Navigation computer for small inertial navigation system

Abstract

The invention provides a navigation computer for a small inertial navigation system, the size of the navigation computer is only 55mm * 86mm * 16mm, a navigation resolving module, an I / F conversion module and a power supply module are integrated, and the power consumption is less than 3W; the navigation resolving module takes a ZYNQ7000 all-programmable SoC as a core processor, and has the functions of inertial device original data acquisition, navigation information preprocessing, navigation resolving and the like; the I / F conversion module can directly convert a current signal of the accelerometer into a pulse signal, and the pulse signal is accessed to the navigation resolving module for navigation resolving; the power supply module can output + 5V (8W),-5V (3W), + 15V (9W) and-15V (3W) isolated voltage-stabilized power supplies to the outside, and can supply power to other loads of the inertial navigation equipment. The method is suitable for laser inertial navigation equipment with small volume, low power consumption and high reliability.

Description

Technical Field

[0001] The present application relates to the technical field of navigation systems, and in particular to a navigation computer for a small micro inertial navigation system. Background Art

[0002] An inertial navigation system is a system that uses gyroscopes and accelerometers installed on a vehicle to measure the state of the vehicle. The gyroscope is used to sense angular motion information, and the accelerometer is used to sense linear motion information. Based on the data from the gyroscope and accelerometer, the inertial navigation system can determine the motion of the vehicle in the inertial reference frame.

[0003] Compared with other types of navigation systems, such as satellite navigation, astronomical navigation, radio navigation and other navigation systems, the inertial navigation system is completely autonomous. It neither transmits signals to the outside nor receives signals from the outside. It uses inertial measurement values ​​to continuously calculate the motion state of the carrier after startup based on the precise position of the carrier at the initial moment. Due to its completely autonomous characteristics, the inertial navigation system is widely used in military fields such as submarines, ships, aircraft, rockets, and satellites.

[0004] The navigation computer is a core key technology of the inertial navigation system. Its main task is to collect the signals output by the gyroscope and accelerometer of the inertial device, and perform navigation solution mechanical arrangement based on the collected inertial information and the initial position information bound externally, so as to obtain the navigation information such as the heading, attitude, speed, and position of the vehicle. The navigation solution mechanical arrangement involves a large number of high-order matrix operations and polynomial operations, which requires a large amount of calculation; and the calculation frequency has a direct impact on the navigation accuracy, which places high demands on the performance of the navigation computer. Traditional navigation computers adopt single DSP+FPGA, dual DSP+FPGA, SoC, PC and other architecture solutions. With the development trend of low-power, miniaturized, and high-precision inertial navigation systems, traditional navigation computers can no longer meet the needs of new inertial navigation. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of large size, high power consumption and limited computing power of traditional navigation computers in inertial navigation systems, and to propose a high-performance, small-sized navigation computer with a size of only 55mm×86mm×16mm, which is suitable for small-sized, low-power-consumption and high-reliability laser inertial navigation equipment.

[0006] The specific technical solution of the present invention is a navigation computer for a small inertial navigation system, which includes an integrated navigation solution module, an I / F conversion module, and a power module, and has a power consumption of less than 3W; wherein the navigation solution module includes a processing module with a ZYNQ7000 fully programmable SoC as a core processor, and has the functions of raw data collection of inertial devices, navigation information preprocessing, and navigation solution;

[0007] The navigation solution module includes a processing module, a digital isolation module, a temperature measurement module, a register module, a memory module and a storage module, and also includes at least one of a digital interface module and a network interface module;

[0008] The digital isolation module is an isolation chip, the input end of the digital isolation module is connected to the inertial measurement unit, and the output end of the digital isolation module is connected to the processing module, which is used to obtain the navigation parameter data in the inertial measurement unit and input it into the processing module;

[0009] The temperature measurement module is a temperature measurement chip, the input end of the temperature measurement module is connected to the inertial measurement unit, and the output end of the temperature measurement module is connected to the processing module, which is used to obtain the temperature parameter data in the inertial measurement unit and input it into the processing module;

[0010] The register module is a QSPI register, and the register module is connected to the processing module;

[0011] The memory module is a memory, and the memory module is connected to the processing module;

[0012] The storage module is a non-volatile memory, and the storage module is connected to the processing module;

[0013] The digital interface module is an isolated transceiver, one end of which is connected to the processing module, and the other end is connected to the information exchange unit, so as to perform data exchange between the processing module and the information exchange unit;

[0014] The network interface module is an Ethernet chip, one end of which is connected to the processing module, and the other end is connected to the information exchange unit, so as to exchange data between the processing module and the information exchange unit;

[0015] The I / F conversion module converts the current signal of the accelerometer into a pulse signal, which is connected to the navigation solution module for navigation solution. The power supply module converts the input primary power supply into four isolated secondary power supplies, which can output isolated regulated power supplies of +5V (8W), -5V (3W), +15V (9W), and -15V (3W) to power the remaining loads of the inertial navigation device.

[0016] Furthermore, the inertial measurement unit includes a gyroscope and an accelerometer with RTD thermal resistors; the temperature measurement module is a temperature measurement chip LTC2983, and the input end of the temperature measurement chip is respectively connected to the RTD thermal resistors inside the gyroscope and the accelerometer.

[0017] Furthermore, the digital isolation module is a six-channel isolation chip ADuM7640; the isolation chip is used to collect pulse data signals of the gyroscope and accelerometer.

[0018] Furthermore, the processing module is a ZYNQ scalable processing platform, and the ZYNQ scalable processing platform includes a programmable logic unit and a dual-core processing system; the dual-core processing system includes core 0 and core 1.

[0019] Furthermore, the memory module includes a DDR3 memory, and the DDR3 memory is connected to core 0.

[0020] Furthermore, the digital interface is an isolated transceiver ADM2582, and the isolated transceiver is used to ensure that the navigation computer is isolated from external signals to prevent external interference signals from interfering with the navigation computer.

[0021] Furthermore, the network interface module is an 88E1512 Gigabit Ethernet transceiver, and the Ethernet transceiver is used to form an adaptive Gigabit Ethernet interface with the ZYNQ scalable processing platform.

[0022] Furthermore, the navigation computer includes a clock module, which is connected to the processing module to provide a clock signal for the processing module.

[0023] Furthermore, the navigation computer includes a power management module, and the power management module is connected to the processor module, the clock module and the temperature measurement module respectively.

[0024] Furthermore, the I / F conversion module is integrated with a function for converting the output current of the quartz flexible accelerometer into a pulse signal proportional thereto, and the absolute value of the I / F conversion module range is ≥16mA and the nonlinearity is ≤30ppm.

[0025] The beneficial effects of the present invention application are:

[0026] The navigation computer in the present invention application has an internally integrated I / F conversion module, which can directly process the current signal output by the accelerometer without the need for additional configuration of the I / F conversion module, and has the advantages of low power consumption and small size.

[0027] The navigation computer in the present invention has an internal integrated power supply module, which can output four-way isolated secondary power supplies without the need for additional power supply modules, and has the advantages of low power consumption and small size.

[0028] The navigation computer in the present invention application adopts the ZYNQ scalable processing platform, which can be used with both the fiber optic gyro inertial navigation system and the laser gyro inertial navigation system, and has the characteristics of good compatibility, strong computing power, low power consumption, small size, rich external interfaces and good scalability.

[0029] The navigation computer in the present invention adopts both digital interface and network interface to interact with user information. The simultaneous use of the two interfaces improves the stability of data transmission. In addition, in special circumstances where one interface cannot be used, another interface is provided to ensure data transmission.

[0030] Compared with the DSP+FPGA architecture solution commonly used in navigation computers in current inertial navigation systems, the navigation computer in the application of the present invention, based on the ZYNQ architecture, realizes functions such as data acquisition, navigation information preprocessing, and navigation solution on a single chip. It has high integration, small size, and low power consumption. Its size is only 55mm×86mm×16mm, and its computing power is greatly improved. The navigation solution frequency of 100Hz commonly used in current inertial navigation systems is increased to 1KHz, thereby improving the data update rate of the navigation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The present invention is a schematic diagram of the structure of a navigation computer for a small inertial navigation system.

[0033] Figure 2 A physical diagram of a navigation computer for a small inertial navigation system for this application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. It should be noted that, in the absence of conflict, the various features in the embodiments of the present application can be combined with each other, and the combined embodiments are still within the scope of protection of the present application.

[0035] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the application is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0036] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] As attached Figure 1 The micro-application is a schematic diagram of the structure of a navigation computer for a small inertial navigation system. The navigation computer for a small inertial navigation system provided by the present invention integrates a navigation solution module, an I / F conversion module, and a power module. The navigation solution module includes an inertial measurement unit, an information exchange unit, and a navigation computer. The navigation computer includes a processing module, a register module, a memory module, a storage module, a clock module, a digital interface module, a network interface module, a digital isolation module, a temperature measurement module, and a power management module.

[0038] The digital isolation module is an isolation chip. The input end of the digital isolation module is connected to the inertial measurement unit to realize the navigation parameter data collection of the gyroscope and accelerometer in the inertial measurement unit and convert the analog signal in the inertial measurement unit into a digital signal; the output end of the digital isolation module is connected to the processing module to transmit the digital signal of the gyroscope and accelerometer pulse data to the processing module.

[0039] The input end of the temperature measurement module is connected to the inertial measurement unit, and the output end is connected to the processing module. It is used to obtain the temperature parameter data of the gyroscope and accelerometer in the inertial measurement unit and to transmit the temperature digital signals of the gyroscope and accelerometer to the processing module.

[0040] The processing module is used to process the acquired navigation parameter data and temperature parameter data.

[0041] The register module is a QSPI register connected to the processing module, storing the navigation compensation model and the navigation solution model used for navigation.

[0042] The memory module is a 1GB memory used to run the navigation preprocessing program and the navigation settlement program.

[0043] The storage module is a non-volatile memory, which is connected to the processing module through the SD bus and is used to save the original data of navigation parameter data and temperature parameter data output by the inertial measurement unit during navigation, so that the data can be used to analyze the working status of the system afterwards.

[0044] The digital interface module is an isolated transceiver. One end of the digital interface module is connected to the processing module, and the other end is connected to the information exchange unit to realize information interaction between the inertial navigation system and the user.

[0045] The network interface module is an Ethernet chip, one end of which is connected to the processor module, and the other end is connected to the information exchange unit, so as to realize information interaction between the inertial navigation system and the user.

[0046] The clock module is connected to the processing module and provides a clock signal to the processing module.

[0047] The I / F conversion module can directly convert the current signal of the accelerometer into a pulse signal, which is then connected to the navigation solution module for navigation solution. The power module can output +5V (power 8W), -5V (power 3W), +15V (power 9W), -15V (power 3W) isolated regulated power supplies to power the rest of the inertial navigation equipment.

[0048] The present invention adopts an accelerometer as the core device of an inertial navigation system and an inertial measurement unit. The accuracy of the accelerometer and its signal conversion circuit directly determines the accuracy of the entire system. The quartz flexible accelerometer used in the present invention uses current as the output signal. The analog current signal needs to be converted into a digital signal and provided to the navigation computer for navigation calculation. The circuit that completes the conversion function is collectively referred to as an I / F conversion circuit or an I / F conversion module.

[0049] In one embodiment, the processing module of the navigation computer is a main control chip ZYNQ XC7Z020CLG400 that integrates an ARM dual-core CortexA9 processor and an 85K programmable logic unit. The main frequency of each ARM core is as high as 766MHz, and a high-precision floating-point unit (VFPU) is integrated, which can meet the requirements of the inertial navigation system for ultra-high computing power of navigation computing power. In the design, Micron's QSPI register chip N25Q128A is selected to connect with ZYNQ to store the ZYNQ chip startup program. The register chip storage capacity is 128Mb, which can meet the storage requirements of the boot program, programmable logic movie program, ARM core 0 program and ARM core 1 program; the memory module is configured with a Micron DDR3 chip MT41K256M16 to expand the ZYNQ chip memory. The expanded memory can make the processor run more efficiently and improve the navigation algorithm operation efficiency. Core 0 and core 1 are each allocated 512MB of memory space to independently run the navigation preprocessing program and navigation settlement program.

[0050] The network interface module uses Marvell's 88E1512, the chip operating voltage is 1.8V, and is connected to the ZYNQ integrated network MAC controller to form an adaptive Gigabit Ethernet interface.

[0051] The digital interface module uses Analog's ADM2582 isolated transceiver, which can provide ±15Kv ESD protection and a data transmission rate of 16Mbps. The isolated transceiver can ensure that the navigation computer is isolated from external signals, prevent external interference signals from crosstalking into the navigation computer, and ensure the reliability of the navigation computer.

[0052] The temperature measurement module uses Analog's multi-sensor high-precision digital temperature measurement integrated chip LTC2983, which can directly digitize RTD, thermocouple, thermistor and diode, and is used to measure the temperature of gyroscope and accelerometer to achieve performance compensation for gyroscope and accelerometer; the LTC2983 temperature measurement chip of the temperature measurement module is connected to the RTD temperature measurement sensor inside the gyroscope and accelerometer respectively; the ZYNQ controller is connected to the LTC2983 through the SPI bus, and the temperature measurement value of the desired channel can be directly read through register configuration.

[0053] The digital isolation module uses the ADuM7640 digital isolation chip from Analog, which can realize 3V / 5V level conversion and a transmission rate of up to 25Mbps. The TTL level signal output by the gyroscope and accelerometer is connected to the isolation chip, which can convert the 5V level to 3.3V for sampling by the ZYNQ controller. The isolation chip can realize level isolation between the gyroscope, accelerometer and navigation computer inside the IMU, avoid signal coupling and interference between modules, and improve system reliability.

[0054] As a processing module, ZYNQ integrates PS and PL in the chip, which can replace the dual DSP+FPGA architecture of the existing mainstream navigation computer. The PL is a programmable logic unit that is programmed through a hardware description language. It mainly implements temperature acquisition, sampling, filtering, and counting of gyroscope and accelerometer pulse signals, and generates interrupts at regular intervals to notify the PS to read the sampled data. The PS includes two ARM cores. The ARM core 0 processor is mainly responsible for the preprocessing of inertial navigation information, including gyroscope and accelerometer temperature compensation, installation error compensation, and cone error compensation, and converts the collected raw data into inertial data that can be used for navigation. ARM core 1 is mainly responsible for the mechanical arrangement of inertial navigation and external interface communication. Core 1 reads the raw data processed by core 0 through shared memory, and calculates the navigation information such as heading, attitude, speed, and position of the inertial navigation system based on the initial position information bound externally and the navigation solution equation. According to external use requirements, the navigation information is sent out through RS422 or Ethernet.

[0055] The effects of the present invention are described as follows in combination with the structure and working principle of the present invention:

[0056] The navigation computer designed by the present invention application is connected to an inertial measurement unit (IMU), the gyroscope output signal in the inertial measurement unit is a TTL pulse signal, and the accelerometer output is a current signal. The gyroscope signal and the accelerometer pulse signal after passing through the I / F conversion module are connected to the PL end (programmable logic unit) of the processing module after passing through the six-channel isolation chip ADuM7640 of the digital isolation module. The PL end filters, edge samples, counts, and caches the pulse signals input by the gyroscope and accelerometer respectively. The LTC2983 temperature measurement chip of the temperature measurement module is connected to the RTD temperature measurement sensor inside the gyroscope and accelerometer respectively. The PL end reads the temperature value measured by the LTC2983 temperature measurement unit through the SPI interface and caches it in the corresponding memory. The PL frequency division generates a high-precision 4KHz interrupt signal to notify the ARM core 0 processor to read the output signal and temperature value of the gyroscope and accelerometer at the corresponding address. The core 0 processor reads the pre-calibrated gyroscope and accelerometer temperature compensation model and installation error model from the QSPI register, and performs temperature compensation and installation error compensation on the gyroscope and accelerometer signals according to the error model. The compensated data is then subjected to a four-sample iteration algorithm to compensate for the error caused by conical motion in the inertial navigation system, and converted into valid data for high-precision navigation solution. Core 0 passes the error-compensated inertial raw data to core 1 through a shared memory method. Core 1 obtains the externally bound initial position information based on the Ethernet chip of the network interface module or the RS422 chip of the digital interface module, runs the navigation solution program, and after the algorithm modules such as attitude update, velocity update, position update and earth parameter update, the navigation computer obtains navigation information such as heading, attitude, velocity, and position. According to external requirements, the information is exchanged with the information exchange unit through the Ethernet chip of the network interface module and the RS422 chip of the digital interface module.

[0057] The navigation computer based on ZYNQ architecture in the present invention realizes the functions of data acquisition, navigation information preprocessing, navigation solution, etc. on a single chip, with high integration, small size, low power consumption, and a size of only 55mm×86mm×16mm. Figure 2 A physical picture of a navigation computer used in a small inertial navigation system.

[0058] Although the present invention has been disclosed as above with preferred embodiments, the embodiments are not intended to limit the present invention. Any equivalent changes or modifications made without departing from the spirit and scope of the present invention also fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the content defined by the claims of the present application.

[0059] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A navigation computer for a small inertial navigation system, characterized in that: It includes an integrated navigation solution module, an I / F conversion module, and a power module, with a power consumption of less than 3W. The navigation solution module includes a processing module with the ZYNQ7000 fully programmable SoC as the core processor, which has the functions of inertial device raw data collection, navigation information preprocessing, and navigation solution. The navigation solution module includes a processing module, a digital isolation module, a temperature measurement module, a register module, a memory module and a storage module, and also includes at least one of a digital interface module and a network interface module; The digital isolation module is an isolation chip, the input end of the digital isolation module is connected to the inertial measurement unit, and the output end of the digital isolation module is connected to the processing module, which is used to obtain the navigation parameter data in the inertial measurement unit and input it into the processing module; The temperature measurement module is a temperature measurement chip, the input end of the temperature measurement module is connected to the inertial measurement unit, and the output end of the temperature measurement module is connected to the processing module, which is used to obtain the temperature parameter data in the inertial measurement unit and input it into the processing module; The register module is a QSPI register, and the register module is connected to the processing module; The memory module is a memory, and the memory module is connected to the processing module; The storage module is a non-volatile memory, and the storage module is connected to the processing module; The digital interface module is an isolated transceiver, one end of which is connected to the processing module, and the other end is connected to the information exchange unit, so as to perform data exchange between the processing module and the information exchange unit; The network interface module is an Ethernet chip, one end of which is connected to the processing module, and the other end is connected to the information exchange unit, so as to exchange data between the processing module and the information exchange unit; The I / F conversion module converts the current signal of the accelerometer into a pulse signal, which is connected to the navigation solution module for navigation solution; The power module converts the input primary power into four isolated secondary power supplies, which can output isolated regulated power supplies of +5V (8W), -5V (3W), +15V (9W), and -15V (3W) to power the remaining loads of the inertial navigation device.

2. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The inertial measurement unit includes a gyroscope and an accelerometer with RTD thermal resistors; the temperature measurement module is a temperature measurement chip LTC2983, and the input end of the temperature measurement chip is respectively connected to the RTD thermal resistors inside the gyroscope and the accelerometer.

3. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The digital isolation module is a six-channel isolation chip ADuM7640; the isolation chip is used to collect pulse data signals of the gyroscope and accelerometer.

4. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The processing module is a ZYNQ scalable processing platform, which includes a programmable logic unit and a dual-core processing system; the dual-core processing system includes core 0 and core 1.

5. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The memory module includes a DDR3 memory, and the DDR3 memory is connected to core 0.

6. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The digital interface is an isolated transceiver ADM2582, and the isolated transceiver is used to ensure that the navigation computer is isolated from external signals to prevent external interference signals from crosstalking into the navigation computer.

7. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The network interface module is an 88E1512 Gigabit Ethernet transceiver, and the Ethernet transceiver is used to form an adaptive Gigabit Ethernet interface with the ZYNQ scalable processing platform.

8. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The navigation computer comprises a clock module, which is connected to the processing module and provides a clock signal for the processing module.

9. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The navigation computer comprises a power management module, and the power management module is respectively connected to the processor module, the clock module and the temperature measurement module.

10. A navigation computer for a small inertial navigation system as claimed in claim 1, characterized in that: The I / F conversion module is integrated with a function of converting the output current of the quartz flexible accelerometer into a pulse signal proportional to the output current. The absolute value of the I / F conversion module range is ≥16mA, and the nonlinearity is ≤30ppm.

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