Inertial navigation module and code table

Abstract

The utility model relates to electronic equipment and navigation technical field, concretely is a kind of inertial navigation module and code table, the inertial navigation module includes main control unit, inertial measurement unit and satellite positioning unit;The main control unit adopts SF32LB557VD3A6 microcontroller;The inertial measurement unit adopts LSM6DSOW six-axis sensor, and its I2C communication pin and interrupt pin are connected to I2C1 bus and general IO pin of main control unit respectively;The satellite positioning unit adopts AG3335M navigation chip, and its UART communication pin, power enable pin and second pulse pin are connected to UART5 bus, power control pin and second pulse input pin of main control unit respectively.The utility model is closely coupled by IMU and GNSS chip with specific hardware interface and main control unit, constructs the hardware foundation with multi-source information fusion capability, can keep positioning continuity by relying on inertial measurement unit when GNSS signal is weak or lost, effectively improves the reliability and trajectory precision of code table under complex environment.

Description

Technical Field

[0001] This utility model relates to the field of electronic equipment and navigation technology, specifically to an inertial navigation module and a codebook. Background Technology

[0002] Currently, bicycle cycling computers primarily rely on the Global Navigation Satellite System (GNSS) for positioning and track recording. However, in environments with weak or interfered GNSS signals, such as tunnels, between buildings, or tree-lined roads, the speed measurement and track recording of the cycling computer may become abnormal or even interrupted, severely impacting the user experience. Although inertial navigation technology can theoretically compensate for this deficiency, existing cycling computer products lack dedicated module designs that deeply couple the IMU and GNSS at the hardware level. Furthermore, some products have attempted to incorporate inertial navigation technology, but their circuit designs often suffer from problems such as improper sensor selection, low communication efficiency with the main controller, and imprecise power management, resulting in the inability to provide continuous, smooth, and accurate dead reckoning (DR) results in the absence of GNSS signals. Utility Model Content

[0003] This utility model addresses the technical problems existing in the prior art by providing an inertial navigation module and a code table.

[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: An inertial navigation module includes: a main control unit, an inertial measurement unit, and a satellite positioning unit; The main control unit uses a microcontroller of model SF32LB557VD3A6; The inertial measurement unit uses a six-axis sensor of model LSM6DSOW; The satellite positioning unit uses a navigation chip of model AG3335M; Specifically, the I2C communication pin of the inertial measurement unit is connected to the I2C1 bus pin of the main control unit; the interrupt pin of the inertial measurement unit is connected to the general purpose input / output pin of the main control unit; the UART communication pin of the satellite positioning unit is connected to the UART5 bus pin of the main control unit; and the power enable pin of the satellite positioning unit is connected to the general purpose input / output pin of the main control unit.

[0005] The beneficial effects of this utility model are: by optimizing hardware selection and precise pin connection design, efficient data interaction between IMU and MCU is achieved, ensuring seamless switching to high-precision inertial navigation mode when GNSS signal is lost.

[0006] Furthermore, the I2C1_SDA and I2C1_SCL pins of the main control unit are connected to the SDA and SCL pins of the inertial measurement unit, respectively; the 6_axis_sensor_INT1 and 6_axis_sensor_INT2 pins of the main control unit are connected to the INT1 and INT2 pins of the inertial measurement unit, respectively.

[0007] Furthermore, the USART5_RXD and USART5_TXD pins of the main control unit are connected to the GPS_UART0_TXD and GPS_UART0_RXD pins of the satellite positioning unit, respectively; the GPS_POWER_EN pin of the main control unit is connected to the CHIP_EN pin of the satellite positioning unit.

[0008] Furthermore, the inertial navigation module also includes a step-down DC-DC converter, model AW37420DNR; the voltage input terminal of the step-down DC-DC converter is connected to the system battery, its enable terminal is connected to the L1_GPS_POWER_EN pin of the main control unit, and its switching node is connected to an inductor and a capacitor to generate a stable power supply voltage to power the satellite positioning unit.

[0009] Furthermore, the GPS_PPS0 pin of the satellite positioning unit is connected to the GPS_PPS0 pin of the main control unit.

[0010] Furthermore, the inertial navigation module also includes a power management unit (PMU), model SF30147. The power supply pins VDD and VDDIO of the inertial measurement unit are electrically connected to the VDD_1V8_SENSOR power supply terminal output by the PMU. The power supply pins VDDIOA and VDDIOB of the main control MCU are both electrically connected to the VDD_1V8_SENSOR power supply terminal output by the PMU.

[0011] This utility model also provides a codebook, including the inertial navigation module as described above, and a display unit, wherein the display unit is connected to the main control unit through a MIPI DSI interface. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the inertial navigation module circuit design of this utility model; Figure 2 This is a schematic diagram of the main control unit circuit design of this utility model; Figure 3 This is a schematic diagram of the satellite positioning unit circuit design of this utility model; Figure 4This is a schematic diagram of the circuit design of the inertial measurement unit of this utility model. Detailed Implementation

[0013] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0014] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0015] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this technology based on the specific circumstances.

[0016] In the description of this application, spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., are used herein to describe the relationship between one element or feature shown in the figures and other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "below" or "under" or "below" of other elements or features will be oriented "above" other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein are interpreted accordingly.

[0017] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to implement and use the present invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the present invention can be implemented without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the present invention with unnecessary detail. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0018] Example 1 refer to Figures 1 to 4 As shown, this utility model provides an inertial navigation module, including: a main control unit (MCU), an inertial measurement unit (IMU), and a satellite positioning unit; The main control unit uses a microcontroller of model SF32LB557VD3A6; The inertial measurement unit uses a six-axis sensor of model LSM6DSOW; The satellite positioning unit uses a navigation chip of model AG3335M; Specifically, the I2C communication pin of the inertial measurement unit is connected to the I2C1 bus pin of the main control unit; the interrupt pin of the inertial measurement unit is connected to the general purpose input / output pin of the main control unit; the UART communication pin of the satellite positioning unit is connected to the UART5 bus pin of the main control unit; and the power enable pin of the satellite positioning unit is connected to the general purpose input / output pin of the main control unit.

[0019] Through the precise hardware circuit design and pin connections described above, this invention constructs a high-efficiency, stable, and low-power inertial navigation module hardware platform. When the codebook detects a loss or weakening of the GNSS signal, the main control MCU can immediately read the acceleration and angular velocity data of the IMU via the high-speed SPI bus, and, combined with the preset dead reckoning algorithm, continuously and smoothly update the user's position and trajectory, thereby solving the technical problem of poor positioning reliability in complex environments.

[0020] The main control unit U32B (SF32LB557VD3A6) serves as the control core of the system. Its I2C1_SDA and I2C1_SCL pins are connected to the SDA and SCL pins of the inertial measurement unit (IMU) for reading acceleration and angular velocity data. Its 6_axis_sensor_INT1 and 6_axis_sensor_INT2 pins are connected to the IMU's INT1 and INT2 pins for timely response to IMU data readiness or event interruptions.

[0021] The USART5_RXD and USART5_TXD pins of the main control unit U32B are cross-connected with the GPS_UART0_TXD and GPS_UART0_RXD pins of the satellite positioning unit U8A (AG3335M) to form a UART communication link for receiving satellite positioning data. The main control unit controls the CHIP_EN pin of the satellite positioning unit through its GPS_POWER_EN pin to achieve energy-saving management of the unit.

[0022] The GPS_PPS0 pin of the satellite positioning unit U8A is connected to the GPS_PPS0 pin of the main control unit U32B, providing a high-precision second pulse signal.

[0023] When the inertial navigation module is applied to the codebook, the main control unit U32B connects to the corresponding interface of the display unit through its MIPI DSI interface (including pins such as DSI_D0N, DSI_D0P, DSI_CLKN, and DSI_CLKP) to display navigation and motion information.

[0024] In a more preferred embodiment, the inertial navigation module further includes a step-down DC-DC converter, the model of which is AW37420DNR; the voltage input terminal of the step-down DC-DC converter is connected to the system battery, its enable terminal is connected to the L1_GPS_POWER_EN pin of the main control unit, and its switching node is connected to an inductor and a capacitor to generate a stable power supply voltage to power the satellite positioning unit.

[0025] The satellite positioning unit is powered by a dedicated step-down DC-DC converter U31 (AW37420DNR). The VIN pin of U31 is connected to the system battery voltage VCC_BAT, its EN pin is controlled by the L1_GPS_POWER_EN pin of the main control unit U32B, and its SW pin is connected to inductor L3 and filter capacitors C45 and C44, outputting a stable DC-DC_0V7_GPS voltage to power the satellite positioning unit.

[0026] In a more preferred embodiment, the inertial navigation module further includes a power management unit (PMU), model SF30147. The power supply pins VDD and VDDIO of the inertial measurement unit (IMU) are electrically connected to the VDD_1V8_SENSOR power supply output of the PMU. The power supply pins VDDIOA and VDDIOB of the main control MCU are also electrically connected to the VDD_1V8_SENSOR power supply output of the PMU. The power supply pins VDD and VDDIO of the IMU are also electrically connected to the VDD_1V8_SENSOR power supply output of the PMU. The ground pin GND of the IMU is electrically connected to system ground. The power supply pins VDDIOA and VDDIOB of the main control MCU are also electrically connected to the VDD_1V8_SENSOR power supply output of the PMU.

[0027] The IMU transmits acceleration and gyroscope data to the main control MCU via the SPI bus. The main control MCU is configured to perform dead reckoning algorithms based on the data received from the IMU when GNSS signals are lost.

[0028] Data flow: GNSS and IMU, as the main sensors, input data to the main control MCU via UART and SPI buses.

[0029] Control flow: The MCU controls the IMU via chip select (CS) and clock (SCL) and receives its interrupt (INT1).

[0030] Power supply flow: The PMU acts as the power supply hub, providing a stable and uniform 1.8V power supply to the critical MCU and IMU.

[0031] The core of the cycle clock circuit of this invention consists of a main control MCU (U1), a six-axis IMU sensor (U2), and a power management unit (PMU) (U3). The main control MCU U1 (model: SF32LB557VD3A6) and IMU U2 (model: LSM6DSOWTR) communicate via a high-speed SPI bus, and their specific pin connections are as follows: The IMU's SCL / SPC pin (SPI clock) is connected to the MCU's PA58 pin.

[0032] The IMU's SDO / SA0 pin (SPI Master Output / Slave Input, i.e., MISO) is connected to the MCU's PA59 pin.

[0033] The IMU's SDI / SDI pin (SPI master input / slave output, i.e., MOSI) is connected to the MCU's PA60 pin.

[0034] The IMU's CS / SPI2_CS pin (SPI chip select) is connected to the MCU's PA61 pin. Furthermore, for efficient event-driven operation, the IMU's interrupt output pin INT1 is connected to the MCU's general-purpose input / output pin PB36. When the IMU's internal data is ready or a preset motion event occurs, it sends an interrupt request to the MCU via the INT1 pin.

[0035] Regarding power management: The PMU U3 (model: SF30147) provides multiple stable voltages for the entire system.

[0036] The power supply pins VDD (core power) and VDDIO (I / O interface power) of IMU U2 are connected in parallel and are connected together to the VDD_1V8_SENSOR (1.8V) power supply terminal output by PMU.

[0037] The I / O power pins VDDIOA and VDDIOB of the main control MCU U1 are also connected to the VDD_1V8_SENSOR power supply terminal, ensuring I / O level matching and signal integrity between the MCU and the IMU.

[0038] All chips have their ground pins (GND) connected to a unified system ground plane.

[0039] The beneficial effects of this utility model are as follows: Advanced hardware selection: It adopts ST's LSM6DSOWTR six-axis IMU, which has a built-in high-performance 3-axis accelerometer and 3-axis gyroscope, and supports a high-speed SPI interface, providing a high-quality raw data source for high-precision dead reckoning.

[0040] High communication efficiency: By configuring the IMU as an SPI slave device and establishing a dedicated high-speed SPI bus connection with the master MCU, it is ensured that IMU data can be transmitted to the MCU in a low-latency, high-bandwidth manner, meeting the calculation requirements of real-time dead reckoning.

[0041] Timely interrupt response: The IMU's interrupt pin is directly connected to the MCU. When the IMU detects a significant motion event (such as a sudden acceleration change), it can immediately wake up the MCU to process it, improving the system's real-time performance and energy efficiency.

[0042] Fine-grained power management: The I / O power supplies of both the IMU and MCU are uniformly supplied by the VDD_1V8_SENSOR power rail of the PMU, which ensures the stability of the power supply and the noise suppression capability, and helps to improve the signal-to-noise ratio of sensor data.

[0043] Example 2 Based on the same inventive concept, this utility model also provides a code table, including the inertial navigation module as described above, and a display unit, wherein the display unit is connected to the main control unit through a MIPI DSI interface.

[0044] This invention constructs a tightly coupled hardware platform by hardware connecting the IMU, GNSS chip, and main control MCU through specific communication interfaces (I2C, UART) and signal lines (interrupt, enable, second pulse). This structure provides a physical basis for the IMU to provide inertial data and perform dead reckoning through the main control unit when the GNSS signal fails, thus ensuring the continuity and reliability of positioning at the hardware level. This invention has a clear structure, well-defined responsibilities for each unit, stable connections, and is suitable for industrial production.

[0045] While embodiments or examples of this disclosure have been described with reference to the accompanying drawings, it should be understood that the above embodiments are merely exemplary embodiments or examples, and the scope of this utility model is not limited by these embodiments or examples, but only by the granted claims and their equivalents. Various elements in the embodiments or examples may be omitted or replaced by their equivalents. Furthermore, the steps may be performed in a different order than that described in this disclosure. Further, various elements in the embodiments or examples may be combined in various ways. Importantly, as the technology evolves, many elements described herein can be replaced by equivalents that appear after this disclosure.

Claims

1. An inertial navigation module, characterized in that, include: Main control unit, inertial measurement unit, and satellite positioning unit; The main control unit uses a microcontroller of model SF32LB557VD3A6; The inertial measurement unit uses a six-axis sensor of model LSM6DSOW; The satellite positioning unit uses a navigation chip of model AG3335M; Specifically, the I2C communication pin of the inertial measurement unit is connected to the I2C1 bus pin of the main control unit; the interrupt pin of the inertial measurement unit is connected to the general purpose input / output pin of the main control unit; the UART communication pin of the satellite positioning unit is connected to the UART5 bus pin of the main control unit; and the power enable pin of the satellite positioning unit is connected to the general purpose input / output pin of the main control unit.

2. The inertial navigation module according to claim 1, characterized in that, The I2C1_SDA and I2C1_SCL pins of the main control unit are connected to the SDA and SCL pins of the inertial measurement unit, respectively; the 6_axis_sensor_INT1 and 6_axis_sensor_INT2 pins of the main control unit are connected to the INT1 and INT2 pins of the inertial measurement unit, respectively.

3. The inertial navigation module according to claim 1, characterized in that, The USART5_RXD and USART5_TXD pins of the main control unit are connected to the GPS_UART0_TXD and GPS_UART0_RXD pins of the satellite positioning unit, respectively; the GPS_POWER_EN pin of the main control unit is connected to the CHIP_EN pin of the satellite positioning unit.

4. The inertial navigation module according to claim 1, characterized in that, The inertial navigation module also includes a step-down DC-DC converter, model AW37420DNR. The voltage input terminal of the step-down DC-DC converter is connected to the system battery, its enable terminal is connected to the L1_GPS_POWER_EN pin of the main control unit, and its switching node is connected to an inductor and a capacitor to generate a stable power supply voltage to power the satellite positioning unit.

5. The inertial navigation module according to claim 1, characterized in that, The GPS_PPS0 pin of the satellite positioning unit is connected to the GPS_PPS0 pin of the main control unit.

6. The inertial navigation module according to claim 1, characterized in that, The inertial navigation module also includes a power management unit (PMU), model SF30147. The power supply pins VDD and VDDIO of the inertial measurement unit are electrically connected to the VDD_1V8_SENSOR power supply terminal output by the PMU. The power supply pins VDDIOA and VDDIOB of the main control unit are both electrically connected to the VDD_1V8_SENSOR power supply terminal output by the PMU.

7. A code table, characterized in that, It includes an inertial navigation module as described in any one of claims 1 to 6, and a display unit, wherein the display unit is connected to the main control unit via a MIPI DSI interface.

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