Regional unmanned aerial vehicle dynamic time synchronization method and system

Abstract

The invention discloses a regional unmanned aerial vehicle dynamic time synchronization method and system, and relates to unmanned aerial vehicles and time synchronization, and the method comprises the steps: generating a clock reference signal as a frequency time reference benchmark of other composition units; modulating a first time synchronization message frame corresponding to the clock reference signal to generate a transmission enhanced radio frequency signal; receiving an enhanced radio frequency signal transmitted by a ground center, demodulating a first time synchronization message frame, and measuring an observed quantity after frame synchronization; forming a second time synchronization message frame according to the measurement time delay and the measurement time information of the unmanned aerial vehicle; analyzing the measurement time delay in the second time synchronization message frame and the measurement time information of the unmanned aerial vehicle to calculate an initial clock difference; performing unmanned aerial vehicle motion error correction on the initial clock error data to generate a corrected clock error result; and adjusting the clock reference signal synchronization of the unmanned aerial vehicle according to the clock error result. The method provided by the invention can improve the time synchronization precision between the loads of the air-based area navigation enhancement system.

Description

Technical Field

[0001] The present application relates to unmanned aerial vehicles and time synchronization technology, and in particular to a regional unmanned aerial vehicle dynamic time synchronization method and system. Background Art

[0002] When the satellite navigation system is unavailable in a certain area due to obstruction, interference, etc., an unmanned aerial vehicle equipped with a navigation enhancement payload can serve as an air-based regional navigation augmentation system to supplement the deficiencies of the satellite navigation system and provide positioning and timing services within the area.

[0003] The basis for the air-based regional navigation augmentation system to achieve high-precision timing and positioning within the region is the accurate synchronization of the system time by each drone. A time error of 1 microsecond will result in a ranging error of 300 meters. Summary of the invention

[0004] The embodiments of the present application provide a method and system for dynamic time synchronization of regional UAVs, which are used to propose a method for dynamic time synchronization between UAVs in a region and a ground center, improve the time synchronization accuracy between payloads of an air-based regional navigation enhancement system, and thereby ensure the high accuracy and availability of air-based regional navigation enhancement services.

[0005] The present application embodiment provides a regional drone dynamic time synchronization method, including:

[0006] Generate a clock reference signal as a frequency and time reference for other components;

[0007] Modulate the first time synchronization message frame corresponding to the clock reference signal to generate a transmission enhanced intermediate frequency signal, up-convert the enhanced intermediate frequency signal into an enhanced radio frequency signal through a frequency conversion power amplifier unit, and transmit the enhanced radio frequency signal to a ground center using a transceiver antenna unit;

[0008] receiving the enhanced radio frequency signal transmitted by the ground center, down-converting the signal into an enhanced intermediate frequency signal through a frequency conversion power amplifier unit, demodulating the first time synchronization message frame, and measuring the observed quantity after frame synchronization, wherein the observed quantity includes the measurement delay;

[0009] A second time synchronization message frame is formed according to the measurement delay and the measurement time information of the UAV itself;

[0010] Parsing the measured delay in the second time synchronization message frame and the measured time information of the drone itself to calculate the initial clock difference;

[0011] Perform drone motion error correction on the initial clock error data to generate the corrected clock error result;

[0012] The UAV local clock reference signal synchronization is adjusted according to the clock difference result.

[0013] Optionally, the generated clock reference signal includes one or more of the following signals: 10 MHz, 10.23 MHz, 1PPS.

[0014] Optionally, the first time synchronization telegram frame includes a frame header, local time, measurement time, measurement delay, and verification content.

[0015] Optionally, measuring the observed value after frame synchronization includes: after acquiring the enhanced signal, measuring the time difference between the rising edge of the first bit of the signal message frame header and the rising edge of the time-frequency unit 1PPS to obtain the measured delay.

[0016] Optionally, the measured delay in the second time synchronization message frame and the measured time information of the drone itself are parsed to calculate the initial clock error to satisfy:

[0017]

[0018] Where T1 and T2 are the UAV delay and ground center delay values ​​measured in the same second, respectively.

[0019] Optionally, the initial clock error data is corrected for the drone motion error to satisfy:

[0020]

[0021] Where v is the radial relative velocity of the line connecting the UAV and the center of the ground; Δt is the time difference between the UAV signal transmission time and the delay measurement time; and c is the speed of light.

[0022] The embodiment of the present application also proposes a regional drone dynamic time synchronization system, including:

[0023] A time-frequency unit, used to generate an internal multi-channel clock reference signal and send it to the enhanced signal transceiver unit;

[0024] An enhanced signal transceiver unit is used to generate a clock reference signal as a frequency and time reference benchmark for other components, modulate the first time synchronization message frame corresponding to the clock reference signal to generate a transmission enhanced intermediate frequency signal, input the enhanced intermediate frequency signal into the variable frequency power amplifier unit, and receive the enhanced intermediate frequency signal output by the variable frequency power amplifier unit, demodulate the first time synchronization message frame, and measure the observed amount after frame synchronization, wherein the observed amount includes the measurement delay;

[0025] A frequency conversion power amplifier unit, used to down-convert the received regional navigation enhanced radio frequency signal to an intermediate frequency, and up-convert the transmitted regional navigation enhanced intermediate frequency signal to radio frequency and power amplify;

[0026] The transceiver antenna unit is used to transmit the radio frequency signal output by the frequency conversion power amplifier unit and input the received spatial signal to the frequency conversion power amplifier unit;

[0027] An information processing unit, used to form a second time synchronization message frame according to the measurement delay and the measurement time information of the drone itself, and send it to the enhanced signal transceiver unit; and

[0028] Parsing the measured delay in the second time synchronization message frame and the measured time information of the drone itself to calculate the initial clock difference;

[0029] Perform drone motion error correction on the initial clock error data to generate the corrected clock error result;

[0030] The UAV local clock reference signal synchronization is adjusted according to the clock difference result.

[0031] The method of the embodiment of the present application can improve the time synchronization accuracy between payloads of the air-based regional navigation augmentation system, thereby ensuring the high accuracy and availability of the air-based regional navigation augmentation service.

[0032] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0034] Figure 1 This is a basic flow diagram of the regional drone dynamic time synchronization method according to an embodiment of the present application;

[0035] Figure 2 It is the regional drone communication architecture of the regional drone dynamic time synchronization method of the embodiment of the present application;

[0036] Figure 3 Schematic diagram of the architecture of the regional drone dynamic time synchronization system according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0038] The present application embodiment provides a method for regional drone dynamic time synchronization, such as Figure 1 , Figure 2 The steps include:

[0039] In step S101, a clock reference signal is generated as a frequency and time reference for other components. In a specific example, it can be implemented based on a time-frequency unit. In a specific example, the clock reference signal generated by the time-frequency unit includes one or more of the following signals: 10MHz, 10.23MHz, 1PPS.

[0040] In step S102, the first time synchronization message frame corresponding to the clock reference signal is modulated to generate a transmission enhanced intermediate frequency signal, and the enhanced intermediate frequency signal is transmitted to the ground center. In a specific example, this step is implemented using an enhanced signal transceiver unit, and the enhanced signal transceiver unit transmits the generated regional navigation enhanced radio frequency signal to the ground area. In a specific example, the frequency of the first time synchronization message frame can be set to 1Hz, and the first time synchronization message frame includes a frame header, local time, measurement time, measurement delay, and verification content.

[0041] In step S103, the enhanced radio frequency signal transmitted by the ground center is received, the first time synchronization message frame is demodulated, and the observed quantity is measured after frame synchronization, and the observed quantity includes the measured delay. In a specific example, measuring the observed quantity after frame synchronization includes: after acquiring the enhanced intermediate frequency signal, measuring the time difference between the first rising edge of the signal message frame header and the rising edge of the time-frequency unit 1PPS to obtain the measured delay.

[0042] In step S104, a second time synchronization message frame is formed according to the measured delay and the drone's own measurement time information, and sent to the enhanced signal transceiver unit, and the measured delay and the drone's own measurement time information in the second time synchronization message frame are parsed to calculate the initial clock difference. Specifically, it can be implemented by an information processing unit, and the content format of the time synchronization message frame is the same as the above example. The information processing unit also parses the time synchronization message frame to extract the delay and measurement time of the ground center measuring the drone in the message.

[0043] In step S105, the initial clock error data is corrected for the drone motion error to generate a corrected clock error result.

[0044] In step S106, the UAV's local clock reference signal synchronization is adjusted according to the clock difference result. In a specific example, the corrected clock difference data is received by the time-frequency unit, and the local clock reference signal is adjusted to be synchronized with the ground center. The adjustment method may include phase modulation, frequency modulation and other methods.

[0045] The method of the embodiment of the present application can improve the time synchronization accuracy between payloads of the air-based regional navigation augmentation system, thereby ensuring the high accuracy and availability of the air-based regional navigation augmentation service.

[0046] In some embodiments, the initial clock error is calculated by parsing the measured delay in the second time synchronization message frame and the drone's own measured time information to satisfy:

[0047]

[0048] Where T1 and T2 are the UAV delay and ground center delay values ​​measured in the same second, respectively.

[0049] In some embodiments, the initial clock error data is corrected for the drone motion error to satisfy:

[0050]

[0051] Where v is the radial relative velocity of the line connecting the UAV and the center of the ground; Δt is the time difference between the UAV signal transmission time and the delay measurement time; and c is the speed of light.

[0052] The method for regional UAV dynamic time synchronization in the embodiment of the present application reuses the regional enhanced radio frequency signal and corrects the original clock error data with a low-speed UAV motion error model, which is highly practical and accurate.

[0053] The present application also proposes a regional drone dynamic time synchronization system, such as Figure 3 As shown, including:

[0054] A time-frequency unit, used to generate an internal multi-channel clock reference signal and send it to the enhanced signal transceiver unit;

[0055] The enhanced signal transceiver unit is used to generate a clock reference signal as a frequency and time reference benchmark for other component units, modulate the first time synchronization message frame corresponding to the clock reference signal to generate a transmitted enhanced intermediate frequency signal, up-convert the enhanced intermediate frequency signal into an enhanced radio frequency signal through a frequency conversion power amplifier unit, transmit the enhanced radio frequency signal to a ground center using a transceiver antenna unit, and receive the enhanced radio frequency signal transmitted by the ground center, down-convert it into an enhanced intermediate frequency signal through a frequency conversion power amplifier unit, demodulate the first time synchronization message frame, and measure the observation amount after frame synchronization, wherein the observation amount includes the measurement delay.

[0056] In a specific example, the receiving function of the enhanced signal transceiver unit is to receive the transmission signal from the ground center, measure the delay, and demodulate the telegram to obtain the delay of the UAV transmission signal measured by the ground center; the transmitting function is to modulate the time synchronization telegram frame, generate the regional navigation enhancement signal and transmit it to the ground area.

[0057] The enhanced signal transceiver unit may include a processor, an analog-to-digital conversion chip, a digital-to-analog conversion chip, a clock chip, a power supply chip, etc.

[0058] A frequency conversion power amplifier unit, used to down-convert the received regional navigation enhanced radio frequency signal to an intermediate frequency, and up-convert the transmitted regional navigation enhanced intermediate frequency signal to radio frequency and power amplify;

[0059] The transceiver antenna unit is used to transmit the radio frequency signal output by the frequency conversion power amplifier unit and input the received spatial signal to the frequency conversion power amplifier unit. In a specific example, the transceiver antenna unit may include an anti-interference receiving antenna, a transmitting antenna, and the like.

[0060] An information processing unit, used to form a second time synchronization message frame according to the measurement delay and the measurement time information of the drone itself, and send it to the enhanced signal transceiver unit; and

[0061] Parsing the measured delay in the second time synchronization message frame and the measured time information of the drone itself to calculate the initial clock difference;

[0062] Perform drone motion error correction on the initial clock error data to generate the corrected clock error result;

[0063] The UAV local clock reference signal synchronization is adjusted according to the clock difference result.

[0064] In a specific example, the information processing unit may include a processor, a network chip, etc.

[0065] The system for dynamic time synchronization of regional drones in the embodiment of the present application utilizes the original business signals and hardware resources of the air-based regional enhancement system to achieve clock synchronization of drones in the region to the ground center through signal interaction of time synchronization telegram frames between drones and the ground center.

[0066] It should be noted that in the various embodiments of the present application, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0067] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0068] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0069] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A regional UAV dynamic time synchronization method, characterized in that: include: Generate a clock reference signal as a frequency and time reference for other components; Modulate the first time synchronization message frame corresponding to the clock reference signal to generate a transmission enhanced intermediate frequency signal, up-convert the enhanced intermediate frequency signal into an enhanced radio frequency signal through a frequency conversion power amplifier unit, and transmit the enhanced radio frequency signal to a ground center using a transceiver antenna unit; receiving the enhanced radio frequency signal transmitted by the ground center, down-converting the signal into an enhanced intermediate frequency signal through a frequency conversion power amplifier unit, demodulating the first time synchronization message frame, and measuring the observed quantity after frame synchronization, wherein the observed quantity includes the measurement delay; Calculate the initial clock error based on the measured time delay and the drone's own measured time information; Perform drone motion error correction on the initial clock error data to generate the corrected clock error result; The UAV local clock reference signal synchronization is adjusted according to the clock difference result.

2. The regional UAV dynamic time synchronization method as claimed in claim 1, characterized in that: The generated clock reference signal includes one or more of the following signals: 10 MHz, 10.23 MHz, 1 PPS.

3. The regional UAV dynamic time synchronization method as claimed in claim 1, characterized in that: The first time synchronization message frame includes a frame header, local time, measurement time, measurement delay, and verification content.

4. The regional UAV dynamic time synchronization method as claimed in claim 3, characterized in that: Measuring the observed quantity after frame synchronization includes: after acquiring the enhanced intermediate frequency signal, measuring the time difference between the rising edge of the first bit of the signal message frame header and the rising edge of the time-frequency unit 1PPS to obtain the measured delay.

5. The regional UAV dynamic time synchronization method as claimed in claim 4, characterized in that: The initial clock error is calculated based on the measured delay and the drone's own measured time information to meet the following requirements: Where T1 and T2 are the UAV delay and ground center delay values ​​measured in the same second, respectively.

6. The regional UAV dynamic time synchronization method as claimed in claim 5, characterized in that: The initial clock error data is corrected for the UAV motion error to meet the following requirements: Where v is the radial relative velocity of the line connecting the UAV and the center of the ground; Δt is the time difference between the UAV signal transmission time and the delay measurement time; and c is the speed of light.

7. A regional UAV dynamic time synchronization system, characterized in that: include: A time-frequency unit, used to generate an internal multi-channel clock reference signal and send it to the enhanced signal transceiver unit; An enhanced signal transceiver unit is used to generate a clock reference signal as a frequency and time reference benchmark for other components, modulate the first time synchronization message frame corresponding to the clock reference signal to generate a transmission enhanced intermediate frequency signal, input the enhanced intermediate frequency signal into the variable frequency power amplifier unit, and receive the enhanced intermediate frequency signal output by the variable frequency power amplifier unit, demodulate the first time synchronization message frame, and measure the observed amount after frame synchronization, wherein the observed amount includes the measurement delay; A frequency conversion power amplifier unit, used to down-convert the received regional navigation enhanced radio frequency signal to an intermediate frequency, and up-convert the transmitted regional navigation enhanced intermediate frequency signal to radio frequency and power amplify; The transceiver antenna unit is used to transmit the radio frequency signal output by the frequency conversion power amplifier unit and input the received spatial signal to the frequency conversion power amplifier unit; An information processing unit, used to form a second time synchronization message frame according to the measurement delay and the measurement time information of the drone itself, and send it to the enhanced signal transceiver unit; and Parsing the measured delay in the second time synchronization message frame and the measured time information of the drone itself to calculate the initial clock difference; Perform drone motion error correction on the initial clock error data to generate the corrected clock error result; The UAV local clock reference signal synchronization is adjusted according to the clock difference result.

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