CN113267186B - Data synchronous acquisition system and data synchronous acquisition method - Google Patents

Data synchronous acquisition system and data synchronous acquisition method Download PDF

Info

Publication number
CN113267186B
CN113267186B CN202110803551.1A CN202110803551A CN113267186B CN 113267186 B CN113267186 B CN 113267186B CN 202110803551 A CN202110803551 A CN 202110803551A CN 113267186 B CN113267186 B CN 113267186B
Authority
CN
China
Prior art keywords
imu
data
pulse
synchronous
acquisition board
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110803551.1A
Other languages
Chinese (zh)
Other versions
CN113267186A (en
Inventor
黎治坤
刘金沧
黄小川
雷雳
马云峰
刘述超
杨建�
杨珂
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SURVEYING AND MAPPING INSTITUTE LANDS AND RESOURCE DEPARTMENT OF GUANGDONG PROVINCE
Chengdu Zongheng Dapeng Unmanned Plane Technology Co ltd
Original Assignee
SURVEYING AND MAPPING INSTITUTE LANDS AND RESOURCE DEPARTMENT OF GUANGDONG PROVINCE
Chengdu Zongheng Dapeng Unmanned Plane Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SURVEYING AND MAPPING INSTITUTE LANDS AND RESOURCE DEPARTMENT OF GUANGDONG PROVINCE, Chengdu Zongheng Dapeng Unmanned Plane Technology Co ltd filed Critical SURVEYING AND MAPPING INSTITUTE LANDS AND RESOURCE DEPARTMENT OF GUANGDONG PROVINCE
Priority to CN202110803551.1A priority Critical patent/CN113267186B/en
Publication of CN113267186A publication Critical patent/CN113267186A/en
Application granted granted Critical
Publication of CN113267186B publication Critical patent/CN113267186B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
    • G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
    • G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
    • G01C21/165—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation combined with non-inertial navigation instruments
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/42—Determining position
    • G01S19/45—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement
    • G01S19/47—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/42—Determining position
    • G01S19/48—Determining position by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
    • G01S19/49—Determining position by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system whereby the further system is an inertial position system, e.g. loosely-coupled

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Automation & Control Theory (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Electric Clocks (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

The application discloses a data synchronous acquisition system and a data synchronous acquisition method. The system comprises a GNSS board card, an IMU, an FPGA and an acquisition board; the GNSS board card and the IMU are both connected with the FPGA, and the GNSS board card and the IMU are both connected with the acquisition board. The GNSS board card transmits the PPS to the FPGA and the acquisition board simultaneously, and transmits GNSS data to the acquisition board; the FPGA generates a synchronous pulse sequence according to the rising edge of the PPS and sends the synchronous pulse sequence to the IMU; the IMU acquires IMU data according to the synchronous pulse sequence, transmits the IMU data to an acquisition board and sends TOV pulse to the acquisition board; and the acquisition board is used for carrying out time synchronization on the IMU data and the GNSS data according to the received PPS and TOV pulses. The FPGA generates high-precision synchronous pulses to improve the counting precision. The pulse edge of the synchronization pulse sequence is aligned with the pulse edge of the PPS, so that the time synchronization precision is improved.

Description

Data synchronous acquisition system and data synchronous acquisition method
Technical Field
The present application relates to the field of communications technologies, and in particular, to a data synchronous acquisition system and a data synchronous acquisition method.
Background
In the technical field of data acquisition in an airborne manner, an airborne terminal generally needs to acquire high-precision pose data. And resolving the flight path and the attitude according to the pose data. Taking the laser radar as an example, the point cloud data can be generated by the calculated navigation attitude and attitude data.
The pose data collected by the airborne end generally includes: navigation data provided by a Global Navigation Satellite System (GNSS) and Inertial Navigation data provided by an Inertial Measurement Unit (IMU). The navigation data is hereinafter referred to as GNSS data, and the inertial navigation data is hereinafter referred to as IMU data. GNSS data is self-contained with accurate satellite synchronization time, thus requiring time synchronization of IMU data with GNSS data.
Fig. 1 shows a prior art data synchronous acquisition system, which includes a GNSS board card, an IMU, and an acquisition board. The IMU is configured to a fixed sampling rate and is synchronized by using time synchronization signal pulses output by the GNSS board card. The time synchronization signal pulse is a Pulse Per Second (PPS), that is, the pulse period is 1 second, and the PPS is hereinafter referred to as the time synchronization signal pulse. The pulses provided by the IMU to the acquisition board are referred to as Time of Validity (TOV) pulses.
In the system shown in fig. 1, the acquisition board captures the PPS and resets the counters inside the acquisition board. The acquisition board captures the TOV pulse provided by the IMU, triggers an internal interrupt with the TOV pulse and reads the current count value to convert the time. Then, the acquisition board reads the next frame of IMU data, and the time converted from the previous frame is used as the synchronization time of the frame of IMU data.
In the system of fig. 1, counting is performed by an internal clock of the acquisition board single chip microcomputer, and then the count value is multiplied by the clock period to be used as the synchronization time of IMU data. This system has the following drawbacks: firstly, the single chip microcomputer usually uses a quartz oscillator or an internal RC clock as a pulse source, and the precision of the pulse period is limited. Secondly, fig. 2 shows the pulses of the PPS and the internal clock of the single chip, and the pulse edge of the PPS is not aligned with the pulse edge of the internal clock, i.e. the delay time T in fig. 2 is unknown. By combining the two points, the time synchronization precision of the IMU data and the GNSS data in the prior art is insufficient. Poor time synchronization accuracy can affect the accuracy of the finally formed point cloud data. The existing airborne laser radar technology has wide application in the fields of surveying and mapping, agricultural plant protection, forestry investigation, electric power inspection and the like. For example, when the accuracy of the point cloud data is insufficient, overlapping portions between the strips cannot be aligned in the multi-strip surveying process, and the data is likely to fail to reach the acceptance quality.
Disclosure of Invention
Based on the above problems, the present application provides a data synchronous acquisition system and a data synchronous acquisition method to solve the problem of low time synchronization precision of IMU data and GNSS data.
The embodiment of the application discloses the following technical scheme:
the present application provides in a first aspect a synchronous data acquisition system, including: the system comprises a global navigation satellite system GNSS board card, an inertial measurement unit IMU, a field programmable gate array FPGA and an acquisition board; the GNSS board card and the IMU are both connected with the FPGA, and the GNSS board card and the IMU are both connected with the acquisition board;
the GNSS board card is used for simultaneously transmitting the PPS to the FPGA and the acquisition board and transmitting GNSS data to the acquisition board;
the FPGA is used for generating a synchronous pulse sequence according to the rising edge of the PPS and sending the synchronous pulse sequence to the IMU; the pulse frequency of the synchronous pulse sequence is determined according to the data sampling rate of the IMU;
the IMU is used for acquiring IMU data according to the synchronous pulse sequence, transmitting the IMU data to the acquisition board and sending a time-effective TOV pulse to the acquisition board according to the synchronous pulse sequence;
and the acquisition board is used for carrying out time synchronization on the IMU data and the GNSS data according to the received PPS and the TOV pulse.
Optionally, the IMU is configured in an out-trigger mode.
Optionally, the IMU is specifically configured to acquire and transmit IMU data once every time a pulse of the synchronization pulse sequence is received.
Optionally, the acquisition board is specifically configured to use the TOV pulse as a clock source of an internal counter.
Optionally, the acquisition board is further configured to reset the count value of the internal counter to 0 when the rising edge of the PPS is captured.
Optionally, the acquisition board is specifically configured to determine a relative synchronization time between the IMU data and the GNSS data according to a count value of the internal counter before the IMU data is received and a pulse period of the synchronization pulse sequence.
Optionally, a rising edge of a first pulse of the synchronization pulse sequence is aligned with a rising edge of the PPS.
Optionally, a delay between a rising edge of a first pulse of the synchronization pulse sequence and a rising edge of the PPS is smaller than a preset threshold, and the delay is a fixed value.
A second aspect of the present application provides a data synchronous acquisition method, which is applied to the data synchronous acquisition system provided in the first aspect; the method comprises the following steps:
the GNSS board card transmits PPS to the FPGA and the acquisition board simultaneously, and transmits GNSS data to the acquisition board;
the FPGA generates a synchronous pulse sequence according to the rising edge of the PPS and sends the synchronous pulse sequence to the IMU; the pulse frequency of the synchronous pulse sequence is determined according to the data sampling rate of the IMU;
the IMU acquires IMU data according to the synchronous pulse sequence, transmits the IMU data to the acquisition board, and sends TOV pulses to the acquisition board according to the synchronous pulse sequence;
and the acquisition board performs time synchronization on the IMU data and the GNSS data according to the received PPS and the received TOV pulse.
Optionally, the IMU acquires IMU data according to the synchronization pulse sequence, and transmits the IMU data to the acquisition board, which specifically includes:
and the IMU acquires and transmits IMU data once every time the IMU receives one pulse of the synchronous pulse sequence.
Optionally, the collecting board performs time synchronization on the IMU data and the GNSS data according to the received PPS and TOV pulses, and specifically includes:
the acquisition board takes the TOV pulse as a clock source of an internal counter; determining the relative synchronization time of the IMU data and the GNSS data according to the counting value of the internal counter before the IMU data is received and the pulse period of the synchronization pulse sequence;
the acquisition board determines first synchronization time according to the GNSS data; the first synchronization time corresponds to a rising edge of the PPS;
and the acquisition board obtains second synchronous time of the IMU data according to the first synchronous time and the relative synchronous time.
Compared with the prior art, the method has the following beneficial effects:
the embodiment of the application provides a data synchronous acquisition system and a data synchronous acquisition method, wherein the system comprises: the system comprises a global navigation satellite system GNSS board card, an inertial measurement unit IMU, a field programmable gate array FPGA and an acquisition board; the GNSS board card and the IMU are both connected with the FPGA, and the GNSS board card and the IMU are both connected with the acquisition board; the GNSS board card is used for simultaneously transmitting the PPS to the FPGA and the acquisition board and transmitting GNSS data to the acquisition board; the FPGA is used for generating a synchronous pulse sequence according to the rising edge of the PPS and sending the synchronous pulse sequence to the IMU; the pulse frequency of the synchronous pulse sequence is determined according to the data sampling rate of the IMU; the IMU is used for acquiring IMU data according to the synchronous pulse sequence, transmitting the IMU data to the acquisition board and sending TOV pulse to the acquisition board; and the acquisition board is used for carrying out time synchronization on the IMU data and the GNSS data according to the received PPS and TOV pulses. The high-precision synchronous pulse generated by the FPGA guides the IMU to generate a high-precision counting pulse, so that the counting precision is improved. Meanwhile, the pulse edge of the synchronization pulse sequence is aligned with the pulse edge of the PPS, so that the time synchronization precision of the IMU data and the GNSS data is improved. Therefore, the problem that the time synchronization precision of the IMU data and the GNSS data is insufficient in the application process of the airborne laser radar system is solved. By taking mapping as an example, the problem that the overlapping parts between the navigation bands cannot be aligned in the multi-navigation-band mapping process due to insufficient accuracy of point cloud data is solved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
FIG. 1 is a schematic diagram of a conventional synchronous data acquisition system;
FIG. 2 is a schematic diagram of an edge of a pulse of the PPS and an internal clock of the single chip microcomputer;
fig. 3 is a schematic structural diagram of a data synchronous acquisition system according to an embodiment of the present application;
fig. 4 is a schematic diagram of pulse edges of synchronization pulses generated by the pulse per second PPS and the FPGA according to an embodiment of the present disclosure;
fig. 5 is a schematic flow chart of a data synchronous acquisition method according to an embodiment of the present application.
Detailed Description
As described above, the current data synchronization acquisition system counts by the internal clock of the acquisition board single chip, and then multiplies the clock period by the numerical value as the synchronization time of the IMU data. This system has the following drawbacks.
Firstly, the single chip microcomputer usually uses a quartz oscillator or an internal RC clock as a pulse source, and the precision of the pulse period is limited. Second, the edges of the PPS are not aligned with the edges of the internal clock, i.e., the delay time T is unknown. By combining the two points, the time synchronization precision of the IMU data and the GNSS data in the prior art is insufficient. Insufficient time synchronization accuracy may affect the accuracy of the finally formed point cloud data.
In order to solve the above problems, the inventors have studied and provided a data synchronous acquisition system and a data synchronous acquisition method. The system comprises: the system comprises a global navigation satellite system GNSS board card, an inertial measurement unit IMU, a field programmable gate array FPGA and an acquisition board; the GNSS board card and the IMU are both connected with the FPGA, and the GNSS board card and the IMU are both connected with the acquisition board; the GNSS board card is used for simultaneously transmitting the PPS to the FPGA and the acquisition board and transmitting GNSS data to the acquisition board; the FPGA is used for generating a synchronous pulse sequence according to the rising edge of the PPS and sending the synchronous pulse sequence to the IMU; the pulse frequency of the synchronous pulse sequence is determined according to the data sampling rate of the IMU; the IMU is used for acquiring IMU data according to the synchronous pulse sequence, transmitting the IMU data to the acquisition board and sending TOV pulse to the acquisition board; and the acquisition board is used for carrying out time synchronization on the IMU data and the GNSS data according to the received PPS and TOV pulses. The time synchronization precision of IMU data and GNSS data is improved by the synchronous pulse sequence generated by the FPGA.
The embodiments of the present application will be described in further detail with reference to the drawings and the detailed description.
Referring to fig. 3, the figure is a schematic structural diagram of a data synchronous acquisition system provided in the embodiment of the present application. As shown in fig. 3, the data synchronous acquisition system provided in the embodiment of the present application includes: the system comprises a global navigation satellite system GNSS board card, an inertial measurement unit IMU, a field programmable gate array FPGA300 and an acquisition board. The GNSS board card and the IMU are connected with the FPGA, and the GNSS board card and the IMU are connected with the acquisition board.
The GNSS board card is used for simultaneously transmitting the PPS to the FPGA and the acquisition board and transmitting GNSS data to the acquisition board. The FPGA is used for generating a synchronous pulse sequence according to the rising edge of the PPS and sending the synchronous pulse sequence to the IMU; the pulse frequency of the synchronization pulse sequence is determined according to the data sampling rate of the IMU. The IMU is used for acquiring IMU data according to the synchronous pulse sequence, transmitting the IMU data to the acquisition board and sending TOV pulses to the acquisition board according to the synchronous pulse sequence. And the acquisition board is used for carrying out time synchronization on the IMU data and the GNSS data according to the received PPS and the received TOV pulse.
It can be understood that the synchronous pulse generated by the FPGA according to the PPS is a high-precision synchronous pulse, that is, the precision of the synchronous pulse period is high, and the problem that the single chip microcomputer generally uses a quartz oscillator or the precision of the internal RC clock pulse period is limited is solved.
As a possible implementation manner, refer to fig. 4, which is a schematic diagram of pulse edges of a pulse per second PPS and a synchronization pulse generated by an FPGA according to an embodiment of the present application. As shown in fig. 4, the rising edge of the first pulse of the synchronization pulse sequence in the embodiment of the present application is aligned with the rising edge of the pulse per second PPS, so that the synchronization pulse generated by the FPGA is better synchronized with the PPS.
As another possible implementation manner, a delay between a rising edge of a first pulse of the synchronization pulse sequence in the embodiment of the present application and a rising edge of the pulse per second PPS is smaller than a preset threshold, and the delay is a fixed value. It will be appreciated that the predetermined threshold is typically much less than the period of the synchronisation pulse and that the delay is a stable value. Therefore, the synchronization pulse generated by the FPGA and the PPS have better synchronism. It should be noted that, according to the actual requirements of the application scenario, the delay may be ignored, or the fixed value of the delay may be measured to process the synchronization pulse so as to completely synchronize with the pulse per second PPS, which is not limited herein.
In conclusion, the synchronous pulse generated by the FPGA has high precision and good synchronism with the PPS.
In an embodiment of the present application, the IMU sends a TOV pulse to the acquisition board according to the synchronization pulse sequence. Specifically, after receiving the synchronization pulse generated by the FPGA, the IMU starts to send a TOV pulse to the acquisition board, and the frequency of the TOV pulse is equal to that of the synchronization pulse generated by the FPGA, and the period of the TOV pulse is the same as that of the synchronization pulse generated by the FPGA. In the embodiment of the present application, the IMU is in an external trigger mode, and as a possible implementation manner, the IMU performs acquisition and transmission of IMU data once every time the IMU receives one pulse of the synchronization pulse sequence. It can be seen that one TOV pulse corresponds to one acquisition and transmission of IMU data.
In order to calculate the synchronization time of the IMU data, in the embodiment of the present application, the acquisition board uses the TOV pulse as a clock source of the internal counter. The acquisition board is further used for resetting the count value of the internal counter to 0 when the rising edge of the PPS is captured. In the embodiment of the application, the PPS and the GNSS data are sent simultaneously, when the acquisition board captures the rising edge of the PPS, the acquisition board receives the GNSS data simultaneously, and the count value of the internal counter is reset to 0. Then, the acquisition board determines the relative synchronization time of the IMU data and the GNSS data according to the count value of the internal counter before receiving the IMU data and the pulse period of the synchronization pulse sequence; in this manner, the relative synchronization time of the IMU data and the GNSS data may be calculated.
One specific way to calculate the relative synchronization time of IMU data and GNSS data is described below: the collecting board takes the TOV pulse as a clock source of an internal counter, and the TOV pulse is used for counting so as to calculate the synchronous time of the IMU data synchronously sent with the TOV pulseN=N*∆T。
The method provided by the implementation of the application not only can calculate the relative synchronization time of the IMU data synchronously transmitted by the TOV pulse, but also can calculate the absolute synchronization time of the IMU data synchronously transmitted by the TOV pulse. In particular, the acquisition board may obtain a first synchronization time (absolute time) from the GNSS data. The integer seconds of absolute time are obtained, which correspond to the rising edge of the pulse per second PPS. The acquisition board may also obtain a second synchronization time of the IMU data based on the first synchronization time and the relative synchronization time.
Therefore, the system provided by the embodiment of the application generates a high-precision counting pulse source by using the high-precision synchronous pulse generated by the field programmable gate array FPGA, so that the precision of the pulse period for counting is improved, and meanwhile, the pulse edge of the pulse source is aligned with the pulse edge of the PPS, or the delay time T is fixed and known. Therefore, the time synchronization precision of the IMU data and the GNSS data is improved, and the problem that the time synchronization precision of the IMU data and the GNSS data is insufficient and the airborne laser radar system is applied is avoided. By taking mapping as an example, the problem that the overlapping parts between the navigation bands cannot be aligned in the multi-navigation-band mapping process due to insufficient accuracy of point cloud data is solved.
According to the data synchronous acquisition system provided by the embodiment, the embodiment of the application further provides a data synchronous acquisition method. Referring to fig. 5, the figure is a schematic flow chart of a data synchronous acquisition method provided in the embodiment of the present application. As shown in fig. 5, a data synchronous acquisition method provided in the embodiment of the present application includes the following steps S501 to S504:
s501, the GNSS board card transmits PPS (pulse per second) to the FPGA and the acquisition board simultaneously and transmits GNSS data to the acquisition board.
S502, the FPGA generates a synchronous pulse sequence according to the rising edge of the PPS and sends the synchronous pulse sequence to the IMU; the pulse frequency of the synchronization pulse sequence is determined according to the data sampling rate of the IMU.
S503, the IMU acquires IMU data according to the synchronous pulse sequence, transmits the IMU data to the acquisition board, and sends TOV pulse to the acquisition board according to the synchronous pulse sequence.
And S504, the acquisition board performs time synchronization on the IMU data and the GNSS data according to the received PPS and the received TOV pulse.
As a possible implementation manner, the IMU acquires IMU data according to the synchronization pulse sequence, and transmits the IMU data to the acquisition board, specifically including: and the IMU acquires and transmits IMU data once every time the IMU receives one pulse of the synchronous pulse sequence.
As a possible implementation manner, the acquisition board performs time synchronization on IMU data and GNSS data according to the received PPS and TOV pulses, specifically including: the acquisition board takes the TOV pulse as a clock source of an internal counter; determining the relative synchronization time of the IMU data and the GNSS data according to the counting value of the internal counter before the IMU data is received and the pulse period of the synchronization pulse sequence; the acquisition board determines first synchronization time according to the GNSS data; the first synchronization time corresponds to a rising edge of the pulse per second PPS; and the acquisition board obtains second synchronous time of the IMU data according to the first synchronous time and the relative synchronous time.
Therefore, the method provided by the embodiment of the application generates a high-precision counting pulse source by using the high-precision synchronous pulse generated by the field programmable gate array FPGA, so that the precision of the pulse period for counting is improved, and meanwhile, the pulse edge of the pulse source is aligned with the pulse edge of the PPS, or the delay time T is fixed and known. Therefore, the time synchronization precision of the IMU data and the GNSS data is improved.
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The above description is only one specific embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (11)

1. A system for synchronously acquiring data, comprising: the system comprises a global navigation satellite system GNSS board card, an inertial measurement unit IMU, a field programmable gate array FPGA and an acquisition board; the GNSS board card and the IMU are both connected with the FPGA, and the GNSS board card and the IMU are both connected with the acquisition board;
the GNSS board card is used for simultaneously transmitting the PPS to the FPGA and the acquisition board and transmitting GNSS data to the acquisition board;
the FPGA is used for generating a synchronous pulse sequence according to the rising edge of the PPS and sending the synchronous pulse sequence to the IMU; the pulse frequency of the synchronous pulse sequence is determined according to the data sampling rate of the IMU;
the IMU is used for acquiring IMU data according to the synchronous pulse sequence, transmitting the IMU data to the acquisition board and sending a time-effective TOV pulse to the acquisition board according to the synchronous pulse sequence;
and the acquisition board is used for carrying out time synchronization on the IMU data and the GNSS data according to the received PPS and the TOV pulse.
2. The system of claim 1, wherein the IMU is configured in an external trigger mode.
3. The system according to claim 1 or 2, wherein the IMU is configured to perform IMU data acquisition and transmission once per pulse of the synchronization pulse sequence received.
4. The system according to claim 1 or 2, wherein the acquisition board is specifically configured to use the TOV pulse as a clock source of an internal counter.
5. The system of claim 4, wherein the acquisition board is further configured to reset the internal counter count value to 0 when a rising edge of the PPS is captured.
6. The system of claim 5, wherein the acquisition board is further configured to determine the relative synchronization time of the IMU data and the GNSS data based on a count of the internal counter prior to receiving the IMU data and a pulse period of the synchronization pulse sequence.
7. The system of any of claims 1, 2, 5 or 6, wherein a rising edge of a first pulse of the sequence of synchronization pulses is aligned with a rising edge of the PPS.
8. The system according to any one of claims 1, 2, 5 or 6, wherein the delay between the rising edge of the first pulse of the synchronization pulse sequence and the rising edge of the PPS is less than a preset threshold, and the delay is a fixed value.
9. A data synchronous acquisition method, which is applied to the data synchronous acquisition system of any one of claims 1 to 8; the method comprises the following steps:
step 1, the GNSS board card transmits PPS to the FPGA and the acquisition board simultaneously, and GNSS data are transmitted to the acquisition board;
step 2, the FPGA generates a synchronous pulse sequence according to the rising edge of the PPS and sends the synchronous pulse sequence to the IMU; the pulse frequency of the synchronous pulse sequence is determined according to the data sampling rate of the IMU;
step 3, the IMU acquires IMU data according to the synchronous pulse sequence, transmits the IMU data to the acquisition board, and sends TOV pulse to the acquisition board according to the synchronous pulse sequence;
and 4, the acquisition board performs time synchronization on the IMU data and the GNSS data according to the received PPS and the received TOV pulse.
10. The method according to claim 9, wherein the IMU acquires IMU data according to the synchronization pulse sequence and transmits the IMU data to the acquisition board, specifically comprising:
and the IMU acquires and transmits IMU data once every time the IMU receives one pulse of the synchronous pulse sequence.
11. The method according to claim 9 or 10, wherein the time synchronization of the IMU data and the GNSS data by the acquisition board according to the received PPS and the TOV pulse comprises:
the acquisition board takes the TOV pulse as a clock source of an internal counter, and when the rising edge of the PPS is captured, the count value of the internal counter is reset to 0; determining the relative synchronization time of the IMU data and the GNSS data according to the counting value of the internal counter before the IMU data is received and the pulse period of the synchronization pulse sequence;
the acquisition board determines first synchronization time according to the GNSS data; the first synchronization time corresponds to a rising edge of the PPS;
and the acquisition board obtains second synchronous time of the IMU data according to the first synchronous time and the relative synchronous time.
CN202110803551.1A 2021-07-16 2021-07-16 Data synchronous acquisition system and data synchronous acquisition method Active CN113267186B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110803551.1A CN113267186B (en) 2021-07-16 2021-07-16 Data synchronous acquisition system and data synchronous acquisition method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110803551.1A CN113267186B (en) 2021-07-16 2021-07-16 Data synchronous acquisition system and data synchronous acquisition method

Publications (2)

Publication Number Publication Date
CN113267186A CN113267186A (en) 2021-08-17
CN113267186B true CN113267186B (en) 2021-10-22

Family

ID=77236589

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110803551.1A Active CN113267186B (en) 2021-07-16 2021-07-16 Data synchronous acquisition system and data synchronous acquisition method

Country Status (1)

Country Link
CN (1) CN113267186B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114754769B (en) * 2022-06-15 2022-11-18 天津大学四川创新研究院 Data synchronization time service system and method for laser radar and inertial sensor

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101930211B (en) * 2010-08-24 2012-01-04 西安交通大学 Clock source device based on GPS second pulse and control method thereof
US9927545B2 (en) * 2011-11-14 2018-03-27 SeeScan, Inc. Multi-frequency locating system and methods
CN102866621B (en) * 2012-09-12 2014-05-28 北京控制工程研究所 High-precision GPS (Global Positioning System) 1pps (1 Pulse Per Second) timer and timing method of spacecraft
CN103616710A (en) * 2013-12-17 2014-03-05 靳文瑞 Multi-sensor combined navigation time synchronizing system based on field programmable gate array (FPGA)
CN104199278B (en) * 2014-09-04 2017-03-08 中国科学院测量与地球物理研究所 The anti-high-precise synchronization clock system for blocking and its synchronous method based on many navigation system
US20170336220A1 (en) * 2016-05-20 2017-11-23 Daqri, Llc Multi-Sensor Position and Orientation Determination System and Device
CN106154299A (en) * 2016-06-22 2016-11-23 陕西宝成航空仪表有限责任公司 A kind of GPS/SINS integrated navigation system method for synchronizing time
US11099277B2 (en) * 2018-11-19 2021-08-24 Intel Corporation Apparatus, system and method of synchronization between Global Navigation Satellite System (GNSS) measurements and inertial measurements
CN112235041A (en) * 2020-12-18 2021-01-15 成都纵横大鹏无人机科技有限公司 Real-time point cloud processing system and method and airborne data acquisition device and method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
基于FPGA的GNSS/INS组合系统时间同步设计;李彩容;《现代科学仪器》;20130430(第2期);第92-94页 *

Also Published As

Publication number Publication date
CN113267186A (en) 2021-08-17

Similar Documents

Publication Publication Date Title
CN111381487B (en) Multi-sensor synchronous time service system, method and device and electronic equipment
CN107655475B (en) Synchronous pulse signal acquisition method, navigation data synchronous processing method and system
CN110133999B (en) Time synchronization method and system based on satellite cloud laser point cloud data acquisition platform
US6678510B2 (en) Method, apparatus and system for GPS time synchronization using cellular signal bursts
CN100461721C (en) System, method and apparatus for testing long-distance frame time delay
CN106909071B (en) A kind of spacecraft synchronization accuracy test macro and method based on pulse per second (PPS)
CN103326802A (en) Wireless network system for achieving synchronous acquisition, synchronous acquisition device and method
CN112543078B (en) Network time server calibration method and device based on satellite common view
EP3217590A1 (en) In-system global clock providing method and device
CN114964175B (en) Multi-sensor data synchronous acquisition device and acquisition method
CN109302255B (en) Time synchronization control method, device and system and computer readable storage medium
CN104317354A (en) Intersystem global clock determination method and structure
CN113267186B (en) Data synchronous acquisition system and data synchronous acquisition method
Faizullin et al. Open-source lidar time synchronization system by mimicking GNSS-clock
CN103412474B (en) Range high-precision expanded circuit when TDC-GP2 based on FPGA surveys
JP2023532150A (en) Radar and radar system
CN115856793A (en) Radar signal frequency deviation estimation compensation method
CN110830732B (en) Exposure time acquisition device and method for automatic driving system
JP2005134215A (en) System for measuring difference of signal arrival time
CN112946693A (en) Method and system for determining system time deviation of satellite navigation system
CN112305568B (en) Method for testing consistency of ranging result and ranging reference change of spacecraft
EP4296619A1 (en) Clock synchronisation
RU2381538C1 (en) Method of distributing precise universal time signals over telecommunication network and system for distributing precise universal time signals
KR20170005202A (en) Apparatus for time synchronization using gps modules and method thereof
Ren et al. Research on Satellite-Based Time Synchronization Technology of Geostationary Orbit Satellites

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant