precision gravity acceleration value and positioning orientation data.

[0076] Correction is to correct the higher precision value on the same axis to improve the accuracy. When the vehicle reaches an unknown complex location to measure gravity acceleration, the gravity component value in the direction perpendicular to the ground is generally large. At this time, it is necessary to assist in correcting the measurement results of the high-precision, small-range three-axis accelerometer in this direction; while the other two directions relative to the horizontal are still based on the measurement results of the high-precision, small-range three-axis accelerometer; at the same time, the high-precision three-axis fiber optic gyroscope is responsible for detecting the angular vibration changes of the vehicle, so that various complex vibration errors can be effectively eliminated. It should be noted that the measurement accuracy of the gravity acceleration value is not less than 5mGal.

[0077] When the vehicle reaches an unknown complex location and measures the positioning and orientation data, the collected signal based on the high-precision medium-range three-axis accelerometer will be converted into a signal based on the high-precision small-range three-axis accelerometer; at the same time, the high-precision three-axis fiber optic gyroscope is responsible for detecting the angular vibration changes of the vehicle, so that various complex vibration errors can be more effectively eliminated, thereby improving the positioning and orientation accuracy of inertial navigation. As an embodiment of the present invention, in order to effectively eliminate the measurement error caused by the vehicle vibration, a correlation filtering algorithm is used to eliminate it.

[0078] Better yet, the high-precision small-range three-axis accelerometer has a measurement accuracy of ≤1mGal and a measurement range of ±2g, to meet the local gravity acceleration measurement requirements when the vehicle is stopped but the engine is still running; the high-precision medium-range three-axis accelerometer has a measurement accuracy of ≤20mGal and a measurement range of ±10g, to meet the acceleration measurement requirements during vehicle driving; the high-precision three-axis fiber optic gyroscope has a measurement accuracy of ≤0.001° / h and a measurement range of ±80° / s, to meet the angular velocity measurement requirements during vehicle driving.

[0079] The vehicle-mounted precision multi-channel odometer includes at least two channels, which are respectively installed on the left and right wheels of the vehicle, ensuring that there is at least one channel on the left and right wheels, and the measurement accuracy is not less than 3600 lines / week. Among them, the passive wheels and driven wheels are preferred for installation, so that the wheels can combine the signal of the main module to achieve fault tolerance in the case of signal distortion such as sideslip and suspension.

[0080] More specifically, the antenna of the Beidou navigation receiver is fixed in a relatively open area on the top of the vehicle to facilitate the reception of navigation satellite signals. Landmarks refer to ground markers with known geographic location information, which can be boundary markers, road signs, marking lines, trees, etc. near the road surface in the vehicle activity area. When the navigation satellite signal can be received normally, the relative position measurement accuracy between the Beidou navigation receiver and the landmark is not less than 2mm, the global positioning accuracy is not less than 2m, and the speed measurement accuracy is not less than 5cm / s. Among them, the geographic location accuracy of the landmark is not less than 0.1m. When the vehicle drives next to the landmark, the relative position between the vehicle's measurement center and the landmark can be measured using a landmark distance measurement auxiliary device (such as a steel ruler, laser rangefinder, etc.), and the measurement accuracy is not less than 2mm.

[0081] It should be noted that after the vehicle arrives at an unknown complex location and stops steadily, the measurement of its gravity acceleration value and positioning and orientation data is carried out synchronously, and high-precision measurement is completed quickly within 2 minutes, providing the aircraft with high-precision gravity acceleration value and positioning and orientation data before takeoff.

[0082] The present invention proposes a system and method for measuring gravity acceleration and positioning and orientation, which fully demonstrates the combined advantages of gravity acceleration measurement and positioning and orientation functions. For the strapdown gravity acceleration measurement method, the high-precision small-range three-axis accelerometer is the core sensor component. The present invention organically combines the large and small-range accelerometers with the fiber optic gyroscope, which not only realizes the function of measuring the local gravity acceleration value, but also realizes the positioning and orientation function.

[0083] In short, the present invention not only organically combines the measurement of gravity acceleration with the positioning and orientation functions, but also adds a set of high-precision small-range three-axis accelerometers, making the system, circuit and signal data processing more complex. In addition to being able to measure gravity acceleration and positioning and orientation, the measurement is also more accurate. After completing self-calibration and self-alignment, the vehicle drives to an unknown area, and the measurement accuracy of the gravity acceleration value in the unknown area is not less than 5mGal. At the same time, it has the positioning and orientation function, and can achieve high-precision measurement of the local gravity acceleration value and positioning and orientation data before takeoff without relying on a position.

[0084] For the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the order of the actions described, because according to the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0085] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0086] In the several embodiments provided by the present invention, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0087] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0088] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0089] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a memory, including several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned memory includes: U disk, read-only memory (ROM), random access memory (RAM), mobile hard disk, magnetic disk or optical disk, etc., various media that can store program codes.

[0090] A person skilled in the art may understand that all or part of the steps in the various methods of the above embodiments may be completed by entering a program to instruct the relevant hardware. The program may be stored in a computer-readable memory, and the memory may include: a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0091] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. The present invention is intended to cover any variation, use or adaptive change of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

[0092] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for measuring gravity acceleration and positioning orientation, characterized in that: The system includes: Measurement modules, including a small-range three-axis accelerometer with independent acquisition channels, a medium-range three-axis accelerometer, and a three-axis fiber optic gyroscope; A calculation control module collects in real time the first signal output by the small-range three-axis accelerometer, the second signal output by the medium-range three-axis accelerometer, and the third signal output by the three-axis fiber optic gyroscope for fusion processing; The fusion process is as follows: The calculation control module determines whether the range of the small-range triaxial accelerometer includes the range of the vehicle engine vibration signal; In the case of including, the calculation control module uses the third signal to correct the first signal and outputs the corrected gravity acceleration value and positioning orientation data after processing; In the absence of inclusion, the calculation control module uses the first signal and the third signal to correct the second signal and outputs the corrected positioning and orientation data after processing.

2. A system for measuring gravitational acceleration and positioning orientation as claimed in claim 1, characterized in that: The measurement module also includes a vehicle-mounted precision multi-channel odometer and / or a Beidou navigation receiver; The calculation and control module also receives a fourth signal output by the vehicle-mounted precision multi-channel odometer and / or the Beidou navigation receiver, uses the fourth signal to correct the second signal to obtain a fifth signal, and then uses the first signal and the third signal to correct the fifth signal and output the corrected positioning and orientation data.

3. A system for measuring gravitational acceleration and positioning orientation as claimed in claim 1 or 2, characterized in that: The small-range three-axis accelerometer has a measurement accuracy of ≤1mGal and a measurement range of ±2g.

4. A system for measuring gravity acceleration and positioning orientation as claimed in claim 1, characterized in that: The measurement accuracy of the mid-range three-axis accelerometer is ≤20mGal, and the measurement range is ±10g; the measurement accuracy of the three-axis fiber optic gyroscope is ≤0.001° / h, and the measurement range is ±80° / s.

5. A system for measuring gravity acceleration and positioning orientation as claimed in claim 2, characterized in that: The vehicle-mounted precision multi-channel odometer includes at least two channels, which are respectively arranged on the left and right wheels of the vehicle, and the measurement accuracy is not less than 3600 lines / cycle.

6. A method for measuring gravitational acceleration and positioning orientation, characterized in that: The method includes: Obtaining a first signal output by a small-range three-axis accelerometer, a second signal output by a medium-range three-axis accelerometer, a third signal output by a three-axis fiber optic gyroscope, and a vibration range of a vehicle engine; determining whether the measuring range of the short-range triaxial accelerometer includes the vehicle engine vibration range, If included, the first signal is corrected by using the third signal and processed, and the corrected gravity acceleration value and positioning orientation data are output simultaneously; If not included, the second signal is corrected using the first signal and the third signal, and the corrected positioning and orientation data is output after processing.

7. A method for measuring gravitational acceleration and positioning orientation as claimed in claim 6, characterized in that: The second signal can also be fused with a fourth signal output by a vehicle-mounted precision multi-channel odometer and / or a Beidou navigation receiver; The fourth signal is used to correct the second signal to obtain a fifth signal, and the first signal and the third signal are used to correct the fifth signal to output the corrected positioning and orientation data.

8. A method for measuring gravitational acceleration and positioning orientation as claimed in claim 6 or 7, characterized in that: The small-range three-axis accelerometer has a measurement accuracy of ≤1mGal and a measurement range of ±2g.

9. A method for measuring gravitational acceleration and positioning orientation as claimed in claim 6, characterized in that: The measurement accuracy of the mid-range three-axis accelerometer is ≤20mGal, and the measurement range is ±10g; the measurement accuracy of the three-axis fiber optic gyroscope is ≤0.001° / h, and the measurement range is ±80° / s.

10. A method for measuring gravity acceleration and positioning orientation as claimed in claim 7, characterized in that: The vehicle-mounted precision multi-channel odometer includes at least two channels, which are respectively arranged on the left and right wheels of the vehicle, and the measurement accuracy is not less than 3600 lines / cycle.

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