Inertial navigation system air alignment method based on differential GPS positioning

Abstract

The invention discloses an inertial navigation system air alignment method based on differential GPS positioning, and the method comprises the following steps: before flight preparation of an aircraft, the inertial navigation system carries out self-inspection and does not carry out ground alignment operation, and the aircraft is normally guided to enter an air flight state through differential GPS positioning; in the air alignment process, preset flight route information of an aircraft is read firstly, on the basis of the preset flight route information of the aircraft, after it is judged that the inertial navigation system meets alignment conditions, the position of the aircraft is corrected in real time through differential GPS positioning, meanwhile, the attitude of the aircraft is corrected and accumulated through a gyroscope part of the inertial navigation system, and the attitude of the aircraft is corrected. When errors of positions, postures and the like are within an error range required by alignment conditions, the inertial navigation system jumps into a combined navigation state and serves as a main navigation mode to guarantee that the aircraft executes tasks. The method saves the ground preparation time before the aircraft flies, provides a new thought for processing the air abnormal faults of the inertial navigation system, improves the stability of the airborne inertial navigation system, and is high in popularization and use value.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft inertial navigation, and in particular relates to an air alignment method of an inertial navigation system based on differential GPS positioning. Background Art

[0002] As a self-service navigation system that does not rely on any external input information, the inertial navigation system can provide accurate attitude, position, speed and acceleration information for aircraft platforms and important airborne systems. It also has extremely high anti-interference and concealment. However, the premise for the stable operation of the inertial navigation system is to complete the alignment operation of the initial position. The conventional strapdown inertial navigation system consists of gyroscopes in three directions, accelerometers in three directions and a CPU processor. The inertial navigation system itself establishes a carrier coordinate system, determines the orientation relationship with the local reference coordinate system through the gyroscope, and converts the position, speed and acceleration measured and calculated by the accelerometer itself into the position, speed and acceleration of the aircraft carrier, which is updated in real time as the aircraft changes in its position in the air. With the rapid development of differential GPS global positioning functions, satellite navigation modules are added to the inertial navigation system, which makes the navigation information update rate of the aircraft carrier high, and the short-term positioning accuracy and stability better, providing a new way for the combined positioning of guided weapons, mission payloads, reconnaissance equipment and airborne platforms carried by aircraft. At present, the navigation information output by the inertial navigation system is obtained through integral calculation. The positioning error gradually increases with the power-on time. Long-term accumulation will lead to poor accuracy and cause the aircraft carrier to deviate from the original route waypoints. The existing inertial navigation system requires initial position alignment before each mission, but the alignment process is complicated and takes a long time, and the maintenance preparation process before the mission is executed is demanding. The conventional idea of ​​​​alignment inspection of the inertial navigation system is to place it in the ground inspection work before flight preparation. Once the aircraft enters the air flight state and the inertial navigation system navigation anomalies occur, the mission can only be terminated and the backup navigation method is used to return to the ground. What's more, if the backup navigation method is insufficient, or if navigation anomalies occur at the same time, it will pose an immeasurable risk to the flight safety of the aircraft. Summary of the invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide an inertial navigation system air alignment method based on differential GPS positioning. This method can save the ground preparation time of the aircraft, and can also realize the inertial navigation air alignment operation of weapons, mission payloads or reconnaissance equipment in the air, and provide a way to realize combined navigation again after powering on and off to deal with abnormal conditions in the air of the aircraft's inertial navigation system equipment.

[0004] The purpose of the present invention is achieved through the following technical solutions: An in-flight alignment method for an inertial navigation system based on differential GPS positioning comprises the following steps: before the flight preparation of an aircraft, the inertial navigation system performs self-checking and does not perform ground alignment operation of the inertial navigation system, and guides the aircraft into an air flight state normally through differential GPS positioning; during the in-flight alignment process, firstly reads the preset route information of the aircraft, and based on the preset route information of the aircraft, after determining that the inertial navigation system meets the alignment condition, the differential GPS positioning performs real-time correction on the position of the aircraft, and at the same time, the gyro part of the inertial navigation system performs correction accumulation on the attitude of the aircraft, so that the errors of the position and attitude are within the error range required by the alignment condition, thereby ensuring that the inertial navigation system completes the in-flight alignment, and the inertial navigation system jumps into the combined navigation mode.

[0005] Furthermore, before the aerial alignment, a section of the route with a stable flight status is selected to perform the aerial alignment operation of the inertial navigation.

[0006] Furthermore, during the flight, before reading the aircraft's preset route information, differential GPS positioning is used to calibrate the aircraft's full time. The inertial navigation system's air alignment process requires the onboard time to be unified to ensure that differential GPS positioning is used to correct the aircraft's position error in real time.

[0007] Furthermore, the aerial alignment method is implemented using an inertial navigation system aerial alignment structure, wherein the inertial navigation system aerial alignment structure comprises an airborne inertial navigation component (1), an airborne mission route management component (2), and a differential GPS positioning system; the differential GPS positioning system comprises a transmitting station and antenna (3) of a ground reference station, a differential processing receiver (4) of the ground reference station, a differential receiving antenna (5) of the ground reference station, a satellite (6), and an airborne differential mobile station; the steps of performing aerial alignment of the inertial navigation system are as follows: The differential receiving antenna (5) of the ground reference station receives the satellite (6) signal, transmits the signal to the differential processing receiver (4) of the ground reference station, and after processing, forms message information, which communicates with the airborne differential mobile station on the aircraft through the transmitting station and antenna (3) of the ground reference station. In the case that the airborne inertial navigation unit (1) is not aligned, the differential GPS positioning system navigates the aircraft to an airborne flight state; After the onboard inertial navigation unit (1) detects that it is normal, it receives the route information transmitted by the onboard mission route management unit (2) as a reference for the onboard position of the aircraft, and after determining that the inertial navigation system meets the conditions for airborne alignment, it prompts the pilot to perform airborne alignment; After the pilot executes the inertial navigation system's airborne alignment command, the alignment timing begins. At the same time, the airborne differential mobile station uses the message information sent from the ground reference station to perform real-time error correction for the aircraft position. The inertial navigation component also uses the normal operation of the gyroscope to perform real-time error correction for the aircraft attitude. After the alignment timing ends, if the errors in the attitude, position, velocity and acceleration of the inertial navigation component are within the error range required by the alignment conditions, it can ensure that the inertial navigation system completes the airborne alignment and the alignment is successful. After the alignment is successful, the airborne inertial navigation system enters the combined navigation state and completes the airborne alignment operation.

[0008] Furthermore, before the onboard inertial navigation component receives the route information transmitted by the onboard mission route management component, the differential GPS positioning system calibrates the entire aircraft time during the flight.

[0009] Furthermore, when the inertial navigation system performs airborne alignment, if the alignment fails, the inertial navigation system prompts that it cannot enter the combined navigation state, and the onboard inertial navigation component needs to be powered on and off again, forcing the inertial navigation component to perform self-detection and then re-determine whether the alignment conditions for airborne alignment are met. Only after the alignment conditions are met can the airborne alignment operation be performed again.

[0010] Furthermore, alignment conditions must be met before the aerial alignment operation, and the alignment conditions include condition one: the inertial navigation component passes the power-on self-detection; condition two: the mission route management component transmits the route information of the inertial navigation component as the reference information for position alignment; condition three: the differential GPS positioning function is normal, and the position information of the inertial navigation component is corrected in real time.

[0011] The present invention utilizes the global, all-weather, all-time domain precise positioning function of differential GPS positioning and the route information preset by aircraft mission management, selects a stable route during the flight of the aircraft to perform the in-flight alignment operation of the inertial navigation system, and after the in-flight alignment is completed, the inertial navigation system can enter the combined navigation mode.

[0012] The aerial alignment method of the present invention can save the alignment check operation of the inertial navigation system during the ground power-on check before flight, save the work of pre-flight preparation and the equipment requirements for flight preparation, save the ground preparation time of the aircraft, and can also realize the inertial navigation aerial alignment operation of weapons, mission payloads or reconnaissance equipment in the air, providing a way to realize combined navigation again after powering on and off to deal with abnormal conditions in the air of the aircraft's inertial navigation system equipment. The present invention is novel in concept, highly practical, and has high value in the practice of aircraft aerial navigation. It has high promotion value and is good instructive for solving the long ground preparation time before aircraft flight and the abnormal conditions in the air of the aircraft's inertial navigation system.

[0013] The promotion and use of the inertial navigation system air alignment method proposed in the present invention provides a new idea for the aircraft to smoothly perform combat missions and flexibly deal with abnormal conditions of the inertial navigation system in the air, and provides a broader prospect for the development and application of the inertial navigation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described in detail below with reference to the accompanying drawings.

[0015] Figure 1 The figure is a flow chart of the inertial navigation system in-air alignment of the present invention.

[0016] Figure 2 The figure is a schematic diagram of the aerial alignment structure of the inertial navigation system based on differential GPS positioning shown in the present invention.

[0017] As shown in the figure: 1- airborne inertial navigation unit, 2- airborne mission route management unit, 3- transmitting station and antenna of ground reference station, 4- differential processing receiver of ground reference station, 5- differential receiving antenna of ground reference station, 6- satellite. DETAILED DESCRIPTION

[0018] The following is an explanation of the implementation of the present invention by specific specific embodiments. People familiar with the technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that the structures, proportions, sizes, etc. drawn in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Example

[0021] like Figure 1 As shown, this embodiment provides an inertial navigation system air alignment method based on differential GPS positioning, comprising the following steps: S1. Constructing an inertial navigation system air alignment structure: the inertial navigation system air alignment structure includes an airborne inertial navigation component 1, an airborne mission route management component 2 and a differential GPS positioning system; the differential GPS positioning system includes a transmitting station and antenna 3 of a ground reference station, a differential processing receiver 4 of a ground reference station, a differential receiving antenna 5 of a ground reference station, a satellite 6 and an airborne differential mobile station. Among them, the airborne inertial navigation component 1, the airborne mission route management component 2 and the airborne differential mobile station are all installed in an aircraft, the airborne inertial navigation component 1 adopts a conventional strapdown inertial navigation system, the airborne mission route management component 2 is also a conventional aircraft structure, and the airborne mission route management component 2 includes a flight management computer system and its control display component, an inertial reference subsystem, a flight automatic control system and an automatic throttle subsystem. The transmitting station and antenna 3 of the ground reference station, the differential processing receiver 4 of the ground reference station, and the differential receiving antenna 5 of the ground reference station are the basic components of the ground reference station, and conventional equipment is also used; the airborne differential mobile station uses conventional equipment, and the airborne differential mobile station includes airborne differential equipment, aviation antenna, airborne data transmission receiving station, airborne station receiving antenna and connecting cables between the equipment.

[0022] S2. Self-check of the airborne inertial navigation unit: Before the flight, the pilot powers on the airborne inertial navigation unit 1, and the airborne inertial navigation unit 1 performs a self-check until it is normal.

[0023] S3. Aircraft takes off: The differential receiving antenna 5 of the self-checking ground reference station of the airborne inertial navigation unit 1 receives the satellite 6 signal, transmits the signal to the differential processing receiver 4 of the ground reference station and after processing, forms a message information which communicates with the airborne differential mobile station on the aircraft through the transmitting station and antenna 3 of the ground reference station. In the case that the airborne inertial navigation unit 1 is not aligned, the differential GPS positioning system is used to navigate the aircraft to an airborne flight state.

[0024] S4. Time calibration: During the flight, the differential GPS positioning system calibrates the aircraft's entire time.

[0025] S5. Reading waypoint position data: After the airborne inertial navigation unit 1 self-checks normally, the airborne inertial navigation unit 1 reads the route information (waypoint position data or route position information) from the airborne mission route management unit 2. The airborne inertial navigation unit 1 receives the route information transmitted by the airborne mission route management unit 2 as the reference of the aircraft's airborne position.

[0026] S6. Determine whether the alignment condition is met: the airborne inertial navigation component 1 determines whether the attitude measurement part of the inertial navigation system meets the inertial navigation system air alignment condition after working normally; if the alignment condition is not met, return to step S5.

[0027] S7. Issue an alignment command: After the onboard inertial navigation unit 1 determines that the attitude measurement part of the inertial navigation system is working normally and meets the inertial navigation system air alignment conditions, it issues an alignment command to prompt the pilot to perform air alignment. Before air alignment, a section of the route with a stable flight state is selected to perform the inertial navigation air alignment operation.

[0028] S8. Differential GPS positioning correction: After the pilot executes the inertial navigation system's airborne alignment command, the alignment timing begins. At the same time, the airborne differential mobile station (airborne differential equipment) performs real-time error correction for the aircraft position through the message information sent from the ground reference station. The inertial navigation component also performs real-time error correction for the aircraft attitude through the normal operation of the gyroscope. After the alignment timing ends, if the errors in the attitude, position, velocity and acceleration of the inertial navigation component are within the error range required by the alignment conditions, it can ensure that the inertial navigation system completes the airborne alignment, that is, the alignment is successful.

[0029] S9. After the alignment is successful, the airborne inertial navigation system enters the integrated navigation state and completes the airborne alignment operation. If the alignment fails, the inertial navigation system prompts that it cannot enter the integrated navigation state, and the airborne inertial navigation component needs to be powered on and off again, and the inertial navigation component is forced to perform self-detection, and then re-determine whether the alignment conditions for re-alignment in the air are met. Only after the alignment conditions are met, the airborne alignment operation is performed again.

[0030] The alignment conditions that need to be met before the aerial alignment operation include condition one: the inertial navigation component passes the power-on self-detection; condition two: the mission route management component transmits the route information of the inertial navigation component as the reference information for position alignment; condition three: the differential GPS positioning function is normal, and the position information of the inertial navigation component is corrected in real time.

[0031] Other aspects of the present invention that are not described in detail are all conventional techniques known to those skilled in the art.

[0032] It should be noted that the terms "comprises", "includes" or any other variations are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0033] The protection scope of the present invention is not limited to the technical solutions disclosed in the specific implementation methods. Any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for air alignment of an inertial navigation system based on differential GPS positioning, characterized in that: The following steps are involved: Before the aircraft is ready for flight, the inertial navigation system performs a self-check and does not perform ground alignment operations on the inertial navigation system. The aircraft is guided normally into the air flight state through differential GPS positioning. During the aerial alignment process, the aircraft's preset route information is first read. Based on the aircraft's preset route information, after determining that the inertial navigation system meets the alignment conditions, differential GPS positioning is used to correct the aircraft's position in real time. At the same time, the gyroscopic part of the inertial navigation system accumulates corrections to the aircraft's attitude, so that the errors in position and attitude are within the error range required by the alignment conditions. This ensures that the inertial navigation system completes the aerial alignment and enters the combined navigation mode.

2. The method for air alignment of an inertial navigation system based on differential GPS positioning according to claim 1, characterized in that: Before air alignment, select a route with stable flight status to perform air alignment operation using inertial navigation.

3. The method for air alignment of an inertial navigation system based on differential GPS positioning according to claim 1, characterized in that: The aerial alignment method is implemented by using an inertial navigation system aerial alignment structure, wherein the inertial navigation system aerial alignment structure comprises an airborne inertial navigation component (1), an airborne mission route management component (2) and a differential GPS positioning system; the differential GPS positioning system comprises a transmitting station and antenna (3) of a ground reference station, a differential processing receiver (4) of the ground reference station, a differential receiving antenna (5) of the ground reference station, a satellite (6) and an airborne differential mobile station; the steps of performing aerial alignment of the inertial navigation system are as follows: The differential receiving antenna (5) of the ground reference station receives the satellite (6) signal, transmits the signal to the differential processing receiver (4) of the ground reference station, and after processing, forms message information, which communicates with the airborne differential mobile station on the aircraft through the transmitting station and antenna (3) of the ground reference station. In the case that the airborne inertial navigation unit (1) is not aligned, the differential GPS positioning system navigates the aircraft to an airborne flight state; After the onboard inertial navigation unit (1) detects that it is normal, it receives the route information transmitted by the onboard mission route management unit (2) as a reference for the onboard position of the aircraft, and after determining that the inertial navigation system meets the conditions for airborne alignment, it prompts the pilot to perform airborne alignment; After the pilot executes the inertial navigation system's air alignment command, the alignment timing begins. At the same time, the airborne differential mobile station uses the message information sent from the ground reference station to perform real-time error correction for the aircraft position. The inertial navigation component also uses the normal operation of the gyroscope to perform real-time error correction for the aircraft attitude. After the alignment timing ends, if the errors in the attitude, position, velocity and acceleration of the inertial navigation component are within the error range required by the alignment conditions, the alignment is successful. After the alignment is successful, the airborne inertial navigation system enters the combined navigation state and completes the air alignment operation.

4. The method for air alignment of an inertial navigation system based on differential GPS positioning according to claim 3, characterized in that: During the flight, the differential GPS positioning system calibrates the entire aircraft time before reading the aircraft's preset route information.

5. The method for air alignment of an inertial navigation system based on differential GPS positioning according to claim 3, characterized in that: Before the onboard inertial navigation component (1) receives the route information transmitted by the onboard mission route management component (2), during the flight, the differential GPS positioning system calibrates the entire aircraft time.

6. The method for air alignment of an inertial navigation system based on differential GPS positioning according to claim 3, characterized in that: When the inertial navigation system performs airborne alignment, if the alignment fails, the inertial navigation system prompts that it cannot enter the integrated navigation state, and the onboard inertial navigation component (1) needs to be powered on and off again, forcing the inertial navigation component (1) to perform self-detection and re-determine whether the alignment conditions for re-airborne alignment are met. Only after the alignment conditions are met can the airborne alignment operation be performed again.

7. The method for air alignment of an inertial navigation system based on differential GPS positioning according to claim 3, characterized in that: Alignment conditions must be met before the aerial alignment operation, and the alignment conditions include condition one, the inertial navigation component passes the power-on self-detection; condition two, the mission route management component transmits the route information of the inertial navigation component as the reference information for position alignment; condition three, the differential GPS positioning function is normal, and the position information of the inertial navigation component is corrected in real time.

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