Beidou independent positioning communication device

Abstract

The invention relates to a Beidou independent positioning communication device, which is characterized by comprising a main control chip, a communication expansion module and an interface module, the interface module comprises a 485 interface, a TTL interface and an antenna interface; the main control chip U1 is connected with an external antenna E1 through an antenna interface J3; an output pin of the main control chip U1 is connected with TTL communication equipment through a TTL interface J2; the communication extension module comprises an RS-485 transceiver chip U2, one side of the RS-485 transceiver chip U2 is connected with the main control chip U1 through an isolation chip U3, the other side of the RS-485 transceiver chip U2 is connected with a 485 interface J1, and the RS-485 transceiver chip U2 is used for performing bidirectional conversion on a UART signal of a TTL level output by the main control chip U1 and a differential RS485 signal. The Beidou independent positioning communication device provided by the invention can be directly butted with external hardware equipment of different communication types, and a communication conversion module does not need to be additionally configured, so that the system integration cost is reduced, and the application range of the device is expanded.

Description

Technical Field

[0001] This invention relates to the field of satellite positioning technology, and in particular to a BeiDou independent positioning device. Background Technology

[0002] With the rapid development of BeiDou positioning and navigation, many industries have imposed strict requirements on equipment positioning. For example, power transmission line online monitoring devices previously relied heavily on GPS positioning. However, due to the critical strategic importance of power transmission lines and information security considerations, the industry now mandates the use of only BeiDou positioning. For manufacturers of power transmission line online monitoring devices, this allows for the rapid integration of a pure BeiDou independent positioning and communication device, reducing development costs. Summary of the Invention

[0003] The purpose of this invention is to provide a BeiDou independent positioning and communication device to enable rapid integration and docking of the BeiDou independent positioning and communication device with existing hardware devices in the future.

[0004] The objective of this invention can be achieved through the following technical solutions: A Beidou independent positioning and communication device includes a main control chip U1, a communication expansion module, and an interface module; The interface module includes: a 485 interface J1, a TTL interface J2, and an antenna interface J3; The main control chip U1 is connected to the external antenna E1 through the antenna interface J3, and the output pins of the main control chip U1 are connected to the external TTL communication device through the TTL interface J2. The communication expansion module includes an RS-485 transceiver chip U2. One side of the RS-485 transceiver chip U2 is connected to the main control chip U1 through an isolation chip U3, and the other side is connected to the 485 interface J1. It is used to bidirectionally convert the TTL level UART signal output by the main control chip U1 to the differential RS485 signal.

[0005] As a preferred technical solution, the external antenna E1 is connected to the RF_IN pin of the main control chip U1 via a microstrip line. The VCC_RF pin of the main control chip U1 is connected to the external antenna E1 in sequence via a grounding capacitor C1 and an inductor L1 to provide a DC bias path for the antenna.

[0006] As a preferred technical solution, the TXD and RXD pins of the main control chip U1 are general serial communication terminals, which are connected to the isolation chip U3 and the TTL interface J2 through resistors R3 and R4 respectively, for transmitting positioning data.

[0007] As a preferred technical solution, the TIMEIMPULSE pin of the main control chip U1 is connected to drive an LED via resistor R1 and diode D1 to indicate the positioning status.

[0008] As a preferred technical solution, the VBCKP pin of the main control chip U1 is connected to the backup battery BAT to store ephemeris data and achieve hot start and rapid positioning.

[0009] As a preferred technical solution, on the input side of the RS-485 transceiver chip U2: the output receive interface RO is connected to the B1 interface of the isolation chip U3; the drive input interface DI is connected to the B2 interface of the isolation chip U3; and the receive / drive enable interface RE / DE is shorted and then connected to VCC. On the output side of the RS-485 transceiver chip U2: a bus termination matching resistor is connected between the differential bus interface A and the differential bus interface B of the RS-485; differential bus interface A is connected to the power supply of the RS-485 transceiver chip U2 through a pull-up resistor, and differential bus interface B is connected to ground through a pull-down resistor; ESD protection diodes are connected in parallel between differential bus interface A, differential bus interface B and ground respectively.

[0010] As a preferred technical solution, the isolation chip U3 is used to achieve signal isolation between the RS-485 side and the main control chip; On the RS-485 side: Signal interfaces B1 and B2 are connected to the output receiving interface RO and the drive input interface DI of the RS-485 transceiver, respectively; VCCB and enable port OE are connected to the RS-485 power supply. On the main control chip side: signal interfaces A1 and A2 are connected to the TXD and RXD pins of the main control chip U1, respectively; VCCA is connected to the 3.3V power supply on the main control chip side.

[0011] As a preferred technical solution, the 485 interface J1 has 4 pin terminals: pin 1 is an external power supply / output pin, providing 5V power to the RS-485 transceiver chip U2; pin 2 is the RS485 communication A line, connected to the differential bus interface A of the RS-485 transceiver chip U2; pin 3 is the RS485 communication B line, connected to the differential bus interface B of the RS-485 transceiver chip U2; pin 4 is the signal ground, connected to the device ground to provide a reference ground for communication and power supply.

[0012] As a preferred technical solution, the TTL interface J2 is a TTL serial port interface, which adopts a 4-pin terminal: pin 1 is the RXD terminal, pin 2 is the TXD terminal, pin 3 is the PPS terminal, and pin 4 is the GND terminal. The TXD terminal is connected to the TXD pin of the main control chip U1, and the RXD terminal is connected to the RXD pin of the main control chip U1, so as to realize the connection between the main control chip U1 and the external TTL communication device.

[0013] As a preferred technical solution, the main control chip U1 and the antenna interface J3 are located on the same side of the PCB; the RS-485 transceiver chip U2, the isolation chip U3, the 485 interface J1 and the TTL interface J2 are located on the other side of the PCB.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The beneficial effects of this invention are as follows: 1) This device integrates TTL and 485 interfaces through the cooperation of the main control chip and the expansion communication chip, achieving compatibility between the two communication protocols. It can directly interface with external hardware devices of different communication types without the need for additional communication conversion modules, thereby reducing system integration costs and expanding the application range of the device.

[0015] 2) This device uses a dual-band BeiDou antenna and a dedicated main control chip, which supports the reception of BeiDou-2 and BeiDou-3 signals in the B1I and B1C bands. This improves the satellite signal reception capability and anti-interference performance, enabling stable positioning in complex environments. It has high positioning and timing accuracy and can meet the needs of high-precision positioning and timing applications.

[0016] 3) This device adopts an isolation design, and uses the isolation chip U3 BC0102 to achieve dual isolation of power supply and signal, thereby improving the anti-interference capability of the positioning device.

[0017] 4) This device achieves high integration and miniaturization, highly integrating functional modules such as main control, communication expansion, and antenna interface. It adopts miniaturized components and a compact PCB layout, resulting in a small overall size and light weight, making it easy to integrate into miniaturized devices such as vehicle navigation, wearable devices, and drones. Attached Figure Description

[0018] Figure 1 This is a circuit diagram of the main control chip U1 in this invention.

[0019] Figure 2 This is a circuit diagram of the RS-485 transceiver chip U2 in this invention.

[0020] Figure 3 This is a circuit diagram of the isolation chip U3 in this invention.

[0021] Figure 4 This is a circuit diagram of the 485 interface J1 in this invention.

[0022] Figure 5 This is a circuit diagram of the TTL interface J2 in this invention.

[0023] Figure 6 This is a PCB circuit design diagram in an embodiment of the present invention. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] Example 1 A BeiDou independent positioning device includes a main control module, a communication expansion module, an interface module, and an antenna module. The main control module is the core control unit, used for receiving, parsing, calculating positioning information, and controlling data output from BeiDou signals. The communication expansion module is connected to the main control module and is used to expand communication interface types, enabling conversion and adaptation to different communication protocols. The interface module includes multiple functional interfaces for communication and antenna connections. The antenna module is connected to the main control module and is used to receive BeiDou satellite signals.

[0028] Furthermore, the main control module uses the UP1612BD main control chip U1, a high-performance single BeiDou positioning and navigation module. This chip integrates a BeiDou signal receiving circuit, a high-performance embedded CPU positioning calculation engine, and a serial communication controller. It supports parallel reception and analysis of BeiDou B1I and B1C dual-band signals, achieving a positioning accuracy of 1-3 meters and a timing accuracy better than 50ns, meeting the requirements of high-precision positioning and timing applications. Figure 1 As shown, the main control chip U1 specifically includes the following parts: The power supply section of the main control chip U1: The 3.3V power supply passes through inductor L2 and a π-type filter network composed of capacitors C2, C3 and C4 to filter out power supply noise before being connected to the VCC pin of the main control chip U1 to provide the main control module with 3.3V main power.

[0029] The RF section of the main control chip U1 is as follows: Antenna E1 (ANTENNA) is connected to the RF_IN pin of the main control chip U1 through a 50Ω impedance microstrip line. The VCC_RF pin of the main control chip U1 provides bias voltage for antenna E1. First, the RF signal is filtered and impedance matched through the grounding capacitor C1, and then the inductor L1 is used to suppress high frequency interference and provide a DC bias path for the antenna.

[0030] The communication and control section of the main control chip U1 is as follows: UART serial port: The TXD and RXD pins of the main control chip U1 are general serial communication terminals, which are connected to the communication expansion module through resistors R3 and R4 respectively, for transmitting positioning data.

[0031] The reset and status indication section of the main control chip U1 is as follows: The RESET pin is used for module reset; the TIMEIMPULSE pin drives an LED through resistor R1 and diode D1 to indicate the positioning status (such as 1PPS pulse output per second).

[0032] The main control chip U1 is also connected to the backup battery BAT via the VBCKP pin to store ephemeris data and enable hot start for rapid positioning.

[0033] Furthermore, the communication expansion module consists of an RS-485 transceiver chip U2, an isolation chip U3, and ESD protection devices, realizing the functions of signal isolation, bus driving, and electrostatic protection, and is suitable for communication links in industrial strong interference scenarios.

[0034] Preferably, in this embodiment, the RS-485 transceiver chip is MAX13487ESA, which is responsible for bidirectional conversion between TTL level UART signals (RS485_TX1_6V, RS485_RX1_6V) and differential RS485 signals (RS485_1_A, RS485_1_B).

[0035] Input side: Output receive interface RO connects to interface B1 of isolation chip U3; drive input interface DI connects to interface B2 of isolation chip U3; receive / drive enable interface RE / DE is shorted and then connected to VCC to keep the transceiver always on (MAX13487 supports AutoDirection, no additional control is required).

[0036] Output side: A / B are RS-485 differential bus interfaces. A bus termination matching resistor R609 is connected between differential bus interface A and differential bus interface B to eliminate signal reflection and improve communication reliability. Resistor R608 pulls differential bus interface A up to 485_5V, and resistor R611 pulls pin B down to ground to ensure a stable differential voltage between A and B when the bus is idle, avoiding receiver misinterpretation. ESD protection diodes D63 and D64 are connected in parallel between differential bus interface A, differential bus interface B and ground, respectively, to clamp electrostatic pulses to a safe voltage and protect the RS-485 bus interface from electrostatic discharge / surge impacts.

[0037] Preferably, in this embodiment, the isolation chip U3 is model BCT0102, which is used to achieve signal isolation between the 5V domain on the RS-485 side and the main control chip, avoiding common ground interference and surge crosstalk between the two circuits.

[0038] On the RS-485 side: Signal interfaces B1 / B2 are connected to the RS-485 transceiver's receive / transmit signals (RS485_RX1_5V, RS485_TX1_5V) respectively; VCCB is connected to the 485's 5V power supply and is equipped with a grounding filter capacitor C872; the enable port OE is connected to the 485_5V power supply to keep the isolation channel always open.

[0039] On the main control chip side: signal interfaces A1 / A2 are connected to the TXD and RXD pins of the main control chip U1 to output isolated receive / transmit signals (RXD, TXD); VCCA is connected to the 3.3V power supply on the main control chip side and is equipped with a grounding filter capacitor C873.

[0040] The RS-485 transceiver chip U2 uses the MAX13487, a low-power RS-485 communication interface chip with bidirectional TTL and RS-485 level conversion capabilities. It works in conjunction with the main control chip U1 to achieve compatibility between TTL serial port and RS-485 communication. The DI pin of the RS-485 transceiver chip U2 is the data input terminal, connected to the TXD1 pin of the main control chip U1, receiving TTL level data output by the main control chip. Its RO pin is the data output terminal, connected to the RXD1 pin of the main control chip U1, feeding back the converted TTL level data to the main control chip. Its DE and RE pins are connected in parallel and pulled high by a resistor, putting the chip in normal transmit / receive mode. Simultaneously, it can be controlled via the GPIO pins of the main control chip to switch communication modes. Its differential bus interfaces A and B are RS-485 communication differential signal terminals, connected to the RS-485 interface in the interface module.

[0041] Furthermore, the interface module includes a 485 interface J1, a TTL interface J2, and a J2 interface J3.

[0042] like Figure 5 As shown, the 485 interface J1 has 4 pin terminals. Pin 1 is the external power supply / output pin, providing 5V power to the RS-485 transceiver chip U2; pin 2 is the RS485 communication A line (positive signal terminal), connected to the differential bus interface A of the RS-485 transceiver chip U2; pin 3 is the RS485 communication B line (negative signal terminal), connected to the differential bus interface B of the RS-485 transceiver chip U2; pin 4 is the signal ground, connected to the device ground to provide a reference ground for communication and power supply.

[0043] like Figure 6As shown, TTL interface J2 is a TTL serial port interface, using a 4-pin terminal. Pin 1 is the RXD terminal, pin 2 is the TXD terminal, pin 3 is the PPS terminal, and pin 4 is the GND terminal. The TXD terminal is connected to the TXD1 pin of the main control chip U1, and the RXD terminal is connected to the RXD1 pin of the main control chip U1, which is used to realize direct connection with external TTL communication devices.

[0044] Antenna interface J3 is a satellite antenna interface, using an SMA-K type RF interface. Its signal end is connected to the main control chip U1 via an RF coaxial cable, and its ground end is connected to the device ground. It is used to connect the Beidou satellite receiving antenna to ensure stable transmission of satellite signals.

[0045] Preferably, the antenna module adopts a Beidou dual-band ceramic antenna, model AT5816. This antenna has a built-in low-noise amplifier (LNA) and bandpass filter, with a gain of up to 28dB and a noise figure of ≤1.5dB. It can effectively receive satellite signals in the Beidou B1I (1561.098MHz) and B1C (1575.42MHz) bands and suppress interference signals. The antenna is connected to the J3 interface through an SMA connector, and a ground plane is set at the bottom of the antenna to reduce the interference of the internal circuit of the device on satellite signal reception and improve the stability of signal reception.

[0046] like Figure 6 As shown, this embodiment presents the PCB circuit design diagram of the Beidou independent positioning device. The main control chip U1 and antenna interface J3 are located on the same side of the PCB; the RS-485 transceiver chip U2, isolation chip U3, 485 interface J1, and TTL interface J2 are located on the other side of the PCB. Based on this design, the overall size of the device is only 30.8mm*20mm.

[0047] The working process of this device is as follows: First, the user securely connects the BeiDou satellite antenna through antenna interface J3, ensuring that the antenna installation direction is unobstructed. The device is then placed in an open, unobstructed environment to ensure normal satellite signal reception. Next, an external power supply is connected. After power-on, the reset circuit triggers the main control chip U1 to automatically reset and initialize. During initialization, the main control chip performs self-checks and configurations on internal registers, communication interfaces, positioning calculation engines, and other modules. After initialization, the main control chip controls the antenna module to begin receiving BeiDou satellite signals. Antenna E1 will receive BeiDou B1I and B1C signals. The frequency band signal is transmitted to the main control chip U1, where the internal signal receiving circuit demodulates and decodes the satellite signal, extracts satellite ephemeris data, and then performs positioning calculation through the positioning calculation engine to obtain positioning information such as longitude, latitude, altitude, speed, and time. Simultaneously, the main control chip U1 encapsulates the positioning information according to the standard NMEA0183 protocol via a serial communication module and outputs it to the communication interface in real time. Users can choose to connect to the device via either the 485 interface J1 or the TTL interface J2, depending on the communication type of the external hardware device. After receiving the NMEA 0183 protocol data, the external device can extract the corresponding positioning data according to its own needs, thus achieving accurate positioning.

[0048] When external devices use RS-485 communication, the TTL level data output by the main control chip U1 is transmitted to the DI pin of the RS-485 transceiver chip U2 via the TXD1 pin. The RS-485 transceiver chip U2 converts the TTL level to RS-485 differential level and transmits it to the external RS-485 device via the J1 interface through the A and B pins. Control commands sent by the external RS-485 device are transmitted to the A and B pins of the RS-485 transceiver chip U2 via the J1 interface. The chip converts the RS-485 differential level to TTL level and transmits it to the RXD1 pin of the main control chip U1 via the RO pin, realizing bidirectional communication. When external devices use TTL communication, they can be directly connected to the TXD1 and RXD1 pins of the main control chip U1 via the J2 interface to realize direct transmission of positioning data without the need for additional conversion modules, simplifying the connection process.

[0049] In summary, the BeiDou independent positioning device provided by this invention achieves compatibility and adaptation between TTL and 485 communication through optimized hardware structure design, improves BeiDou signal reception performance and positioning accuracy, and has the advantages of high integration, low power consumption and ease of use. It can effectively empower various hardware devices that do not support pure BeiDou positioning and has broad application prospects and practical value in multiple fields.

[0050] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A BeiDou independent positioning and communication device, characterized in that, Includes the main control chip U1, communication expansion module, and interface module; The interface module includes: a 485 interface J1, a TTL interface J2, and an antenna interface J3; The main control chip U1 is connected to the external antenna E1 through the antenna interface J3, and the output pins of the main control chip U1 are connected to the external TTL communication device through the TTL interface J2. The communication expansion module includes an RS-485 transceiver chip U2. One side of the RS-485 transceiver chip U2 is connected to the main control chip U1 through an isolation chip U3, and the other side is connected to the 485 interface J1. It is used to bidirectionally convert the TTL level UART signal output by the main control chip U1 to the differential RS485 signal.

2. The BeiDou independent positioning and communication device according to claim 1, characterized in that, The external antenna E1 is connected to the RF_IN pin of the main control chip U1 via a microstrip line. The VCC_RF pin of the main control chip U1 is connected to the external antenna E1 in sequence via a grounding capacitor C1 and an inductor L1 to provide a DC bias path for the antenna.

3. The BeiDou independent positioning and communication device according to claim 1, characterized in that, The TXD and RXD pins of the main control chip U1 are general serial communication terminals, which are connected to the isolation chip U3 and the TTL interface J2 through resistors R3 and R4 respectively, for transmitting positioning data.

4. A BeiDou independent positioning and communication device according to claim 1, characterized in that, The TIMEIMPULSE pin of the main control chip U1 is connected to an LED via resistor R1 and diode D1 to indicate the positioning status.

5. A BeiDou independent positioning and communication device according to claim 1, characterized in that, The VBCKP pin of the main control chip U1 is connected to the backup battery BAT to store ephemeris data and enable hot start for rapid positioning.

6. A BeiDou independent positioning and communication device according to claim 1, characterized in that, On the input side of the RS-485 transceiver chip U2: the output receive interface RO is connected to the B1 interface of the isolation chip U3; the drive input interface DI is connected to the B2 interface of the isolation chip U3; the receive / drive enable interface RE / DE is shorted and then connected to VCC; On the output side of the RS-485 transceiver chip U2: a bus termination matching resistor is connected between the differential bus interface A and the differential bus interface B of the RS-485; Differential bus interface A is connected to the power supply of RS-485 transceiver chip U2 via a pull-up resistor, and differential bus interface B is connected to ground via a pull-down resistor; ESD protection diodes are connected in parallel between differential bus interface A, differential bus interface B and ground respectively.

7. A BeiDou independent positioning and communication device according to claim 1, characterized in that, The isolation chip U3 is used to achieve signal isolation between the RS-485 side and the main control chip; On the RS-485 side: Signal interfaces B1 and B2 are connected to the output receiving interface RO and the drive input interface DI of the RS-485 transceiver, respectively; VCCB and enable port OE are connected to the RS-485 power supply. On the main control chip side: signal interfaces A1 and A2 are connected to the TXD and RXD pins of the main control chip U1, respectively; VCCA is connected to the 3.3V power supply on the main control chip side.

8. A BeiDou independent positioning and communication device according to claim 1, characterized in that, The 485 interface J1 has 4 pin terminals: pin 1 is the external power supply / output pin, providing 5V power to the RS-485 transceiver chip U2; pin 2 is the RS485 communication A line, connected to the differential bus interface A of the RS-485 transceiver chip U2; pin 3 is the RS485 communication B line, connected to the differential bus interface B of the RS-485 transceiver chip U2; pin 4 is the signal ground, connected to the device ground to provide a reference ground for communication and power supply.

9. A BeiDou independent positioning and communication device according to claim 1, characterized in that, The TTL interface J2 is a TTL serial port interface, using 4-pin terminals: pin 1 is the RXD terminal, pin 2 is the TXD terminal, pin 3 is the PPS terminal, and pin 4 is the GND terminal. The TXD terminal is connected to the TXD pin of the main control chip U1, and the RXD terminal is connected to the RXD pin of the main control chip U1, thereby realizing the connection between the main control chip U1 and external TTL communication devices.

10. A BeiDou independent positioning and communication device according to claim 1, characterized in that, The main control chip U1 and the antenna interface J3 are located on the same side of the PCB; the RS-485 transceiver chip U2, the isolation chip U3, the 485 interface J1 and the TTL interface J2 are located on the other side of the PCB.

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