Carrying type unmanned aerial vehicle testing system and positioning precision testing method

Abstract

The invention belongs to the technical field of unmanned aerial vehicle testing, and discloses a carrying type unmanned aerial vehicle testing system and a positioning precision testing method.The system comprises a sky end and a ground control center, and the sky end is installed on a tested unmanned aerial vehicle, integrates a high-precision GNSS, an attitude sensor and a radio station and is used for collecting the accurate position and attitude data of the unmanned aerial vehicle in real time; the ground control center receives sky end data in real time through a radio station, and the sky end data are displayed and processed on an upper computer in real time. The method comprises the steps of performing calibration when the unmanned aerial vehicle is static, and calculating a fixed position vector of a test equipment antenna and the gravity center of the unmanned aerial vehicle; compensating the track of the equipment by using the real-time attitude measured by the test equipment in flight, and converting to obtain the accurate track of the gravity center of the unmanned aerial vehicle; time synchronization is carried out on the self-reported position data of the tested unmanned aerial vehicle through an interpolation algorithm by taking the timestamp of the test system as a reference; and finally, comparing the compensated accurate track with the synchronized self-reporting track, and calculating the positioning precision.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) testing technology, specifically relating to an onboard UAV testing system and a positioning accuracy testing method. Background Technology

[0002] With the increasingly widespread application of drones across various industries, the performance and safety of drone products have attracted significant attention, and market regulators have also imposed higher regulatory requirements on drones. Therefore, the development of a drone testing system that provides accurate test results and is easy to operate has become increasingly urgent.

[0003] Onboard UAV testing systems are fundamental tools for evaluating UAV flight performance, particularly positioning performance. Their core principle involves acquiring the UAV's flight trajectory using high-precision GNSS (Global Positioning System) equipment and processing and analyzing the data. To obtain high-precision positioning data, current technologies commonly employ RTK (Real-Time Kinematics) technology.

[0004] However, in the process of realizing this invention, the inventor's existing mounted testing equipment has at least the following problems:

[0005] 1. To reduce equipment weight and minimize the impact on the flight of the tested drone, many devices adopt an offline working mode of data acquisition followed by download. The drawback of this mode is that testers cannot determine in real time during flight whether the test meets specifications (such as flight duration, altitude changes, etc.) or whether the quality of the acquired data is acceptable. If invalid data is found after the test, a significant amount of time and resources are required for retesting.

[0006] 2. In offline mode, there is a time asynchrony issue between the aerial data acquisition equipment and the host computer used for ground analysis. Although some technical solutions propose clock synchronization before testing, the system clock accuracy of the host computer is limited and may be affected by interference from the operating system and other software, leading to synchronization failure and ultimately affecting the accuracy of the test results.

[0007] 3. The positioning accuracy test of UAV is an important part of performance evaluation. For example, the specific test requirements and calculation methods are given in the national standard GB42590-2023. However, in practical application, there are two major problems: first, the center of gravity and the antenna position do not coincide. The installation position of the GNSS antenna of the test equipment cannot completely coincide with the center of gravity (CG) of the UAV being tested. Due to the attitude change of the UAV in flight, there is a dynamic deviation between the trajectory recorded by the test equipment and the actual trajectory of the center of gravity of the UAV. If the trajectory recorded by the equipment is directly used for calculation, systematic errors will be introduced. The second is the asynchronous data sampling. The data acquisition frequency of the test equipment may not be consistent with the frequency of the positioning data recorded by the UAV itself. Even if the frequency is the same, the sampling time of the two cannot be completely aligned, which makes it impossible to compare the data points one by one. Complex post-processing is required to solve the problem, which increases the processing difficulty and may introduce interpolation errors. SUMMARY

[0008] The present application aims to at least partially solve the above technical problems. To this end, the present application aims to provide a carried UAV test system and a positioning accuracy test method.

[0009] The technical solution adopted by the present application is:

[0010] A carried UAV test system, comprising a sky end and a ground control center.

[0011] The sky end is adapted to be installed on the UAV being tested, and comprises a sky end controller, a sky end GNSS antenna, an attitude sensor and a sky end radio. The core function of the sky end controller is to collect and process high-precision positioning data from the sky end GNSS antenna and attitude data from the attitude sensor in real time, and to transmit these fused data to the outside in real time through the sky end radio.

[0012] The ground control center comprises a ground controller, an upper computer and a ground radio. The ground controller receives the test data sent by the sky end in real time through the ground radio, performs preliminary processing, and then transmits it to the upper computer. The upper computer not only can display the flight trajectory, attitude and other key test data in real time, but also integrates the positioning accuracy test method, which is convenient for users to monitor and analyze.

[0013] Through real-time radio communication between the sky end and the ground control center, the present application changes the traditional offline mode to online real-time mode. The test personnel can intuitively monitor the entire test process on the upper computer, ensure that the test process meets the standard, and judge the data quality in the first time, avoiding invalid test and repeated work. At the same time, all data are transmitted and recorded based on the high-precision clock of the test system itself, which fundamentally solves the time synchronization problem between the sky end and the ground end.

[0014] Further, in order to realize RTK high-precision positioning, the ground control center can further include a base station GNSS antenna. The ground controller contains a GNSS base station solution board, which is used to generate GNSS differential data and send it to the sky end through the ground radio. After receiving, the sky end can perform RTK calculation to obtain centimeter-level positioning accuracy.

[0015] In order to adapt to different forms of measured unmanned aerial vehicles and reduce the influence on flight, the components (such as controllers, antennas, batteries, etc.) of the sky end are designed as independent modules connected by cables. When installed, the layout can be flexible, the weight can be reasonably distributed, and the influence on the center of gravity of the unmanned aerial vehicle can be minimized.

[0016] The application also provides a matching positioning accuracy test method, which is executed by the host computer of the test system, and solves the center of gravity compensation and data asynchronous problems mentioned in the background art. The method includes the following core steps:

[0017] The calibration step: before the test starts, the initial positions and attitudes of the test system and the measured unmanned aerial vehicle are recorded simultaneously in the static state of the unmanned aerial vehicle. The deviation between the two initial states is used to calculate the fixed position vector (in the unmanned aerial vehicle body coordinate system) of the test system GNSS antenna relative to the center of gravity of the unmanned aerial vehicle. This vector remains unchanged throughout the test process.

[0018] The acquisition step: when the unmanned aerial vehicle flies as required, the test system records the high-precision position and attitude data sequence with a unified time stamp. At the same time, the position data sequence recorded by the measured unmanned aerial vehicle is derived.

[0019] The trajectory compensation step: using the accurate attitude data of the test system obtained in the acquisition step and the fixed position vector calculated in the calibration step, each position point recorded by the test system is subjected to coordinate transformation. The purpose of this step is to accurately convert the trajectory measured at the antenna position into the real trajectory of the center of gravity of the unmanned aerial vehicle, and obtain an accurate trajectory data sequence of the center of gravity of the measured unmanned aerial vehicle.

[0020] The time synchronization step: since the data sampling time points of the test system and the measured unmanned aerial vehicle are not consistent, this step takes the accurate time stamp sequence of the test system as the reference, and uses linear interpolation (or other trajectory fitting interpolation algorithm) to process the position data sequence recorded by the measured unmanned aerial vehicle itself, to calculate the self-positioning position of the measured unmanned aerial vehicle at each sampling time of the test system. In this way, two sets of data sequences with completely aligned time stamps are generated.

[0021] Precision calculation step: the true center of gravity position obtained after trajectory compensation is compared with the self-reported center of gravity position obtained after time synchronization point by point, the deviation of both in east, north, and sky directions is calculated, and according to the standard requirements of GB42590-2023 and the like, the root mean square value of the positioning error is calculated, and the final horizontal positioning accuracy and elevation positioning accuracy are obtained.

[0022] The beneficial effects of the present application are:

[0023] The present application realizes real-time data communication between the sky end and the ground through the radio station, the test personnel can monitor the flight state and data quality in real time on the upper computer, avoids repeated testing caused by non-compliance testing or poor data quality, and significantly improves the test efficiency.

[0024] All data of the present application are transmitted and processed in real time in the system, the time reference is unified, and the problem of time asynchronization in offline mode is completely solved, providing a reliable premise for accurate calculation.

[0025] The positioning accuracy test method provided by the present application accurately eliminates the system error introduced by the non-coincidence of the installation position of the test equipment and the center of gravity of the unmanned aerial vehicle through initial calibration and dynamic attitude compensation.

[0026] The present application solves the problem of asynchronous data sampling between the test system and the measured unmanned aerial vehicle through the time interpolation algorithm, realizes the accurate alignment of data points, and makes the error calculation scientific and reasonable. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a structural block diagram of a carried unmanned aerial vehicle test system according to the present application.

[0028] Figure 2 is a flowchart of a positioning accuracy test method according to the present application. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] It should be understood that it should also be noted that the functions / actions appearing in the embodiments may not appear in the order shown in the drawings. For example, depending on the functions / actions involved, two figures shown in succession can actually be performed substantially concurrently, or sometimes in the reverse order.

[0031] Please refer to Figure 1The application provides a kind of carrying type unmanned plane test system, mainly by ground control center 100 and sky end 200 two major parts are formed, and both are carried out real-time two-way data communication by radio station.

[0032] Ground control center 100 includes host computer 101, base station GNSS antenna 102, ground controller 110 and ground radio antenna 103.

[0033] Ground controller 110 is integrated with GNSS base station solution board card 111, base station microprocessor board 112, ground radio station 113 and battery 114 inside. Among them, the power management module 115 is integrated on the base station microprocessor board 112, which supplies power to each part of the ground controller 110.GNSS base station solution board card 111 is connected with base station GNSS antenna 102, which is used to receive satellite signals and generate RTK differential correction data.The microprocessor on the base station microprocessor board 112 is connected with host computer 101, GNSS base station solution board card 111 and ground radio station 113 through serial port respectively.The main task is:

[0034] Receive the differential data generated by GNSS base station solution board card 111, and send it to sky end 200 through ground radio station 113.

[0035] Receive real-time test data from sky end 200 through ground radio station 113, and send it to host computer 101 through serial port after processing.

[0036] Receive the control instructions (such as start / stop test) sent by host computer 101, and send them to sky end 200 through ground radio station 113 after processing.

[0037] Host computer 101 runs man-machine interface and data processing program, users can set test parameters, start and stop test through the interface, and can real-time view the flight trajectory, height, speed, attitude of unmanned plane and the working state of test equipment, etc.Information.After test, data processing program automatically runs positioning accuracy test algorithm and gives the result.

[0038] Sky end 200 is designed to be carried on the unmanned plane to be tested, including sky end controller 210, sky end GNSS antenna 201, attitude sensor 202, sky end radio antenna 203 and sky end battery 204.In order to reduce the influence on the center of gravity of the unmanned plane to be tested, these components are independent modules, connected by cable, which can be fixed on the machine body flexibly and distributedly according to the specific form of the unmanned plane.

[0039] The internal of the sky end controller 210 integrates a GNSS data resolving board card 211 (as a mobile station of RTK), a mobile station microprocessor board 212 and a sky end radio station 213. The mobile station microprocessor board 212 integrates a power management module 215 and a memory 216. The power management module 215 supplies power for all needed power supply devices (such as GNSS board card, microprocessor, attitude sensor, radio station) of the sky end 200. The microprocessor on the mobile station microprocessor board 212 is connected with the GNSS data resolving board card 211, the attitude sensor 202 and the sky end radio station 213 respectively through serial ports. The main tasks thereof are as follows:

[0040] receiving high-precision position and speed data resolved by the GNSS data resolving board card 211.

[0041] receiving real-time attitude data (such as roll, pitch and yaw angles) measured by the attitude sensor 202.

[0042] receiving RTK differential data and control instructions transmitted from the ground control center 100 by the sky end radio station 213.

[0043] fusing and processing all the above data, and then sending the processed data back to the ground control center 100 in real time through the sky end radio station 213.

[0044] Meanwhile, all the collected and processed data are written into the memory 216 as backup in case of unexpected interruption of wireless communication.

[0045] Please refer to Figure 2 The positioning precision test method provided by the application is integrated in the software of the upper computer 101, and the specific implementation steps are as follows:

[0046] Step S10: system installation and coordinate system setting

[0047] firmly install all components of the test system sky end 200 on the measured unmanned aerial vehicle, which can be regarded as rigid connection. Set a unified station heart coordinate system {ENU}, and the origin O e (B0, L0, H0) can select a convenient point on the test site, for example, the longitude, latitude and altitude before takeoff of the unmanned aerial vehicle. The origin O β of the body coordinate system of the measured unmanned aerial vehicle is defined as the center of gravity.

[0048] Step S20: static calibration, calculating fixed position vector

[0049] When the measured unmanned aerial vehicle is static on the ground, perform calibration.

[0050] read the initial position (E0, N0, U0) and attitude (Φ0, θ0, φ0) output by the positioning system of the measured unmanned aerial vehicle.

[0051] At the same time, the test system records the initial position (E0', N0', U0') measured by the sky-end GNSS antenna 201 and the initial attitude (Φ0', θ0', φ0') measured by the attitude sensor 202.

[0052] According to the above data, the fixed position vector of the GNSS antenna of the test device in the body coordinate system of the unmanned aerial vehicle being tested is calculated . This vector represents the physical offset from the center of gravity of the unmanned aerial vehicle to the test antenna. The calculation formula is as follows:

[0053]

[0054] Since it is rigidly connected, this vector is constant throughout the flight process.

[0055] Step S30: Flight test, data collection

[0056] According to the test specification requirements of GB42590-2023 and the like, the unmanned aerial vehicle is operated to fly. For example: manual or autonomous flight for 10 minutes, during which the flight height changes by not less than 100m...

[0057] During the flight, the test system records a series of high-precision data with timestamps, including longitude, latitude, altitude and attitude, denoted as {Lon i ', Lon i ', Lat i ', Alt i ', Φ i ', θ i ', φ i '} (i=1, 2,..., n). The collection frequency is not less than 10Hz.

[0058] After the flight, the position data recorded by the unmanned aerial vehicle being tested itself within the test time range is derived from the flight record of the unmanned aerial vehicle being tested, usually the station-centered coordinate system position with timestamps, denoted as {t j ', e j ', n j ', u j '} (j=1, 2,..., m).

[0059] Firstly, the longitude, latitude and altitude data {Lon i ', Lat i ', Alt i '} recorded by the test system are converted into the same station-centered coordinate system as the unmanned aerial vehicle being tested, to obtain {t i ', E i ', N i ', U i ', Φ i ', θ i ', φi ′.

[0060] Step S40: Trajectory compensation, calculate the precise trajectory of the UAV's center of gravity

[0061] The purpose of this step is to convert the trajectory of the measured antenna position (obtained in step S30) into the real trajectory of the measured UAV's center of gravity. For each data point i of the test system, using its attitude data (Φ i ′, θ i ′, φ i ′) and the fixed position vector obtained in step S20 , the precise position of the UAV's center of gravity at that moment (E i , N i , U i ) is calculated by inverse operations of coordinate rotation and translation. Thus, the precise trajectory data sequence of the measured UAV's center of gravity {T i ′, E i , N i , U i} is obtained.

[0062] Step S50: Time synchronization, align data by interpolation

[0063] At this time, there are two sets of data: one is the precise trajectory of the UAV's center of gravity {T i ′, E i , N i , U i}, and the other is the self-reported position trajectory of the UAV {t j ", e j ", n j ", u j "}. The timestamps T i ′ and t j " of the two sets of data are usually inconsistent.

[0064] This step takes the timestamp T i ′ of the precise trajectory as the reference to linearly interpolate the self-reported position data of the UAV. For each T i ′, find the two time points t j " and t j+1 " in the t" sequence that are closest to it (so that t j "≤T i ′<t j+1 "). Then estimate the self-positioning position of the UAV at T i ′ (E i ", N i ", U i ") according to the following formula:

[0065]

[0066]

[0067]

[0068] Through this step, the measured unmanned aerial vehicle self-positioning position data sequence {T i ′,E i ",N i ",U i "} corresponding to the precise trajectory timestamp is obtained. The present application is not limited to linear interpolation, and other higher-order trajectory fitting interpolation algorithms are also supported.

[0069] Step S60: Calculate the error to obtain the positioning accuracy

[0070] Now there are two sets of time-stamped position data that are completely synchronized and represent the position of the unmanned aerial vehicle's center of gravity: precise position {E i ,N i ,U i} and self-reported position {E i ",N i ",U i "}.

[0071] First, calculate the error component of each point:

[0072]

[0073]

[0074]

[0075] Then, according to the formula in GB42590-2023 standard, calculate the root mean square (RMS) of the positioning error:

[0076] (East component)

[0077] (North component)

[0078] (Elevation / Up component)

[0079] Finally, calculate the horizontal positioning accuracy σ L :

[0080]

[0081] These calculated σ L and σ H are the final unmanned aerial vehicle positioning accuracy test results, which will be displayed in the report by the host computer program.

[0082] Through the above system and method, the present application effectively solves many pain points in the prior art, and provides a complete, efficient and accurate solution for unmanned aerial vehicle performance testing and supervision.

[0083] The present application is not limited to the above optional embodiments, and anyone can derive other various forms of products under the inspiration of the present application, but regardless of any changes in shape or structure, any technical solutions falling within the scope defined by the claims of the present application fall within the protection scope of the present application.

Claims

1. A piggybacked unmanned aerial vehicle test system, comprising: The system comprises: a sky end adapted to be mounted on the unmanned aerial vehicle to be tested, the sky end comprising a sky end controller, a sky end GNSS antenna, an attitude sensor and a sky end radio station; the sky end controller is used for collecting and processing high-precision positioning data from the sky end GNSS antenna and attitude data from the attitude sensor in real time, and transmitting data to the outside through the sky end radio station; a ground control center comprising a ground controller, a host computer and a ground radio station; the ground controller is used for receiving data transmitted by the sky end in real time through the ground radio station, and transmitting the processed data to the host computer; the host computer is used for displaying test data in real time and running a positioning accuracy test method.

2. The piggyback drone test system of claim 1, wherein, The ground control center further comprises a base station GNSS antenna; the ground controller comprises a GNSS base station solving board card, a base station microprocessor board and a battery; the GNSS base station solving board card is connected with the base station GNSS antenna, and is used for generating GNSS differential data; the base station microprocessor board is used for receiving the differential data and transmitting the differential data to the sky end through the ground radio station, so that the sky end realizes RTK high-precision positioning.

3. The piggyback drone test system of claim 1 or 2, wherein, The sky end further comprises a sky end battery and a memory; each component of the sky end is an independent module and is connected through a cable; the memory is used for backup storage of test data.

4. The piggyback drone test system of claim 2, wherein, The base station microprocessor board is connected with the host computer, the GNSS base station solving board card and the ground radio station through a serial port, and is used for receiving and processing instructions from the host computer, data from the sky end, and transmitting the processed information to the host computer for real-time display.

5. The piggyback drone test system of claim 1, wherein, The sky end controller comprises a GNSS data solving board card and a mobile station microprocessor board; the mobile station microprocessor board is connected with the GNSS data solving board card, the attitude sensor and the sky end radio station through a serial port, and is used for integrated processing of positioning data, attitude data and information received from the ground control center, and transmitting the processed information to the ground control center in real time.

6. A method of testing positioning accuracy, characterized by The system is executed by the mounted unmanned aerial vehicle test system according to any one of claims 1-5, comprising the following steps: a calibration step: when the unmanned aerial vehicle to be tested is stationary, the initial position and attitude recorded by the unmanned aerial vehicle to be tested are obtained, and the initial position and attitude measured by the test system are obtained, and a fixed position vector of the test system GNSS antenna relative to the center of gravity of the unmanned aerial vehicle to be tested is calculated; an acquisition step: during the flight of the unmanned aerial vehicle to be tested, the test system records a time-stamped accurate position and attitude data sequence of itself in real time, and obtains a time-stamped position data sequence recorded by the unmanned aerial vehicle to be tested; a trajectory compensation step: based on the accurate attitude data sequence recorded by the test system and the fixed position vector, the accurate position data sequence recorded by the test system is compensated, and an accurate trajectory data sequence of the center of gravity of the unmanned aerial vehicle to be tested is calculated; a time synchronization step: taking the time stamp of the test system as a reference, the position data sequence recorded by the unmanned aerial vehicle to be tested is calculated by interpolation, and a self-positioning position data sequence of the unmanned aerial vehicle to be tested corresponding to the time stamp of the accurate trajectory data sequence is obtained. The precision calculation step comprises: comparing the accurate trajectory data sequence and the self-positioning position data sequence of the measured UAV to calculate the positioning precision of the measured UAV.

7. The positioning accuracy test method of claim 6, wherein, In the calibration step, the fixed position vector In the measured UAV body coordinate system, the formula is as follows: Wherein, (E0, N0, U0) and (Φ0, θ0, φ0) are respectively the position and attitude of the measured UAV in the station-centered coordinate system in the static state; (E0', N0', U0') and (Φ0', θ0', φ0') are respectively the position and attitude of the test system in the same station-centered coordinate system in the static state.

8. The positioning accuracy test method of claim 6, wherein, The time synchronization step employs a linear interpolation algorithm, for any timestamp T i of the test system, finds the adjacent t j and t j+1 in the timestamp sequence of the unmanned aerial vehicle under test, and calculates the synchronized unmanned aerial vehicle under test self-positioning position (E i , N i , U i ) according to the following formula: wherein (e j ",n j ",u j ") is the position recorded by the UAV at the time t j ".

9. The positioning accuracy test method of claim 6, wherein, The precision calculation step includes calculating the root mean square σ E , σ N , σ H , and the root mean square σ L of the horizontal positioning error in the east, north, and sky directions, according to the following formulas: Wherein, (E i , N i , U i ) is the precise position of the measured unmanned aerial vehicle center of gravity after trajectory compensation, (E i , N i , U i ) is the self-positioning position of the measured unmanned aerial vehicle after time synchronization, and n is the total number of data points.

10. The positioning accuracy test method of claim 6, wherein, The method is integrated in a data processing program of the host computer, and the host computer provides a human-computer interaction interface for starting the test, monitoring the test process in real time, and displaying the final positioning precision result.

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