A speed error compensation circuit for a ship's gyrocompass

Abstract

The application relates to a speed error compensation circuit for a gyrocompass of a ship, which comprises a rotary transformer, a speed-adjusting potentiometer and a demodulation circuit, the primary winding input end of the rotary transformer is connected with an alternating current (AC) sine wave excitation signal, and the cosine winding output end of the rotary transformer is connected with a fixed tapping end of the speed-adjusting potentiometer; one fixed tapping end and a sliding tapping end of the speed-adjusting potentiometer are connected with the signal input end of the demodulation circuit, and the speed-adjusting potentiometer is used for inputting an AC signal to the demodulation circuit; the excitation input end of the demodulation circuit is connected in parallel with the primary winding input end of the rotary transformer and is connected with the AC sine wave excitation signal; the demodulation circuit converts the input AC signal into a direct current (DC) signal; the demodulation circuit inputs the DC signal to a horizontal moment device of the gyrocompass, and the horizontal moment device generates a speed error compensation moment. The application adopts the combination of electromechanical and electronic modes, realizes the internal compensation of the speed error in a more simple and reliable mode, and achieves the purposes of simplifying the circuit and improving the reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ship navigation, and particularly relates to a speed error compensation circuit for a gyro compass of a ship. BACKGROUND

[0002] The gyro compass is a self-contained navigation device independent of external information, which can not only provide accurate and reliable heading information for ship navigation, but also provide a bearing reference for other ship equipment.

[0003] The gyro compass is installed on the ship and moves with the ship relative to the earth. The speed component of the ship in the north-south direction will cause the gyro compass to move at an angular velocity of / R (R is the radius of the earth) relative to the horizontal plane of the earth, so that the main shaft of the gyro compass deviates from the original stable position, and thus a speed error occurs.

[0004] The speed error is a principle error of the gyro compass, which is irrelevant to the structural parameters of the compass, and is only related to the speed V, the heading K and the geographical latitude φ. The speed error angle ΔK can be calculated by formula (1); formula (1): .

[0005] There are mainly three methods to eliminate the error:

[0006] 1. Table lookup method: first calculate the speed error angle ΔK under different conditions of speed V, heading K and geographical latitude φ according to formula (1), and draw a table or chart.

[0007] When used, first find the corresponding speed error angle ΔK according to the current speed V, heading K and geographical latitude φ, and then read the current heading K of the compass, and subtract the speed error angle ΔK to obtain the true heading of the ship.

[0008] The advantage of this method is that no speed error compensation mechanism needs to be added in the gyro compass device, and the disadvantage is that the heading indicated by the gyro compass and sent to each load device includes the speed error angle, which needs to be manually calculated and subtracted to obtain the true heading of the ship.

[0009] 2. External compensation method: a speed error compensation mechanism is arranged in the heading sending link (such as a sending box) of the gyro compass, which calculates the speed error angle according to formula (1) by a mechanical simulation method, so that the heading sending part is turned through an angle value equal in size and opposite in direction to the speed error angle, so as to correct the speed error angle.

[0010] The method has the advantages that no manual calculation is needed, and the heading sent by the gyro compass to each load device is the true heading of the ship; the disadvantages are that although the heading sending link (such as a sending box) of the gyro compass indicates the true heading of the ship, the main shaft of the gyroscope is not directed to the true north, and the structure of the speed error compensation mechanism is relatively complex, the cost is high, and accurate compensation is difficult to achieve.

[0011] 3. Internal compensation method: As known from the foregoing, the speed error of the gyro compass is caused by the pitching motion of the main shaft of the gyroscope relative to the horizontal plane of the earth due to the speed component of the ship in the north-south direction . Therefore, the speed error can be avoided by preventing the pitching motion of the main shaft of the gyroscope.

[0012] The internal compensation method, also known as the moment compensation method, provides a speed error compensation mechanism in the gyro compass, calculates and outputs a proper speed error compensation current to the horizontal moment device by using an electrical calculation method, so that the horizontal moment device generates a compensation moment . Under the action of the compensation moment , the main shaft of the gyroscope generates a horizontal precession, and the precession angular velocity is just enough to offset the angular velocity of the pitching motion of the main shaft of the gyroscope relative to the horizontal plane of the earth , thereby avoiding the generation of the speed error.

[0013] In the internal compensation method, the compensation moment to be applied to the main shaft of the gyroscope is calculated by formula (2); and the speed error compensation current to the horizontal moment is calculated by formula (3):

[0014] ,

[0015] ,

[0016] In the above formulae, H is the angular momentum of the gyroscope, V is the speed of the ship, K is the heading, R is the radius of the earth, and K is the moment coefficient of the horizontal moment device; in formula (3), the radius of the earth R is a constant, the angular momentum of the gyroscope H and the moment coefficient of the horizontal moment device K are also constants, which are determined in the design of the gyroscope. Therefore, the size of the required speed error compensation current can be determined only according to the current speed V and heading K of the ship.

[0017] The internal compensation method has the advantages that not only the heading sending link (such as a sending box) of the gyro compass indicates the true heading of the ship, but also the main shaft of the gyroscope is located in the meridian plane and directed to the true north direction, and the compensation method is easy to operate and easy to achieve accurate compensation.

[0018] At present, the internal compensation method generally adopts the following specific circuit: the gyro compass receives the digital quantity speed V information sent by the external speed sensor (such as GPS, log) through the serial port, CAN network, Ethernet and other interfaces, and sends the information to the microprocessor (such as single-chip microcomputer, ARM, DSP). The microprocessor also receives the heading K information inside the gyro compass, calculates according to formula (3), and outputs the corresponding digital quantity information to the digital-analog conversion circuit. The digital-analog conversion circuit applies the required speed error compensation current to the horizontal moment device according to the digital quantity information sent by the microprocessor . This speed error compensation circuit mainly depends on external speed information. Once the external speed sensor cannot output correct speed information, the gyro compass will not be able to accurately compensate for the speed error. In addition, the structure of the analog-digital conversion circuit is relatively complex, and the precision level, temperature drift coefficient and other parameters of the used components are required to be high. SUMMARY

[0019] In order to solve the problems existing in the current internal compensation method, the application provides a speed error compensation circuit for a gyro compass of a ship, which uses a more simple and reliable circuit combining electromechanical and electronic to complete the internal compensation of speed error, and does not need to rely on external speed information, so as to achieve the purpose of simple circuit and improve reliability.

[0020] The technical purpose of the application is realized by the following technical scheme:

[0021] A speed error compensation circuit for a gyro compass of a ship, comprising a rotary transformer, a speed regulating potentiometer, a demodulation circuit,

[0022] The rotary transformer comprises a primary winding input end and a cosine winding output end; the speed regulating potentiometer comprises two fixed tap ends and one sliding tap end; the demodulation circuit comprises a signal input end, an excitation input end and a demodulation circuit output end;

[0023] The primary winding input end of the rotary transformer is connected with an alternating sinusoidal excitation signal, and the cosine winding output end of the rotary transformer is connected with the fixed tap end of the speed regulating potentiometer;

[0024] One fixed tap end and the sliding tap end of the speed regulating potentiometer are connected to the signal input end of the demodulation circuit, and the speed regulating potentiometer is used to input an alternating signal to the demodulation circuit;

[0025] The excitation input end of the demodulation circuit is connected in parallel with the primary winding input end of the rotary transformer and connected with the alternating sinusoidal excitation signal; the demodulation circuit output end is connected with the horizontal moment device of the gyro compass; the demodulation circuit is used to convert the alternating signal input by the speed regulating potentiometer into a direct current signal; the demodulation circuit inputs the direct current signal to the horizontal moment device, and the horizontal moment device generates a speed error compensation moment;

[0026] The rotating transformer comprises a rotating shaft, and the gyrocompass comprises a bearing ring, the rotating shaft and the bearing ring of the gyrocompass are connected through a gear transmission, and the transmission ratio of the gear transmission is 1:1.

[0027] Further, the demodulation circuit comprises an analog switch circuit N1 and an inverter circuit N2.

[0028] The analog switch circuit comprises a first switch, a second switch, a third switch and a fourth switch, each of the first switch, the second switch, the third switch and the fourth switch is provided with a control end, an input end and an output end; the inverter circuit comprises a first inverter and a second inverter; the output end of the first inverter is connected to the input end of the second inverter, the control end of the second switch and the control end of the fourth switch respectively, the output end of the second inverter is connected to the control end of the first switch and the control end of the third switch respectively; the input end of the first switch and the input end of the second switch are short-circuited as one end of a demodulation signal input end, and the input end of the third switch and the input end of the fourth switch are short-circuited as the other end of the demodulation signal input end.

[0029] Further, the demodulation circuit further comprises a stabilizing diode and a first resistor, one end of the first resistor is one end of a field excitation input end of the demodulation circuit, the other end of the first resistor is connected to the negative end of the stabilizing diode and the input end of the first inverter simultaneously; the positive end of the stabilizing diode is the other end of the field excitation input end of the demodulation circuit and is connected to a signal ground.

[0030] Further, the demodulation circuit further comprises a potentiometer, a second resistor, a first capacitor and a second capacitor, the potentiometer comprises a fixed tap end and a sliding tap end; the output end of the first switch and the output end of the fourth switch are short-circuited and then connected to a signal ground, the output end of the second switch and the output end of the third switch are short-circuited and connected to one fixed tap end of the potentiometer, the sliding tap end of the potentiometer is connected to one end of the first capacitor and one end of the second resistor simultaneously, the other end of the second resistor is connected to one end of the second capacitor, and the connection between the other end of the second resistor and one end of the second capacitor is further connected to a horizontal torque device; the other ends of the first capacitor and the second capacitor are connected to the signal ground.

[0031] Further, the rotation angle of the bearing ring of the gyrocompass is a current heading K, the rotation angle of the rotating shaft of the rotating transformer is equal to the heading K of the ship, the output voltage of the cosine winding of the rotating transformer is Uc, and Uc=B×Uh× wherein B is the transformation ratio of the rotating transformer, and Uh is an AC sine wave excitation signal input into the rotating transformer.

[0032] Further, the speed regulating potentiometer is a single-turn disc potentiometer, and a scale indicating the sailing speed V is arranged on an outer circle of a handle of the speed regulating potentiometer, the minimum value of the sailing speed V is 0, and the maximum value Vmax of the sailing speed V is the maximum designed sailing speed; the alternating current signal inputted by the speed regulating potentiometer to the demodulation circuit is Ui, .

[0033] Further, the alternating current signal inputted by the speed regulating potentiometer to the demodulation circuit is Ui, and the direct current voltage signal outputted by the demodulation circuit generates a speed error compensation current on the horizontal torque device , wherein F is a transfer coefficient of the demodulation circuit, is a resistance value of the horizontal torque device.

[0034] Uc=B×Uh× , and are integrated to obtain , it can be known from the comparison formula (3) that only the condition of = needs to be met, and the speed error compensation circuit for the gyro compass can realize the internal compensation function of the speed error.

[0035] Compared with the prior art, the speed error compensation circuit for the gyro compass has the beneficial effects that:

[0036] 1. The speed error compensation circuit for the gyro compass adopts the combination of electromechanical and electronic, and is more simple and reliable to realize the internal compensation of the speed error, so that the purpose of simplifying the circuit and improving the reliability is realized.

[0037] 2. The speed error compensation circuit for the gyro compass does not need to depend on external speed information, and only needs to turn the handle of the speed regulating potentiometer to the scale value of the current sailing speed, so that an electrical calculation mode is used to output a speed error compensation current to the horizontal torque device, the horizontal torque device generates a compensation torque, the internal compensation of the speed error is completed, and the error compensation caused by the error or loss of the external speed information is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a composition schematic diagram of the speed error compensation circuit for the gyro compass.

[0039] Figure 2 is a circuit principle diagram of the speed error compensation circuit for the gyro compass in the application.

[0040] Figure 3 is a waveform comparison schematic diagram of Uh, Uj1, Uj2 and Uj3 in the embodiment of the application.

[0041] Figure 4Fig. 2 is a waveform comparison schematic diagram of the AC input signal Ui and the excitation signal Uh in phase in the embodiment of the present application.

[0042] Figure 5 Fig. 3 is a waveform comparison schematic diagram of the AC input signal Ui and the excitation signal Uh in reverse phase in the embodiment of the present application.

[0043] Figure 6 Fig. 4 is a handle schematic diagram of the speed regulating potentiometer RV1 in the present application.

[0044] In the figure, 1, a rotary transformer; 2, a speed regulating potentiometer; 3, a demodulation circuit; 4, a horizontal torque device; 5, a primary winding input end; 6, a cosine winding output end; 7, a signal input end; 8, a demodulation circuit output end; 9, an excitation input end; 10, a fixed tap end; 11, a sliding tap end. DETAILED DESCRIPTION

[0045] The technical solutions of the present application are further described below in combination with specific embodiments:

[0046] A speed error compensation circuit for a ship gyrocompass, as shown in Fig. 1, comprises a rotary transformer 1, a speed regulating potentiometer 2, and a demodulation circuit 3, wherein: Figure 1

[0047] The rotary transformer 1 comprises a primary winding input end 5 and a cosine winding output end 6; the speed regulating potentiometer 2 comprises two fixed tap ends 10 and a sliding tap end 11; the demodulation circuit 3 comprises a signal input end 7, an excitation input end 9, and a demodulation circuit output end 8;

[0048] The primary winding input end 5 of the rotary transformer 1 is connected to an AC sine wave excitation signal Uh, and the cosine winding output end 6 of the rotary transformer 1 is connected to the two fixed tap ends 10 of the speed regulating potentiometer 2;

[0049] One fixed tap end 10 and the sliding tap end 11 of the speed regulating potentiometer 2 are connected to the signal input end 7 of the demodulation circuit 3, and the speed regulating potentiometer 2 is used to input an AC signal to the demodulation circuit 3;

[0050] The excitation input end 9 of the demodulation circuit 3 is connected in parallel to the primary winding input end 5 of the rotary transformer 1 to input the AC sine wave excitation signal; the demodulation circuit output end 8 is connected to the horizontal torque device 4 of the gyrocompass; the demodulation circuit 3 is used to convert the AC signal input by the speed regulating potentiometer 2 into a DC signal; the demodulation circuit 3 inputs the DC signal to the horizontal torque device 4, and the horizontal torque device 4 generates a speed error compensation torque;

[0051] ​The rotary transformer includes a shaft, and the gyrocompass includes an azimuth ring. The shaft and the azimuth ring are connected by a gear transmission with a 1:1 ratio. The rotation angle of the gyrocompass azimuth ring is the current heading K; therefore, the shaft rotation angle of the rotary transformer T1 is equal to the ship's heading K. The output voltage of the cosine winding of the rotary transformer is Uc, where Uc = B × Uh × Where B is the transformer ratio of the rotary transformer, and Uh is the AC sinusoidal excitation signal connected to the rotary transformer.

[0052] In this embodiment, as Figure 2 As shown, the speed-regulating potentiometer RV1 is a single-turn disc potentiometer. The outer ring of the RV1 handle has a scale indicating the ship's speed V. The minimum value of V is 0, and the maximum value is Vmax, which is the maximum design speed. When the RV1 handle is rotated to 0°, the scale points to 0 knots, and the voltage Ui at the signal input terminal of the demodulation circuit is 0V. When the RV1 handle is rotated to its maximum value, the scale points to the ship's maximum design speed Vmax, and the voltage Ui at the signal input terminal of the demodulation circuit is the output voltage Uc of the cosine winding of the rotary transformer T1. When the RV1 handle rotates between 0 knots and Vmax, the voltage Ui at the signal input terminal of the demodulation circuit changes linearly with the rotation angle of the RV1 handle (i.e., the ship's speed V). .

[0053] Specifically, the demodulation circuit includes a Zener diode V1, a first resistor R1, an analog switch circuit N1, an inverter circuit N2, a potentiometer RW1, a second resistor R2, a first capacitor C1, and a second capacitor C2.

[0054] The analog switch circuit N1 includes a first switch N1A, a second switch N1B, a third switch N1C, and a fourth switch N1D. Each of the first switch N1A, the second switch N1B, the third switch N1C, and the fourth switch N1D has a control terminal, an input terminal, and an output terminal. The inverter circuit includes a first inverter N2A and a second inverter N2B (an inverter circuit generally includes more than two inverter gate circuits).

[0055] One end of the first resistor R1 is one end of the excitation input terminal of the demodulation circuit, and the other end of the first resistor R1 is connected to both the negative terminal of the Zener diode V1 and the input terminal of the first inverter N2A; the positive terminal of the Zener diode V1 is the other end of the excitation input terminal of the demodulation circuit and is connected to signal ground.

[0056] The output end of the first inverter N2A is connected to the input end of the second inverter N2B, the control end of the second switch N1B and the control end of the fourth switch N1D, respectively; the output end of the second inverter N2B is connected to the control end of the first switch N1A and the control end of the third switch N1C, respectively; the input end of the first switch N1A and the input end of the second switch N1B are short-circuited to serve as one end of the demodulation signal input end; the input end of the third switch N1C and the input end of the fourth switch N1D are short-circuited to serve as the other end of the demodulation signal input end.

[0057] The output end of the first switch N1A and the output end of the fourth switch N1D are short-circuited to connect to the signal ground; the output end of the second switch N1B and the output end of the third switch N1C are short-circuited to connect to one fixed tap end of the potentiometer RW1; the sliding tap end of the potentiometer RW1 is connected to one end of the first capacitor C1 and one end of the second resistor R2, and the other end of the second resistor R2 is connected to one end of the second capacitor C2; the other end of the first capacitor C1 and the other end of the second capacitor C2 are connected to the signal ground.

[0058] The first resistor R1 and the voltage stabilizing diode V1 form a half-wave rectification circuit, a clipped half-wave signal Uj1 of the same frequency and phase as the excitation signal Uh is formed at the input end of the first inverter N2A, a square wave signal Uj2 opposite to the clipped half-wave signal Uj1 is formed at the output end of the first inverter N2A, and a square wave signal Uj3 opposite to the square wave signal Uj2 is formed at the output end of the second inverter N2B, as shown in Figure 3 The amplitudes and frequencies of the square wave signal Uj2 and the square wave signal Uj3 are the same, but the phases are opposite by 180°, and they control the on-off of the two analog switches, respectively.

[0059] Suppose the value of the heading K is in the first and fourth quadrants, and cosK is positive, at this time the AC input signal Ui is in phase with the excitation signal Uh, as shown in Figure 4As shown. When the waveform of the excitation signal Uh is positive half cycle, the square wave signal Uj2 is low, the second switch N1B and the fourth switch N1D are disconnected; the square wave signal Uj3 is high, the first switch N1A and the third switch N1C are turned on. At this time, the AC input signal Ui is also positive half cycle, the AC input signal Ui is transmitted backward through the first switch N1A and the third switch N1C, and the voltage signal Uj4 at the fixed tap end of the potentiometer RW1 is flipped to negative half cycle sine wave. When the waveform of the excitation signal Uh is negative half cycle, the square wave signal Uj2 is high, the second switch N1B and the fourth switch N1D are turned on; the square wave signal Uj3 is low, the first switch N1A and the third switch N1C are disconnected. At this time, the AC input signal Ui is also negative half cycle, the AC input signal Ui is transmitted backward through the second switch N1B and the fourth switch N1D, and the voltage signal Uj4 at the fixed tap end of the potentiometer RW1 is still negative half cycle sine wave. This cycle is repeated, and the voltage signal Uj4 at the fixed tap end of the potentiometer RW1 will be continuous negative half cycle sine wave.

[0060] On the contrary, assuming that the value of the heading K is in the second and third quadrants, cosK is negative, at this time the AC input signal Ui and the excitation signal Uh are opposite, as shown. Figure 5 As shown. When the waveform of the excitation signal Uh is positive half cycle, the square wave signal Uj2 is low, the second switch N1B and the fourth switch N1D are disconnected; the square wave signal Uj3 is high, the first switch N1A and the third switch N1C are turned on. At this time, the AC input signal Ui is also positive half cycle, the AC input signal Ui is transmitted backward through the first switch N1A and the third switch N1C, and the voltage signal Uj4 at the fixed tap end of the potentiometer RW1 is flipped to negative half cycle sine wave. When the waveform of the excitation signal Uh is negative half cycle, the square wave signal Uj2 is high, the second switch N1B and the fourth switch N1D are turned on; the square wave signal Uj3 is low, the first switch N1A and the third switch N1C are disconnected. At this time, the AC input signal Ui is also positive half cycle, the AC input signal Ui is transmitted backward through the second switch N1B and the fourth switch N1D, and the voltage signal Uj4 at the fixed tap end of the potentiometer RW1 is still negative half cycle sine wave. This cycle is repeated, and the voltage signal Uj4 at the fixed tap end of the potentiometer RW1 will be continuous negative half cycle sine wave.

[0061] Continuous positive half cycle sine wave or negative half cycle sine wave through the π type RC filter circuit composed of the potentiometer RW1, the second resistor R2, the first capacitor C1 and the second capacitor C2, will produce a small AC ripple DC voltage signal Uo at the output end of the demodulation circuit. The output end of the demodulation circuit is connected with the horizontal torque, which will produce a speed error compensation current , the AC input signal Ui and the speed error compensation current The relationship between the speed error compensation current and the handle angle of the speed regulating potentiometer RV1 is approximately linear, and the resistance of the speed regulating potentiometer RW1 is variable The expression is as follows:

[0062] where F is the transfer coefficient of the demodulation circuit, the resistance of the speed regulating potentiometer RW1 is variable, and F is variable, The resistance of the horizontal moment device is R.

[0063] In this embodiment, the gyroscope angular momentum H of the gyrocompass is 2x10 4 (g﹒cm﹒s), and the moment coefficient Lz of the horizontal moment device is 0.5(g﹒cm / mA). The known earth radius R is 6.37x10 8 (cm). According to the original formula , the compensation current needs to be applied to the horizontal moment device of the gyrocompass to avoid the generation of the speed error.

[0064] According to the method in this embodiment, the model of the rotary transformer T1 is 20XZ20-6, the excitation signal Uh inputted to the primary winding is AC 26V / 400Hz, and the transformation ratio B is 0.45. According to the formula (Uc=BxUhx ), the output voltage Uc of the cosine winding of the rotary transformer T1 is 11.70x cos K (volt).

[0065] In this embodiment, the speed regulating potentiometer RV1 is a WX14-12-100R single-turn disc potentiometer, and a digital dial is installed at the handle part of the speed regulating potentiometer RV1, as shown in Figure 6 , the numbers and scales of the dial are used to indicate the sailing speed V, and the maximum designed sailing speed Vmax is 60 knots=3086.66(cm / s). When the handle angle of the speed regulating potentiometer RV1 is 0°, the dial points to the sailing speed 0 knot, and at this time, the voltage Ui at the signal input end of the demodulation circuit is 0V; when the handle angle of the speed regulating potentiometer RV1 is the maximum, the dial points to 60 knots, and at this time, the voltage Ui at the signal input end of the demodulation circuit is the output voltage Uc of the cosine winding of the rotary transformer T1. According to the formula , when the handle of the potentiometer rotates between 0 knot and 60 knot, the voltage Ui at the signal input end of the demodulation circuit is VxUc / 3086.66=3.79x10 -3 xVx cos K (volt).

[0066] In this embodiment, the resistance R L of the horizontal moment device of the gyrocompass is 600(Ω). The resistance of the speed regulating potentiometer RW1 is adjusted to make the transfer coefficient F of the demodulation circuit be 0.01. According to the formula ) calculation, the speed error compensation current of the embodiment of the application = -1.67 x 10 -5 -0.063 x V x cos K (unit: ), and the same as the theoretical calculation formula calculated by the original formula ) calculation , the speed error compensation of the gyro compass in the embodiment can be completed.

[0067] The embodiment is only a further explanation of the application, and is not a limitation of the application. Those skilled in the art can make non-creative modifications to the embodiment according to needs after reading the specification, but as long as the modifications are within the scope of the claims of the application, they are protected by the patent law.

Claims

1. A speed error compensation circuit for a gyrocompass of a ship, characterized in that, The rotation transformer, the speed regulating potentiometer, and the demodulation circuit, The rotation transformer includes a primary winding input end and a cosine winding output end; the speed regulating potentiometer includes a sliding tap end and two fixed tap ends; the demodulation circuit includes a signal input end, an excitation input end, and a demodulation circuit output end; The primary winding input end of the rotation transformer is connected to an AC sine wave excitation signal, and the cosine winding output end of the rotation transformer is connected to the fixed tap end of the speed regulating potentiometer. One fixed tap end and the sliding tap end of the speed regulating potentiometer are connected to the signal input end of the demodulation circuit, and the speed regulating potentiometer is used to input an AC signal to the demodulation circuit. The excitation input end of the demodulation circuit is connected in parallel to the primary winding input end of the rotation transformer to input the AC sine wave excitation signal, the demodulation circuit output end is connected to the horizontal torque device of the gyrocompass, the demodulation circuit is used to convert the AC signal input by the speed regulating potentiometer into a DC signal, and the demodulation circuit inputs the DC signal to the horizontal torque device to generate a speed error compensation torque. The rotation transformer includes a rotating shaft, and the gyrocompass includes an azimuth ring, the rotating shaft and the azimuth ring of the gyrocompass are connected through a gear transmission, and the transmission ratio of the gear transmission is 1:

1.

2. A speed error compensating circuit for a gyrocompass of a marine vessel according to claim 1, characterized in that, The demodulation circuit includes an analog switch circuit N1 and an inverter circuit N2. The analog switch circuit includes a first switch, a second switch, a third switch, and a fourth switch, each of the first switch, the second switch, the third switch, and the fourth switch is provided with a control end, an input end, and an output end; the inverter circuit includes a first inverter and a second inverter; the output end of the first inverter is connected to the input end of the second inverter, the control end of the second switch, and the control end of the fourth switch, respectively; the output end of the second inverter is connected to the control end of the first switch and the control end of the third switch, respectively; the input end of the first switch and the input end of the second switch are short-circuited to serve as one end of a demodulation signal input end, and the input end of the third switch and the input end of the fourth switch are short-circuited to serve as the other end of the demodulation signal input end.

3. A speed error compensating circuit for a gyrocompass of a marine vessel according to claim 2, characterized in that, The demodulation circuit further includes a voltage stabilizing diode and a first resistor, one end of the first resistor is one end of an excitation input end of the demodulation circuit, and the other end of the first resistor is connected to the negative end of the voltage stabilizing diode and the input end of the first inverter; the positive end of the voltage stabilizing diode is the other end of the excitation input end of the demodulation circuit and is connected to a signal ground.

4. A speed error compensating circuit for a gyrocompass of a marine vessel according to claim 2, wherein The demodulation circuit further includes a potentiometer, a second resistor, a first capacitor, and a second capacitor, the potentiometer includes a fixed tap end and a sliding tap end; the output end of the first switch and the output end of the fourth switch are short-circuited and then connected to a signal ground, the output end of the second switch and the output end of the third switch are short-circuited and connected to one fixed tap end of the potentiometer, the sliding tap end of the potentiometer is connected to one end of the first capacitor and one end of the second resistor, the other end of the second resistor is connected to one end of the second capacitor, and the other end of the second resistor connected to one end of the second capacitor is further connected to the horizontal torque device; the other ends of the first capacitor and the second capacitor are connected to the signal ground.

5. A speed error compensating circuit for a gyrocompass of a marine vessel as claimed in claim 1, characterized in that, The rotation angle of the azimuth ring of the gyrocompass is the current heading K, the rotation angle of the rotation axis of the resolver is equal to the heading K of the ship, and the resolver outputs a voltage Uc at the cosine winding output, where B is the transformation ratio of the resolver, and Uh is the AC sine wave excitation signal input to the resolver.

6. A speed error compensating circuit for a gyrocompass of a marine vessel according to claim 5, wherein The speed regulating potentiometer is a single-turn disc potentiometer, and a scale indicating the sailing speed V is arranged on an outer circle of a handle of the speed regulating potentiometer, the minimum value of the sailing speed V is 0, and the maximum value Vmax is the maximum designed sailing speed; and the alternating current signal inputted by the speed regulating potentiometer to the demodulation circuit is Ui, .

7. A speed error compensating circuit for a gyrocompass of a marine vessel according to claim 6, characterized in that, The AC signal inputted by the speed regulating potentiometer to the demodulation circuit is Ui, and the DC voltage signal outputted by the demodulation circuit generates a speed error compensation current on the horizontal torque motor , Wherein F is the transfer coefficient of the demodulation circuit, is the resistance value of the horizontal torque motor.

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