Error correction system for inertial navigation device and error correction method thereof

Abstract

The present application provides an error correction system for an inertial navigation device and an error correction method thereof, which can appropriately correct errors such as offset errors generated by an inertial navigation device mounted on a flying body. In an error correction system for an inertial navigation device in a plurality of flying bodies that perform autonomous flight based on positions and attitudes calculated by the mounted inertial navigation devices, an error correction device mounted on each flying body corrects errors generated by the inertial navigation device of the own flying body based on angle measurement residuals (ΔAZ, ΔEL), which are differences between an azimuth angle AZ1 and an elevation angle EL1 of the other flying body based on own flying body data calculated based on coordinates of the other flying body observed from the own flying body calculated by a coordinate calculation device, and an azimuth angle AZ2 and an elevation angle EL2 of the other flying body based on other flying body data calculated based on information on a position of the other flying body received from the other flying body by a wireless communication device.

Description

Technical Field

[0001] This invention relates to an error correction system for an inertial navigation device mounted on an aircraft and an error correction method for the inertial navigation device. Background Technology

[0002] As a method for autonomous flight by controlling itself in an unmanned aerial vehicle, there are known methods that involve carrying a GPS receiver and determining its own position based on GPS signals received from multiple GPS satellites.

[0003] However, GPS-based methods are susceptible to interference and / or the influence of surrounding buildings, etc. As a method that is not affected by these or is difficult to be affected by these, methods using inertial navigation devices are known (see Patent Documents 1, 2, etc.).

[0004] Typically, in an inertial navigation system, its position (latitude, longitude, altitude) and / or attitude (pitch, roll, yaw) are calculated by integrating the acceleration and angular velocity measured by the accelerometer and angular velocity sensor.

[0005] Moreover, the control unit of the unmanned aerial vehicle is configured to perform automatic manipulation based on the calculated position and / or attitude.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-147111

[0009] Patent Document 2: Japanese Patent Application Publication No. 2019-115012 Summary of the Invention

[0010] Technical issues

[0011] However, in addition to randomly generated errors, the measurements from accelerometers and / or angular velocity sensors also include bias errors, which are errors in the signals generated by the sensors when there is no turning and / or acceleration. This bias error is one of the main causes of error in the position and / or attitude calculated by the inertial navigation device.

[0012] Moreover, this problem exists not only for unmanned aerial vehicles, but also for inertial navigation systems mounted on manned aircraft.

[0013] The present invention was made in view of the above-mentioned problems, and its object is to provide an error correction system and an error correction method for an inertial navigation device that can appropriately correct errors such as offset errors generated by an inertial navigation device mounted on an aircraft.

[0014] Technical solution

[0015] To address the aforementioned problems, the invention described in the first aspect is characterized by an error correction system for the inertial navigation devices of multiple flight bodies that autonomously fly based on the positions and attitudes calculated by the onboard inertial navigation devices.

[0016] Each of the aforementioned aircraft is equipped with an inertial navigation device, a wireless communication device, a coordinate calculation device for calculating the coordinates of other aircraft as observed from this aircraft, and an error correction device.

[0017] The error correction device calculates the azimuth and elevation angles of the other aircraft based on the coordinates of the other aircraft observed from the main body, calculated by the coordinate calculation device.

[0018] The error correction device calculates the azimuth and elevation angles of the other aircraft based on the position information of the other aircraft calculated by its inertial navigation device and the position information of the current aircraft calculated by its own inertial navigation device, which are received by the wireless communication device from the other aircraft.

[0019] The error correction device corrects the error generated by the inertial navigation device of the main body based on the angle measurement residual, wherein the angle measurement residual is the difference between the azimuth and elevation angles of the other body based on the data of the main body and the azimuth and elevation angles of the other body based on the data of the other body.

[0020] The invention described in the second aspect is characterized in that, based on the error correction system of the inertial navigation device described in the first aspect, the error correction device calculates the azimuth and elevation angles of other bodies based on the data of the main body, using the coordinates of other bodies observed from the main body as calculated by the coordinate calculation device and the attitude information of the main body calculated by the inertial navigation device of the main body.

[0021] The invention described in the third aspect is characterized in that, based on the error correction system of the inertial navigation device described in the first or second aspect, the error correction device calculates the azimuth and elevation angles of the vector from the position of the main body calculated by the inertial navigation device of the main body to the position of the other body calculated by the inertial navigation device of the other body, and uses the azimuth and elevation angles of the other body based on the data of the other body.

[0022] The invention described in the fourth aspect is characterized in that, based on the error correction system of the inertial navigation device in any one of the first to third aspects, when the error correction device determines that the position information of the other body calculated by the inertial navigation device of the other body received from the other body is unreliable, it sends a signal to the other body, including the other body, indicating that the position information of the other body is unreliable.

[0023] The invention described in the fifth aspect is characterized in that, based on the error correction system of the inertial navigation device in any one of the first to fourth aspects, the error correction device weights the angular measurement residual in such a way that the greater the distance of other bodies from the main body, the greater the weight, and corrects the error generated by the inertial navigation device of the main body based on the angular measurement residual.

[0024] The invention described in the sixth aspect is characterized in that, based on the error correction system of the inertial navigation device in any one of the first to fifth aspects, when the solid angle of the solid angle calculated for a certain other body is below a threshold, the error correction device sends an accuracy determination signal including the identification information of the certain other body.

[0025] The invention described in the seventh aspect is characterized by an error correction method for the inertial navigation devices in multiple flight bodies that perform autonomous flight based on the position and attitude calculated by the onboard inertial navigation devices.

[0026] The error correction method for the inertial navigation device includes:

[0027] In the coordinate calculation step, the flying body calculates the coordinates of other flying bodies as observed from its own body;

[0028] The calculation steps for the azimuth and elevation angles of other aircraft based on the data of this aircraft are as follows: the azimuth and elevation angles of other aircraft observed from this aircraft are calculated based on the coordinates of other aircraft observed from this aircraft in the coordinate calculation steps.

[0029] The calculation steps for the azimuth and elevation angles of other aircraft based on data from other aircraft involve calculating the azimuth and elevation angles of the other aircraft based on the position information of the other aircraft calculated by its inertial navigation device and received from the other aircraft via a wireless communication device, and the position information of the current aircraft calculated by its own inertial navigation device.

[0030] The error correction step corrects the error generated by the inertial navigation device of the main body based on the angle measurement residual, which is the difference between the azimuth and elevation angles of the other body based on the data of the main body and the azimuth and elevation angles of the other body based on the data of the other body.

[0031] Invention Effects

[0032] According to the present invention, it is possible to appropriately correct errors such as offset errors generated by the inertial navigation device mounted on the aircraft. Attached Figure Description

[0033] Figure 1 This diagram illustrates the case where the error correction system of the inertial navigation device of this embodiment consists of multiple autonomously flying bodies.

[0034] Figure 2 This is a block diagram showing the configuration related to the error correction system of the inertial navigation device of each aircraft.

[0035] Figure 3 This diagram illustrates how the coordinates of other organisms observed from this organism are calculated by performing coordinate transformations on the image coordinates of other organisms in the image.

[0036] Figure 4 This is a flowchart illustrating the steps of the error correction method for the inertial navigation device according to this embodiment.

[0037] Figure 5 This diagram illustrates how the azimuth and elevation angles of other aircraft are calculated based on the coordinates of other aircraft observed from this aircraft and the attitude of this aircraft.

[0038] Figure 6 This diagram illustrates how the azimuth and elevation angles of another aircraft are calculated based on the position of that other aircraft calculated by its inertial navigation device and the position of this aircraft calculated by its own inertial navigation device.

[0039] Figure 7 This diagram illustrates that the greater the distance between this machine and other machines, the smaller the errors in the azimuth and elevation angles of other machines observed from this machine, corresponding to the positional error.

[0040] Symbol Explanation

[0041] 1. Error correction system for inertial navigation devices

[0042] 2. Flying bodies

[0043] 2a This body

[0044] 2b Other units

[0045] 10 Inertial Navigation Device

[0046] 11 Wireless communication devices

[0047] 12 Coordinate Calculation Device

[0048] 13 Error Correction Device

[0049] ALT Height (Position)

[0050] (az, el) Coordinates of other machines as observed from this machine

[0051] AZ1, EL1: Azimuth and elevation angles of other aircraft based on the data of this aircraft.

[0052] AZ2 and EL2: Azimuth and elevation angles of other mechs based on data from other mechs.

[0053] LAT Latitude (Location)

[0054] Lj Distance from the main body

[0055] LON (Longitude / Location)

[0056] Nj: Number of effective angle measurement targets (number of signals to determine accuracy)

[0057] p Pitch (posture)

[0058] r Roll (posture)

[0059] V vector

[0060] wj weight

[0061] y (yawing / attitude)

[0062] (ΔAZ, ΔEL) Angular residuals

[0063] σj is the standard deviation of the angle measurement residual (fluctuation of the angle measurement residual).

[0064] Ω solid angle Detailed Implementation

[0065] Hereinafter, embodiments of the error correction system and error correction method of the inertial navigation device of the present invention will be described with reference to the accompanying drawings.

[0066] Error correction system for inertial navigation devices

[0067] In the error correction system 1 of the inertial navigation device of this embodiment, such as Figure 1As shown, multiple flight bodies 2 that are equipped with inertial navigation devices and / or wireless communication devices, etc., and fly autonomously, while communicating with each other wirelessly, correct for errors generated by their own inertial navigation devices.

[0068] At this time, the flying body 2 can be an unmanned aircraft or a manned aircraft.

[0069] In addition, the multiple flying bodies 2 may be, for example, wingmen acting in coordination with each other, or unrelated aircraft that happen to be flying nearby.

[0070] In addition, multiple flying bodies 2 can be just the two of them, namely the main body 2a and the other body 2b, or they can be three or more.

[0071] The error correction system 1 of the inertial navigation device of this embodiment will be described in detail below.

[0072] Figure 2 This is a block diagram showing the configuration related to the error correction system of the inertial navigation device in each aircraft.

[0073] [The composition of each flying body]

[0074] Each flying body 2 is equipped with an inertial navigation device 10, a wireless communication device 11, a coordinate calculation device 12, and an error correction device 13, and performs autonomous flight based on the position (latitude, longitude, altitude) and attitude (pitch, roll, yaw) calculated by the inertial navigation device 10.

[0075] In addition, in this embodiment, each flying body 2 is equipped with a light 14. By making the light 14 flash in a predetermined flashing pattern, the user’s ID (identification information) is notified to other flying bodies 2 (hereinafter referred to as other bodies) according to the flashing pattern of the light 14.

[0076] The inertial navigation device 10 includes an acceleration sensor 10A and an angular velocity sensor 10B. It calculates the position and / or attitude of the flight body 2 by integrating the acceleration and / or angular velocity output by the acceleration sensor 10A and / or the angular velocity sensor 10B, and sends the calculated position and / or attitude information to the control unit 20 of the flight body 2.

[0077] In addition, the inertial navigation device 10 assigns the position (latitude, longitude, altitude) information from the calculated position and attitude information to the ID of the flight body 2 it carries, and transmits it to all other aircraft via the wireless communication device 11.

[0078] Here, all other aircraft refer to the aircraft 2 that can communicate with this aircraft via wireless communication device 11.

[0079] In addition, if the wireless communication device 11 receives information about the location (latitude, longitude, altitude) of another machine body, which is calculated by the inertial navigation device 10 of that other machine body and assigned an ID to that other machine body, it will send the location information of the other machine body with the assigned ID to the coordinate calculation device 12 and the error correction device 13.

[0080] [Calculation of coordinates of other mechs as observed from this mech]

[0081] The coordinate calculation device 12 is a device used to calculate the coordinates (az, el) of other aircraft as observed from the main body (i.e., the aircraft 2 equipped with the coordinate calculation device 12).

[0082] The following describes the method for calculating the coordinates (az, el) of other bodies observed from the main body by the coordinate calculation device 12 in this embodiment.

[0083] The coordinate calculation device 12 includes a camera 12A. Here, the camera 12A is configured to change its orientation in any direction or within a predetermined range. Alternatively, an omnidirectional camera or the like can be used as the camera 12A.

[0084] Furthermore, this embodiment describes the case of capturing moving images using camera 12A, but it can also be configured to capture still images. It should be noted that when capturing still images using camera 12A, a new mechanism is provided for obtaining the IDs of other machines captured in the image by camera 12A.

[0085] The coordinate calculation device 12 analyzes the dynamic image captured by the camera 12A, infers the flashing pattern of the lights 14 of other machines captured in the image (i.e., each image that constitutes each frame of the dynamic image), and infers the ID of the other machine captured in the image.

[0086] Furthermore, if the wireless communication device 11 receives location information (i.e., location information assigned to the inferred ID) from other bodies captured in the moving image and transmits it to the coordinate calculation device 12, then as follows Figure 3 As shown, the coordinate calculation device 12 infers the image coordinates (u, v) of the other body 2b in the image captured at that moment (an image constituting one frame of the moving image).

[0087] Then, the coordinate calculation device 12 calculates the coordinates (az, el) of the other body 2b as observed from the main body 2a, based on the orientation of the camera 12A at the aforementioned moment and the image coordinates (u, v) of the other body 2b.

[0088] In other words, such as Figure 3 As shown, the coordinate calculation device 12 performs coordinate transformation on the image coordinates (u, v) of the other body 2b in the image, thereby calculating the azimuth (az) and elevation (el) of the other body 2b relative to the front (FWD) axis in the Cartesian coordinate system with the front (FWD), right (RH), and bottom (DWN) of the body 2a as the coordinate axes.

[0089] It should be noted that the above description describes the case where the coordinate calculation device 12 analyzes the image captured by the camera 12A to calculate the coordinates (az, el) of the other body 2b observed from the main body 2a. However, the present invention is not limited to this case. For example, it can also be configured to calculate the coordinates (az, el) of the other body 2b observed from the main body 2a using information obtained from radar or the like.

[0090] The coordinate calculation device 12 performs the above processing on all other bodies 2b. If the coordinates (az, el) of the other body 2b observed from the main body 2a are calculated, the calculated coordinates (az, el) of the other body 2b observed from the main body 2a are assigned the inferred ID of the other body 2b and sent to the error correction device 13 respectively.

[0091] [Correction of errors caused by inertial navigation devices]

[0092] Next, the method for correcting errors generated by the inertial navigation device 10 of the main body 2a in the error correction device 13 of this embodiment will be described. It should be noted that it can also be configured as part of the processing of the error correction device 13, which is described below using a coordinate calculation device 12, etc. In addition, the coordinate calculation device 12 and the error correction device 13, etc., can also be configured as a single device.

[0093] In addition, the error correction method of the inertial navigation device of this embodiment will also be described.

[0094] Error correction methods for inertial navigation devices include Figure 4 The steps shown illustrate the method for correcting errors generated by the inertial navigation device 10 of the main body 2a, following its flow.

[0095] The coordinate calculation step (step S1) for calculating the coordinates (az, el) of other bodies 2b observed from this body 2a using the coordinate calculation device 12 is as described above.

[0096] [Calculation of azimuth and elevation angles for other mechs based on this mech's data]

[0097] The error correction device 13 calculates the azimuth and elevation angles of the other body 2b observed from the main body 2a based on the coordinates (az, el) calculated by the coordinate calculation device 12 (calculation steps such as azimuth angle of the other body based on the main body data (step S2)).

[0098] In this step, if the error correction device 13 is sent with the coordinates (az, el) of the other body 2b observed from the body 2a as calculated by the coordinate calculation device 12, the attitude (pitch, roll, yaw) of the body 2a is obtained by the inertial navigation device 10 of the body 2a at the moment when the position information of the other body 2b captured in the image is received.

[0099] Moreover, such as Figure 5 As shown, the error correction device 13 calculates the azimuth angle AZ1 (north reference) of the other aircraft 2b observed from the main body 2a based on the coordinates (az, el) calculated by the coordinate calculation device 12 and the attitude (p, r, yaw) of the main body 2a calculated by the inertial navigation device 10 of the main body 2a. Figure 5 The N-axis and elevation angle EL1 (horizontal plane reference).

[0100] However, in this case, the "azimuth angle AZ1 and elevation angle EL1 of other aircraft 2b" are ultimately calculated based on the attitude (pitch p, roll r, yaw y) of the aircraft 2a calculated by the inertial navigation device 10 of the aircraft 2a, and may contain errors. Therefore, it is called "azimuth angle AZ1 and elevation angle EL1 of other aircraft based on the data of this aircraft".

[0101] [Calculation of the azimuth and elevation angles of this other mech based on data from other mechs]

[0102] On the other hand, the error correction device 13 calculates the azimuth and elevation angle of the other aircraft 2b based on the information of the position (latitude, longitude, and altitude) of the other aircraft 2b calculated by the inertial navigation device 10 of the other aircraft 2b received by the wireless communication device 11 from the other aircraft 2b, and the information of the position (latitude, longitude, and altitude) of the own aircraft 2a calculated by the inertial navigation device 10 of the own aircraft 2a at the moment when the wireless communication device 11 receives the position information of the other aircraft 2b (step S3).

[0103] In this step, such as Figure 6As shown, the error correction device 13 calculates the azimuth angle AZ2 (north reference) and elevation angle EL2 (horizontal reference) of the vector V of the position (latitude LATa, longitude LONa, altitude ALTa) of the main body 2a calculated by the inertial navigation device 10 of the main body 2a and the position (latitude LATb, longitude LONb, altitude ALTb) of the other body 2b calculated by the inertial navigation device 10 of the other body 2b, as the azimuth angle AZ2 and elevation angle EL2 of the other body 2b.

[0104] In this case, the "azimuth angle AZ2 and elevation angle EL2 of other aircraft 2b" are ultimately calculated based on the position (latitude, longitude, altitude) of other aircraft 2b, which may contain errors, calculated by the inertial navigation device 10 of other aircraft 2b. Therefore, it is distinguished from the "azimuth angle AZ1 and elevation angle EL1 of other aircraft based on the data of this aircraft" mentioned above and is called "azimuth angle AZ2 and elevation angle EL2 of other aircraft based on the data of other aircraft".

[0105] It should be noted that steps S2 (calculation of azimuth and elevation angles of other aircraft based on the data of this aircraft) and S3 (calculation of azimuth and elevation angles of other aircraft based on the data of other aircraft) can be processed in reverse order, or can be executed simultaneously.

[0106] [Correction of errors caused by inertial navigation devices]

[0107] Next, the error correction device 13 calculates the angle measurement residuals (ΔAZ, ΔEL) and corrects the errors generated by the inertial navigation device 10 of the main body 2a (in this embodiment, the offset error of the accelerometer 10A and the offset error of the angular velocity sensor 10B of the inertial navigation device 10) based on the calculated angle measurement residuals (ΔAZ, ΔEL) (error correction step (step S4)). The angle measurement residuals are the differences between the azimuth angle AZ1 and elevation angle EL1 of the other body 2b calculated in step S2 based on the data of the main body and the azimuth angle AZ2 and elevation angle EL2 of the other body 2b calculated in step S3 based on the data of the other body.

[0108] Specifically, the error correction device 13 calculates as follows:

[0109] ΔAZ=AZ1-AZ2…(1)

[0110] ΔEL=EL1-EL2…(2)

[0111] The angle measurement residuals (ΔAZ, ΔEL) are then calculated, and based on the calculated angle measurement residuals (ΔAZ, ΔEL), the sensor deviation values ​​of the accelerometer 10A and the angular velocity sensor 10B of the inertial navigation device 10 are calculated respectively.

[0112] Furthermore, in this embodiment, the error correction device 13 adds the calculated sensor deviation value of the accelerometer 10A to the acceleration output by the accelerometer 10A of the inertial navigation device 10, and adds the calculated sensor deviation value of the angular velocity sensor 10B to the angular velocity output by the angular velocity sensor 10B, thereby correcting the offset error of the accelerometer 10A and the offset error of the angular velocity sensor 10B of the inertial navigation device 10, respectively.

[0113] Then, the inertial navigation device 10 calculates the position (latitude, longitude, altitude) and / or attitude (pitch, roll, yaw) of the aircraft 2a by integrating the corrected acceleration and / or angular velocity.

[0114] In the error correction system 1 and error correction method of the inertial navigation device in this embodiment, each of the above steps S1 to S4 is repeated, and the above processing is performed on all other bodies 2b. By correcting the acceleration and / or angular velocity output by the acceleration sensor 10A and / or angular velocity sensor 10B of the inertial navigation device 10, errors such as offset errors generated by the inertial navigation device 10 are corrected.

[0115] [Effect]

[0116] As described above, according to the error correction system 1 and error correction method of the inertial navigation device of this embodiment, the error correction device 13 is configured to correct the error generated by the inertial navigation device 10 of the main body 2a based on the angle measurement residual (ΔAZ, ΔEL). The angle measurement residual is the difference between the azimuth angle AZ1 and elevation angle EL1 of the other body 2b based on the data of the main body and the azimuth angle AZ2 and elevation angle EL2 of the other body 2b based on the data of the other body. The azimuth angle AZ1 and elevation angle EL1 of the other body 2b based on the coordinates (az, el) of the other body 2b observed from the main body 2a are calculated based on the coordinates (az, el) of the other body 2b observed from the main body 2a. The azimuth angle AZ2 and elevation angle EL2 of the other body 2b based on the data of the other body are calculated based on the positions of the main body 2a and the other body 2b respectively calculated by the inertial navigation device 10 of the main body 2a and the inertial navigation device 10 of the other body 2b.

[0117] Therefore, it is possible to properly correct errors generated by the inertial navigation device 10 mounted on the flight body 2 (such as offset errors generated by the acceleration sensor 10A and / or angular velocity sensor 10B of the inertial navigation device 10).

[0118] Therefore, in the GPS-based method, even when the location (latitude, longitude, altitude) of the aircraft 2a is difficult to determine due to interference and / or the influence of surrounding buildings, or when GPS signals cannot be received, the inertial navigation device 10 can be used to calculate the location (latitude, longitude, altitude) and / or attitude (pitch, roll, yaw) of the aircraft 2a and perform autonomous flight.

[0119] [Regarding processing methods used to improve the accuracy of error correction, etc.]

[0120] It should be noted that in the above embodiment, the case of correcting the errors generated by the inertial navigation device 10 of the main body 2a (such as offset errors generated in the accelerometer 10A and angular velocity sensor 10B of the inertial navigation device 10) by equally processing (i.e., calculating their average value, etc.) all the angle measurement residuals (ΔAZ, ΔEL) is explained. All the angle measurement residuals are the angle measurement residuals calculated for all other bodies 2b (i.e., the flight bodies 2 that can communicate with the main body 2a via the wireless communication device 11).

[0121] However, there may be situations where the inertial navigation device 10 of other bodies 2b malfunctions, or other bodies 2b (or others impersonating them) deliberately send incorrect information for the purpose of obstruction, which may lead to a decrease in the accuracy of error correction.

[0122] Therefore, in order to improve the accuracy of error correction, several processes that can be added to the above process will be explained below.

[0123] [Regarding suspicious signals and usage judgment]

[0124] As described above, each aircraft body 2 (the main aircraft body 2a and other aircraft bodies 2b) transmits information about its own position (latitude, longitude, altitude) calculated by its own onboard inertial navigation device 10. However, for example, the position information transmitted from the other aircraft body 2b is considered unreliable in the following cases.

[0125] (A) For a case where the fluctuation (standard deviation σi) of the angle measurement residuals (ΔAZi, ΔELi) repeatedly calculated for another body 2bi is small, but the magnitude of the angle measurement residuals (ΔAZi, ΔELi) itself is large.

[0126] Specifically, for example, the standard deviation σi of the angle measurement residuals (ΔAZi, ΔELi) repeatedly calculated for the other body 2bi is less than a predetermined threshold and the fluctuation is small, that is, the fluctuation of the angle measurement residuals (ΔAZi, ΔELi) is small, but one or both of the absolute values ​​of ΔAZi and ΔELi are larger than the predetermined threshold.

[0127] That is, the angle measurement residuals (ΔAZi, ΔELi) calculated for the other body 2bi are always the same value, but the state of the angle measurement residuals (ΔAZi, ΔELi) being larger continues.

[0128] It is believed that this is due to a malfunction in the inertial navigation device 10 of the other body 2bi, or that the other body 2bi (or someone else) deliberately sent incorrect information.

[0129] (B) For cases where the fluctuation (standard deviation σi) of the angle measurement residuals (ΔAZi, ΔELi) repeatedly calculated for another body 2bi is large. That is, for cases where the standard deviation of the angle measurement residuals (ΔAZi, ΔELi) calculated for this other body 2bi each time is above a predetermined threshold and fluctuates greatly.

[0130] This is believed to be a malfunction of the inertial navigation device 10 of the other body 2bi.

[0131] Therefore, in this embodiment, under the circumstances described above, that is, when the angular residuals (ΔAZi, ΔELi) calculated from the position (latitude, longitude, altitude) of another body 2bi received from the inertial navigation device 10 of that other body 2bi are deemed unreliable, for example, if they meet the conditions (A) or (B) above, the error correction device 13 of this body 2a sends a signal to the other body 2b, including that other body 2bi, indicating that the position information of that other body 2bi is unreliable.

[0132] Hereinafter, this signal will be referred to as a suspicious signal.

[0133] The suspicious signal includes, for example, the ID of another body 2bi that is judged to be an untrustworthy object sending the information, the ID of the body 2a that sent the suspicious signal, and the type of suspiciousness (e.g., (A) or (B) above).

[0134] Furthermore, if the main body 2a and / or another other body 2b sends a suspicious signal to a certain other body 2bi, the error correction device 13 of the main body 2a can be configured to make a usage determination in a manner that does not use the angle measurement residuals (ΔAZi, ΔELi) calculated for that other body 2bi to correct the error generated by the inertial navigation device 10 of the main body 2a.

[0135] With this configuration, information such as the position of another body 2bi calculated by the inertial navigation device 10 of another body 2bi that has malfunctioned, as well as information about the position of another body 2bi that is intentionally sending incorrect information for the purpose of obstruction, can be used to correct the error generated by the inertial navigation device 10 of this body 2a, thereby improving the accuracy of error correction.

[0136] On the other hand, if other machines 2bi send suspicious signals to many other machines (including the original machine 2a) other than itself, it is possible that the inertial navigation device 10 of the other machine 2bi itself has malfunctioned.

[0137] Alternatively, there is the possibility that the other machine 2bi (or someone else) is deliberately sending out suspicious signals frequently for the purpose of disrupting the system.

[0138] Therefore, if a certain other body 2bi sends a suspicious signal to another other body 2b (including the main body 2a) of a predetermined proportion (e.g., half) or more of all communicable flying bodies 2, the error correction device 13 of the main body 2a can be configured to ignore the suspicious signal sent by the other body 2bi.

[0139] In this case, the error correction device 13 of the main body 2a can be configured to use the angle measurement residuals (ΔAZ, ΔEL) calculated for other bodies 2b other than the other bodies 2bi that frequently emit suspicious signals to correct the error generated by the inertial navigation device 10 of the main body 2a.

[0140] It should be noted that, in this case, for other bodies 2b (i.e., other bodies 2b that are considered to have no malfunction of the inertial navigation device 10 and do not have the purpose of disturbing the system) that send suspicious signals, the error correction device 13 of this body 2a determines that it will not use the angle measurement residuals (ΔAZ, ΔEL) calculated for other bodies 2b to correct the errors generated by the inertial navigation device 10 of this body 2a.

[0141] Alternatively, it is also possible to incorporate other references into the decision on whether to use the angular residuals (ΔAZ, ΔEL) calculated for another body 2b to correct the errors generated by the inertial navigation device 10 of the body 2a.

[0142] [Regarding weighted average]

[0143] Alternatively, it can be configured to weight the angle measurement residuals (ΔAZ, ΔEL) calculated for all other aircraft 2b (i.e., the aircraft 2 that can communicate with the main aircraft 2a via the wireless communication device 11) and use them to correct the errors generated by the inertial navigation device 10 of the main aircraft 2a.

[0144] The following explains several factors that can be considered when performing weighting.

[0145] [Regarding the distance between this unit and other units]

[0146] like Figure 7 As shown, for example, the error Δ in the position (latitude, longitude, altitude) calculated by the inertial navigation devices 10 of two other aircraft 2b (in... Figure 7 (Illustrated schematically with up and down arrows.) Under the same conditions, the greater the distance L between this body 2a and other bodies 2b, the smaller the error δ of the azimuth and / or elevation angle of the other bodies 2b observed from this body 2a, corresponding to the position error Δ.

[0147] That is, compared with the case where the distance L from the main body 2a to the other body 2b is close, when the distance L from the main body 2a to the other body 2b is far, even if there is a slightly larger error Δ in the position calculated by the inertial navigation device 10 of the other body 2b, the accuracy of the angle measurement residual (ΔAZ, ΔEL) calculated for the other body 2b that is far from L is higher than the accuracy of the angle measurement residual (ΔAZ, ΔEL) calculated for the other body 2b that is close to L, because the impact on the azimuth and / or elevation angle of the other body 2b observed from the main body 2a is small.

[0148] Therefore, the error correction device 13 of the main body 2a can be configured to weight the angle measurement residuals (ΔAZj, ΔELj) in such a way that the other bodies 2bj that are farther away from the main body 2a by a distance Lj are given greater weights, thereby correcting the error generated by the inertial navigation device 10 of the main body 2a based on the angle measurement residuals.

[0149] In this case, the weight wj, that is, the weight wj(Lj) related to the distance Lj between this machine and other machines, can be in the following form:

[0150] wj(Lj)=exp(-α / Lj)…(3)

[0151] (α is a constant).

[0152] [Regarding the number of effective angle measurement targets]

[0153] Furthermore, in this embodiment, when the solid angle Ω is below the set threshold and relatively small, the error correction device 13 of the main body 2a determines the accuracy of the position and attitude calculated by the inertial navigation device 10 of the main body 2a at least relative to the other body 2b, and sends an accuracy determination signal containing the ID of the other body 2b. The solid angle Ω is the angle in which the angular residual (ΔAZ, ΔEL) calculated for a certain other body 2b is expressed as a solid angle.

[0154] The accuracy determination signal includes, in addition to the ID of the other machine 2b that is the object of accuracy determination, at least the ID of the machine 2a that sent the accuracy determination signal. It should be noted that the threshold set for the solid angle Ω can also be made variable; for example, it can be configured such that the threshold is set to a larger value when the machine 2a first identifies the other machine 2b, and gradually decreases each time a repetition error is corrected.

[0155] In this configuration, the more precision determination signals Nj containing the ID of another body 2bj (hereinafter referred to as the number of effective angle measurement targets Nj) there are (i.e., the more flight bodies 2 Nj that list another body 2bj as precision determined objects), the more precision the other body 2bj has in determining the position and attitude of more flight bodies 2.

[0156] Furthermore, if the weighting is increased when the angle measurement residuals (ΔAZj, ΔELj) calculated for the other body 2bj are used to correct the error generated by the inertial navigation device 10 of the body 2a, the accuracy of error correction can be improved.

[0157] Therefore, the error correction device 13 of the main body 2a can be configured to perform weighting in such a way that the more precision determination signals Nj (i.e., the number of effective angle measurement targets Nj) that include the ID of another main body 2bj, the greater the weight wj of the angle measurement residuals (ΔAZj, ΔELj) calculated for that other main body 2bj, so as to correct the error generated by the inertial navigation device 10 of the main body 2a based on the angle measurement residuals.

[0158] In this case, the weight wj, that is, the weight wj(Nj) related to the number of effective angle measurement targets Nj, can be in the following form:

[0159] wj(Nj)=exp(-β / Nj)…(4)

[0160] (β is a constant).

[0161] [On the stability of fluctuations in angle measurement residuals]

[0162] Furthermore, as explained in the section on suspicious signals above, although the fluctuation (standard deviation σi) of the angle measurement residuals (ΔAZi, ΔELi) calculated for a certain other body 2bi is small, if the magnitude of the angle measurement residuals (ΔAZi, ΔELi) itself is large (refer to (A) above), there is a possibility that the inertial navigation device 10 of the other body 2bi is malfunctioning or that the other body 2bi (or someone else) is deliberately sending incorrect information.

[0163] However, as described above, for other bodies 2bj whose solid angle Ωj is below the threshold and fluctuates little, and which are the objects of the transmitted precision determination signal, there is no possibility that the inertial navigation device 10 of the other body 2bj is malfunctioning or that the other body 2bj (or others) intentionally sends incorrect information, or the possibility is very small. The solid angle Ωj is the angle represented by the solid angle of the angle measurement residual (ΔAZj, ΔELj) calculated for a certain other body 2bj.

[0164] In this case, if the configuration is such that the reliability of the angle measurement residual when the fluctuation of the angle measurement residual (ΔAZj, ΔELj) calculated for the other body 2bj is small (i.e., the change of the angle measurement residual is stable) is higher than the reliability of the angle measurement residual when the fluctuation of the angle measurement residual (ΔAZj, ΔELj) calculated for the other body 2bj is large, the weighting of such angle measurement residual when it is used to correct the error generated by the inertial navigation device 10 of the body 2a can be increased, thereby improving the accuracy of error correction.

[0165] Therefore, the error correction device 13 of the main body 2a can be configured to weight the angle measurement residuals (ΔAZj, ΔELj) calculated for other bodies 2bj that are the objects of the transmitted accuracy determination signal, in order to correct the error generated by the inertial navigation device 10 of the main body 2a based on the angle measurement residuals. The smaller the fluctuation (standard deviation σj) of the angle measurement residuals (ΔAZi, ΔELi) calculated for the other bodies 2bj, the larger the weight wj.

[0166] In this case, the weight wj, that is, the weight wj(σj) related to the standard deviation σj of the angular residual, has the following form for example:

[0167] wj(σj)=exp(-γ·σj)…(5)

[0168] (γ is a constant).

[0169] Furthermore, in this embodiment, considering the above equations (3) to (5), the error correction device 13 of the main body 2a calculates the weight wj of the angle measurement residual (ΔAZj, ΔELj) calculated for a certain other main body 2bj according to the following equation (6).

[0170]

Mathematical Formula 1

[0171]

[0172] In this embodiment, by weighting the angle measurement residuals (ΔAZj, ΔELj) calculated for other aircraft bodies 2b in such a way as to reduce the weight wj of the low reliability angle measurement residuals (ΔAZj, ΔELj) and to give a larger weight wj to the angle measurement residuals (ΔAZj, ΔELj) with higher reliability, the error generated by the inertial navigation device 10 of the main aircraft body 2a is corrected based on the angle measurement residuals. This increases the accuracy determination of other aircraft bodies 2b, and the error generated by the inertial navigation device 10 can be reduced as a whole among the multiple aircraft bodies 2 (including the main aircraft body 2a) that are equipped with the inertial navigation device 10 and fly autonomously.

[0173] It should be noted that the present invention is not limited to the above-described embodiments, etc., and appropriate modifications can be made as long as they do not depart from the spirit of the present invention.

Claims

1. An error correction system for an inertial navigation device, characterized by, It is an error correction system for the inertial navigation systems of multiple flying bodies that perform autonomous flight based on the position and attitude calculated by the onboard inertial navigation system. Each of the aforementioned aircraft is equipped with an inertial navigation device, a wireless communication device, a coordinate calculation device for calculating the coordinates of other aircraft as observed from this aircraft, and an error correction device. The error correction device calculates the azimuth and elevation angles of the other aircraft based on the coordinates of the other aircraft observed from the main body, calculated by the coordinate calculation device. The error correction device calculates the azimuth and elevation angles of the other aircraft based on the position information of the other aircraft calculated by its inertial navigation device and the position information of the current aircraft calculated by its own inertial navigation device, which are received by the wireless communication device from the other aircraft. The error correction device corrects the error generated by the inertial navigation device of the main body based on the angle measurement residual, wherein the angle measurement residual is the difference between the azimuth and elevation angles of the other body based on the data of the main body and the azimuth and elevation angles of the other body based on the data of the other body.

2. The error correction system for an inertial navigation device according to claim 1, characterized in that, The error correction device calculates the azimuth and elevation angles of other aircraft based on the coordinates of other aircraft observed from the main body by the coordinate calculation device and the attitude information of the main body calculated by the inertial navigation device of the main body.

3. The error correction system for the inertial navigation device according to claim 1, characterized in that, The error correction device calculates the azimuth and elevation angles of the vector from the position of the main body calculated by the inertial navigation device of the main body to the position of the other body calculated by the inertial navigation device of the other body, and uses these as the azimuth and elevation angles of the other body based on the data of the other body.

4. The error correction system for an inertial navigation device according to claim 2, characterized in that, The error correction device calculates the azimuth and elevation angles of the vector from the position of the main body calculated by the inertial navigation device of the main body to the position of the other body calculated by the inertial navigation device of the other body, and uses these as the azimuth and elevation angles of the other body based on the data of the other body.

5. The error correction system for an inertial navigation device according to any one of claims 1 to 4, characterized in that, If the error correction device determines that the position information of another machine body calculated by the inertial navigation device of that other machine body received from that other machine body is unreliable, it sends a signal to other machines body including that other machine body indicating that the position information of that other machine body is unreliable.

6. The error correction system for an inertial navigation device according to any one of claims 1 to 4, characterized in that, The error correction device weights the angle measurement residual in such a way that the farther away other bodies are from the main body, the greater the weight, and corrects the error generated by the inertial navigation device of the main body based on the angle measurement residual.

7. The error correction system for an inertial navigation device according to claim 5, characterized in that, The error correction device weights the angle measurement residual in such a way that the farther away other bodies are from the main body, the greater the weight, and corrects the error generated by the inertial navigation device of the main body based on the angle measurement residual.

8. The error correction system for an inertial navigation device according to any one of claims 1 to 4, characterized in that, When the solid angle of the calculated angular residual for another machine is below a threshold, the error correction device sends an accuracy determination signal containing the identification information of that other machine.

9. The error correction system for an inertial navigation device according to claim 5, characterized in that, When the solid angle of the calculated angular residual for another machine is below a threshold, the error correction device sends an accuracy determination signal containing the identification information of that other machine.

10. The error correction system for an inertial navigation device according to claim 6, characterized in that, When the solid angle of the calculated angular residual for another machine is below a threshold, the error correction device sends an accuracy determination signal containing the identification information of that other machine.

11. The error correction system for an inertial navigation device according to claim 7, characterized in that, When the solid angle of the calculated angular residual for another machine is below a threshold, the error correction device sends an accuracy determination signal containing the identification information of that other machine.

12. An error correction method for an inertial navigation device, characterized by, It is an error correction method for the inertial navigation devices in multiple flying bodies that perform autonomous flight based on the position and attitude calculated by the onboard inertial navigation devices. The error correction method for the inertial navigation device includes: In the coordinate calculation step, the flying body calculates the coordinates of other flying bodies as observed from its own body; The calculation steps for the azimuth and elevation angles of other aircraft based on the data of this aircraft are as follows: the azimuth and elevation angles of other aircraft observed from this aircraft are calculated based on the coordinates of other aircraft observed from this aircraft in the coordinate calculation steps. The calculation steps for the azimuth and elevation angles of other aircraft based on data from other aircraft involve calculating the azimuth and elevation angles of the other aircraft based on the position information of the other aircraft calculated by its inertial navigation device and received from the other aircraft via a wireless communication device, and the position information of the current aircraft calculated by its own inertial navigation device. The error correction step corrects the error generated by the inertial navigation device of the main body based on the angle measurement residual, which is the difference between the azimuth and elevation angles of the other body based on the data of the main body and the azimuth and elevation angles of the other body based on the data of the other body.

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