RU2375679C2 - Inertial-satellite navigation, orientation and stabilisation system - Google Patents

Abstract

FIELD: physics; navigation.

SUBSTANCE: invention relates to navigation satellite corrected inertial navigation and gyrostabilisation systems for sea objects and can be used on ships and other vessels in a wide range of navigating conditions. The inertial-satellite navigation, orientation and stabilisation system has a gyrostabilised platform in a triaxial cardan suspension with angle sensors, on which are mounted three rate integrating gyroscopes and three accelerometres, digital device, corrector, where outputs of the angle sensors for rotation of the rings of the cardan suspension and outputs of the accelerometres of the gyrostabilised platform are connected to inputs of the digital device, one of the outputs of which is connected to the input of the gyrostabilised platform, and the other to the corrector. The inertial-satellite navigation system is fitted with a control console which generates system control signals, and the system is also fitted with an accelerated correction unit, the input of which receives current values of coordinates of navigation satellites used, generated by the satellite receiving device and current device values of parametres of orientation of the gyrostabilised platform, a channel switch for standard and accelerated correction, where outputs of the correctors are connected to inputs of the switch, outputs of which are connected to the digital device.

EFFECT: determination of course error from coordinate data of only two satellites of a satellite navigation system and current device parametres of orientation of an object, generated by an inertial navigation system.

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Description

The invention relates to the field of inertial navigation and gyro stabilization systems corrected for navigation satellites for marine objects and can be used on ships and vessels in a wide range of sailing conditions. At the same time, inertial systems provide the solution of the problem of determining the coordinates of the place, course and speed of a marine object, as well as the solution of the problems of orientation and stabilization of on-board devices, weapon systems and the generation of dynamic parameters of the ship’s movement. Satellite facilities provide periodic correction of the inertial navigation system (ANN).

At present, domestic configurations of corrected ANNs are known and tested [1], the mandatory property of which is the need to use information from satellite navigation aids (SNA).

Also known marine unified system of inertial navigation and stabilization (SINS "Ladoga - M") [2], adopted as a prototype. The system is designed to develop a full range of output parameters necessary both for solving navigation problems and for information support of shipboard air defense systems, anti-submarine and guided missile weapons.

The development of the Ladoga-M system was completed in 1999, the system was fully tested.

The prototype system is represented by a block diagram in figure 1.

SINS "Ladoga - M" produces and issues the following information:

- geographical coordinates of the place - latitude and longitude;

- geographic course in the horizon;

- pitching angles measured in the frame plane and pitching angles measured in the vertical plane;

- angular speeds of rolling and pitching and course changes;

- two components of the linear velocity of the ship relative to the ground in a geographical coordinate system;

- three components of the instantaneous speed of the ship in the geographical coordinate system, caused by the rolling and orbital motion of the ship at the installation site of the gyro;

- three components of the linear movement of the ship in the geographical coordinate system caused by the rolling and orbital movement of the ship at the installation site of the gyrometer;

- total angle of inclination of the deck.

The system implements the classical semi-analytical type ANN algorithm with correction.

The system includes: GP - gyrometer (1), TS - thermostabilization device (2), UMT - thermostabilization power amplifier (3), PC - digital device (4), PU - control device (5), B-41 - computer “Baguette - 41” (6).

The system operates as follows. Three acceleration components (W _x , W _y , W _z ), pitching angles and azimuth angle (θ _k , ψ, A) come from the GP to the PC through analog-to-digital converters, and control signals are sent from the PC to the GP

(Ω _x , Ω _y , Ω _z ).

SINS correction is carried out by generating corrective information for navigation data (ΔND) by computer algorithms B-41 (6) according to the data of the PC (4) ND and receiving equipment of the satellite navigation system (SNA), which generates information on coordinates and speed V _c .

The system receives the following external information:

- speed from the lag V _l ,

- a rough course from the gyrocompass To _about ,

- coordinates φ _c , λ _c , speed V _s and track angle from the SNA receiver.

The system has two operating modes:

- adjustable mode (KR),

- offline mode (AR).

At each startup of the system, it is calibrated, which lasts from 6 to 8 hours (depending on operating conditions). Calibration requires the receipt of external positional and speed data. For KR, information from the SNA receiver and lag is used, and in the AR, only from the lag.

Despite the high characteristics of the functioning of the system shown during the tests, it is impossible not to note its significant drawbacks regarding the interaction of SINS "Ladoga - M" and correction tools.

Being a non-autonomous radio engineering navigation system, the SNA has shown itself to be dependent on many external factors affecting the functioning of its components. These factors include: the quantitative composition and condition of the orbital constellation of spacecraft (OG KA), the functioning of the ground control complex (GCC), the operation of on-board equipment of consumers (AP). In addition, SNA information transmission channels are affected. All of these and other disturbing effects lead to a deterioration in the performance of the correction system and the difficulties in implementing the corrected SINS operation mode.

In the normal state, the SNA contains exhaust gases from 21-24 spacecraft uniformly distributed in the near-Earth space. According to the requirements of the International Maritime Organization, the current system must have certain properties. The main operational features of the SNA are availability and integrity. According to the requirements, the global SNA in the normal mode of operation should provide availability> 99.8% for 30 days, and the integrity of the system should be <10 s. In modern real operating conditions of the GLONASS SNA, the correction system does not ensure the normal operation of the Ladoga-M SINS in the corrected mode and encourages the improvement of the equipment and structure of the navigation aids interaction.

Among the tasks solved by SINS, there is the task of information support of ship systems of anti-submarine and guided missile weapons. The use of weapons is not limited to certain regions and can be used anywhere and anytime. According to SINS on the coordinates and course of the ship, target designation and missile launch are carried out. A necessary condition for the implementation of the task are the maximum accuracy and stealth operation. The regular use of SINS for information support of missile weapons is accompanied by the need for a long observation session based on SNA signals and the danger of being detected by enemy observation means. Reducing the duration of the observation session leads to a decrease in the accuracy of the generation of heading data.

The technical solution to the problem of minimizing the time interval for preparation for launching missiles and increasing the accuracy of target designation consists in implementing the method for determining the course correction based on the coordinates of only two SNA satellites and the current instrumental values of the object orientation parameters generated by the ANN. The implementation of the method provides both one-time and continuous determination with high accuracy of the course correction in real time in any navigation area, including high-latitude areas of the Earth.

Currently, the phase method is mainly used to determine the course and pitching angles of an object from the signals of mid-orbit navigation satellites. This method is based on the use of diversity receiving antennas fixed relative to the body of a moving object, followed by measurement and conversion of the phase differences of the received signals.

However, the implementation of the phase method at offshore facilities is associated with certain difficulties. In [3], it is noted that when determining the orientation of an object according to phase measurements, interferometers with a base reaching several meters are used. At the same time, real phase measuring devices have a range of unambiguous measurements within the same wavelength. This gives rise to a problem of ambiguity of decisions when measuring the phase difference of signals received at diversity antennas. In addition, due to the non-identity of the high-frequency channels of the equipment, systematic measurement errors arise, which must be taken into account when solving the navigation problem.

Attempts at the practical implementation of the phase method on marine moving objects do not give grounds for excessive optimism. The realized accuracy of determining the orientation parameters of the object often does not satisfy the given requirements [4]. The reasons for reducing the accuracy of the equipment, in addition, are the errors of alignment of extended antenna systems on the ship, the rigidity of the structural elements of the object, the multipath propagation of signals.

To solve the problem of determining the orientation parameters of the object, we propose to use data on the coordinates of the navigation satellites used for observation (figure 2).

The use of data on the coordinates of the SNA satellites to determine the orientation of an object is possible if the relationship between the angles ψ, υ, γ is known with the data obtained during the observation. Such a relationship is revealed when considering the expressions for the projections of the sighting vectors of the spacecraft on the axis of the trihedra Mξηζ and Mxyz (figure 2). In the case under consideration, these expressions correspond to the matrix dependence

where r _cx r _cy r _cz are the coordinates of the spacecraft in the Mxyz system;

r _cη r _cζ r _cξ — spacecraft coordinates in the Mξηζ system;

is the transforming matrix corresponding to the considered geometry [5].

According to gyro instruments, current values of the ship's orientation angles are generated, which contain errors.

The instrumental values of the angles of heel, trim and yaw can be represented by the expressions

where ψ _a , υ _a , γ _a , are the instrumental angles;

ψ, υ, γ are the true values of the angles;

Δψ, Δυ, Δγ - errors in the development of angles.

Since the angles ψ, υ, γ, and ψ _а , υ _а , γ _а represent the orientation of the true and instrumental positions of the trihedron Mxyz in the horizontal axis system, their relative position can be described by the matrix of directional cosines for the case of small mismatch of coordinate systems

where I is the identity matrix;

- кососимметрическая матрица погрешностей выработки углов ориентации автономными средствами.

- skew-symmetric matrix of errors in generating orientation angles by autonomous means.

In view of formula (3), expression (1) takes the form

where B _A is the matrix of guide cosines B containing the instrumental values of the orientation angles.

Thus, the vector-matrix dependence (4) was obtained, which unambiguously reflects the relationship between the current instrumental values of the angles ψ _а , υ _а , γ _а , and the information of the naval equipment of the SNA (r _cη r _cζ r _cξ , r _cx r _cy r _cz ) with the values errors of autonomous measurements of angles (Δψ, Δυ, Δγ) to be corrected.

Expression (4) taking into account the matrix CB _{A is} rather complicated. However, when solving practical problems, we can assume that the angles ψ, υ, γ vary within (0 ° ÷ ± 6 °), when cosx≈1, sinx≈x, x ² ≈0 can be represented. Then the matrix CB _A takes the form

Taking into account formula (5), the mathematical description of the relationship between satellite and autonomous information displays a significant range of real operating conditions of equipment on a marine object and can be used to construct an algorithm for calculating and correcting errors of devices for independently determining orientation parameters.

Given the need to determine the orientation of an object in space by signals from at least two spacecraft, one can write (4) in a vector-matrix form in the form of a system of linear equations for unknown error values of autonomous means for determining angles

Further transformations allow us to obtain calculation formulas for the unknowns (Δψ, Δυ, Δγ).

Transformations of equations (6) consist of the following actions.

1. The choice of the corresponding pairs of equations of system (6) for the first and second spacecraft with respect to the variables (Δψ, Δυ), (Δψ, Δγ), (Δυ, Δγ).

2. The solution of each pair of equations obtained for unknown Δψ, Δυ, Δγ. For the azimuthal channel for generating corrections, we obtain

An analysis of the calculation formulas for the corrections to the orientation parameters allows us to determine the amount of information necessary for calculating. This information includes a complete set of current instrumental values of the roll angles (γ _a ), trim (υ _a ), yaw (ψ _a ) of the object and a complete set of current coordinates of two navigation spacecraft in a topocentric (r _cη r _cζ r _cξ ) and associated with the object (r _cx r _cy r _cz ) coordinate systems (c = 1,2).

The formation of the basic elements (r _cη r _cζ r _cξ ) of the calculation formulas for the development of amendments is carried out by the algorithms of the receiving equipment of the SNA. High accuracy and reliability of determining the coordinates of the spacecraft in the normal mode of operation of the SNA is guaranteed by the high operational characteristics of the global navigation system.

The procedure for calculating the coordinates of the navigation spacecraft in the system associated with the object (r _cx r _cy r _cz ) can be carried out using the instrumental values of the angles ψ _a , υ _a , γ _a . These values can be used as elements of matrix B to calculate the coordinates of navigation satellites. The performance of the algorithm is confirmed by the results of mathematical modeling.

To assess the capabilities of the method under consideration, mathematical modeling of the course correction process was carried out. In this case, the mathematical model of the GLONASS SNS was used in the staff of the orbital group.

On the Earth’s surface in the meridian plane, 8 control points are defined at which the task of determining the course guidance correction is solved. At the control points, the receiving equipment receives SNA signals, generates data on the coordinates of the visible navigation satellites, and selects satellites. After selecting a pair of satellites suitable for determining orientation, and receiving autonomous measurement information, the current heading correction values are calculated.

The simulation results are shown in the table and presented in the form of graphs in figure 3.

The table contains the numerical values of the error in determining the course (ψ = 34.377 ang. Min) in the latitude range (0 ° -80 °) for the time interval (t = 4800-4850 s). The correction process is carried out according to the signals of two navigation satellites, the numbers of which are given in the table. The correction results are presented by the numerical values of the course determination correction (Δψ ang. Min) in increments of 10 s.

Table
The simulation results of the correction process Δψ. t Latitude, hail Δψ, min ψ, min No. KA1 No. KA2 4800 0 -3.027 34.377 3 24 4810 0 -3.02 34.377 3 24 4820 0 -3.013 34.377 3 24 4830 0 -3.006 34.377 3 24 4840 0 -2.998 34.377 3 24 4850 0 -2.991 34.377 3 24 4800 10 0.034 34.377 3 22 4810 10 0.033 34.377 3 22 4820 10 0.032 34.377 3 22 4830 10 0.031 34.377 3 22 4840 10 0.031 34.377 3 22 4850 10 0.030 34.377 3 22 4800 twenty -0.117 34.377 3 22 4810 twenty -0.118 34.377 3 22 4820 twenty -0.119 34.377 3 22 4830 twenty -0.119 34.377 3 22 4840 twenty -0.12 34.377 3 22 4850 twenty -0.12 34.377 3 22 4800 thirty -0.232 34.377 3 22 4810 thirty -0.232 34.377 3 22 4820 thirty -0.233 34.377 3 22 4830 thirty -0.233 34.377 3 22 4840 thirty -0.234 34.377 3 22 4850 thirty -0.234 34.377 3 22 4800 40 -1.192 34.377 3 twenty 4810 40 -1.188 34.377 3 twenty 4820 40 -1.184 34.377 3 twenty 4830 40 -1.18 34.377 3 twenty 4840 40 -1.176 34.377 3 twenty 4850 40 -1.172 34.377 3 twenty 4800 fifty 0.396 34.377 one twenty 4810 fifty 0.394 34.377 one twenty 4820 fifty 0.393 34.377 one twenty 4830 fifty 0.392 34.377 one twenty 4840 fifty 0.390 34.377 one twenty 4850 fifty 0.389 34.377 one twenty 4800 60 -0.044 34.377 four 22 4810 60 -0.043 34.377 four 22 4820 60 -0.042 34.377 four 22 4830 60 -0.041 34.377 four 22 4640 60 -0.04 34.377 four 22 4850 60 -0.039 34.377 four 22 4800 70 -0.165 34.377 four 21 4810 70 -0.164 34.377 four 21 4820 70 -0.164 34.377 four 21 4830 70 -0.163 34.377 four 21 4840 70 -0.163 34.377 four 21 4850 70 -0.162 34.377 four 21 4800 80 -0.266 34.377 four 21 4810 80 -0.265 34.377 four 21 4820 80 -0.265 34.377 four 21 4830 80 -0.264 34.377 four 21 4840 80 -0.264 34.377 four 21 4850 80 -0.263 34.377 four 21

Figure 3 presents graphs of the error in the development of course corrections Δψ depending on the latitude of the site and the number of used navigation satellites (1; 3; 4). The nature of the change in the error graphs indicates a high accuracy in the development of course corrections according to the SNA. Over the entire range of changes in the latitude of the object (φ = 0 ... 80 °), the error Δψ does not exceed -3 ... + 4 angles. min There is completely no dependence of accuracy on the latitude of the object. At the same time, the relationship between the error and the relative position of the navigation satellites and the object is obvious. The solution to the problem is carried out in real time.

Based on the results of the research, we can conclude that the considered method of correcting the orientation parameters of the object is highly efficient.

The essence of the method for determining the course correction from the data on the coordinates of the satellites is as follows:

- choose a constellation of navigation satellites available for observation;

- form pairs of available satellites;

- choose a pair of satellites with the lowest value of the geometric factor;

- receive gyro data on the current values of the object orientation parameters;

- receive measurement signals and ephemeris information of the satellite system;

- compute the coordinates of the satellites in a topocentric and associated coordinate systems;

- calculate the corrections to the current values of the orientation parameters of the object according to the current values of the orientation parameters, the coordinates of the satellites in the topocentric and coordinate systems associated with the object.

The technical solution of the problem is carried out in the process of interaction of the structural elements of the corrected navigation, orientation and stabilization systems.

The invention is illustrated by the drawing of figure 4, which shows the corrected system of inertial navigation and stabilization, containing a gyro-stabilized platform (1) in a triaxial cardan suspension with angle sensors, on which three two-stage integrating gyroscopes and three linear accelerometers are installed; a digital device (4) that implements the inertial system functioning algorithms, as well as a standard (6) and backup (7) correction blocks and a correction switch (8). In this case, the outputs of the sensors for the angle of rotation of the rings of the cardan suspension and the outputs of the accelerometers are connected to the inputs of the digital device, one of the outputs of which is connected to the input of the gyro-stabilized platform, and the other is connected to correction units, the outputs of which are connected to the correction switch (8). The system is controlled from the remote control (PU), which provides the formation of system control signals by command K, coming from the equipment of consumers of the SNA. On command K, the standard one (B-41) is turned on, and on command K _p , an accelerated correction block (BEECH).

The structure retains the basic functional elements and communications of the prototype system and presents a new element - an accelerated correction unit (ACL) and new communications of an ACD with a digital instrument (PC) and SNA consumer equipment, which ensures the generation of coordinates of used satellites.

The interaction of the accelerated correction block with the ANN elements is carried out in a corrected mode of operation. The corrected mode is activated by the signals of the AP SNS K or K _p , which means the receipt of corrective information. At the signal K, the standard CD is turned on. The consumer equipment generates information about the current values of the coordinates of the object’s location, the navigation data (NL) and satellite information φ _s , λ _s are received at the inputs of the standard correction block (B-41). The B-41 algorithms generate the current values of the SINS error corrections (ΔND), which are fed to the input of the PC unit in position I of the contacts of the PC switch.

By the signal K _p , a backup KR is realized. The consumer equipment generates information about the current values of the coordinates of the satellites used, navigation data (ND) and information about the coordinates of the satellites are received at the inputs of the accelerated correction block (BEC). The ALM algorithms generate the current values of the ANN error corrections, which are fed to the input of the PC unit in position II of the contacts of the PC switch.

The proposed structure of the interaction of navigational aids in the complex of equipment provides globality, increased stealth and high accuracy of operation.

References

1. Marine navigation technology. Handbook edited by Smirnova E.R. - St. Petersburg: "Elmore", 2002.

2 VG Peshekhonov et al. Unified inertial navigation and stabilization system "Ladoga-M". Marine Electronics No. 1 (4), 2003, pp. 26-30.

3. Technical proposals for the development of navigation equipment. / Krasnoyarsk: Research Institute of Radio Engineering KSTU, 1996.

4. Andreev A.A., Kokorin V.I. et al. Results of high-latitude tests of modern Russian marine compasses. Proceedings of the international conference on integrated navigation systems. - St. Petersburg: Central Research Institute "Elektropribor", 2004, p.137-139.

5. Rivkin S.S. Statistical synthesis of gyroscopic devices. - L .: Shipbuilding, 1970.

Claims (1)

An inertial-satellite navigation, orientation and stabilization system containing a gyrostabilized platform in a three-axis gimbal with angle sensors, on which three two-stage integrating gyroscopes and three accelerometers are installed, a digital device that implements the algorithms of the inertial system, a correction unit that ensures the system operates in a regular corrective the mode, and the outputs of the sensors of the angles of rotation of the rings of the cardan suspension and the outputs of the accelerometers of the gyro-stabilized platform s are connected to the inputs of the digital device, one of the outputs of which is connected to the input of the gyrostabilized platform, and the other is connected to the correction unit, while the inertial-satellite navigation system is equipped with a control panel for generating system control signals, characterized in that the system is equipped with an accelerated correction unit, at the input of which the current coordinates of the used navigation satellites and the current instrumental values of the orient ation gyrostabilized platform switch regular and accelerated correction channel, and outputs the correction blocks are connected to the switch input, the output of which is connected to the input of the digital device.

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