An inertial navigation system with wake-up circuit and method of use

Abstract

The application discloses a kind of inertial navigation system with wake-up circuit and use method, the inertial navigation system with wake-up circuit, comprising: internal power supply domain, internal storage circuit and wake-up circuit;The internal power supply domain is used to measure the angular motion and linear motion information of carrier, and provides the navigation information of carrier to the outside world;The internal storage circuit is used to store the alignment information of the inertial navigation system;The wake-up circuit is used to wake up or close the internal power supply domain, and the wake-up circuit includes power module, power supply wake-up generation module, first latch and second latch.The application adds wake-up circuit in the power supply module of inertial navigation system, and can well solve the technical problem that initial alignment time of inertial navigation system is too long.By adding wake-up circuit in inertial navigation system, the on-off state of internal power supply domain can be controlled, so that the inertial navigation system is switched between standby and working state.

Description

Technical Field

[0001] This invention relates to the field of inertial navigation technology, and more specifically to an inertial navigation system with a wake-up circuit and its usage method. Background Technology

[0002] A strapdown inertial navigation system (SINS) is a system composed of gyroscopes, accelerometers, and a navigation computer, enabling autonomous navigation. An inertial navigation system, often simply called an inertial navigation system (INS), requires initialization of navigation information before it can begin operating. This process of obtaining initial attitude information is called initial alignment. Initial alignment is a prerequisite for autonomous navigation and is essential for maintaining high navigation accuracy over a long period without any auxiliary means. The quality of the initial alignment directly affects the navigation accuracy of the INS.

[0003] Initial alignment typically comprises two stages: coarse alignment and fine alignment. Fine alignment is performed based on coarse alignment and requires pre-existing initial alignment attitude information of a certain accuracy. Both coarse and fine alignment are indispensable in initial alignment, with a minimum alignment time of 3-5 minutes. Navigation can only commence after alignment is completed. This approach presents significant limitations for applications requiring rapid navigation. The purpose of initial alignment for inertial systems is to establish a navigation coordinate system before entering normal operating conditions and to calculate the initial strapdown attitude matrix between the vehicle coordinate system and the navigation coordinate system. This process is essential and time-consuming. Summary of the Invention

[0004] In view of this, the present invention provides an inertial navigation system with a wake-up circuit and a method of using it, which can solve the technical problem of excessively long initial alignment time of the inertial navigation system.

[0005] To solve the above-mentioned technical problems, the present invention is implemented as follows.

[0006] An inertial navigation system with a wake-up circuit includes:

[0007] Internal power domain, internal storage circuitry, and wake-up circuitry;

[0008] The internal power domain includes an inertial measurement unit and a navigation computer board; the internal power domain is used to measure the angular motion and linear motion information of the carrier and to provide the carrier's navigation information to the outside world.

[0009] The internal storage circuit is used to store the alignment information of the inertial navigation system, and the internal storage circuit is always powered on.

[0010] The wake-up circuit is used to wake up or turn off the internal power domain. The wake-up circuit includes a power module, a power wake-up generation module, a first latch, and a second latch. The input of the wake-up circuit is connected to the transmission signal of the carrier. The wake-up circuit is used to receive a power-off signal and / or a power-on signal sent by the carrier. The power module is used to supply power to the power wake-up generation module. The outputs of the first latch and the second latch are both connected to the power supply circuit of the internal power domain. The inertial navigation system is mounted on the carrier.

[0011] Preferably, the internal power domain, internal storage circuit, and wake-up circuit are all installed inside the inertial navigation system housing.

[0012] Preferably, the internal power domain uses fiber optic gyroscopes and quartz flexural accelerometers to measure the angular and linear motion information of the carrier. The navigation computer board then uses mathematical calculations to obtain the heading, attitude, and position information of the carrier, thereby providing continuous navigation information of the carrier to the outside world.

[0013] Preferably, when the inertial navigation system is not required to provide navigation information, the carrier sends a power-off control signal. When the power-on generation module of the wake-up circuit receives the power-off control signal sent by the carrier to the internal power domain of the inertial navigation system, the first latch of the wake-up circuit latches the power-off control signal. The wake-up circuit generates a power-off signal according to the latched power-off control signal, thereby de-energizing the internal power domain.

[0014] Preferably, when navigation information is required from the navigation system, the power wake-up generation module of the wake-up circuit receives the power wake-up control signal sent by the carrier to the internal power domain. The second latch of the wake-up circuit latches the power wake-up signal. The wake-up circuit triggers the wake-up control signal latched by the second latch according to the latched power wake-up signal and clears the power-off control signal, thereby powering on the internal power domain, enabling the inertial navigation system to power on, output navigation information, and provide navigation information to the carrier.

[0015] A method of using an inertial navigation system with a wake-up circuit, comprising the following steps:

[0016] Step S31: When the carrier is working, the carrier sends a power wake-up signal to the wake-up circuit, and the wake-up circuit supplies power to the internal power domain, so that the inertial navigation system is in a powered-on state.

[0017] Step S32: The inertial navigation system performs initial alignment and stores the initial alignment data in the memory of the inertial navigation system; if the carrier does not require navigation information from the inertial navigation system, proceed to step S33; otherwise, proceed to step S36; the initial alignment data includes the velocity and position information of the carrier at the initial moment.

[0018] Step S33: The wake-up circuit receives the power-off control signal sent by the carrier and shuts off the power supply to the internal power domain of the inertial navigation system, maintaining only the power supply to the memory of the inertial navigation system;

[0019] Step S34: The inertial navigation system remains in standby mode;

[0020] Step S35: Listen to the control information sent by the carrier. If the carrier needs the inertial navigation system to provide navigation information to control the carrier's guidance, the carrier sends a power wake-up signal to the wake-up circuit. The wake-up circuit supplies power to the internal power domain of the inertial navigation system, so that the inertial navigation system is powered on and enters the working state. Then, based on the alignment data stored in the internal storage circuit, the inertial navigation system is started and enters the navigation state, proceeding to step S36.

[0021] Step S36: The inertial navigation system performs system navigation and outputs the speed and position information of the carrier to control the carrier's operating route and attitude.

[0022] Beneficial effects:

[0023] (1) This invention, by adding a wake-up circuit to the power supply module of the inertial navigation system, effectively solves the technical problem of excessively long initial alignment time in the inertial navigation system. By adding a wake-up circuit to the inertial navigation system, the power-on and power-off states of the internal power domain (other parts of the inertial navigation system excluding memory) can be controlled, allowing the inertial navigation system to switch between standby and working states. By energizing the internal power domain through the wake-up circuit, the inertial navigation system enters the working state. The data stored in the inertial navigation system's memory after the current alignment is completed enables the inertial navigation system to immediately switch from the alignment state to the navigation state, realizing the system's fast navigation function.

[0024] (2) When the wake-up circuit receives the shutdown control signal from the carrier to the inertial navigation system, it generates a power-off signal to control the internal power domain to shut down; when it receives the wake-up signal from the carrier to the inertial navigation system, it generates a power-on signal to clear the power-off control signal and power on the internal power domain. In operating mode, the inertial navigation system supplies power for initial alignment and navigation; when the inertial navigation system is not needed, only the system memory circuit is powered, and it is in standby mode to maintain the currently stored alignment data. When the carrier needs to operate, power is supplied to the inertial navigation system to realize its normal navigation function. The wake-up circuit can also automatically turn on after the power is turned off.

[0025] (3) When the inertial navigation system is in standby mode, the current alignment data is stored in the memory. By waking up the power control system to control the power supply to switch on and off, the system can immediately complete the alignment and enter the navigation state. This reduces the initial alignment process, realizes the system's fast navigation function, improves the reaction speed, and thus improves the carrier's survivability.

[0026] (4) The present invention is simple to implement and easy to operate. Attached Figure Description

[0027] Figure 1 A schematic diagram of the wake-up circuit provided by the present invention.

[0028] Figure 2 This is a schematic diagram illustrating the workflow of an inertial navigation system without a wake-up circuit, as provided by the present invention.

[0029] Figure 3 This is a schematic diagram illustrating the workflow of the inertial navigation system including a wake-up circuit provided by the present invention. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] The inertial navigation system (INS) is mounted on the carrier. The carrier sends a power-on signal to the INS, which then begins initial alignment. The carrier's swaying interference is directly applied to the gyroscopes and accelerometers. The navigation computer processes the measurement outputs from the gyroscopes and accelerometers, calculates the attitude matrix and velocity error, and estimates the misalignment angle from the velocity error. Once the misalignment angle estimation reaches a steady state, the attitude matrix is ​​corrected using the estimated misalignment angle value.

[0032] The self-alignment of an inertial navigation system (INS) consists of two processes: coarse alignment and fine alignment. In coarse alignment, the attitude matrix is ​​directly calculated from the outputs of the gyroscopes and accelerometers. This approach effectively ignores the effects of swaying interference, approximating the gyroscope and accelerometer outputs as measurements of the Earth's rotational angular velocity and gravitational acceleration. Therefore, the coarse alignment error mainly depends on the severity of the swaying interference. Fine alignment is performed after coarse alignment. During this process, the system calculates the attitude matrix based on the attitude matrix determined by coarse alignment and the real-time output of the gyroscopes. Simultaneously, it calculates the velocity output based on the accelerometer output. Since the vehicle is stationary, this velocity output is actually the velocity error, containing attitude error angle information. From this, the attitude error angle can be estimated. Once the estimation stabilizes, this estimate is used to correct the attitude matrix, and this corrected attitude matrix is ​​used as the initial attitude matrix for navigation calculation. Initial alignment is then complete. Only then can the INS enter navigation mode. When the vehicle is operating, the navigation system in navigation mode outputs navigation information, providing direction and attitude for the vehicle's operation.

[0033] like Figure 1 As shown, this invention proposes an inertial navigation system with a wake-up circuit, comprising:

[0034] The system comprises an internal power domain, an internal storage circuit, and a wake-up circuit. The internal power domain includes an inertial measurement unit (IMU) and a navigation computer board. The internal power domain measures the angular and linear motion information of the carrier and provides navigation information to the outside world. The internal storage circuit is a storage function circuit used to store the alignment information of the inertial navigation system, and the internal storage circuit is always powered on. The wake-up circuit is used to wake up or shut down the internal power domain. The wake-up circuit includes a power module, a power wake-up generation module, a first latch, and a second latch. The input of the wake-up circuit is connected to the carrier's transmission signal, and the wake-up circuit is used to receive power-off signals and / or power-on signals sent by the carrier. The power module supplies power to the power wake-up generation module. The outputs of the first latch and the second latch are both connected to the power supply circuit of the internal power domain. The inertial navigation system is mounted on the carrier.

[0035] The internal power domain, internal storage circuit, and wake-up circuit are all installed within the inertial navigation system housing. Furthermore, the internal power domain uses fiber optic gyroscopes and quartz flexural accelerometers to measure the angular and linear motion information of the carrier. The navigation computer board then uses mathematical calculations to obtain the carrier's heading, attitude, and position information, thereby providing continuous navigation information of the carrier to the outside world.

[0036] In this embodiment, the internal storage circuit stores the alignment data at the end of the current alignment and is always powered on. When the internal power domain is powered on, it immediately sends alignment information to the inertial navigation system, causing the inertial navigation system to enter the navigation state. The wake-up circuit is responsible for the power-on and power-off state of the internal power domain, receiving power-off control signals or power-on wake-up signals sent by the carrier. When the wake-up circuit receives the power-on wake-up signal, the internal power domain is powered on, and the navigation system receives the alignment completion data stored in the memory circuit and enters the navigation state. When the wake-up circuit receives the power-off control signal, the internal power domain is powered off, and the navigation system is in standby mode. At this time, only the internal storage circuit is working.

[0037] Furthermore, when the carrier is not in operation and does not require navigation information from the inertial navigation system, the carrier sends a power-off control signal. When the power-on generation module of the wake-up circuit receives the power-off control signal sent by the carrier to the internal power domain of the inertial navigation system, the first latch of the wake-up circuit latches the power-off control signal. The wake-up circuit generates a power-off signal based on the latched power-off control signal, thereby de-energizing the internal power domain and powering off the inertial navigation system, putting it into standby mode.

[0038] In this embodiment, when the carrier enters the working state and needs navigation information from the navigation system, the power wake-up generation module of the wake-up circuit receives the power wake-up control signal sent by the carrier to the internal power domain. The second latch of the wake-up circuit latches the power wake-up signal. The wake-up circuit triggers the wake-up control signal latched by the second latch according to the latched power wake-up signal and clears the power-off control signal, thereby energizing the internal power domain, enabling the inertial navigation system to power on, output navigation information, and provide navigation information for the carrier.

[0039] Furthermore, if the carrier is not in operation for an extended period, the internal power domain is partially powered off by the wake-up circuit, while the memory circuit remains powered on and stores the alignment data of the current operating state. If the carrier requires navigation, a power wake-up signal is sent to the wake-up circuit, which then powers the internal power domain. The alignment data stored in the memory enables the inertial navigation system to immediately switch from the alignment state to the navigation state, thereby enabling the system to perform rapid navigation and providing the carrier with information such as heading and attitude.

[0040] The quality of initial alignment directly affects the navigation accuracy of the inertial navigation system (INS). The purpose of initial alignment of the INS is to determine the strapdown matrix. However, calculations can only yield the attitude transformation matrix from the carrier coordinate system to the platform coordinate system. The calculated platform coordinate system still has an error angle relative to the navigation coordinate system. remember For an antisymmetric matrix φ, the following relationship holds:

[0041]

[0042] Right now

[0043]

[0044] It is not difficult to see that, in obtaining Afterwards, if the misalignment angle can be determined... Then we can calculate...

[0045] The initial alignment of an inertial navigation system is divided into two stages: coarse alignment and fine alignment. Coarse alignment is the process of obtaining the initial... The process of fine alignment is used to estimate the misalignment angle; and against Make corrections.

[0046] Coarse alignment aims to align the platform to a certain accuracy range as quickly as possible to provide a foundation for subsequent fine alignment. This can be achieved using analytical alignment or a single-pass alignment method. The coarse alignment result is calculated analytically using static measurement data from the 30 seconds prior to the start of motion. Coarse alignment prioritizes obtaining the initial values ​​of the strapdown matrix; speed is paramount, while accuracy requirements are relatively lower. Because the time required for coarse alignment is very short, the coarse alignment process of the strapdown inertial navigation system can also be performed under static conditions. During analytical coarse alignment, the platform must remain stationary, and the local longitude λ and latitude L must be known. Thus, the gravitational acceleration g and the Earth's rotational angular velocity ω... ie The components in the navigation coordinate system are constant values, and the components in the vehicle coordinate system can be measured using gyroscopes and accelerometers. The initial strapdown matrix can be directly calculated from the measurements of inertial instruments. After coarse alignment, the main objective in the fine alignment stage is to achieve the final alignment accuracy. Fine alignment is achieved through filtering using a combined Kalman filter.

[0047] Kalman filtering is a recursive linear variance minimization estimator. Based on the state equations describing a linear system, it can estimate the various state variables of the system in real time from noisy observations. Specifically, in inertial systems, based on the system's error equations, Kalman filtering is used to estimate various navigation parameter errors and other system error sources. In practice, Kalman filtering requires that the statistical characteristics of both system noise and observation noise are known, and that both should be white noise. If the system noise or observation noise is colored noise, it needs to be whitened using state augmentation or measurement augmentation methods. To prevent filter divergence, various adaptive filtering algorithms can be used. When the state dimension is high and computational power is insufficient, various forms of suboptimal filtering methods can be employed to improve computational speed.

[0048] The selection method for Kalman filter parameters is as follows: First, a set of basic filter parameters is determined based on empirical values ​​and the actual values ​​used for static base alignment. Then, considering that the dynamic error of inertial instruments is larger than the static error, this set of basic filter parameters is appropriately adjusted. Reference navigation information is the foundation for alignment; its accuracy and sampling frequency directly affect the performance of the initial alignment. Using the speed information calculated by the integrated navigation system as a benchmark, if there is a large difference between the GPS output speed and the system output speed at the current moment, then the reference navigation data is considered erroneous and skipped in the alignment calculation. The threshold for judging speed difference is determined based on actual data. Through the preprocessing of the reference navigation data, the initial alignment effect is significantly improved. The accuracy and speed of the initial alignment directly affect the accuracy and rapid response capability achievable by the entire system.

[0049] like Figures 2-3As shown, the present invention provides a method for using an inertial navigation system with a wake-up circuit. Using the inertial navigation system with a wake-up circuit as described above, the method includes the following steps:

[0050] Step S31: When the carrier is working, the carrier sends a power wake-up signal to the wake-up circuit, and the wake-up circuit supplies power to the internal power domain, so that the inertial navigation system is in a powered-on state.

[0051] Step S32: The inertial navigation system performs initial alignment and stores the initial alignment data in the memory of the inertial navigation system; if the carrier does not require navigation information from the inertial navigation system, proceed to step S33; otherwise, proceed to step S36; the initial alignment data includes the velocity and position information of the carrier at the initial moment.

[0052] Step S33: The wake-up circuit receives the power-off control signal sent by the carrier and shuts off the power supply to the internal power domain of the inertial navigation system, maintaining only the power supply to the memory of the inertial navigation system;

[0053] Step S34: The inertial navigation system remains in standby mode;

[0054] Step S35: Listen to the control information sent by the carrier. If the carrier needs the inertial navigation system to provide navigation information to control the carrier's guidance, the carrier sends a power wake-up signal to the wake-up circuit. The wake-up circuit supplies power to the internal power domain of the inertial navigation system, so that the inertial navigation system is powered on and enters the working state. Then, based on the alignment data stored in the internal storage circuit, the inertial navigation system is started and enters the navigation state, proceeding to step S36.

[0055] Step S36: The inertial navigation system performs system navigation and outputs the speed and position information of the carrier to control the carrier's operating route and attitude.

[0056] Furthermore, the method of use also includes providing the carrier with information such as heading and attitude.

[0057] Furthermore, the method of use also includes: powering off the inertial navigation system.

[0058] The specific embodiments described above only illustrate the design principles of the present invention. The shapes and names of the components in this description may differ and are not limited. Therefore, those skilled in the art can modify or make equivalent substitutions to the technical solutions described in the foregoing embodiments; and these modifications and substitutions do not depart from the inventive spirit and technical solutions of the present invention, and should all fall within the protection scope of the present invention.

Claims

1. An inertial navigation system with a wake-up circuit, characterized in that, The inertial navigation system with a wake-up circuit includes: Internal power domain, internal storage circuitry, and wake-up circuitry; The internal power domain includes an inertial measurement unit and a navigation computer board; the internal power domain is used to measure the angular and linear motion information of the carrier and to provide the carrier's navigation information to the outside world. The internal storage circuit is used to store the alignment information of the inertial navigation system, and the internal storage circuit is always powered on. The wake-up circuit is used to wake up or turn off the internal power domain. The wake-up circuit includes a power module, a power wake-up generation module, a first latch, and a second latch. The input of the wake-up circuit is connected to the transmission signal of the carrier. The wake-up circuit is used to receive a power-off signal and / or a power-on signal sent by the carrier. The power module is used to supply power to the power wake-up generation module. The outputs of the first latch and the second latch are both connected to the power supply circuit of the internal power domain. The inertial navigation system is mounted on the carrier. When the inertial navigation system is not required to provide navigation information, the carrier sends a power-off signal. When the power-on generation module of the wake-up circuit receives the power-off signal sent by the carrier to the internal power domain of the inertial navigation system, the first latch of the wake-up circuit latches the power-off signal. The wake-up circuit generates a power-off signal according to the latched power-off signal, thereby de-energizing the internal power domain. When navigation information is required from the inertial navigation system, the power wake-up generation module of the wake-up circuit receives the power wake-up signal sent by the carrier to the internal power domain. The second latch of the wake-up circuit latches the power wake-up signal. The wake-up circuit triggers the wake-up signal latched by the second latch according to the latched power wake-up signal and clears the power-off signal, thereby powering on the internal power domain, enabling the inertial navigation system to power on, output navigation information, and provide navigation information to the carrier.

2. The inertial navigation system as described in claim 1, characterized in that, The internal power domain, internal storage circuit, and wake-up circuit are all installed inside the inertial navigation system housing.

3. The inertial navigation system as described in claim 2, characterized in that, The internal power domain uses fiber optic gyroscopes and quartz flexural accelerometers to measure the angular and linear motion information of the carrier. The navigation computer board then uses mathematical calculations to obtain the heading, attitude, and position information of the carrier, thereby providing continuous navigation information of the carrier to the outside world.

4. A method of using an inertial navigation system with a wake-up circuit, comprising the following steps: Step S31: When the carrier is working, the carrier sends a power wake-up signal to the wake-up circuit, and the wake-up circuit supplies power to the internal power domain, so that the inertial navigation system is in a powered-on state. Step S32: The inertial navigation system performs initial alignment and stores the initial alignment data in the internal storage circuit of the inertial navigation system; if the carrier does not require navigation information from the inertial navigation system, proceed to step S33; otherwise, proceed to step S36; the initial alignment data includes the velocity and position information of the carrier at the initial moment; Step S33: The wake-up circuit receives the power-off signal sent by the carrier and shuts off the power supply to the internal power domain of the inertial navigation system, while maintaining the power supply to the internal storage circuit of the inertial navigation system. Step S34: The inertial navigation system remains in standby mode; Step S35: Listen to the control information sent by the carrier. If the carrier needs the inertial navigation system to provide navigation information to control the carrier's guidance, the carrier sends a power wake-up signal to the wake-up circuit. The wake-up circuit supplies power to the internal power domain of the inertial navigation system, so that the inertial navigation system is powered on and enters the working state. Then, based on the alignment data stored in the internal storage circuit, the inertial navigation system is started and enters the navigation state, and proceeds to step S36. Step S36: The inertial navigation system performs system navigation and outputs the speed and position information of the carrier to control the carrier's operating route and attitude.

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