A Strong Real-Time High-Speed Attitude Measurement Information Assurance Method

Abstract

The present invention discloses a strong real-time, high-speed attitude measurement information assurance method, which relates to the technical field of inertial equipment attitude measurement information assurance, including: using the time code information of the whole ship time reference as the absolute time, and using the synchronous second pulse of the time reference to complete the inertial navigation attitude information timestamp synchronization; determining the target frequency according to the interpolation requirements, and linearly interpolating the data packets sent by the inertial device into data of the target frequency; after converting the data of the target frequency into an optical signal, transmitting the information via light waves to achieve strong real-time transmission of high-speed attitude measurement information. The present invention designs an attitude measurement data packet time synchronization method, a high-speed attitude measurement information interpolation method, and an information transmission method. Through a combination of software and hardware design, the attitude reference measurement information update rate and strong real-time transmission are greatly improved, and strong real-time, high-speed attitude information assurance is achieved for important reference users such as shipborne radars.

Description

Technical Field

[0001] The present invention relates to the technical field of inertial device attitude measurement information assurance technology, and in particular to a strong real-time and high-speed attitude measurement information assurance method. Background Art

[0002] With the increasing use of various high-precision equipment onboard ships, the demand for accurate navigation reference information from the ship platform is increasing. The transmission of navigation attitude reference information from the main inertial navigation system to user equipment is affected by ship angular deformation, time delay, and platform motion. When the ship deformation between the main inertial navigation system and the user equipment is significant, a local reference is typically configured near the user equipment installation. After initial alignment of the local reference is completed using methods such as inertial transfer alignment, the local reference provides local attitude measurement information to the user equipment. This approach effectively mitigates the effects of ship deformation on attitude reference transmission between the main inertial navigation system and the user equipment, but the cost of configuring a dedicated local reference is high. When the ship deformation between the inertial navigation system and the user equipment is relatively small, the user equipment often directly uses the main inertial navigation system's attitude measurement information as the reference for related solutions. In this approach, navigation reference transmission errors caused by time delay and platform motion become key issues that need to be addressed. (The impact of time delay on navigation reference transmission refers to the delay required for processing and transmission of reference information from the main inertial navigation system before it is delivered to the user equipment. If the user directly uses this information, attitude changes caused by ship platform motion will be superimposed.)

[0003] In view of the increasing demand for reference accuracy from navigation users who directly use the main inertial navigation attitude measurement information and the limited update rate of the main inertial navigation output data, it is necessary to develop a strong real-time and high-speed guarantee method for the main inertial navigation attitude measurement information to minimize the navigation reference transmission error caused by delay and platform motion, and effectively improve the level of navigation attitude reference information guarantee. Summary of the Invention

[0004] In response to the increasing demand for benchmark accuracy among navigation users and the limited update rate of main inertial navigation attitude measurement information, the embodiments of the present invention propose a strong real-time and high-speed attitude measurement information assurance method, design an attitude measurement data packet time synchronization method, a high-speed attitude measurement information interpolation method and an information transmission method. Through a combination of software and hardware design, the attitude benchmark measurement information update rate and strong real-time transmission are greatly improved, thereby achieving strong real-time and high-speed attitude information assurance for important benchmark users such as shipborne radars.

[0005] In a first aspect, the present invention provides a strong real-time high-speed attitude measurement information assurance method, comprising:

[0006] The time code information of the whole ship time reference is used as the absolute time, and the synchronous second pulse of the time reference is used to complete the time stamp synchronization of the inertial navigation attitude information;

[0007] Determine the target frequency according to the interpolation requirements, and linearly interpolate the data packets sent by the inertial device into data of the target frequency;

[0008] After converting the data of the target frequency into an optical signal, the information is transmitted via light waves to achieve strong real-time transmission of high-speed attitude measurement information.

[0009] In some examples, using the time code information of the whole ship time reference as the absolute time and using the synchronized second pulse of the time reference to complete the inertial navigation attitude information timestamp synchronization includes:

[0010] The navigation information processing board of the main inertial navigation system, which includes a DSP and an FPGA, is used to introduce data packets and PPS pulse-per-second information of the time reference sent by the inertial device into the navigation information processing board. The data packets include attitude information.

[0011] The FPGA in the navigation information processing board is triggered by the rising edge of the second pulse to latch the data packet closest to the second pulse, and transmit the latched data packet and the delay between the data packet and the second pulse to the serial port of the DSP for analysis;

[0012] The DSP synchronously analyzes the full-second data packets latched by the FPGA and the time code information of the time reference device to calculate the time difference between Beijing time and the inertial navigation operation time;

[0013] When the DSP receives the data packet, if the inertial navigation operation time in the data packet is parsed, the corresponding timestamp is obtained from the time difference between Beijing time and the inertial navigation operation time.

[0014] In some instances, the time difference Δt between Beijing time and the inertial navigation operating time is calculated by Δt = t1-t2 +Δt1+Δt2, where t1 is the Beijing time in the time code information, t2 is the inertial navigation device operating time in the data packet, Δt1 is the delay between the data packet and the second pulse, and Δt2 is the delay error caused by the inertial device from data generation to transmission to the navigation information processing board.

[0015] In some examples, the corresponding timestamp t1′ is obtained by t1′=Δt + t2′, where t2′ is the inertial navigation running time in the data packet.

[0016] In some examples, determining the target frequency according to the interpolation requirement and linearly interpolating the data packet sent by the inertial device into data of the target frequency includes:

[0017] Determine the target frequency based on the interpolation requirements and use the FPGA's built-in quartz crystal oscillator to generate an interrupt at the target frequency;

[0018] Each time an interrupt is triggered, the time difference between the packet and the most recent packet is obtained and the value is interpolated based on the time difference.

[0019] In some examples, determining the target frequency according to the interpolation requirement includes:

[0020] The maximum roll amplitude under the allowable sea conditions is R0, and the minimum roll period is Tr. The maximum pitch amplitude under the allowable sea conditions is P0, and the minimum pitch period is T p ;

[0021] The user requires the roll to be R′ and the pitch to be P′ for the attitude reference transfer error caused by time delay and platform motion. The main inertial navigation attitude measurement information frequency is G0, and the user's target frequency of the main inertial navigation attitude measurement information is G1. Therefore: R0 / (Tr*G1)≤R′, P0 / (Tp*G1)≤P′.

[0022] In some instances, the interpolated pitch P2, roll R2, and heading H2 are respectively: P2 = P1 + PV1*Δt′, R2 = R1 + RV1*Δt′, H2 = H1 + HV1*Δt′, where Δt′ is the time difference between each interrupt trigger and the most recent data packet, P1 is the pitch parsed from the data packet sent by the inertial device, R1 is the roll parsed from the data packet sent by the inertial device, H1 is the heading parsed from the data packet sent by the inertial device, PV1 is the pitch angular rate parsed from the data packet sent by the inertial device, RV1 is the roll angular rate parsed from the data packet sent by the inertial device, and HV1 is the heading angular rate parsed from the data packet sent by the inertial device.

[0023] In some embodiments, converting the data of the target frequency into an optical signal and then transmitting the information via the optical wave includes:

[0024] Optical fiber communication is selected to convert the data of the target frequency into an optical signal through a photoelectric conversion module, and then the information is transmitted through light waves to achieve strong real-time transmission of high-speed posture measurement information.

[0025] In some examples, the optoelectronic conversion module includes an optical transmitter, an optical fiber interface, a repeater, and an optical receiver connected in sequence.

[0026] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0027] This method is applied to the design of attitude measurement information assurance for main inertial navigation equipment. The update rate of main inertial navigation attitude measurement information is improved through interpolation. On this basis, an optical fiber communication module is adopted to meet the strong real-time and high-speed attitude information assurance requirements of attitude reference users such as radar. The present invention is not limited to surface ship navigation systems and can be used and extended to other information systems with similar processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is a schematic diagram of a strong real-time high-speed attitude measurement information assurance method provided by an embodiment of the present invention;

[0030] Figure 2 1 is a schematic diagram of a flow chart for obtaining a timestamp of posture information provided by an embodiment of the present invention;

[0031] Figure 3 1 is a schematic diagram of a posture information interpolation process according to an embodiment of the present invention;

[0032] Figure 4 It is a schematic diagram of the optical fiber communication composition provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] In the following description, specific embodiments of the present invention will be described with reference to steps and symbols performed by one or more computers, unless otherwise specified. Therefore, these steps and operations will be mentioned several times as being performed by a computer, and computer execution as referred to herein includes operations by a computer processing unit that represents electronic signals of data in a structured form. This operation converts the data or maintains it at a location in the computer's memory system, which can be reconfigured or otherwise change the operation of the computer in a manner familiar to testers in the field. The data structure in which the data is maintained is a physical location in the memory, which has specific characteristics defined by the data format. However, the principles of the present invention are described in the above text, which does not represent a limitation, and testers in the field will understand that the various steps and operations below can also be implemented in hardware.

[0035] As used herein, the terms "module" or "unit" may be considered software objects executed on the computing system. The various components, modules, engines, and services herein may be considered implementation objects on the computing system. While the devices and methods herein are preferably implemented in software, they may also be implemented in hardware and remain within the scope of protection of the present invention.

[0036] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, "connected" or "coupled" as used herein may include wireless connections or wireless couplings. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0037] An embodiment of the present invention proposes a high-speed, strong real-time assurance method for the attitude measurement information of a shipborne main inertial navigation device. The method is mainly used in the design process of navigation attitude reference information assurance for large and medium-sized surface ships. It is used to overcome reference transmission error factors such as ship platform motion and transmission delay as much as possible, and solve the problem of accurately transmitting attitude information of the shipborne main inertial navigation device to reference users such as shipborne radars, thereby effectively ensuring the high-precision information assurance requirements of various navigation attitude reference information users such as shipborne radars.

[0038] The embodiment of the present invention aims to solve the problem that the reference transmission error may occur due to the movement of the ship platform and the transmission delay during the transmission of navigation attitude reference information of large and medium-sized surface ships. A strong real-time high-speed attitude measurement information assurance method is proposed. Specifically, it includes a time synchronization method for attitude measurement data packets, a high-speed attitude measurement information interpolation method, and an information transmission method selection method. Figure 1 As shown, the following steps are included:

[0039] S101: Using the time code information of the whole ship time reference as the absolute time, the synchronous second pulse of the time reference is used to complete the time stamp synchronization of the inertial navigation attitude information;

[0040] S102: Determine the target frequency according to the interpolation requirement, and linearly interpolate the data packet sent by the inertial device into data of the target frequency;

[0041] S103: After converting the data of the target frequency into an optical signal, the information is transmitted via light waves to achieve strong real-time transmission of high-speed attitude measurement information.

[0042] In an embodiment of the present invention, the time synchronization method for the attitude measurement data packet in step S101 specifically includes: using the time code information of the entire ship time reference as the absolute time, using the 1PPS second pulse of the time reference to complete the whole second latch of the navigation information, thereby deducing the Beijing time generated in real time by the navigation information, and realizing the synchronization relationship between the data and the time reference.

[0043] like Figure 2 As shown in FIG, a method for synchronizing the inertial navigation attitude information timestamp based on the synchronized second pulse of the time reference device mainly includes the following steps:

[0044] S1: Utilizes the navigation information processing board containing DSP and FPGA in the main inertial navigation system;

[0045] S2: Introduces the 200Hz attitude information and PPS pulse-per-second information of the time base sent by the inertial device into the navigation information processing board containing FPGA;

[0046] S3: Based on the two signals, the FPGA uses the rising edge of the second pulse to trigger and latch the 200Hz data packet closest to the second pulse. It then transmits the latched data packet and the delay between the data packet and the second pulse to the DSP serial port for analysis.

[0047] S4: DSP synchronously analyzes the full second data packet latched by FPGA and the time code information of the time reference device;

[0048] Assume that the Beijing time in the time code information is t1, the inertial navigation device running time in the data packet is t2 (the internal counter of the inertial navigation device, which accumulates over time), the delay between the data packet and the second pulse is Δt1, and then deduct the delay error caused by the inertial unit IMU from data generation to transmission to the solver board as Δt2, so the time difference between Beijing time and the inertial navigation running time is calculated as:

[0049] Δt = t1-t2 +Δt1+Δt2

[0050] S5: When the DSP receives the 200Hz attitude information, if the inertial navigation running time in the data packet is parsed as t2′, the corresponding timestamp t1′ can be obtained as:

[0051] t1′=Δt + t2′

[0052] In an embodiment of the present invention, the high-speed posture measurement information interpolation method in step S102 includes:

[0053] like Figure 3 As shown, the steps for linearly interpolating 200Hz data to 1000Hz data are as follows:

[0054] S1: Use the FPGA's built-in quartz crystal to generate a 1000Hz interrupt;

[0055] S2: Each time the 1000 Hz interrupt is triggered, a time difference with the most recent 200 Hz data is obtained, which is set as Δt′.

[0056] Furthermore, the following process is included:

[0057] ① Interpolation requirement determination method

[0058] The maximum roll amplitude under the sea conditions allowed by the platform is R0, and the minimum roll period is Tr; the maximum pitch amplitude under the sea conditions allowed by the platform is P0, and the minimum pitch period is T p The user requires the roll to be R' and the pitch to be P' for the attitude reference transfer error caused by time delay and platform motion; the main inertial navigation attitude measurement information update rate is G0; the main inertial navigation attitude measurement information update rate required by the user is G1; then:

[0059] R0 / (Tr*G1)≤R′

[0060] P0 / (Tp*G1)≤P′

[0061] ②Information interpolation design method

[0062] The linear interpolation method is used to greatly improve the data output update rate to achieve the high-speed output requirement of attitude measurement information. The conversion of the main inertial navigation 200Hz attitude measurement information to 1000Hz high-frequency data is taken as an example: specifically, the pitch P1, roll R1, heading H1, pitch angular rate PV1, roll angular rate RV1, and heading angular rate HV1 parsed from the 200Hz data packet are assumed, and Δt′ is the time difference between the interpolation moment and the full 5ms data (the data interval of the main inertial navigation 200Hz attitude measurement information).

[0063] The interpolated pitch P2, roll R2, and heading H2 are:

[0064] P2 = P1 + PV1*Δt′

[0065] R2 = R1 + RV1*Δt′

[0066] H2 = H1 + HV1*Δt′

[0067] You can get high-speed attitude information updated at a frequency of 1000Hz.

[0068] In an embodiment of the present invention, the real-time transmission method selection in step S103 includes:

[0069] Optical fiber communication is selected to convert the data of the target frequency into an optical signal through a photoelectric conversion module, and then the information is transmitted through light waves to achieve strong real-time transmission of high-speed posture measurement information.

[0070] like Figure 4 As shown in FIG, the electrical signal passes through the optical transmitter, optical fiber interface, repeater, and optical receiver module to form an optical fiber communication channel.

[0071] The strong real-time and high-speed posture information assurance method provided by the embodiment of the present invention first establishes a data transmission model using the principle of optical fiber communication; then takes advantage of the advantages of FPGA and DSP in processing high-speed data to complete the acquisition of timestamps through data latching and time deduction; and then uses the linear interpolation method to complete the conversion of 200Hz data to 1000Hz data.

[0072] The above is a detailed introduction to a strong real-time high-speed posture measurement information assurance method provided by an embodiment of the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for technical personnel in this field, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A strong real-time high-speed attitude measurement information assurance method, characterized in that: include: The time code information of the whole ship time reference is used as the absolute time, and the synchronous second pulse of the time reference is used to complete the time stamp synchronization of the inertial navigation attitude information; Determine the target frequency according to the interpolation requirements, and linearly interpolate the data packets sent by the inertial device into data of the target frequency; After converting the data of the target frequency into an optical signal, the information is transmitted via light waves to achieve strong real-time transmission of high-speed attitude measurement information; The method uses the time code information of the whole ship time reference as the absolute time and utilizes the synchronous second pulse of the time reference to complete the time stamp synchronization of the inertial navigation attitude information, including: The navigation information processing board of the main inertial navigation system, which includes a DSP and an FPGA, is used to introduce data packets and PPS pulse-per-second information of the time reference sent by the inertial device into the navigation information processing board. The data packets include attitude information. The FPGA in the navigation information processing board is triggered by the rising edge of the second pulse to latch the data packet closest to the second pulse, and transmit the latched data packet and the delay between the data packet and the second pulse to the serial port of the DSP for analysis; The DSP synchronously analyzes the full-second data packets latched by the FPGA and the time code information of the time reference device to calculate the time difference between Beijing time and the inertial navigation operation time. The time difference Δt between Beijing time and the inertial navigation operation time is calculated by Δt = t1-t2 +Δt1+Δt2, where t1 is the Beijing time in the time code information, t2 is the inertial navigation device operation time in the data packet, Δt1 is the delay between the data packet and the second pulse, and Δt2 is the delay error caused by the inertial device from data generation to transmission to the navigation information processing board; When the DSP receives the data packet, if the inertial navigation operation time in the data packet is parsed, the corresponding timestamp is obtained from the time difference between Beijing time and the inertial navigation operation time; The determining of the target frequency according to the interpolation requirement includes: The maximum roll amplitude under the allowable sea conditions is R0, and the minimum roll period is Tr. The maximum pitch amplitude under the allowable sea conditions is P0, and the minimum pitch period is T p ; The user requires the roll to be R′ and the pitch to be P′ for the attitude reference transfer error caused by time delay and platform motion. The main inertial navigation attitude measurement information frequency is G0, and the user's target frequency of the main inertial navigation attitude measurement information is G1. Therefore: R0 / (Tr*G1)≤R′, P0 / (Tp*G1)≤P′.

2. The method according to claim 1, wherein The corresponding timestamp t1′ is obtained by t1′=Δt + t2′, where t2′ is the inertial navigation running time in the data packet.

3. The method according to claim 1 or 2, characterized in that Determining the target frequency according to the interpolation requirement and linearly interpolating the data packet sent by the inertial device into data of the target frequency includes: Determine the target frequency based on the interpolation requirements and use the FPGA's built-in quartz crystal oscillator to generate an interrupt at the target frequency; Each time an interrupt is triggered, the time difference between the packet and the most recent packet is obtained and the value is interpolated based on the time difference.

4. The method according to claim 3, wherein The interpolated pitch P2, roll R2, and heading H2 are: P2 = P1 + PV1*Δt′, R2 = R1 + RV1*Δt′, H2 = H1 + HV1*Δt′, where Δt′ is the time difference between each interrupt trigger and the most recent data packet, P1 is the pitch parsed from the data packet sent by the inertial device, R1 is the roll parsed from the data packet sent by the inertial device, H1 is the heading parsed from the data packet sent by the inertial device, PV1 is the pitch angular rate parsed from the data packet sent by the inertial device, RV1 is the roll angular rate parsed from the data packet sent by the inertial device, and HV1 is the heading angular rate parsed from the data packet sent by the inertial device.

5. The method according to claim 4, characterized in that After converting the target frequency data into an optical signal, transmitting the information via the optical wave includes: Optical fiber communication is selected to convert the data of the target frequency into an optical signal through a photoelectric conversion module, and then the information is transmitted through light waves to achieve strong real-time transmission of high-speed posture measurement information.

6. The method according to claim 5, characterized in that The photoelectric conversion module includes an optical transmitter, an optical fiber interface, a repeater and an optical receiver which are connected in sequence.

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