WO2021253487A1 - Underwater navigation and gravity measurement integrated system - Google Patents

Abstract

An underwater navigation and gravity measurement integrated system, comprising three laser gyroscopes (8), three pendulum-type flexible accelerometers (9), three gravity sensors (2), a transposition and angle measurement apparatus (4), a temperature sensor (7), a temperature control box (5), a Doppler log, a depth gauge, two computers, a data collection and processing platform, an LCD display, and circuit boards (3, 6). The three gyroscopes (8) and the three accelerometers (9) are arranged on the transposition mechanism (4) to constitute a laser gyroscope single-axis rotation inertial measurement unit; the gravity sensors (2) are placed in the temperature control box (5) and are rigidly and fixedly connected to the laser gyroscope single-axis rotation inertial measurement unit. The data collection and processing platform processes and records signals of each sensor in real-time. The two computers respectively calculate navigation parameters and local gravity values of the underwater navigation and gravity measurement integrated system. The underwater navigation and gravity measurement integrated system can meet the needs for long-endurance, high-precision, and low-cost navigation and gravity measurement of underwater carriers.

Description

Integrated system of underwater navigation and gravity measurement Technical field

The invention relates to an integrated system of underwater navigation and gravity measurement, and belongs to the technical field of integrated navigation and gravity measurement.

Background technique

The ocean contains abundant oil and gas mineral resources, and the exploration and development of the ocean is of great significance to the development of the national economy. The distribution of oil and gas mineral resources is closely related to the ocean gravity field, and underwater gravity measurement helps to discover them. The current difficulty of underwater gravity measurement is that the existing gravity measurement system is difficult to ensure long-term accurate positioning underwater and low-cost continuous operation. In order to solve these problems, the present invention provides an integrated system of underwater navigation and gravity measurement, which can meet the requirements of long-endurance, high-precision and low-cost underwater navigation and gravity measurement.

Summary of the invention

The purpose of the present invention is to solve the above-mentioned problems and provide an integrated system of underwater navigation and gravity measurement, which can meet the requirements of long-endurance, high-precision and low-cost underwater navigation and gravity measurement.

In order to achieve the above objective, the technical solution adopted by the present invention is: an integrated underwater navigation and gravity measurement system, which is mainly composed of 3 laser gyroscopes, 3 pendulum flexible accelerometers, 3 gravity sensors, indexing and Angle measuring device, temperature sensor, temperature control device, Doppler log, depth gauge, 2 computers, data acquisition and processing platform, LCD display and circuit board.

Three laser gyroscopes and three pendulum flexible accelerometers are placed on the indexing mechanism to form a single-axis rotation inertial measurement unit of the laser gyroscope.

The three gravity sensors are placed in the temperature control box, rigidly fixed with the laser gyro single-axis rotating inertial measurement unit, and have the same attitude angle as the accelerometer of the laser gyro single-axis rotating inertial measurement unit.

The data acquisition and processing platform processes and records the signals of laser gyroscopes, accelerometers, gravity sensors, indexing and angle measurement devices, temperature sensors, Doppler logs, and depth gauges in real time.

A computer receives laser gyroscope, high-precision accelerometer, Doppler log, depth gauge, indexing angle information and temperature information, and uses the speed information of the Doppler log and the water depth information of the depth gauge as the laser gyroscope The appearance measurement of the single-axis rotating inertial measurement unit applies the extended Kalman filter to calculate the position, speed and attitude of the integrated underwater navigation and gravity measurement system.

A computer receives the gravity sensor information, temperature information, the position, speed and attitude information of the integrated underwater navigation and gravity measurement system, calculates the specific force of the gravity sensor in the local geographic coordinate system, and performs gravity measurement correction and low-pass filtering Processing to get the local gravity value.

As an improvement of the present invention, the data acquisition and processing platform and computer adopt FPGA+DSP+ARM architecture.

Beneficial effects:

The integrated system of underwater navigation and gravity measurement provided by the present invention can meet the requirements of long-endurance, high-precision, low-cost navigation and gravity measurement of underwater vehicles.

Description of the drawings

FIG. 1 is a schematic diagram of the structure of the integrated device of the inertial measurement unit and the gravity sensor of the present invention.

Figure 2 is a schematic diagram of the data acquisition and processing platform and computer of the present invention.

[Corrected according to Rule 91 17.07.2020]
Fig. 3 is a flowchart of the navigation algorithm of the underwater integrated navigation system of the present invention.

detailed description

The present invention will be further described below in conjunction with specific embodiments.

As shown in Figure 1, this embodiment discloses an integrated system for underwater navigation and gravity measurement, which is mainly composed of an integrated device of an inertial measurement unit and a gravity sensor, a Doppler log, a depth gauge, two computers, and a data acquisition platform. And LCD display composition.

The integrated device of the inertial measurement unit and the gravity sensor includes a protective housing 1, 3 laser gyroscopes 8 arranged in the protective housing, 3 pendulum flexible accelerometers 9, 3 gravity sensors 2, indexing and angle measuring devices 4. Temperature sensor 7, temperature control device 5, circuit board 3, 6.

Three 90-type two-frequency machine-shaking laser gyroscopes, three high-precision pendulum flexible accelerometers, indexing and angle measuring devices and circuit boards, etc. constitute the laser gyroscope single-axis rotating inertial measurement unit, indexing and angle measuring device 4 It is composed of a torque motor, a driver, a photoelectric code disc goniometer, a conductive slip ring and mechanical parts.

The three gravity sensors are placed in the temperature control box, rigidly fixed with the laser gyro single-axis rotating inertial measurement unit, and have the same attitude angle as the accelerometer of the laser gyro single-axis rotating inertial measurement unit. The temperature control box is composed of a temperature control board, a thermistor, and a heating plate.

The data acquisition and processing platform and computer adopt FPGA+DSP+ARM architecture, as shown in Figure 2, FPGA and ARM are responsible for data acquisition and processing, and DSP as the computer is responsible for navigation and gravity calculation.

The data acquisition and processing platform processes and records the signals of laser gyroscopes, accelerometers, gravity sensors, indexing and angle measurement devices, temperature sensors, Doppler logs, and depth gauges in real time.

The computer performs integrated navigation calculations and real-time gravity data processing tasks. A computer receives laser gyroscope, high-precision accelerometer, Doppler log, depth gauge, indexing angle information and temperature information, and uses Doppler log The speed information and the depth information of the depth gauge are used as the appearance measurement of the single-axis rotating inertial measurement unit of the laser gyro. The extended Kalman filter is applied to calculate the position, speed and attitude of the integrated underwater navigation and gravity measurement system. The algorithm flow is shown in the figure. 3 shown.

The filter state equation of the underwater integrated navigation system is

Among them, X _k is the system state vector, Φ _k+1/k is the state transition matrix, Γ _k+1 is the noise transition matrix of the system, and W _K is the noise matrix. The state vector is:

in,

These are the three error angles of the strapdown inertial navigation mathematics platform, δV _E , δV _N , δV _UP are the east, north and sky velocity errors, δL, δλ, and δh are the longitude, latitude, and altitude errors, respectively, and δG _x , ΔG _y and δG _z are the zero drifts of the X, Y, and Z axes of the gyroscope, and δA _x , δA _y and δA _z are the zero offsets of the X, Y, and Z axes of the accelerometer, respectively. The W noise matrix consists of the white noise of the gyroscope and accelerometer:

W=[w _gx ,w _gy ,w _gz ,w _ax ,w _ay ,w _az ] ^T (2)

State transition matrix:

Φ _k+1/k ≈E _n +F _k ·Δt (3)

Wherein, E _n is a unit matrix, F _k is the combination of systematic error matrix _{equation, F = [f i, j} ], i, j = 1, ... 15, f i, j nonzero entries as: f _1,9 = _{N N} ; f _1,13 = c11; f _1,14 = c12; f _1,15 = c13; f _2,7 = -f _1,8 = n _h ; f _2,13 = c21; f _2,14 = C22; f _2,15 = c23; f _3,8 = -f _2,9 = n _E ; f _3,13 = c31; f _3,14 = c32; f _3,15 = c33;

f _6,3 = 1; f _7,9 = -f _9,7 = -ω _N ,

f _8,9 =-f _9,8 =ω _E ,

f _8,10 = c21; f _8,11 = c22; f _8,12 = c23;

f _9,10 = c31, f _9,11 = c32, f _9,12 = c33; f _7,10 = c11; f _7,11 = c12; f _7,12 = c13.

c _ij is the element of the attitude matrix, U is the angular rate of the earth's rotation, n _E , n _N , and n _h are the accelerometer specific forces in the northeast sky direction respectively.

The observation equation of the underwater integrated navigation system is

Z _k+1 = H _k+1 X _k+1 +V _k+1 (4)

Among them, Z _k+1 is the observation vector, H _k+1 is the observation matrix, and V _k+1 is the observation noise matrix. The details are as follows:

Among them, V _{E, I} and V _{N, I} are the east and north velocities calculated by the laser gyro single-axis rotation strapdown inertial navigation system _{, respectively, and V E, DVL} and V _{N, BVL} are output from the Doppler log. For east and north directions, h _I is the depth calculated by the single-axis rotation strapdown inertial navigation system of the laser gyro, and h _D is the depth output by the depth gauge. The non-zero items in the observation matrix H _k+1 =[h _i,j ]i=1,...5,j=1,...15 are: h _1,1 = h _{2, 2} = h _{3, 3} = 1, h _1,8 = -V _N , h _2,8 = V _E.

A computer receives the gravity sensor information, temperature information, the position, speed and attitude information of the integrated underwater navigation and gravity measurement system, calculates the gravity sensor's specific force in the local geographic coordinate system, and conducts the gravity measurement of the gravity sensor's specific force Correction, such as Uttforth correction, zero drift correction, hysteresis effect correction, etc., perform Fir low-pass filtering on the corrected data to obtain the local gravity value.

The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art. It should be pointed out that for those of ordinary skill in the art, several improvements can be made without departing from the principle of the present invention. And equivalent replacements, these technical solutions after improvements and equivalent replacements to the claims of the present invention all fall into the protection scope of the present invention.

Claims (3)

1. An integrated system for underwater navigation and gravity measurement, which is characterized in that it includes 3 laser gyroscopes, 3 pendulum flexible accelerometers, 3 gravity sensors, indexing and angle measurement devices, temperature sensors, and temperature control boxes , Doppler log, depth gauge, 2 computers, data acquisition and processing platform, LCD display and circuit board; the 3 laser gyroscopes and 3 pendulum flexible accelerometers are placed on the indexing mechanism, The laser gyro single-axis rotating inertial measurement unit is formed; the gravity sensor is placed in the temperature control box, rigidly fixed with the laser gyro single-axis rotating inertial measurement unit, and is connected to the accelerometer of the laser gyro single-axis rotating inertial measurement unit Have the same attitude angle.
2. The integrated system for underwater navigation and gravity measurement according to claim 1, wherein the data acquisition and processing platform processes and records real-time recording laser gyroscopes, accelerometers, gravity sensors, indexing and angle measurement devices, and temperature sensors , Doppler log, depth gauge signal; of the two computers, one of them receives laser gyroscope, pendulum flexible accelerometer, Doppler log, depth gauge, indexing Angle information and temperature information, the speed information of the Doppler log and the depth information of the depth gauge are used as the appearance measurement of the single-axis rotating inertial measurement unit of the laser gyro, and the extended Kalman filter is applied to calculate the integration of underwater navigation and gravity measurement The position, speed and attitude of the system; another computer receives the gravity sensor information, temperature information and the position, speed and attitude information of the integrated underwater navigation and gravity measurement system, and calculates the specific force of the gravity sensor in the local geographic coordinate system , Carry out gravity measurement correction and low-pass filter processing to get the local gravity value.
3. The integrated underwater navigation and gravity measurement system according to claim 1, wherein the data acquisition and processing platform and computer adopt an FPGA+DSP+ARM architecture.

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