Time calibration system for laser inertial navigation

Abstract

The invention discloses a time calibration system for laser inertial navigation, which comprises a laser inertial navigation device, a PPS signal sending device and a time calibration reference device, the PPS signal sending device and the time calibration reference device are connected with the laser inertial navigation device through a data serial port, and the laser inertial navigation device comprises time calibration software. The timing software is used for receiving a pulse per second signal sent by the PPS signal sending equipment and a time signal sent by the timing reference equipment, and the timing software is used for judging the validity of the time signal; and the PPS signal sending equipment is used for sending the second pulse signal to the laser inertial navigation equipment. The method has the beneficial effects that time calibration software in the laser inertial navigation equipment receives a time signal sent by the time calibration reference equipment and a second pulse signal sent by the PPS signal sending equipment and judges whether the time signal and the second pulse signal are effective and continuously available or not; and if so, initializing time information in the laser inertial navigation equipment by using an effective time signal received from the outside.

Description

Technical Field

[0001] The invention relates to the field of navigation technology, and in particular to a time calibration system for laser inertial navigation. Background Art

[0002] The main function of laser inertial navigation is to provide high-precision autonomous navigation capability, which is independent of external information and has extremely high concealment and anti-interference. The laser inertial navigation system uses inertial devices such as laser gyroscopes and accelerometers to measure the angular velocity and specific force information of the carrier, combined with the initial conditions, and calculates navigation parameters such as speed, position and attitude in real time. At present, with the development of laser inertial navigation technology, the advantages of laser inertial navigation have been further developed. At present, laser inertial navigation is widely used in ships, automobiles, aircraft and other fields.

[0003] For example, a time calibration system and method for a satellite with application number CN115903443B and announcement date 2024.04.26, the system includes: an SMU processor module and a navigation satellite system module that is communicatively connected to the SMU processor module, wherein the navigation satellite system module is configured to receive a second pulse signal and a timing data packet from the navigation satellite system, and transmit the second pulse signal to the SMU processor module. The SMU processor module is configured to: generate a crystal oscillator clock time local to the satellite based on an oscillation signal of the crystal oscillator; and determine the first time information corresponding to the second pulse signal according to the crystal oscillator clock time.

[0004] Inertial navigation is closely related to time. The accuracy of time directly affects the accuracy of navigation results and the stability of the system. One of the principles of the inertial navigation system is to measure the acceleration of the carrier and calculate the speed and position by time integration, which means that the accuracy of time is crucial to the accuracy of navigation results. Since inertial navigation is based on the principle of time integration, errors will gradually accumulate over time. Therefore, accurate control and management of time are also crucial to limiting the accumulation of errors. Therefore, it is urgent to design a time calibration system for laser inertial navigation to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a time calibration system for laser inertial navigation to solve the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A time calibration system for laser inertial navigation comprises a laser inertial navigation device, a PPS signal sending device and a time calibration reference device, wherein the PPS signal sending device and the time calibration reference device are both connected to the laser inertial navigation device via a data serial port.

[0008] The laser inertial navigation device includes a time calibration software, which is used to receive the second pulse signal sent by the PPS signal sending device and the time signal sent by the time calibration reference device, and the time calibration software is used to judge the validity of the time signal;

[0009] The PPS signal sending device is used to send the pulse per second signal to the laser inertial navigation device;

[0010] The timing reference device is used to send a time signal to a laser inertial navigation device.

[0011] Furthermore, the PPS signal sending device generates one pulse per second, that is, one time mark per second.

[0012] Furthermore, the timing software of the laser inertial navigation device determines whether the time signal is valid based on:

[0013] (1) Whether the year, month, day, hour, minute and second are normal;

[0014] (2) Whether the month exceeds 31 days;

[0015] (3) Whether the seconds exceed 60 seconds.

[0016] Furthermore, the time signal validity judgment results are divided into the following two types:

[0017] (1) Time signal is valid: calculate the difference between the currently received time signal and the previously received time signal;

[0018] (2) Time signal invalid: Continue waiting for a valid time signal.

[0019] Furthermore, when the time signal is valid, the difference of the time signal is calculated in the following three cases:

[0020] a. The value of the currently received time signal is smaller than the value of the previously received time signal, indicating that the date has been updated across days;

[0021] b. If the difference between the currently received time signal and the previously received time signal is greater and the difference is within one second, the number of valid time signals is added;

[0022] c. If the difference between the currently received time signal and the previously received time signal is greater than one second, the number of valid time signals is set to zero and information reception and judgment continue.

[0023] Furthermore, in case b of the three cases of calculating the difference, the specific way of superimposing the number of time-valid signals is: if the difference between the time signal currently received and the time signal previously received is greater each time and is within one second, the number of time-valid signals is increased by one.

[0024] Furthermore, in case b of the three cases of calculating the difference, when the number of time-valid signals reaches three times, it can help determine whether the laser inertial navigation device is keeping time normally.

[0025] Furthermore, when the number of valid time signals reaches three times and the pulse-per-second signal is valid, it is determined whether the laser inertial navigation device is keeping time normally.

[0026] Furthermore, if the laser inertial navigation device is on time normally, no other operation is required.

[0027] Furthermore, if the laser inertial navigation device is not keeping time normally, the received time signal is used as the date of the laser inertial navigation device, that is, the rough value of the time signal.

[0028] In the above technical solution, the present invention provides a time calibration system for laser inertial navigation,

[0029] 1. Through the laser inertial navigation device, PPS signal sending device and time calibration reference device, the time calibration software in the laser inertial navigation device receives the time signal sent by the time calibration reference device and the second pulse signal sent by the PPS signal sending device and determines whether they are valid and continuously available. If the laser inertial navigation device is not in good timekeeping, the time information inside the laser inertial navigation device is initialized using the effective time signal received from the outside world. If the laser inertial navigation device is in good timekeeping, it can continue to receive time information. The time calibration system can calibrate the time of the laser inertial navigation device well, which is helpful to improve the accuracy of speed measurement and positioning. Accurate time information is a key factor in calculating the heading change and position offset of the carrier with the laser inertial navigation device, which helps to reduce the cumulative deviation caused by time error, improves the safety of the carrier during the journey, ensures the synchronous operation of each sensor, and improves the reliability of the system, so it has extremely considerable application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0031] Figure 1 A schematic diagram of the system structure provided for an embodiment of a time calibration system for laser inertial navigation of the present invention.

[0032] Figure 2 A schematic diagram of the structure of a method flow provided in an embodiment of a time calibration system for laser inertial navigation of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] like Figure 1-2 As shown, a time calibration system for laser inertial navigation provided by an embodiment of the present invention includes a laser inertial navigation device, a PPS signal sending device and a time calibration reference device, wherein the PPS signal sending device and the time calibration reference device are both connected to the laser inertial navigation device through a data serial port.

[0035] The laser inertial navigation device includes a time calibration software, which is used to receive the second pulse signal sent by the PPS signal sending device and the time signal sent by the time calibration reference device, and the time calibration software is used to judge the validity of the time signal;

[0036] The PPS signal sending device is used to send the pulse per second signal to the laser inertial navigation device;

[0037] The timing reference device is used to send the time signal to the laser inertial navigation device.

[0038] The present invention provides a time calibration system for laser inertial navigation, comprising a laser inertial navigation device, a PPS signal sending device and a time calibration reference device, wherein the PPS signal sending device and the time calibration reference device are both connected to the laser inertial navigation device via a data serial port.

[0039] The laser inertial navigation device includes a time calibration software, which is used to receive the second pulse signal sent by the PPS signal sending device and the time signal sent by the time calibration reference device, and the time calibration software is used to judge the validity of the time signal;

[0040] The PPS signal sending device is used to send the pulse per second signal to the laser inertial navigation device;

[0041] The timing reference device is used to send the time signal to the laser inertial navigation device.

[0042] In one embodiment provided by the present invention, the PPS signal sending device generates one pulse per second, that is, one time mark per second.

[0043] In another embodiment provided by the present invention, the timing software of the laser inertial navigation device determines whether the time signal is valid based on:

[0044] (1) Whether the year, month, day, hour, minute and second are normal;

[0045] (2) Whether the month exceeds 31 days;

[0046] (3) Whether the seconds exceed 60 seconds.

[0047] In another embodiment provided by the present invention, the time signal validity judgment results are divided into the following two types:

[0048] (1) Time signal is valid: calculate the difference between the currently received time signal and the previously received time signal;

[0049] (2) Time signal invalid: Continue waiting for a valid time signal.

[0050] In an embodiment provided by the present invention, when the time signal is valid, the difference of the time signal is calculated in the following three cases:

[0051] a. The value of the currently received time signal is smaller than the value of the previously received time signal, indicating that the date has been updated across days;

[0052] b. If the difference between the currently received time signal and the previously received time signal is greater and the difference is within one second, the number of valid time signals is added;

[0053] The specific method of superposition of the number of valid time signals is: if the difference between the time signal currently received and the time signal previously received is greater each time and is within one second, the number of valid time signals is increased by one. When the number of valid time signals reaches three times, it can help determine whether the laser inertial navigation device is keeping time normally.

[0054] c. If the difference between the currently received time signal and the previously received time signal is greater than one second, the number of valid time signals is set to zero and information reception and judgment continue.

[0055] In another embodiment provided by the present invention, when the number of valid time signals reaches three times and the pulse-per-second signal is valid, it is determined whether the laser inertial navigation device is keeping time normally.

[0056] In another embodiment provided by the present invention, if the laser inertial navigation device is on time normally, no other operation is required.

[0057] In one embodiment provided by the present invention, if the laser inertial navigation device is not keeping time normally, the received time signal is used as the date of the laser inertial navigation device, that is, the rough value of the time signal.

[0058] Working principle:

[0059] (1) Power on the laser inertial navigation device and PPS signal transmission device to ensure that they can stably send out time information and pulse per second signals;

[0060] (2) Connect the laser inertial navigation device, PPS signal sending device and the corresponding data serial port of the laser inertial navigation device according to the system composition;

[0061] (3) After receiving the time signal, the time calibration software of the laser inertial navigation device determines the validity of the time signal, that is, whether the year, month, day, hour, minute, and second are normal, whether the month exceeds 31 days, and whether the second exceeds 60 seconds; if it is determined to be valid, the hour, minute, second, and millisecond of the day in the current time signal are used as the timing unit in milliseconds, and the difference between the current received time signal and the previous received time signal is calculated, and the process goes to step (4); otherwise, it continues to wait for a valid time signal;

[0062] (4) If the value of the time signal currently received is smaller than that of the previous time signal received, it means that the date has been updated across days;

[0063] (5) If the difference between the time signal currently received and the time signal previously received is large and within one second, the number of valid time signals is increased by one; otherwise, the number of valid time signals is set to zero and the process continues with step (3);

[0064] (6) If the time signal is valid three times and the pulse-per-second signal is valid, determine whether the laser inertial navigation device is keeping time normally; otherwise, return to step (3) to continue receiving and determining information;

[0065] (7) If the laser inertial navigation device keeps time normally, no other operation is required and the time information can continue to be received; if the laser inertial navigation device does not keep time normally, the received time signal is used as the date of the laser inertial navigation device, i.e., the rough value of the time signal.

[0066] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A time calibration system for laser inertial navigation, comprising a laser inertial navigation device, a PPS signal sending device and a time calibration reference device, characterized in that: The PPS signal sending device and the timing reference device are both connected to the laser inertial navigation device through a data serial port. The laser inertial navigation device includes a time calibration software, which is used to receive the second pulse signal sent by the PPS signal sending device and the time signal sent by the time calibration reference device, and the time calibration software is used to judge the validity of the time signal; The PPS signal sending device is used to send the pulse per second signal to the laser inertial navigation device; The timing reference device is used to send a time signal to a laser inertial navigation device.

2. A time calibration system for laser inertial navigation according to claim 1, characterized in that: The PPS signal sending device generates one pulse per second, that is, one time mark per second.

3. The time calibration system for laser inertial navigation according to claim 1, characterized in that: The time calibration software of the laser inertial navigation device determines whether the time signal is valid based on: (1) Whether the year, month, day, hour, minute and second are normal; (2) Whether the month exceeds 31 days; (3) Whether the seconds exceed 60 seconds.

4. The time calibration system for laser inertial navigation according to claim 1, characterized in that: The time signal validity judgment results are divided into the following two types: (1) Time signal is valid: calculate the difference between the currently received time signal and the previously received time signal; (2) Time signal invalid: Continue waiting for a valid time signal.

5. The time calibration system for laser inertial navigation according to claim 4, characterized in that: When the time signal is valid, the difference of the time signal is calculated in the following three cases: a. The value of the currently received time signal is smaller than the value of the previously received time signal, indicating that the date has been updated across days; b. If the difference between the currently received time signal and the previously received time signal is greater and the difference is within one second, the number of valid time signals is added; c. If the difference between the currently received time signal and the previously received time signal is greater than one second, the number of valid time signals is set to zero and information reception and judgment continue.

6. The time calibration system for laser inertial navigation according to claim 4, characterized in that: In case b of the three cases of calculating the difference, the specific way of superimposing the number of time valid signals is: each time the difference between the currently received time signal and the previously received time signal is greater and is within one second, the number of time valid signals is increased by one.

7. The time calibration system for laser inertial navigation according to claim 4, characterized in that: In case b of the three cases of calculating the difference, when the number of time-valid signals reaches three times, it can help determine whether the laser inertial navigation device is keeping time normally.

8. The time calibration system for laser inertial navigation according to claim 7, characterized in that: When the number of valid time signals reaches three times and the pulse-per-second signal is valid, it is determined whether the laser inertial navigation device is keeping time normally.

9. A time calibration system for laser inertial navigation according to claim 8, characterized in that: If the laser inertial navigation device is on time normally, no other operation is required.

10. The time calibration system for laser inertial navigation according to claim 8, characterized in that: If the laser inertial navigation device is not keeping time normally, the received time signal is used as the date of the laser inertial navigation device, that is, the rough value of the time signal.

Images