Preventive detection method for precision of optical fiber inertial navigation

Abstract

The invention discloses an optical fiber inertial navigation precision preventive detection method. The method comprises the following steps: carrying out repetitive alignment precision detection on optical fiber inertial navigation through an unmanned aerial vehicle system; carrying out alignment state detection on the data of the alignment repeatability alignment precision detection; sending an instruction through an unmanned aerial vehicle system to enable optical fiber inertial navigation to enter a pure inertial mode, determining pure optical fiber inertial navigation positioning precision, speed measurement precision and attitude angle precision, and carrying out pure inertial precision detection; and performing pure inertial state detection on the data of the pure inertial precision detection, and if the pure inertial state detection is qualified, completing the preventive detection of the optical fiber inertial navigation precision. By establishing the accurate error model, the optical fiber inertial navigation error is analyzed to prevent faults and keep the optical fiber inertial navigation error in a specified state, a method is provided for preliminary detection of the external field level optical fiber inertial navigation precision, the state safety of the in-service unmanned aerial vehicle is ensured, and the method is suitable for popularization and application. A basis is provided for detecting and calibrating whether the optical fiber inertial navigation needs to be returned to a factory or not; meanwhile, the manpower, material resources and transportation cost are obviously reduced.

Description

Technical Field

[0001] The present invention relates to the field of precision detection of unmanned aerial vehicle avionics equipment, and more specifically, to a preventive detection method for fiber optic inertial navigation precision. Background Art

[0002] Medium-altitude long-flight fixed-wing UAVs have the advantages of long range, long flight time and strong mounting capacity. They play an important role in agriculture, forestry and military fields. High reliability and strong survivability are the key to ensuring their successful completion of reconnaissance and strike tasks in complex environments and safe return. Fiber-optic inertial navigation, as the core equipment of UAVs, is the key to various combined navigation, especially in satellite denial or visual obstruction. Pure inertial navigation is the last line of defense to ensure the safety of UAVs. The accuracy of fiber-optic inertial navigation determines the success or failure of flight missions and even directly affects the safety of UAVs.

[0003] Fiber optic inertial navigation will experience error drift as its service time increases. These errors entering the navigation solution loop will further cause navigation errors. Excessive errors will affect the execution of this mission.

[0004] Currently, there are generally two types of periodic calibration of FOINS: one is that the FOINS is directly returned to the factory when the calibration period is reached, and the manufacturer uses a turntable and special instruments to recalibrate the parameters of the FOINS and conduct a factory functional retest. Although this solution ensures the accuracy of the FOINS flight, it has a longer time cycle and transportation cost. The second is to use a special calibration turntable and testing instruments to calibrate in the field. This solution requires professional equipment, a specific environment and professional technicians; furthermore, if preventive testing also uses the return to the factory for testing and calibration, it will greatly increase costs and affect the availability of in-service equipment.

[0005] Therefore, it is necessary to develop a preventive detection method for fiber optic inertial navigation accuracy.

[0006] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0007] The present invention proposes a preventive detection method for fiber optic inertial navigation accuracy, which can analyze the fiber optic inertial navigation error by establishing an accurate error model to prevent faults from occurring and keep it in a specified state, providing a method for preliminary detection of field-level fiber optic inertial navigation accuracy, ensuring the safety of the status of unmanned aerial vehicles in service, and providing a basis for whether the fiber optic inertial navigation needs to be returned to the factory for inspection and calibration, while significantly reducing manpower, material resources and transportation costs.

[0008] In a first aspect, an embodiment of the present disclosure provides a preventive detection method for fiber optic inertial navigation accuracy, comprising:

[0009] Repeatable alignment accuracy testing of fiber optic inertial navigation system is performed through UAV system;

[0010] Perform alignment status detection on the data of quasi-repeatability alignment accuracy detection;

[0011] Send instructions through the UAV system to make the fiber-optic inertial navigation enter the pure inertial mode, determine the pure fiber-optic inertial navigation positioning accuracy, speed measurement accuracy, attitude angle accuracy, and perform pure inertial accuracy testing;

[0012] A pure inertial state test is performed on the data of the pure inertial accuracy test. If the pure inertial state test is qualified, the fiber optic inertial navigation accuracy preventive test is completed.

[0013] Preferably, the repeatability alignment accuracy detection of the fiber optic inertial navigation system by the UAV system includes:

[0014] Record the pitch angle, roll angle, and heading angle output by the fiber optic inertial navigation system. After recording, the fiber optic inertial navigation system is powered off and restarted, and multiple sets of pitch angles, roll angles, and heading angles are recorded repeatedly, which are multiple sets of fiber optic inertial navigation data.

[0015] The heading angle accuracy, pitch angle accuracy and roll angle accuracy are calculated based on multiple sets of fiber optic inertial navigation data, and repeatable alignment accuracy detection is performed.

[0016] Preferably, the heading angle accuracy, pitch angle accuracy and roll angle accuracy are:

[0017]

[0018] Among them, θ i , γ i , i The pitch angle, roll angle, and heading angle of the device are aligned n times. is the average value of the pitch angle, roll angle, and heading angle of the device n times of alignment, σ θ , σ γ , σ ψ is the pitch angle, roll angle, and heading angle accuracy of the device, and n is the number of times the alignment results are recorded.

[0019] Preferably, if the heading angle accuracy, the pitch angle accuracy and the roll angle accuracy are all less than or equal to corresponding thresholds, the repeatability alignment accuracy test is qualified.

[0020] Preferably, performing alignment state detection on the data of quasi-repeatability alignment accuracy detection includes:

[0021] For multiple groups of fiber optic inertial navigation data, the alignment status word and the fault word are extracted. If there is no abnormality in the alignment status word and the fault word, the alignment status detection is qualified.

[0022] Preferably, the UAV system sends a command to make the fiber optic inertial navigation enter the pure inertial mode, and the positioning accuracy, speed measurement accuracy, and attitude angle accuracy of the pure fiber optic inertial navigation are determined by:

[0023] Send instructions through the UAV system to put the fiber optic inertial navigation into pure inertial mode and collect pure inertial fiber optic inertial navigation data;

[0024] The fiber optic inertial navigation system is powered off and restarted, and multiple sets of pure inertial fiber optic inertial navigation data are repeatedly collected to calculate the pure inertial accuracy, including the pure inertial horizontal velocity accuracy, horizontal position accuracy, heading angle accuracy, pitch angle accuracy, and roll angle accuracy;

[0025] Perform pure inertial accuracy test based on pure inertial accuracy.

[0026] Preferably, the pure inertial horizontal velocity accuracy is:

[0027]

[0028]

[0029] Among them, V0 is the horizontal speed when the FOINS alignment is completed and the navigation begins, V mj is the jth horizontal velocity output sample value of the mth test data in the pure inertial stage of fiber-optic inertial navigation, N is the sample size of the test data; δV m is the horizontal velocity accuracy of the mth time in the pure inertial stage of FOINS, Q is the number of tests, and δV is the horizontal velocity accuracy of the pure inertial stage of FOINS.

[0030] Preferably, the pure inertial horizontal position accuracy is:

[0031]

[0032] in, The latitude and longitude when the FOINS alignment is completed and the navigation begins. is the i-th sampling value of pure inertial latitude and pure inertial longitude of FOINS, is the error of pure inertial latitude and pure inertial longitude of FOINS, and δd is the pure inertial horizontal position error of FOINS.

[0033] Preferably, the pure inertial pitch angle accuracy, roll angle accuracy, and heading angle accuracy are:

[0034]

[0035] Among them, θ i , γ i , iare the n-times sampled values ​​of the pitch angle, roll angle and heading angle of the device; θ0, γ0 and ψ0 are the pitch angle, roll angle and heading angle values ​​of the device when the device completes navigation; δθ, δγ and δψ are the pitch angle, roll angle and heading angle accuracy of the device; and n is the number of data sampling and storage times for the power-on test of 1 hour.

[0036] Preferably, performing pure inertia state detection on the data of pure inertia accuracy detection includes:

[0037] For multiple groups of fiber optic inertial navigation pure inertia, the pure inertia status word and fault word are extracted. If there is no abnormality in the pure inertia status word and fault word, the pure inertia status detection is qualified.

[0038] Its beneficial effects are:

[0039] The present invention can accurately detect whether the accuracy of the fiber optic inertial navigation in the UAV meets the use requirements, and identify whether the working status of the fiber optic inertial navigation in service is normal; without using any professional tools and high-precision tools, a method is provided for the periodic maintenance detection and preventive maintenance detection of the fiber optic inertial navigation, and data support is provided for the factory return detection and calibration of the fiber optic inertial navigation, which is in line with the actual situation; on the basis of ensuring the safety of the UAV in service, the service attendance time of the UAV can be guaranteed to the greatest extent, saving costs.

[0040] The method of the present invention has other characteristics and advantages, which will be apparent from the accompanying drawings and subsequent detailed descriptions incorporated herein, or will be described in detail in the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0042] Figure 1 A flow chart showing the steps of a method for preventive detection of fiber optic inertial navigation accuracy according to an embodiment of the present invention.

[0043] Figure 2 The diagram shows the alignment state and fault dot-line diagram during the fiber optic inertial navigation alignment accuracy detection according to an embodiment of the present invention.

[0044] Figure 3 A dot-line diagram of horizontal position drift of a fiber optic inertial navigation pure inertial stage according to an embodiment of the present invention is shown.

[0045] Figure 4 A dot-line diagram of pure inertial state and fault during pure inertial accuracy detection of fiber-optic inertial navigation according to an embodiment of the present invention is shown.

[0046] Figure 5 A dotted line graph showing the variation of pure inertial longitude and latitude of a fiber-optic inertial navigation system over time according to an embodiment of the present invention is shown.

[0047] Figure 6 A dotted line graph showing the variation of the pure inertial horizontal velocity of the fiber-optic inertial navigation system over time according to an embodiment of the present invention is shown.

[0048] Figure 7 A dotted line graph showing the variation of the pure inertial pitch angle, roll angle and heading angle of the fiber optic inertial navigation with time according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0050] Figure 1 A flow chart showing the steps of a method for preventive detection of fiber optic inertial navigation accuracy according to an embodiment of the present invention.

[0051] like Figure 1 As shown, the fiber optic inertial navigation accuracy preventive detection method includes:

[0052] Step 101, performing repeatability alignment accuracy detection on the fiber optic inertial navigation system through the UAV system;

[0053] Step 102, performing alignment state detection on the data of quasi-repeatability alignment accuracy detection;

[0054] Step 103, sending a command through the UAV system to make the fiber-optic inertial navigation enter the pure inertial mode, determining the positioning accuracy, speed measurement accuracy, and attitude angle accuracy of the pure fiber-optic inertial navigation, and performing a pure inertial accuracy test;

[0055] Step 104 , performing a pure inertial state test on the data of the pure inertial accuracy test, and completing the preventive test of the fiber optic inertial navigation accuracy if the pure inertial state test is qualified.

[0056] In one example, repeatable alignment accuracy testing of fiber optic inertial navigation via a UAV system includes:

[0057] Record the pitch angle, roll angle, and heading angle output by the fiber optic inertial navigation system. After recording, the fiber optic inertial navigation system is powered off and restarted, and multiple sets of pitch angles, roll angles, and heading angles are recorded repeatedly, which are multiple sets of fiber optic inertial navigation data.

[0058] The heading angle accuracy, pitch angle accuracy and roll angle accuracy are calculated based on multiple sets of fiber optic inertial navigation data, and repeatable alignment accuracy detection is performed.

[0059] In one example, the heading angle accuracy, pitch angle accuracy, and roll angle accuracy are:

[0060]

[0061] Among them, θ i , γ i , i The pitch angle, roll angle, and heading angle of the device are aligned n times. is the average value of the pitch angle, roll angle, and heading angle of the device n times of alignment, σ θ , σ γ , σ ψ is the pitch angle, roll angle, and heading angle accuracy of the device, and n is the number of times the alignment results are recorded.

[0062] In one example, if the heading angle accuracy, the pitch angle accuracy, and the roll angle accuracy are all less than or equal to corresponding thresholds, the repeatability alignment accuracy test is qualified.

[0063] In one example, performing alignment status detection on data of quasi-repeatable alignment accuracy detection includes:

[0064] For multiple groups of fiber optic inertial navigation data, the alignment status word and the fault word are extracted. If there is no abnormality in the alignment status word and the fault word, the alignment status detection is qualified.

[0065] In one example, the UAV system sends a command to make the fiber-optic inertial navigation enter the pure inertial mode, and the positioning accuracy, speed measurement accuracy, and attitude angle accuracy of the pure fiber-optic inertial navigation are determined as follows:

[0066] Send instructions through the UAV system to put the fiber optic inertial navigation into pure inertial mode and collect pure inertial fiber optic inertial navigation data;

[0067] The fiber optic inertial navigation system is powered off and restarted, and multiple sets of pure inertial fiber optic inertial navigation data are repeatedly collected to calculate the pure inertial accuracy, including the pure inertial horizontal velocity accuracy, horizontal position accuracy, heading angle accuracy, pitch angle accuracy, and roll angle accuracy;

[0068] Perform pure inertial accuracy test based on pure inertial accuracy.

[0069] In an example, the pure inertial horizontal velocity accuracy is:

[0070]

[0071]

[0072] Among them, V0 is the horizontal speed when the FOINS alignment is completed and the navigation begins, V mjis the jth horizontal velocity output sample value of the mth test data in the pure inertial stage of fiber-optic inertial navigation, N is the sample size of the test data; δV m is the horizontal velocity accuracy of the mth time in the pure inertial stage of FOINS, Q is the number of tests, and δV is the horizontal velocity accuracy of the pure inertial stage of FOINS.

[0073] In an example, the pure inertial horizontal position accuracy is:

[0074]

[0075] in, The latitude and longitude when the FOINS alignment is completed and the navigation begins. is the i-th sampling value of pure inertial latitude and pure inertial longitude of FOINS, is the error of pure inertial latitude and pure inertial longitude of FOINS, and δd is the pure inertial horizontal position error of FOINS.

[0076] In an example, the pure inertial pitch angle accuracy, roll angle accuracy, and heading angle accuracy are:

[0077]

[0078] Among them, θ i , γ i , i are the n-times sampled values ​​of the pitch angle, roll angle and heading angle of the device; θ0, γ0 and ψ0 are the pitch angle, roll angle and heading angle values ​​of the device when the device completes navigation; δθ, δγ and δψ are the pitch angle, roll angle and heading angle accuracy of the device; and n is the number of data sampling and storage times for the power-on test of 1 hour.

[0079] In one example, performing pure inertia state detection on data of pure inertia accuracy detection includes:

[0080] For multiple groups of fiber optic inertial navigation pure inertia, the pure inertia status word and fault word are extracted. If there is no abnormality in the pure inertia status word and fault word, the pure inertia status detection is qualified.

[0081] Specifically, determine the status of the drone system, ensure that the drone system can work normally, collect and save telemetry data, and keep the drone stationary when it is in an open area and powered on. Support personnel are required to check the status of the entire drone system to ensure that the fiber optic inertial navigation, satellite receiver, flight control computer, link system, and ground station connection are normal; after the inspection, the drone needs to be parked in an open apron and fixed to the ditch with wheel blocks and rope tighteners to ensure that the drone is stationary and the satellite antenna is unobstructed; after the preparations are completed, power on the drone through the ground power supply, and check the parameters of the entire machine according to the pre-takeoff process. It is hereby stated that because the subsequent data collection time is long, in order to ensure that data collection is not interrupted, it is recommended to use AC power supply. Before the test, the drone should be inspected as much as possible according to the pre-takeoff process; check the status settings of the ground monitoring software to ensure that the fiber optic inertial navigation data can be collected and stored in real time.

[0082] The fiber optic inertial navigation system is repeatedly aligned and its alignment accuracy is tested by powering on and off the drone system. The fiber optic inertial navigation system is judged whether it needs to be returned to the factory for inspection and calibration based on the results of multiple alignment repeatability accuracy. Generally, the fiber optic inertial navigation system can be aligned 5 minutes after it is powered on and receives the correction information and second pulse from the satellite receiver. During the alignment stage, the drone must be stationary. After alignment, the heading angle ψ is recorded. i , pitch angle θ i , rolling angle γ i , i ranges from 1 to n. Heading angle accuracy σ ψ , pitch angle accuracy σ θ and roll angle accuracy σ γ The calculation process is as follows:

[0083]

[0084] Among them, ψ i ,θ i , γ i The pitch angle, roll angle, and heading angle of the device are aligned n times, in degrees; is the average value of the pitch angle, roll angle, and heading angle of the device n times of alignment, unit: °; σ ψ , σ θ , σ γ is the pitch angle, roll angle, and heading angle accuracy of the device, in degrees; n is the number of times the alignment result is recorded.

[0085] Compare the calculated result with the specified value. If the heading angle accuracy σ γ ≤ the specified value of the heading angle accuracy of the fiber-optic inertial navigation system, and the pitch angle accuracy σ θ ≤Fiber optic inertial navigation pitch angle accuracy specified value, and roll angle accuracyσ γ ≤ the specified value of the fiber optic inertial navigation rolling angle accuracy, the accuracy of multiple alignments meets the index requirements.

[0086] Perform alignment status detection based on all the data collected from multiple alignment repeatability and alignment accuracy detections to determine whether the fiber optic inertial navigation system needs to be returned to the factory for inspection and calibration. Open the fiber optic inertial navigation data stored in the ground monitoring software for n times, extract the alignment status word (enter alignment status identification word, enter combined navigation status identification word) and alignment fault word (gyro data abnormality, table data abnormality, calibration parameter out of tolerance); check that there is no abnormality in the n-time recorded data status word and fault word, and the alignment process working status detection is qualified.

[0087] Send instructions through the drone system to put the fiber-optic inertial navigation system into pure inertial mode, collect multiple sets of 1-hour pure inertial status data, and determine whether the fiber-optic inertial navigation system needs to be returned to the factory for inspection and calibration based on the pure fiber-optic inertial navigation positioning accuracy, speed measurement accuracy, and attitude angle accuracy.

[0088] After the FIBER INS is aligned and switched to navigation, send the "one-key pure inertial" command to the FIBER INS through the ground monitoring software; check that the FIBER INS is working in pure inertial mode, and collect and store all FIBER INS data in real time through the ground monitoring software, including at least horizontal speed, horizontal position, pitch angle, roll angle, and heading angle; after "pure inertial" for 1 hour, save the data, power off the drone, repeat steps S41-S43, and record 3 sets of data in total. Calculate the pure inertial accuracy based on the recorded data, including horizontal speed accuracy, horizontal position accuracy, heading angle accuracy, pitch angle accuracy, and roll angle accuracy.

[0089] The pure inertial horizontal position accuracy is:

[0090]

[0091]

[0092] in, The latitude and longitude at the time when the device ends alignment and enters navigation, in degrees; The i-th sampling value of the pure inertial latitude and pure inertial longitude of the device, unit: °; is the error of the pure inertial latitude and pure inertial longitude of the device, unit: nmile; δd is the pure inertial horizontal position error of the device, unit: nmile.

[0093] The accuracy of the pure inertial horizontal speed (eastward speed, northward speed) of the equipment is:

[0094]

[0095]

[0096] Where V0 is the initial horizontal speed of the equipment (eastward speed, northward speed), unit: m / s; V mjOutput sample value of the jth horizontal velocity (eastward velocity, northward velocity) of the mth test data, unit: m / s; N is the sample size of the test data; δV m is the horizontal velocity (eastward velocity, northward velocity) accuracy of the mth time, unit: m / s; Q is the number of tests; δV is the horizontal velocity (eastward velocity, northward velocity) accuracy of the equipment, unit: m / s.

[0097] The pitch angle, roll angle and heading angle accuracy of the pure fiber-optic inertial navigation equipment are:

[0098]

[0099] Among them, θ i , γ i , i is the nth sampling value of the pitch angle, roll angle and heading angle of the device in the pure inertia stage, unit: °; θ0, γ0, ψ0 are the pitch angle, roll angle and heading angle values ​​of the device when it completes navigation, unit: °; δθ, δγ, δψ are the pitch angle, roll angle and heading angle accuracy of the device, unit: °; n is the number of data sampling and storage times for the power-on test of 1 hour.

[0100] If the horizontal velocity accuracy of pure inertia is ≤ the specified value of the horizontal velocity accuracy of fiber-optic inertial navigation, the horizontal position accuracy of pure inertia is ≤ the specified value of the horizontal position accuracy of fiber-optic inertial navigation, the horizontal velocity accuracy of pure inertia is ≤ the specified value of the horizontal velocity accuracy of fiber-optic inertial navigation, the heading angle accuracy of pure inertia is ≤ the specified value of the heading angle accuracy of fiber-optic inertial navigation, the pitch angle accuracy of pure inertia is ≤ the specified value of the pitch angle accuracy of fiber-optic inertial navigation, and the roll angle accuracy of pure inertia is ≤ the specified value of the roll angle accuracy of fiber-optic inertial navigation, then the pure inertial accuracy test is qualified.

[0101] Perform pure inertial status detection based on all collected data to determine whether the fiber optic inertial navigation system needs to be returned to the factory for inspection and calibration.

[0102] Open the n times of fiber optic inertial navigation pure inertial data stored in the ground monitoring software, extract the pure inertial status word (entering pure inertial status identification word) and pure inertial fault word (abnormal gyro data, abnormal inertial device temperature gradient, inertial device temperature out of range, inertial device temperature jump, abnormal accelerometer output pulse, calibration parameter out of tolerance); check that there is no abnormality in the pure inertial status word and fault word of the n times recorded data, then the working status detection of the pure inertial process is qualified.

[0103] To facilitate understanding of the solution and effects of the embodiments of the present invention, a specific application example is given below. Those skilled in the art should understand that this example is only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0104] Example 1

[0105] For the determined UAV and airport apron, 7 sets of alignment data and 1 set of pure inertial data are collected through ground monitoring software. The 7 alignment data are shown in Table 1.

[0106] Table 1 Actual recorded 7 navigation time data of fiber optic inertial navigation

[0107] frequency Roll angle(°) Pitch angle (°) Heading angle (°) 1 -0.47 -0.31 184.91 2 -0.46 -0.31 184.67 3 -0.44 -0.31 184.2 4 -0.44 -0.33 184.6 5 -0.45 -0.35 185.24 6 -0.46 -0.36 185.33 7 -0.46 -0.37 185.04

[0108] Get the average value of the pitch angle, roll angle, and heading angle of the device for 7 alignments:

[0109]

[0110] Then the pitch angle, roll angle and heading angle accuracy of the device can be calculated as:

[0111]

[0112] The technical requirements of the equipment are queried to obtain the specified values ​​of pitch angle, roll angle and heading angle as follows:

[0113] Specified value of heading angle accuracy (1σ): ≤0.5°;

[0114] Navigation horizontal attitude angle (pitch angle, roll angle) accuracy requirement (1σ): ≤0.05°;

[0115] After comparison, it can be seen that the detected pitch angle, roll angle and heading angle accuracies are all less than the specified values, so the pitch angle, roll angle and heading angle alignment accuracy of the equipment meets the requirements.

[0116] Figure 2 The diagram shows the alignment state and fault dot-line diagram during the fiber optic inertial navigation alignment accuracy detection according to an embodiment of the present invention.

[0117] The alignment status and fault dot-line diagrams during FIBS alignment are drawn by the collected data, such as Figure 2 shown.

[0118] The status word transitions from the alignment stage to the combined navigation stage. The turning point is called the navigation moment. The fault words in both stages are "0", indicating that the status detection of the fiber optic inertial navigation equipment is normal.

[0119] Figure 3 A dot-line diagram of horizontal position drift of a fiber optic inertial navigation pure inertial stage according to an embodiment of the present invention is shown.

[0120] There is position drift in the pure inertial stage of fiber optic inertial navigation. Figure 3 shown.

[0121] Figure 4 A dot-line diagram of pure inertial state and fault during pure inertial accuracy detection of fiber-optic inertial navigation according to an embodiment of the present invention is shown.

[0122] Fiber optic inertial navigation status and fault word conditions are as follows Figure 4 As shown, analysis of the data shows that the accuracy detection of the pure inertial stage of FOINS needs to go through three stages, namely: alignment stage, combination stage, and pure inertial stage. Among them, the turning point from the alignment stage to the combination stage is called the navigation moment, and the turning point from the combination stage to the pure inertial stage is achieved by sending a "pure inertial command" through the ground monitoring software or by physically disconnecting the FOINS correction information. This example is achieved by sending a "pure inertial command". Through data analysis, it can be seen that the fault words in the three stages are all "0", and the FOINS device status detection is normal.

[0123] Figure 5 A dotted line graph showing the variation of pure inertial longitude and latitude of a fiber-optic inertial navigation system over time according to an embodiment of the present invention is shown.

[0124] The change of longitude and latitude over time in the pure inertial phase of fiber optic inertial navigation is as follows Figure 5 As shown, through analysis, it can be seen that the navigation time is 13:43:55, and it enters the pure inertia stage at 14:01:40. One hour later, at 15:01:40, the equipment is powered off. The longitude and latitude drift with time, and the maximum value is at 15:01:40. The records are shown in Table 2.

[0125] Table 2 Horizontal position data obtained during the pure inertial stage accuracy test of fiber optic inertial navigation

[0126] time Longitude (°) Latitude (°) 13:43:55 92.344186 28.425134 15:01:40 92.541586 28.459155

[0127] Then we can know that:

[0128]

[0129]

[0130] Then the horizontal position accuracy (max) is 10.416nmile<index (max) 20nmile

[0131] Figure 6 A dotted line graph showing the variation of the pure inertial horizontal velocity of the fiber-optic inertial navigation system over time according to an embodiment of the present invention is shown.

[0132] Figure 6 The horizontal speed changes with time. From the data, we can see that the navigation time is 13:43:55, and it enters the pure inertia stage at 14:01:40. The maximum recorded data of horizontal speed are shown in Table 3.

[0133] Table 3 Horizontal velocity data obtained during the pure inertial stage accuracy test of fiber optic inertial navigation

[0134] time Eastward speed (m / s) Northward speed (m / s) 13:43:55 0.55 -0.08 \ 7.98 2.66

[0135]

[0136]

[0137] Then the horizontal speed accuracy (max) is 7.43m / s<index (max) 10m / s

[0138] Figure 7 A dotted line graph showing the variation of the pure inertial pitch angle, roll angle and heading angle of the fiber optic inertial navigation with time according to an embodiment of the present invention is shown.

[0139] Figure 7 The figure is a dot-line graph of the pure inertial pitch angle, roll angle and heading angle of the fiber-optic inertial navigation over time. From the data, we can see that the navigation time is 13:43:55, and it enters the pure inertial stage at 14:01:40, and ends the pure inertial stage at 15:01:40 one hour later.

[0140] The equipment has completed alignment, and the pitch angle θ0 = -0.32°, the roll angle γ0 = -0.47°, and the heading angle ψ0 = 184.94° at the navigation moment.

[0141] The equipment accuracy is calculated according to the accuracy formula and compared as follows:

[0142] Pitch angle accuracy δθ=0.036°<index (1σ) 0.1°

[0143] Roll angle accuracy δγ=0.036°<index (1σ) 0.1°

[0144] Heading angle accuracy δψ=0.035°<index (1σ)0.5°

[0145] After comprehensive calculation of all the accuracy of the example, all the accuracy indicators of the fiber-based inertial navigation are summarized as shown in Table 4.

[0146] Table 4 Summary of all accuracy indicators of fiber optic inertial navigation

[0147] Serial number parameter Index requirements Measured and calculated values Eligibility 1 Multiple alignment pitch angle accuracy ＜0.05° 0.026 qualified 2 Multiple alignment of roll-on angle accuracy ＜0.05° 0.011 qualified 3 Multiple alignment heading angle accuracy ＜0.5° 0.396 qualified 4 Alignment status and fault words No trouble No trouble qualified 5 Pure inertial horizontal position accuracy (max) <20nmile 10.416nmile qualified 6 Pure inertial horizontal velocity accuracy (max) <10m / s 7.43m / s qualified 7 Pure inertial pitch angle accuracy (1σ) ＜0.1° 0.036° qualified 8 Pure inertial roll angle accuracy (1σ) ＜0.1° 0.036° qualified 9 Pure inertial heading angle accuracy (1σ) ＜0.25° 0.035° qualified 10 Pure inertia state and fault word No trouble No trouble qualified

[0148] By comparison, the above indicators all meet the requirements and the fiber optic inertial navigation system can continue to be used.

[0149] Those skilled in the art should understand that the purpose of the above description of the embodiments of the present invention is only to exemplarily illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0150] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A preventive detection method for fiber optic inertial navigation accuracy, characterized in that: include: Repeatable alignment accuracy testing of fiber optic inertial navigation system is performed through UAV system; Perform alignment status detection on the data of quasi-repeatability alignment accuracy detection; Send instructions through the UAV system to make the fiber-optic inertial navigation enter the pure inertial mode, determine the pure fiber-optic inertial navigation positioning accuracy, speed measurement accuracy, attitude angle accuracy, and perform pure inertial accuracy testing; A pure inertial state test is performed on the data of the pure inertial accuracy test. If the pure inertial state test is qualified, the fiber optic inertial navigation accuracy preventive test is completed.

2. The preventive detection method for fiber optic inertial navigation accuracy according to claim 1, wherein: Repeatable alignment accuracy testing of fiber optic inertial navigation via UAV systems includes: Record the pitch angle, roll angle, and heading angle output by the fiber optic inertial navigation system. After recording, the fiber optic inertial navigation system is powered off and restarted, and multiple sets of pitch angles, roll angles, and heading angles are recorded repeatedly, which are multiple sets of fiber optic inertial navigation data. The heading angle accuracy, pitch angle accuracy and roll angle accuracy are calculated based on multiple sets of fiber optic inertial navigation data, and repeatable alignment accuracy detection is performed.

3. The preventive detection method for fiber optic inertial navigation accuracy according to claim 2, wherein: The heading angle accuracy, pitch angle accuracy and roll angle accuracy are: Among them, θ i , γ i , i The pitch angle, roll angle, and heading angle of the device are aligned n times. is the average value of the pitch angle, roll angle, and heading angle of the device n times of alignment, σ θ , σ γ , σ ψ is the pitch angle, roll angle, and heading angle accuracy of the device, and n is the number of times the alignment results are recorded.

4. The preventive detection method for fiber optic inertial navigation accuracy according to claim 2, wherein: If the heading angle accuracy, pitch angle accuracy, and roll angle accuracy are all less than or equal to the corresponding thresholds, the repeatability alignment accuracy test is qualified.

5. The preventive detection method for fiber optic inertial navigation accuracy according to claim 2, wherein: The alignment status detection for the data of quasi-repeatability alignment accuracy detection includes: For multiple groups of fiber optic inertial navigation data, the alignment status word and the fault word are extracted. If there is no abnormality in the alignment status word and the fault word, the alignment status detection is qualified.

6. The preventive detection method for fiber optic inertial navigation accuracy according to claim 1, wherein: Sending commands through the UAV system makes the fiber optic inertial navigation enter the pure inertial mode, and determining the pure fiber optic inertial navigation positioning accuracy, speed measurement accuracy, and attitude angle accuracy include: Send instructions through the UAV system to put the fiber optic inertial navigation into pure inertial mode and collect pure inertial fiber optic inertial navigation data; The fiber optic inertial navigation system is powered off and restarted, and multiple sets of pure inertial fiber optic inertial navigation data are repeatedly collected to calculate the pure inertial accuracy, including the pure inertial horizontal velocity accuracy, horizontal position accuracy, heading angle accuracy, pitch angle accuracy, and roll angle accuracy; Perform pure inertial accuracy test based on pure inertial accuracy.

7. The preventive detection method for fiber optic inertial navigation accuracy according to claim 6, wherein: The pure inertial horizontal velocity accuracy is: Among them, V0 is the horizontal speed when the FOINS alignment is completed and the navigation begins, V mj is the jth horizontal velocity output sample value of the mth test data in the pure inertial stage of fiber-optic inertial navigation, N is the sample size of the test data; δV m is the horizontal velocity accuracy of the mth time in the pure inertial stage of FOINS, Q is the number of tests, and δV is the horizontal velocity accuracy of the pure inertial stage of FOINS.

8. The preventive detection method for fiber optic inertial navigation accuracy according to claim 6, wherein: The pure inertial horizontal position accuracy is: in, The latitude and longitude when the FOINS alignment is completed and the navigation begins. is the i-th sampling value of pure inertial latitude and pure inertial longitude of FOINS, is the error of pure inertial latitude and pure inertial longitude of FOINS, and δd is the pure inertial horizontal position error of FOINS.

9. The preventive detection method for fiber optic inertial navigation accuracy according to claim 1, wherein: The pitch angle accuracy, roll angle accuracy, and heading angle accuracy of pure inertia are: Among them, θ i , γ i , i are the n-times sampled values ​​of the pitch angle, roll angle and heading angle of the device; θ0, γ0 and ψ0 are the pitch angle, roll angle and heading angle values ​​of the device when the device completes navigation; δθ, δγ and δψ are the pitch angle, roll angle and heading angle accuracy of the device; and n is the number of data sampling and storage times for the power-on test of 1 hour.

10. A preventive detection method for fiber optic inertial navigation accuracy as claimed in claim 1, wherein: The pure inertia state detection for the pure inertia accuracy detection data includes: For multiple groups of fiber optic inertial navigation pure inertia, the pure inertia status word and fault word are extracted. If there is no abnormality in the pure inertia status word and fault word, the pure inertia status detection is qualified.

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