Noise evaluation method for fiber-optic gyroscope circuit

Abstract

The invention particularly relates to a noise evaluation method for a fiber-optic gyroscope circuit, and solves the technical problem that the performance index of a fiber-optic gyroscope is influenced as a certain difference exists between theoretical estimation and theoretical calculation according to a noise parameter model of a component in a traditional circuit noise evaluation method. The invention relates to a noise evaluation method of a fiber-optic gyroscope circuit, which comprises the following steps: S1, inputting a reference voltage signal into a pre-amplification circuit of the fiber-optic gyroscope circuit to be tested, amplifying the reference voltage signal, and sending the amplified reference voltage signal into an analog-to-digital conversion unit; s2, collecting the amplified reference voltage signal according to the set sampling frequency; s3, the summation of the first m data and the summation of the last m data of each sampling period are solved; (n-1) difference values # imgabs0 # are obtained through subtraction, then sliding filtering is carried out on the difference values # imgabs1 #, the sum of # imgabs2 # of each sliding period is obtained and recorded as data # imgabs3 # S4, and the data # imgabs4 # are sent to an external control unit; and S5, calculating a peak-to-peak value and / or a standard deviation of the curve for representing the noise level of the fiber-optic gyroscope circuit.

Description

Technical Field

[0001] The invention specifically relates to a noise evaluation method for a fiber optic gyroscope circuit. Background Art

[0002] Fiber optic gyroscope is an integrated optical-mechanical-electrical product with the advantages of impact resistance, high sensitivity, long life, large dynamic range, short start-up time, etc. It has been widely used in inertial navigation systems. Fiber optic gyroscope is an angular velocity sensor based on the Sagnac principle, which consists of two parts: optical path and circuit. The optical path in the fiber optic gyroscope includes light source, coupler, Y waveguide and fiber ring, photodetector. The main function of the light source is to provide the fiber optic gyroscope with the appropriate optical signal required to produce the Sagnac effect, and stably output the optical power, so that the fiber optic gyroscope can obtain an interference signal with a higher signal-to-noise ratio. The main function of the coupler, Y waveguide and fiber ring is to obtain the phase difference of the interference signal through the Sagnac effect in the closed optical path. The function of the photodetector is to convert the optical signal into an electrical signal. The main function of the circuit is to condition weak signals, implement algorithms and drive the Y waveguide phase modulation, angular velocity resolution and output.

[0003] The performance indicators of fiber optic gyroscopes are usually affected by the optical path (the indicators of the optical devices in the optical path, the fiber tail winding and fusion, the parameter matching between the optical paths, etc.), the circuit (including algorithm implementation) and the mechanical characteristics of the structure. The circuit is used to realize the demodulation and modulation of the angular velocity information of the fiber optic gyroscope. The noise level of the circuit restricts the performance indicators of high-precision or ultra-high-precision fiber optic gyroscopes to a certain extent. The traditional circuit noise evaluation method is theoretically estimated according to the noise parameter model of the components, which can evaluate the noise level of the circuit to a certain extent from the principle level. However, the batch differences of circuit components, the layout and wiring of the circuit board to be tested, and the thermal environment and electromagnetic environment of the circuit make the noise performance of the circuit in engineering applications different from the theoretical calculation. When the circuit board to be tested is assembled in the fiber optic gyroscope, it will affect the performance indicators of the fiber optic gyroscope to a certain extent. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the traditional circuit noise evaluation method performs theoretical estimation according to the noise parameter model of components, which is different from the theoretical calculation and affects the performance indicators of the fiber optic gyroscope, and provide a noise evaluation method for the fiber optic gyroscope circuit.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A noise evaluation method for a fiber optic gyroscope circuit, the fiber optic gyroscope circuit comprising a preamplifier circuit, an analog-to-digital conversion unit, and a processing unit connected in sequence;

[0007] The special thing about it is that it includes the following steps:

[0008] S1, inputting a reference voltage signal into the preamplifier circuit of the fiber optic gyro circuit to be tested, and the reference voltage signal is amplified by the preamplifier circuit and then sent to the analog-to-digital conversion unit;

[0009] S2. The analog-to-digital conversion unit collects the amplified reference voltage signal according to the sampling frequency set by the processing unit of the fiber optic gyroscope circuit to be tested, and records the collected data of the i-th sampling cycle and the j-th sampling point as the effective sampling data D ij ; Wherein, i=1,…,n; j=1,…,2m; n and m are both natural numbers greater than 0;

[0010] S3, the processing unit of the fiber optic gyro circuit to be tested processes 2m valid sampling data D in each sampling period. ij Sum the first m data and the last m data to get S i前 and S i后 ; Then use the S of two adjacent cycles i前 With S i后 Subtract and get (n-1) difference values Then the difference Perform sliding filtering to obtain the The sum is recorded as data Where k represents the kth sliding period;

[0011] S4, the processing unit of the fiber optic gyro circuit to be tested will all the data sent to an external control unit;

[0012] S5, the external control unit receives all the data Draw a curve and obtain the peak-to-peak value and / or standard deviation of the curve to characterize the noise level of the fiber optic gyroscope circuit.

[0013] Furthermore, in step S1, a reference voltage signal is input to the preamplifier circuit using a standard voltage source.

[0014] Furthermore, in step S2, the sampling frequency is 20 MHz; the sampling period is 10 μs, and the sampling points are 200.

[0015] Furthermore, step S3 is specifically as follows:

[0016] 3.1. The processing unit of the fiber optic gyro circuit to be tested uses the following formula to calculate the 2m valid sampling data D in each sampling period: ij Sum the first m data i前 And then sum up the next m data S i后 :

[0017]

[0018] 3.2. Use S of two adjacent cycles i前 With S i后 By subtracting the following formula, we can get (n-1) differences. Specifically:

[0019]

[0020] 3.3. Difference Perform sliding filtering to obtain all The sum is recorded as data Where k represents the kth sliding period.

[0021] Furthermore, in step 3.3, the sliding period of the sliding filter is 0.5 ms.

[0022] Further, step S4 is specifically as follows:

[0023] The processing unit of the fiber optic gyro circuit to be tested transmits data according to the RS422 communication protocol. Sent to an external control unit.

[0024] Beneficial effects of the present invention:

[0025] 1. The noise evaluation method of the fiber optic gyroscope circuit of the present invention enables batch differences of circuit components and layout and wiring of the circuit board to be tested to be directly and objectively reflected through testing, thereby avoiding their influence on the performance indicators of the fiber optic gyroscope.

[0026] 2. The noise evaluation method of a fiber optic gyroscope circuit of the present invention utilizes a reference voltage signal output by a standard voltage source to be input into the fiber optic gyroscope circuit to be tested, and monitors the noise of the fiber optic gyroscope circuit in real time through its preamplifier circuit, analog-to-digital conversion unit, and processing unit through an external control unit, thereby overcoming the influence of other factors on the performance indicators of the fiber optic gyroscope in advance.

[0027] 3. The noise evaluation method of the fiber optic gyroscope circuit of the present invention performs noise testing on the fiber optic gyroscope circuit to achieve the purpose of intuitively evaluating the noise level of the fiber optic gyroscope circuit. At the same time, the fiber optic gyroscope circuit can be classified according to the noise index to adapt to fiber optic gyroscopes of different precisions; in particular, for a three-axis fiber optic gyroscope, when the requirements for different axial precision indicators are inconsistent, adaptation can also be performed based on the test results of the circuit noise level. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of data collection in an embodiment of a noise evaluation method for a fiber optic gyroscope circuit of the present invention;

[0029] Figure 2is a plotted curve 1 obtained by testing a fiber optic gyroscope circuit to be tested in an embodiment of a method for evaluating noise of a fiber optic gyroscope circuit of the present invention;

[0030] Figure 3 This is a second plotted curve obtained by testing the fiber optic gyroscope circuit to be tested in an embodiment of a method for evaluating noise of a fiber optic gyroscope circuit of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The fiber optic gyro circuit includes a preamplifier circuit, an analog-to-digital conversion unit, and a processing unit; the present invention uses a standard voltage source to input a reference voltage signal to the preamplifier circuit of the fiber optic gyro circuit; the reference voltage signal enters the analog-to-digital conversion unit after amplification; the analog-to-digital conversion unit collects the amplified reference voltage signal and converts it into a digital signal; the processing unit inputs a sampling frequency to the analog-to-digital conversion unit, processes the sampling data output by the analog-to-digital conversion unit to obtain effective sampling data, and sends it to an external external control unit; the external control unit is used to draw a curve after processing the effective sampling data to characterize the noise level of the circuit. The sampling frequency should not be greater than the maximum sampling frequency of the A / D converter. In this embodiment, the sampling frequency is 20MHz, and the analog-to-digital conversion unit adopts an A / D converter; the processing unit adopts FPGA; and the external control unit adopts an industrial computer. When the fiber optic gyro is used in a complex environment such as a thermal environment and an electromagnetic environment, it is not affected by the external environment, and the performance indicators of the fiber optic gyro can be directly reflected through testing.

[0033] The noise evaluation method of the fiber optic gyroscope circuit of the present invention comprises the following steps:

[0034] S1, using a standard voltage source to input a reference voltage signal into the preamplifier circuit of the fiber optic gyroscope circuit to be tested, and the reference voltage signal is amplified by the preamplifier circuit of the fiber optic gyroscope circuit to be tested and then sent to its analog-to-digital conversion unit;

[0035] S2, such as Figure 1 As shown, the processing unit of the fiber optic gyro circuit to be tested is used to input the sampling frequency to its analog-to-digital conversion unit, and the analog-to-digital conversion unit starts to collect data, and the collected data of the i-th sampling cycle and the j-th sampling point are recorded as the effective sampling data D ij ; Wherein, i = 1, ..., n; j = 1, ..., 2m; n, m are both natural numbers greater than 0; In this embodiment, the sampling frequency f = 20MHz, the sampling period τ = 10μs, the sampling point 2m = 10

[0036] μs*20MHz=200;

[0037] 3.1. The processing unit of the fiber optic gyro circuit to be tested processes 200 valid sampling data D in each sampling period of 10 μs. ij The sum is performed, where the first 100 sampling data of i sampling cycles are summed up in turn:

[0038]

[0039] Sum the last 100 samples:

[0040]

[0041] That is, the first 100 sampling data and the last 100 sampling data of the first sampling cycle are summed:

[0042]

[0043] The first 100 sampling data and the last 100 sampling data of the second sampling cycle are summed:

[0044]

[0045] By analogy, the first 100 sampling data and the last 100 sampling data of the nth sampling period are summed:

[0046]

[0047] 3.2. The sum S of the last m data of two adjacent cycles i前 The sum of the first m data of two adjacent cycles S i后 Subtract by the following formula:

[0048]

[0049] Then, for the sum of the sampled data in the ith period, we can obtain and The sum of the sampling data of the i+1th cycle is obtained and The difference is:

[0050]

[0051] Specifically

[0052]

[0053] …

[0054] And so on, we get the (n-1) difference

[0055]

[0056] 3.3. Difference Perform sliding filtering (i.e. fixed period summation). When the sliding period of the sliding filter is 0.5ms, Get 50 sum k is the kth 0.5ms cycle:

[0057]

[0058] Among them, the first 0.5ms output data is:

[0059]

[0060] The second 0.5ms output data is:

[0061]

[0062] And so on, until all The sum is data

[0063] S4. The processing unit of the fiber optic gyro circuit to be tested transmits the data according to the RS422 communication protocol. Sent to the external control unit, when the external control unit collects 10s of data, it can get indivual and 10 6 -1 as well as indivual

[0064] S5, the external control unit receives 20000 The data is plotted into a curve, and the peak-to-peak value and / or standard deviation of the curve are obtained to characterize the noise level of the circuit.

[0065] like Figure 2 , Figure 3 As shown in the figure, the external control unit tested the noise of the two fiber optic gyro circuits for 10 seconds respectively. It can be seen from the test curve that Figure 2 The peak-to-peak noise of the fiber optic gyroscope circuit is Figure 3 The peak-to-peak noise of the fiber optic gyro circuit is equivalent to Figure 2 The noise test curve of the fiber optic gyro circuit in the figure shows a standard deviation of 25.1614. Figure 3 The noise test curve of the fiber optic gyro circuit in the figure can be obtained with a standard deviation of 25.3838; therefore Figure 2The noise level of the fiber optic gyro circuit is better than Figure 3 Noise level in fiber optic gyro circuits.

[0066] The method of the present invention performs noise testing on the fiber optic gyroscope circuit to achieve the purpose of intuitively evaluating the noise level of the fiber optic gyroscope circuit. At the same time, the fiber optic gyroscope circuit can be classified according to the noise index to adapt to fiber optic gyroscopes of different precisions. In particular, for a three-axis fiber optic gyroscope, when the requirements for different axial precision indicators are inconsistent, adaptation can also be performed according to the test situation of the circuit noise level.

[0067] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A noise evaluation method for a fiber optic gyroscope circuit, wherein the fiber optic gyroscope circuit comprises a preamplifier circuit, an analog-to-digital conversion unit, and a processing unit connected in sequence; It is characterized in that The following steps are involved: S1, inputting a reference voltage signal into the preamplifier circuit of the fiber optic gyro circuit to be tested, and the reference voltage signal is amplified by the preamplifier circuit and then sent to the analog-to-digital conversion unit; S2. The analog-to-digital conversion unit collects the amplified reference voltage signal according to the sampling frequency set by the processing unit of the fiber optic gyroscope circuit to be tested, and records the collected data of the i-th sampling cycle and the j-th sampling point as the effective sampling data D ij ; Wherein, i=1,…,n; j=1,…,2m; n and m are both natural numbers greater than 0; S3, the processing unit of the fiber optic gyro circuit to be tested processes 2m valid sampling data D in each sampling period. ij Sum the first m data and the last m data to get S i前 and S i后 ; Then use the S of two adjacent cycles i前 With S i后 Subtract and get (n-1) difference values Then the difference Perform sliding filtering to obtain the The sum is recorded as data Where k represents the kth sliding period; S4, the processing unit of the fiber optic gyro circuit to be tested will all the data sent to an external control unit; S5, the external control unit receives all the data Draw a curve and obtain the peak-to-peak value and / or standard deviation of the curve to characterize the noise level of the fiber optic gyroscope circuit.

2. The noise evaluation method of a fiber optic gyro circuit according to claim 1, characterized in that: In step S1: A standard voltage source is used to input a reference voltage signal to the preamplifier circuit.

3. The noise evaluation method of a fiber optic gyro circuit according to claim 2, characterized in that: In step S2, the sampling frequency is 20 MHz; the sampling period is 10 μs, and the sampling points are 200.

4. The noise evaluation method of a fiber optic gyro circuit according to claim 3, characterized in that: Step S3 is specifically as follows: 3.

1. The processing unit of the fiber optic gyro circuit to be tested uses the following formula to calculate the 2m valid sampling data D in each sampling period: ij Sum the first m data i前 And then sum up the next m data S i后 : 3.

2. Use S of two adjacent cycles i前 With S i后 By subtracting the following formula, we can get (n-1) differences. Specifically: 3.

3. Difference Perform sliding filtering to obtain all The sum is recorded as data Where k represents the kth sliding period.

5. The noise evaluation method of a fiber optic gyro circuit according to claim 4, characterized in that: In step 3.3, the sliding period of the sliding filter is 0.5 ms.

6. The noise evaluation method of a fiber optic gyro circuit according to claim 5, characterized in that: Step S4 is specifically as follows: The processing unit of the fiber optic gyro circuit to be tested transmits data according to the RS422 communication protocol. Sent to an external control unit.

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