Time synchronization method and system for narrowband communication signals among multiple devices

Abstract

The invention discloses a time synchronization method and system for a narrowband communication signal among multiple devices, and the system comprises a signal calibration module which generates a single-tone signal with a specified frequency, configures an independent control network, and transmits a periodic pulse signal; a common GPS chip and a BD chip are arranged in the signal receiving module, and the signal receiving module is used for receiving GPS signals or BD signals, obtaining time and position information and outputting the time information to other modules for use; and the time synchronization module receives the time pulse of the signal receiving module to generate time information, is connected with a network cable of the signal calibration module for autonomous communication, and controls the signal calibration module to send a signal. According to the scheme, the time synchronization precision between the devices is greatly improved, and the synchronization precision between the devices can reach the nanosecond level.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrashort wave signal detection and reception, and in particular to a time synchronization method and system for narrowband communication signals between multiple devices. Background Art

[0002] As drones are increasingly used in civilian and military fields, in the civilian field, many unapproved "black flights" appear in no-fly zones. In the military field, foreign troops frequently use drones for reconnaissance. Accurate positioning of the above targets will change combat methods, enhance the timeliness of combat command, and make battlefield information more transparent. This project intercepts the continuous communication signals used by drones and performs passive time difference positioning on them. The measurement station in this positioning technology does not actively radiate electromagnetic waves to determine the target position silently.

[0003] Passive time difference positioning technology adopts a time difference positioning method based on Tdoa. When it is implemented, it can be regarded as the intersection of hyperboloids (lines) or ellipsoids, and the intersection points are used to calculate the geographic coordinates. The basic principle is: more than three signal acquisition nodes are required, and the time synchronization accuracy must be guaranteed between each acquisition node. In the acquisition node, the master node sends a signal instruction to receive the radiation source at the same time. Each acquisition node collects the received data to the master node, and uses the signal synchronization correlation method to estimate the signal transmission time difference between each acquisition node and the master node. The time difference is multiplied by the signal transmission speed to get the distance difference. According to the distance difference and the position information of all nodes, a set of hyperboloids (lines) or ellipsoids can be obtained with the focus in space, and their intersection points are regarded as the location of the target.

[0004] From the above, it can be seen that the time synchronization accuracy between multiple devices is the prerequisite for Tdoa-based time difference positioning technology and the key factor affecting positioning accuracy. It is necessary to improve the time synchronization accuracy between devices as much as possible.

[0005] The prior art has the following defects: Currently, most devices use GPS / BD chips and antennas for timing. The devices collect pulse signals to obtain time through interruptions. The pulses cannot be collected synchronously between devices, resulting in time deviations, with errors up to microseconds. The clock sampling rate is low. Currently, most clock sampling rates are 102.4MHz. Each clock cycle is about 9.2ns. Adding the periodic waveform will introduce multiple cycle time errors. The device lacks a time synchronization module and an optimized clock synchronization mechanism. Summary of the invention

[0006] In view of the above technical problems, the present invention provides a method and system for time synchronization of narrowband communication signals between multiple devices.

[0007] The present invention is implemented by adopting the following technical solution: a time synchronization system for narrowband communication signals between multiple devices, comprising the following modules: Signal calibration module: generates a single tone signal of a specified frequency and configures an independent control network to send a periodic pulse signal; Signal receiving module: built-in commonly used GPS chip and BD chip, receive GPS signal or BD signal, obtain time and location information, and output the time information to other modules for use; Time synchronization module: Receives the time pulse of the signal receiving module to generate time information, connects the network cable with the signal calibration module for autonomous communication, and controls the signal calibration module to send signals.

[0008] Specifically, the signal calibration module and the time synchronization module are automatically matched using a built-in communication protocol, and the signal delay time and duration are set.

[0009] Specifically, the time synchronization module is configured with an analog signal acquisition function to acquire the input single-tone signal at a high sampling rate; and is also configured with a burst signal detection function based on the time domain to detect the time position of the first sample point of the signal.

[0010] Specifically, the signal receiving module and the time synchronization module are equipped in each device, and the signal calibration module is independently configured and used.

[0011] A method for time synchronization of narrowband communication signals between multiple devices is implemented based on the time synchronization system for narrowband communication signals between multiple devices, and comprises the following steps: Step S1: connecting the time synchronization module of the first device, the time synchronization module of the second device and the signal calibration module; Step S2: start time synchronization, the time synchronization module of the first device controls the signal calibration module to send a signal after T1 seconds, and the duration is T2; Step S3: the time synchronization module of the first device and the second device collect signals, and the calibration module transmits a signal of a specified frequency; Step S4: The first device and the second device start a burst signal detection function based on the time domain to obtain signal occurrence times T001-1 and T002-1; Step S5: The time synchronization modules of the first device and the second device exchange time information to obtain a time error F nanoseconds; Step S6: compensating the error F nanoseconds into the time information of the second device; Step S7: Repeat steps S2 to S5 to obtain a time error F2 nanoseconds. If F2<1 nanosecond, the calibration is completed, otherwise continue to repeat steps S2 to S5.

[0012] Specifically, step S4 includes the following sub-steps: S401. Load signal simulation data and set the sampling rate to 1 GHz and 1000000000 Hz; S402. Perform burst signal detection to obtain a signal occurrence sampling point position S; S403. Calculate the position P of the sample point S in the data frame; S404. Calculate the time of the signal sample S in the frame, T1 = P*1000000000 / 1000000000Hz; S405. Get the frame header time TS; S406. Calculate the occurrence time as: T = TS+T1, in nanoseconds.

[0013] Specifically, the burst signal detection function based on the time domain includes the following steps: Get the first 100 samples of I-channel data and the first 100 samples of Q-channel data; Calculate the average values ​​of the I-channel data and the Q-channel data, expressed as Pi and Pq, respectively, and compare them with data sample point 1; If the amplitude of sample point I is greater than Pi or the amplitude of sample point Q is greater than Pq, it is judged that a burst is detected and the sample point position Pos is output; If the amplitude of sample point I is not greater than Pi and the amplitude of sample point Q is not greater than Pq, the comparison process is repeated and compared with the next sample point until the last sample point N; The comparison ends and the feedback is that no burst is detected.

[0014] Specifically, the signal calibration module workflow includes: the signal calibration module receives a control instruction, sends the instruction to the FPGA through network communication, and the FPGA controls the frequency and output level to the DA playback, and generates a signal output as a single tone signal.

[0015] Specifically, the time synchronization module workflow includes: FPGA receives timing information, and controls AD to collect single-tone signals to generate IQ data through control instructions; IQ data is packaged together with the timestamp of FPGA, and after detection and calculation, time information is fed back in network communication.

[0016] The beneficial effects of the present invention are as follows: based on high sampling rate technology, the present invention enables the burst signal detection accuracy based on the time domain to reach the nanosecond level, adds a time synchronization module and optimizes the clock synchronization mechanism, greatly improves the time synchronization accuracy between devices, and enables the synchronization accuracy between devices to reach the nanosecond level, effectively ensuring the accuracy of using the device for Tdoa time difference positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 A system structure block diagram in an embodiment of the present invention; Figure 2 It is a flowchart of the method of the present invention; Figure 3 It is a flowchart of the burst signal detection and time calculation process of step S4 of the present invention; Figure 4 This is a principle block diagram of a signal calibration module in an embodiment of the present invention; Figure 5 This is a principle block diagram of a time synchronization module in an embodiment of the present invention; Figure 6 This is a flow chart of a burst signal detection based on the time domain in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0021] The following is combined with Figures 1 to 6 , some embodiments of the present invention are described in detail. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0022] The present invention proposes a method and system for time synchronization of narrowband communication signals between multiple devices. In a first aspect, a time synchronization system for narrowband communication signals between multiple devices comprises the following modules: Signal calibration module: generates a single tone signal of a specified frequency and configures an independent control network to send a periodic pulse signal; Signal receiving module: built-in commonly used GPS chip and BD chip, receive GPS signal or BD signal, obtain time and location information, and output the time information to other modules for use; Time synchronization module: Receives the time pulse of the signal receiving module to generate time information, connects the network cable with the signal calibration module for autonomous communication, and controls the signal calibration module to send signals.

[0023] In this embodiment, the signal calibration module and the time synchronization module are automatically matched using a built-in communication protocol, and the signal delay time and duration are set.

[0024] In this embodiment, the time synchronization module is configured with an analog signal acquisition function to acquire the input single-tone signal at a high sampling rate; it is also configured with a burst signal detection function based on the time domain to detect the time position of the first sample point of the signal.

[0025] In this embodiment, the signal receiving module and the time synchronization module are equipped in each device, and the signal calibration module is independently configured and used.

[0026] The present invention also accordingly proposes a method for time synchronization of narrowband communication signals between multiple devices, comprising the following steps: Step S1: connecting the time synchronization module of the first device, the time synchronization module of the second device and the signal calibration module; Step S2: start time synchronization, the time synchronization module of the first device controls the signal calibration module to send a signal after T1 seconds, and the duration is T2; Step S3: the time synchronization module of the first device and the second device collect signals, and the calibration module transmits a signal of a specified frequency; Step S4: The first device and the second device start a burst signal detection function based on the time domain to obtain signal occurrence times T001-1 and T002-1; Step S5: The time synchronization modules of the first device and the second device exchange time information to obtain a time error F nanoseconds; Step S6: compensating the error F nanoseconds into the time information of the second device; Step S7: Repeat steps S2 to S5 to obtain a time error F2 nanoseconds. If F2<1 nanosecond, the calibration is completed, otherwise continue to repeat steps S2 to S5.

[0027] In this embodiment, step S4 includes the following sub-steps: S401. Load signal simulation data and set the sampling rate to 1 GHz and 1000000000 Hz; S402. Perform burst signal detection to obtain a signal occurrence sampling point position S; S403. Calculate the position P of the sample point S in the data frame; S404. Calculate the time of the signal sample S in the frame, T1 = P*1000000000 / 1000000000Hz; S405. Get the frame header time TS; S406. Calculate the occurrence time as: T = TS+T1, in nanoseconds.

[0028] In this embodiment, the burst signal detection function based on the time domain is as follows: Figure 6 As shown, the following steps are included: Get the first 100 samples of I-channel data and the first 100 samples of Q-channel data; Calculate the average values ​​of the I-channel data and the Q-channel data, expressed as Pi and Pq, respectively, and compare them with data sample point 1; If the amplitude of sample point I is greater than Pi or the amplitude of sample point Q is greater than Pq, it is judged that a burst is detected and the sample point position Pos is output; If the amplitude of sample point I is not greater than Pi and the amplitude of sample point Q is not greater than Pq, the comparison process is repeated and compared with the next sample point until the last sample point N; The comparison ends and the feedback is that no burst is detected.

[0029] In this embodiment, the signal calibration module workflow is as follows: Figure 4 As shown, it includes: the signal calibration module receives the control instruction, sends the instruction to the FPGA through network communication, the FPGA controls the frequency and output level to the DA playback, and the generated signal output is a single tone signal.

[0030] In this embodiment, the time synchronization module works as follows: Figure 5 As shown, it includes: FPGA receives timing information, and controls AD to collect single-tone signals to generate IQ data through control instructions; IQ data is packaged together with the timestamp of FPGA, and after detection and calculation, time information is fed back in network communication.

[0031] In another embodiment, if Figure 1 As shown, a high-precision time synchronization system for narrowband communication signals between multiple devices, the modules required to be used in the system include a signal calibration module, a GPS / BD receiving module (signal receiving module) and a time synchronization module.

[0032] The signal calibration module supports the generation of a single-tone signal of a specified frequency, with an output power of up to 0dBm, and is used in an independent control network. It can automatically match the time synchronization module using a built-in communication protocol, and can also set the signal delay time and duration. The module also supports the sending of periodic pulse signals. See the attached schematic diagram of the signal calibration module. Figure 5 .

[0033] The GPS / BD receiving module (signal receiving module) has a built-in common GPS / BD chip, which can receive GPS or BD signals, obtain time and location information, and output the time information for use by other modules.

[0034] The time synchronization module generates time information by receiving the time pulse of the GPS / BD receiving module (signal receiving module), and can communicate autonomously with the signal calibration module by connecting the network cable. It can control the signal calibration module to send signals. The time synchronization module supports the analog signal acquisition function and performs high sampling rate acquisition on the input single-tone signal, with a sampling rate of 1GHz. The time synchronization module has a burst signal detection function based on the time domain, which can detect the time position of the first sample point of the signal. At a sampling rate of up to 1GHz, the signal occurrence time accuracy can reach 1 nanosecond, and the calculated time is T. The principle block diagram of the time synchronization module is attached. Figure 5 The burst signal detection process based on time domain is shown in Figure 6 .

[0035] Each device is equipped with a GPS / BD receiving module (signal receiving module) and a time synchronization module, and the signal calibration module is used independently.

[0036] A high-precision time synchronization method for narrowband communication signals between multiple devices, such as Figure 2 As shown, the following steps are included: S1. Connect the time synchronization module of device 001, the time synchronization module of device 002, and the signal calibration module. See the system diagram for the connection method; S2 starts time synchronization, the time synchronization module of device 001 controls the signal calibration module to send a signal after T1 seconds, and the duration is T2; S3 equipment 001, equipment 002 time synchronization module acquisition signal calibration module transmits a signal of a specified frequency; S4. Device 001 and device 002 start the burst signal detection function based on the time domain and obtain the signal occurrence time T001-1 and T002-1; S5. The time synchronization module of device 001 and device 002 interacts with each other to obtain a time error of F nanoseconds; S6. The error F nanoseconds is compensated to the time information of the device 002; S7. Repeat steps 2 to 5 to obtain a time error F2 nanoseconds. If F2<1 nanosecond, the calibration is completed. Otherwise, continue to repeat steps 2 to 5.

[0037] In this embodiment, step S4 is as follows: Figure 3 As shown, there are the following sub-steps: S401. Load signal simulation data, sampling rate 1GHz and 1000000000Hz; S402. Perform burst signal detection to obtain a signal occurrence sampling point position S; S403. Calculate the position P of the sample point S in the data frame; S404. Calculate the time of the signal sample S in the frame, T1 = P*1000000000 / 1000000000Hz; S405. Get the frame header time TS; S406. Calculate the occurrence time T = TS+T1, in nanoseconds.

[0038] For the aforementioned embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily required by the present application.

[0039] The above embodiments describe the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the changes and modifications made by those skilled in the art shall be within the scope of protection of the appended claims of the present invention without departing from the spirit and scope of the present invention.

Claims

1. A time synchronization system for narrowband communication signals between multiple devices, characterized in that: Includes the following modules: Signal calibration module: generates a single tone signal of a specified frequency and configures an independent control network to send a periodic pulse signal; Signal receiving module: built-in commonly used GPS chip and BD chip, receive GPS signal or BD signal, obtain time and location information, and output the time information to other modules for use; Time synchronization module: Receives the time pulse of the signal receiving module to generate time information, connects the network cable with the signal calibration module for autonomous communication, and controls the signal calibration module to send signals.

2. A time synchronization system for narrowband communication signals between multiple devices as claimed in claim 1, characterized in that: The signal calibration module and the time synchronization module are automatically matched using a built-in communication protocol, and the signal delay time and duration are set.

3. A time synchronization system for narrowband communication signals between multiple devices as claimed in claim 1, characterized in that: The time synchronization module is configured with an analog signal acquisition function to acquire the input single-tone signal at a high sampling rate; and is also configured with a burst signal detection function based on the time domain to detect the time position of the first sample point of the signal.

4. A time synchronization system for narrowband communication signals between multiple devices as claimed in claim 1, characterized in that: The signal receiving module and the time synchronization module are equipped in each device, and the signal calibration module is independently configured and used.

5. A method for time synchronization of narrowband communication signals between multiple devices, implemented based on a time synchronization system for narrowband communication signals between multiple devices as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: Step S1: connecting the time synchronization module of the first device, the time synchronization module of the second device and the signal calibration module; Step S2: start time synchronization, the time synchronization module of the first device controls the signal calibration module to send a signal after T1 seconds, and the duration is T2; Step S3: the time synchronization module of the first device and the second device collect signals, and the calibration module transmits a signal of a specified frequency; Step S4: The first device and the second device start a burst signal detection function based on the time domain to obtain signal occurrence times T001-1 and T002-1; Step S5: The time synchronization modules of the first device and the second device exchange time information to obtain a time error F nanoseconds; Step S6: compensating the error F nanoseconds into the time information of the second device; Step S7: Repeat steps S2 to S5 to obtain a time error F2 nanoseconds. If F2<1 nanosecond, the calibration is completed, otherwise continue to repeat steps S2 to S5.

6. A method for time synchronization of narrowband communication signals between multiple devices as claimed in claim 5, characterized in that: The step S4 comprises the following sub-steps: S401. Load signal simulation data and set the sampling rate to 1 GHz and 1000000000 Hz; S402. Perform burst signal detection to obtain a signal occurrence sampling point position S; S403. Calculate the position P of the sample point S in the data frame; S404. Calculate the time of the signal sample S in the frame, T1 = P*1000000000 / 1000000000Hz; S405. Get the frame header time TS; S406. Calculate the occurrence time as: T = TS+T1, in nanoseconds.

7. A method for time synchronization of narrowband communication signals between multiple devices as claimed in claim 6, characterized in that: The burst signal detection function based on time domain comprises the following steps: Get the first 100 samples of I-channel data and the first 100 samples of Q-channel data; Calculate the average values ​​of the I-channel data and the Q-channel data, expressed as Pi and Pq, respectively, and compare them with data sample point 1; If the amplitude of sample point I is greater than Pi or the amplitude of sample point Q is greater than Pq, it is judged that a burst is detected and the sample point position Pos is output; If the amplitude of sample point I is not greater than Pi and the amplitude of sample point Q is not greater than Pq, the comparison process is repeated and compared with the next sample point until the last sample point N; The comparison ends and the feedback is that no burst is detected.

8. A method for time synchronization of narrowband communication signals between multiple devices as claimed in claim 5, characterized in that: The signal calibration module workflow includes: the signal calibration module receives a control instruction, sends the instruction to the FPGA through network communication, and the FPGA controls the frequency and output level to the DA playback, and generates a signal output as a single tone signal.

9. A method for time synchronization of narrowband communication signals between multiple devices as claimed in claim 5, characterized in that: The time synchronization module workflow includes: FPGA receives timing information, and controls AD to collect single-tone signals to generate IQ data through control instructions; IQ data is packaged together with the timestamp of FPGA, and after detection and calculation, time information is fed back in network communication.

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