Fixed-point indication calibration inertial navigation method and fixed-point indication device

Abstract

The invention relates to the technical field of flight navigation, and discloses a fixed-point indication calibration inertial navigation method and a fixed-point indication device.In the calibration inertial navigation method, airborne equipment receives a fixed-point indication signal when an aircraft flies, then position coordinates of the airborne equipment are calculated according to pre-stored working parameters and position information of the fixed-point indication device, and the position coordinates of the airborne equipment are calculated according to the working parameters and the position information of the fixed-point indication device; the fixed-point indication signal is an electromagnetic wave signal emitted to the air by a fixed-point indication device placed at a preset fixed-point position on the ground, and the fixed-point indication device comprises a parameter setting module, a signal generation module, a signal processing module, a power amplification module and an antenna. The inertial navigation data can be corrected only when the aircraft flies over the fixed-point indicating device, and the fixed-point indicating signal can be automatically utilized to complete correction, so that manual correction with larger errors can be replaced, and the aircraft can replace satellite navigation to carry out inertial navigation calibration when the satellite navigation is unavailable, so that the aircraft can fly according to a plan, and the flight safety is ensured.

Description

Technical Field

[0001] The invention relates to the field of flight navigation technology, and in particular to a fixed-point indicating calibration inertial navigation method and a fixed-point indicating device. Background Art

[0002] Inertial navigation is an autonomous navigation system that does not rely on external information or radiate energy to the outside world. It measures the acceleration of the aircraft and automatically performs integration operations to obtain the aircraft's instantaneous speed and position data. The navigation and positioning errors of inertial navigation mainly come from the system errors caused by the internal gyroscope and accelerometer and the initial calibration errors, and these errors will continue to increase with the accumulation of time. At present, the main navigation method used is the "satellite navigation + inertial navigation" combination, that is, the satellite navigation positioning information is used to continuously correct the inertial navigation error. However, if the satellite navigation is deceived, the inertial navigation error will increase instantaneously.

[0003] In recent years, satellite navigation has been frequently deceived or denied. To address this problem, pilots can currently calibrate the inertial navigation by flying over fixed visual landmarks, that is, resetting the inertial navigation coordinates when flying over the landmarks. However, this method has errors caused by human reaction (human judgment of whether to fly over known coordinates).

[0004] Based on this problem, the present invention proposes a solution for calibrating an inertial navigation system by fixed-point indication. Summary of the invention

[0005] In view of the technical problems in the prior art, the present invention provides a fixed-point indicating and calibrating inertial navigation method and a fixed-point indicating device.

[0006] In a first aspect, the present invention includes a method for calibrating an inertial navigation system by fixed-point indication, the method comprising:

[0007] The airborne device receives a fixed-point indication signal when the aircraft is flying; the fixed-point indication signal is an electromagnetic wave signal emitted into the air by a fixed-point indication device placed at a preset point position on the ground;

[0008] Calculating the position coordinates of the onboard device according to the fixed-point indication signal and the pre-stored working parameters and position information of the fixed-point indication device;

[0009] The inertial navigation data is corrected according to the position coordinates.

[0010] Furthermore, the airborne device receives the fixed-point indication signal when the aircraft is flying, including:

[0011] Controlling the aircraft to enter the radiation range of the fixed-point indicating device according to the pre-stored position information and inertial navigation data of the fixed-point indicating device;

[0012] The fixed-point indication signal is received in real time, and the change of the power of the fixed-point indication signal is analyzed.

[0013] Furthermore, the position coordinates of the onboard device are calculated according to the fixed-point indication signal and the pre-stored working parameters and position information of the fixed-point indication device, including:

[0014] When the power of the fixed-point indication signal is at a maximum, the position coordinates of the onboard device are calculated according to the pre-stored working parameters and position information of the fixed-point indication device.

[0015] Furthermore, the fixed-point location where the fixed-point indicating device is placed includes a navigation station and an indicating point selected on the route.

[0016] Furthermore, the emission direction of the fixed-point indication signal is vertically upward from the position directly above the fixed-point indication device into the sky, and the emission range of the fixed-point indication signal is concentrated emission.

[0017] Furthermore, the fixed-point indication signals emitted by different fixed-point indication devices have different Morse codes and signal emission frequencies.

[0018] In a second aspect, the present invention includes an airborne device, the airborne device includes a signal receiving module, a position coordinate calculation module and an inertial navigation data correction module, wherein:

[0019] The signal receiving module is connected to the position coordinate calculation module; the signal receiving module is used to receive a fixed-point indication signal when the aircraft is flying; the fixed-point indication signal is an electromagnetic wave signal emitted into the air by a fixed-point indication device placed at a preset point position on the ground;

[0020] The position coordinate calculation module is connected to the signal receiving module and the inertial navigation data correction module; the position coordinate calculation module is used to calculate the position coordinates of the onboard device according to the fixed-point indication signal and the pre-stored working parameters and position information of the fixed-point indication device;

[0021] The inertial navigation data correction module is connected to the position coordinate calculation module; the inertial navigation data correction module is used to correct the inertial navigation data according to the position coordinates.

[0022] In a third aspect, the present invention includes a fixed-point indicating device, which is used to transmit a fixed-point indicating signal to the air at a preset point position on the ground, so that the airborne equipment can implement the fixed-point indicating calibration inertial navigation method as described in any one of claims 1 to 6; the fixed-point indicating device includes a parameter setting module, a signal generating module, a signal processing module, a power amplification module and an antenna;

[0023] The parameter setting module is electrically connected to the signal generating module; the parameter setting module is used to set the signal content and working parameters of the fixed-point indication signal to be emitted by the fixed-point indication device;

[0024] The signal generating module is electrically connected to the signal processing module; the signal generating module is used to generate a corresponding electrical signal according to the signal content of the fixed-point indication signal;

[0025] The signal processing module is electrically connected to the parameter setting module and the power amplification module; the signal processing module is used to modulate the electrical signal according to the working parameters of the fixed-point indication signal;

[0026] The power amplification module is electrically connected to the parameter setting module and the antenna; the power amplification module is used to amplify the power of the modulated electrical signal according to the working parameters of the fixed-point indication signal;

[0027] The antenna is used to transmit the fixed-point indication signal into the air in the form of an electromagnetic wave signal.

[0028] Furthermore, the signal generating module includes a Morse code generating circuit, an audio generating circuit and an analog switch; the parameter setting module is electrically connected to the Morse code generating circuit, the Morse code generating circuit and the audio generating circuit are both electrically connected to the analog switch, and the analog switch is electrically connected to the signal processing module.

[0029] Furthermore, the signal processing module includes an amplitude modulation circuit, a carrier oscillation amplifier and an adding circuit; the analog switch is electrically connected to the amplitude modulation circuit, and the amplitude modulation circuit is electrically connected to the adding circuit; the parameter setting module is electrically connected to the carrier oscillation amplifier, and the carrier oscillation amplifier is electrically connected to the amplitude modulation circuit and the adding circuit; the adding circuit is electrically connected to the power amplification module.

[0030] The fixed-point indication calibration inertial navigation method of the present invention is that the airborne equipment receives the fixed-point indication signal when the aircraft is flying, and then calculates the position coordinates of the onboard equipment according to the fixed-point indication signal and the working parameters and position information of the pre-stored fixed-point indication device, and then automatically corrects the inertial navigation data according to the position coordinates, wherein the fixed-point indication signal is an electromagnetic wave signal emitted into the air by the fixed-point indication device placed at a preset fixed-point position on the ground, and the fixed-point indication device includes a parameter setting module, a signal generation module, a signal processing module, a power amplification module and an antenna. The present invention corrects the inertial navigation data only when flying over the fixed-point indication device, and can automatically use the fixed-point indication signal to complete the correction, thereby replacing the manual correction with a larger error, and can also replace the satellite navigation to perform the inertial navigation calibration when the satellite navigation is not available, so that the aircraft can fly as planned and ensure flight safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A flowchart of the steps of a method for calibrating an inertial navigation system with fixed-point indication according to an embodiment of the present invention;

[0033] Figure 2 Schematic diagram of signal radiation of a fixed-point indicating device in an embodiment of the present invention (I);

[0034] Figure 3 Schematic diagram of signal radiation of the fixed-point indicating device in an embodiment of the present invention (II);

[0035] Figure 4 Schematic diagram of signal radiation of the fixed-point indicating device in an embodiment of the present invention (III);

[0036] Figure 5 A diagram showing the module composition of an airborne device according to an embodiment of the present invention;

[0037] Figure 6 A module composition diagram of a fixed-point indicating device according to an embodiment of the present invention;

[0038] Figure 7 A module composition diagram of another fixed-point indicating device according to an embodiment of the present invention;

[0039] Among them: 100-fixed-point indicating device, 101-parameter setting module, 102-signal generating module, 1021-Morse code generating circuit, 1022-audio generating circuit, 1023-analog switch, 103-signal processing module, 1031-amplitude modulation circuit, 1032-carrier oscillation amplifier, 1033-addition circuit, 104-power amplification module, 105-antenna, 200-airborne equipment, 201-signal receiving module, 202-position coordinate calculation module, 203-inertial navigation data correction module. DETAILED DESCRIPTION

[0040] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, 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 belong to the protection scope of the present invention.

[0041] Based on the fact that there are many errors in the inertial navigation of aircraft in the prior art, the embodiment of the present invention proposes a method for calibrating the inertial navigation with a fixed point indication, such as Figure 1 As shown, the method comprises the following steps:

[0042] Step S10: The airborne device receives a fixed-point indication signal when the aircraft is flying.

[0043] The fixed-point indication signal in the embodiment of the present invention is an electromagnetic wave signal emitted into the air by a fixed-point indication device 100 placed at a preset point position on the ground. When the aircraft flies into the radiation range where the fixed-point indication signal is emitted by the fixed-point indication device 100, the airborne device 200 can receive the fixed-point indication signal emitted by the fixed-point indication device 100.

[0044] When the embodiment of the present invention is implemented, the frequency of the electromagnetic wave signal received by the airborne device 200 can be preset, and there is no specific limitation. Preferably, the frequency of the electromagnetic wave signal received by the airborne device 200 during the flight of the aircraft is set to X1, and when a fixed-point indication signal is received, the frequency of receiving the fixed-point indication signal is adjusted to X2, and the value of X1 is less than the value of X2. In this way, the frequency of receiving the fixed-point indication signal is increased only after the aircraft flies into the signal radiation range of the fixed-point indication device 100, and before that, the signal receiving frequency is reduced as much as possible to reduce power consumption.

[0045] Specifically, the placement position of the fixed-point indicating device 100 is not specifically limited in this step, but the placement position information thereof is known to the airborne device 200. Preferably, in this embodiment, the fixed-point location where the fixed-point indicating device 100 is placed includes an existing navigation station and a known indicating point selected on the route. When the aircraft flies over the fixed-point indicating device 100, the airborne device 200 can receive the fixed-point indicating signal.

[0046] Specifically, in this embodiment, the transmission direction of the fixed-point indication signal is set to be transmitted vertically upward from the position directly above the fixed-point indication device 100 to the sky, and the transmission range of the fixed-point indication signal is concentrated. In order to make the calibration result of the inertial navigation more accurate, the signal radiation range of the fixed-point indication device 100 in the embodiment of the present invention should be as concentrated as possible, so the fixed-point indication device 100 adopts a directional antenna design, such as Figure 2 As shown, the signal is radiated only to the top of the fixed-point pointing device 100, and there is no signal in other areas. The narrower the radiation beam is, the less the calibration error can be.

[0047] When the inertial navigation is calibrated using a fixed-point indicating device 100 with multiple known coordinate points, in order to distinguish different coordinate points, different Morse codes and signal frequencies can be set in the fixed-point indicating device 100, that is, the fixed-point indicating signals emitted by different fixed-point indicating devices 100 have different Morse codes and signal emission frequencies, so that the onboard equipment 200 or the flight crew can judge whether the aircraft has arrived at a certain known coordinate point through the Morse code.

[0048] Specifically, step S10 of the embodiment of the present invention specifically includes:

[0049] Step S101: Controlling the aircraft to enter the radiation range of the fixed-point indicating device according to the pre-stored position information of the fixed-point indicating device and the inertial navigation data.

[0050] The aircraft cannot receive the fixed-point indication signal when it does not enter the signal radiation range of the fixed-point indication device 100, so the aircraft should fly to the template fixed-point indication device 100 according to the pre-stored position information and inertial navigation data of the fixed-point indication device 100 and enter the signal radiation range of the fixed-point indication device 100.

[0051] Specifically, the aircraft in this step can be guided by a navigation station such as a distance measuring device DME, a very high frequency omnidirectional beacon VOR, a tactical air navigation system TACAN, or by other navigation methods to enter the radiation range of the fixed-point indicating device 100, such as Figure 3 and 4 The circle range shown.

[0052] Step S102: receiving a fixed-point indication signal in real time, and analyzing a change in the power of the fixed-point indication signal.

[0053] In principle, the inertial navigation data can be corrected after the aircraft flies into the signal radiation range of the fixed-point indicating device 100. However, in fact, since there are fixed-point indicating signals within the signal radiation range of the fixed-point indicating device 100, the correction effect of the inertial navigation data is better only when the aircraft is closer to the center of the radiation range and the aircraft is closer to the known coordinate point of the fixed-point indicating device 100. According to the principle of electromagnetic wave propagation, the closer to the radiation source, the greater the signal power received by the receiver, and the radiation source is the fixed-point indicating device 100 located at the known coordinate point, so the greater the power of the fixed-point indicating signal received by the airborne device 200 is equivalent to the closer to the known coordinate point. Directly above the fixed-point indicating device 100, the aircraft is closest to the fixed-point indicating device and the power should be the largest. Therefore, the airborne device 200 in this step receives the fixed-point indicating signal in real time and analyzes the change in the power of the fixed-point indicating signal.

[0054] like Figure 3 and Figure 4As shown in the figure, after the aircraft flies into the circle, the power of the received fixed-point indication signal changes from small to large and then from large to small. Therefore, for the analysis of the power of the fixed-point indication signal, the power of two adjacent fixed-point indication signals can be compared. If the latter is greater than the former, it means that the aircraft is flying towards the center point. If the latter is less than the former, it means that the aircraft is flying away from the center point.

[0055] After the airborne device 200 receives and analyzes the fixed-point indication signal, it executes subsequent steps.

[0056] Step S20: Calculate the position coordinates of the onboard device according to the fixed-point indication signal and the pre-stored working parameters and position information of the fixed-point indication device.

[0057] Combined with the description of the previous step, it can be known that when the aircraft is at different positions in the radiation range, the signal power of the received fixed-point indication signal is different. Therefore, based on the pre-stored working parameters and position information of the fixed-point indication device 100 combined with the power of the fixed-point indication signal and the attenuation characteristics of the electromagnetic wave signal, the position coordinates of the aircraft relative to the fixed-point indication device 100 can be calculated.

[0058] Regarding the calculation of the position coordinates of the aircraft, there are three implementation methods in the embodiments of the present invention. First, after each fixed-point indication signal is received, the position coordinates of the aircraft or the airborne equipment 200 are calculated according to the pre-stored working parameters and position information of the fixed-point indication device 100; second, the position coordinates of the aircraft or the airborne equipment 200 are calculated according to the set calculation frequency and the pre-stored working parameters and position information of the fixed-point indication device 100, for example, the position coordinates are calculated once after each two fixed-point indication signals are received; third, when the power of the fixed-point indication signal is maximum, the position coordinates of the onboard equipment are calculated according to the pre-stored working parameters and position information of the fixed-point indication device, such as Figure 4 As shown, the position marked by the five-pointed star is the position where the power of the fixed-point indication signal received in the flight trajectory of the aircraft is the largest.

[0059] Step S30: Correct the inertial navigation data according to the position coordinates.

[0060] The inertial navigation data is corrected according to the position data of the aircraft obtained in the above steps. Accordingly, the timing of correcting the inertial navigation data in this embodiment corresponds to the calculation of the position coordinates of the aircraft in the previous step, and also includes three methods: first, after each fixed-point indication signal is received, the position coordinates are calculated accordingly and the inertial navigation data is corrected; second, after the position coordinates are calculated according to the set calculation frequency, the inertial navigation data is corrected according to the position coordinates; third, which is also the most preferred embodiment of the present invention, the inertial navigation data is corrected according to the position coordinates calculated when the power of the fixed-point indication signal is maximum, such as Figure 4 As shown in the figure, the position marked by the five-pointed star is the best correction point for the inertial navigation data.

[0061] In addition, the embodiment of the present invention further includes an airborne device 200, such as Figure 5 As shown, the airborne device 200 includes a signal receiving module 201, a position coordinate calculation module 202 and an inertial navigation data correction module 203, wherein:

[0062] The signal receiving module 201 is connected to the position coordinate calculation module 202; the signal receiving module 201 is used to receive the fixed-point indication signal when the aircraft is flying; the fixed-point indication signal is an electromagnetic wave signal emitted into the air by a fixed-point indication device placed at a preset point position on the ground;

[0063] The position coordinate calculation module 202 is connected to the signal receiving module 201 and the inertial navigation data correction module 203; the position coordinate calculation module 202 is used to calculate the position coordinates of the onboard device according to the fixed-point indication signal and the working parameters and position information of the pre-stored fixed-point indication device;

[0064] The inertial navigation data correction module 203 is connected to the position coordinate calculation module 202; the inertial navigation data correction module 203 is used to correct the inertial navigation data according to the position coordinates.

[0065] The functional implementation of the modules in the airborne device 200 can be understood in conjunction with the aforementioned implementation example of the fixed-point indication and calibration inertial navigation method, and will not be elaborated here.

[0066] The fixed-point indication calibration inertial navigation method and airborne equipment of the embodiments of the present invention only correct the inertial navigation data when flying over the fixed-point indication device, and can automatically use the fixed-point indication signal to complete the correction, thereby replacing the manual correction with larger errors, and also replacing the satellite navigation method that is easily deceived, so that the aircraft can fly as planned and ensure flight safety.

[0067] The embodiment of the present invention further includes a fixed-point indicating device 100, such as Figure 6 and Figure 7 As shown, the fixed-point indicating device 100 is used to transmit a fixed-point indicating signal to the air at a preset point position on the ground, so that the airborne device 200 implements the fixed-point indicating calibration inertial navigation method as described in the above embodiment. The fixed-point indicating device 100 of the embodiment of the present invention includes a parameter setting module 101, a signal generating module 102, a signal processing module 103, a power amplification module 104 and an antenna 105; wherein:

[0068] The parameter setting module 101 is electrically connected to the signal generating module 102; the parameter setting module 101 is used to set the signal content and working parameters of the fixed-point indication signal to be sent by the fixed-point indication device 100;

[0069] The signal generating module 102 is electrically connected to the signal processing module 103; the signal generating module 102 is used to generate a corresponding electrical signal according to the signal content of the fixed-point indication signal;

[0070] The signal processing module 103 is electrically connected to the parameter setting module 101 and the power amplification module 104; the signal processing module 103 is used to modulate the electrical signal according to the working parameters of the fixed-point indication signal;

[0071] The power amplification module 104 is electrically connected to the parameter setting module 101 and the antenna 105; the power amplification module 104 is used to amplify the power of the modulated electrical signal according to the working parameters of the fixed-point indication signal;

[0072] The antenna 105 is used to transmit the fixed-point indication signal into the air in the form of an electromagnetic wave signal.

[0073] In this embodiment, the parameter setting module 101 can be regarded as a parameter setting port. The specific input carrier is not limited in this embodiment and can be realized through a keyboard or a touch screen, etc. The manager sets the signal content and working parameters of the fixed-point indication signal emitted by the fixed-point indication device 100 through the parameter setting module 101. The signal content can be understood as information that can represent the identity of the fixed-point indication device 100, and the working parameters may include the frequency and power of the signal transmission. The signal generation module 102 generates an electrical signal according to the setting of the parameter setting module 101, and then the signal processing module 103 processes and modulates the electrical signal. Finally, the power of the electrical signal is amplified by the power amplification module 104 according to the set working parameters, and then the antenna 105 radiates it into the air.

[0074] The airborne equipment 200 of this embodiment corrects the inertial navigation data only when flying over the fixed-point indicating device 100, so the effective range requirement of the fixed-point indicating device 100 is not high. The requirement can be met by only allowing the fixed-point indicating device 100 to radiate directionally, so a portable and miniaturized product design method can be adopted. In addition, the power of the fixed-point indicating device 100 of this embodiment will not be very high. By adopting an upward directional radiation signal, its radiation range is limited, so it will not affect the communication of the navigation station.

[0075] Specifically, Figure 7As shown, the signal generating module 102 in this embodiment includes a Morse code generating circuit 1021, an audio generating circuit 1022 and an analog switch 1023; the parameter setting module 101 is electrically connected to the Morse code generating circuit 1021, the Morse code generating circuit 1021 and the audio generating circuit 1022 are both electrically connected to the analog switch 1023, and the analog switch 1023 is electrically connected to the signal processing module 103. The signal generating module 102 in this embodiment includes a Morse code generating circuit 1021 and an audio generating circuit 1022, the Morse code generating circuit 1021 is used to generate a Morse code signal representing the identity of the fixed-point indicating device 100, and the audio generating circuit 1022 is used to generate an audio signal used for communication, and the output of the signal is controlled by the analog switch 1023. In addition, the signal processing module 103 in this embodiment includes an amplitude modulation circuit 1031, a carrier oscillator amplifier 1032 and an adding circuit 1033; the analog switch 1023 is electrically connected to the amplitude modulation circuit 1031, and the amplitude modulation circuit 1031 is electrically connected to the adding circuit 1033; the parameter setting module 101 is electrically connected to the carrier oscillator amplifier 1032, and the carrier oscillator amplifier 1032 is electrically connected to the amplitude modulation circuit 1031 and the adding circuit 1033; the adding circuit 1033 is electrically connected to the power amplification module 104.

[0076] In the fixed-point indication calibration inertial navigation method of the present invention, the airborne device receives the fixed-point indication signal when the aircraft is flying, and then calculates the position coordinates of the onboard device according to the fixed-point indication signal and the working parameters and position information of the pre-stored fixed-point indication device, and then automatically corrects the inertial navigation data according to the position coordinates, wherein the fixed-point indication signal is an electromagnetic wave signal emitted into the air by the fixed-point indication device placed at a preset fixed-point position on the ground, and the fixed-point indication device includes a parameter setting module, a signal generation module, a signal processing module, a power amplification module and an antenna. The present invention corrects the inertial navigation data only when flying over the fixed-point indication device, and can automatically use the fixed-point indication signal to complete the correction, thereby replacing the manual correction with a larger error, and can also replace the satellite navigation for inertial navigation calibration when the satellite navigation is not available, so that the aircraft can fly as planned and ensure flight safety.

[0077] The present invention is further described above with the aid of specific embodiments. However, it should be understood that the specific description here should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in the field after reading this specification are all within the scope of protection of the present invention.

Claims

1. A method for calibrating an inertial navigation system by fixed-point indication, characterized in that: The method comprises: The airborne device receives a fixed-point indication signal when the aircraft is flying; the fixed-point indication signal is an electromagnetic wave signal emitted into the air by a fixed-point indication device placed at a preset point position on the ground; Calculating the position coordinates of the onboard device according to the fixed-point indication signal and the pre-stored working parameters and position information of the fixed-point indication device; The inertial navigation data is corrected according to the position coordinates.

2. A method for calibrating an inertial navigation system with fixed-point indication as claimed in claim 1, characterized in that: The airborne device receives a fixed-point indication signal when the aircraft is flying, including: Controlling the aircraft to enter the radiation range of the fixed-point indicating device according to the pre-stored position information and inertial navigation data of the fixed-point indicating device; The fixed-point indication signal is received in real time, and the change of the power of the fixed-point indication signal is analyzed.

3. A method for calibrating an inertial navigation system by fixed-point indication as claimed in claim 2, characterized in that: The position coordinates of the onboard device are calculated according to the fixed-point indication signal and the pre-stored working parameters and position information of the fixed-point indication device, including: When the power of the fixed-point indication signal is at a maximum, the position coordinates of the onboard device are calculated according to the pre-stored working parameters and position information of the fixed-point indication device.

4. A method for calibrating an inertial navigation system by fixed-point indication according to any one of claims 1 to 3, characterized in that: The fixed-point positions where the fixed-point indicating device is placed include navigation stations and indicating points selected on the route.

5. A method for calibrating an inertial navigation system by fixed-point indication as claimed in claim 4, characterized in that: The emission direction of the fixed-point indication signal is vertically upward from the position directly above the fixed-point indication device to the sky, and the emission range of the fixed-point indication signal is concentrated emission.

6. A method for calibrating an inertial navigation system with fixed-point indication as claimed in claim 4, characterized in that: The fixed-point indication signals emitted by different fixed-point indication devices have different Morse codes and signal emission frequencies.

7. An airborne device, characterized in that: The airborne device includes a signal receiving module, a position coordinate calculation module and an inertial navigation data correction module, wherein: The signal receiving module is connected to the position coordinate calculation module; the signal receiving module is used to receive a fixed-point indication signal when the aircraft is flying; the fixed-point indication signal is an electromagnetic wave signal emitted into the air by a fixed-point indication device placed at a preset point position on the ground; The position coordinate calculation module is connected to the signal receiving module and the inertial navigation data correction module; the position coordinate calculation module is used to calculate the position coordinates of the onboard device according to the fixed-point indication signal and the pre-stored working parameters and position information of the fixed-point indication device; The inertial navigation data correction module is connected to the position coordinate calculation module; the inertial navigation data correction module is used to correct the inertial navigation data according to the position coordinates.

8. A fixed-point indicating device, characterized in that: The fixed-point indicating device is used to transmit a fixed-point indicating signal to the air at a preset point position on the ground, so that the airborne equipment can implement the fixed-point indicating calibration inertial navigation method according to any one of claims 1 to 6; the fixed-point indicating device includes a parameter setting module, a signal generating module, a signal processing module, a power amplification module and an antenna; The parameter setting module is electrically connected to the signal generating module; the parameter setting module is used to set the signal content and working parameters of the fixed-point indication signal to be emitted by the fixed-point indication device; The signal generating module is electrically connected to the signal processing module; the signal generating module is used to generate a corresponding electrical signal according to the signal content of the fixed-point indication signal; The signal processing module is electrically connected to the parameter setting module and the power amplification module; the signal processing module is used to modulate the electrical signal according to the working parameters of the fixed-point indication signal; The power amplification module is electrically connected to the parameter setting module and the antenna; the power amplification module is used to amplify the power of the modulated electrical signal according to the working parameters of the fixed-point indication signal; The antenna is used to transmit the fixed-point indication signal into the air in the form of an electromagnetic wave signal.

9. A fixed-point indicating device as claimed in claim 8, characterized in that: The signal generating module comprises a Morse code generating circuit, an audio generating circuit and an analog switch; the parameter setting module is electrically connected to the Morse code generating circuit, the Morse code generating circuit and the audio generating circuit are both electrically connected to the analog switch, and the analog switch is electrically connected to the signal processing module.

10. A fixed-point indicating device as claimed in claim 9, characterized in that: The signal processing module includes an amplitude modulation circuit, a carrier oscillation amplifier and an adding circuit; the analog switch is electrically connected to the amplitude modulation circuit, and the amplitude modulation circuit is electrically connected to the adding circuit; the parameter setting module is electrically connected to the carrier oscillation amplifier, and the carrier oscillation amplifier is electrically connected to the amplitude modulation circuit and the adding circuit; the adding circuit is electrically connected to the power amplification module.

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