RU2754128C1 - Method for restoring performance capacity of platformless inertial navigation system after hardware failure - Google Patents

Abstract

FIELD: regulating.

SUBSTANCE: invention relates to the field of instrument manufacture and can be applied in navigation systems of mobile objects, such as aerial vehicles (AVs). The method for restoring the performance capacity of a platformless inertial navigation system after a hardware failure consists in using the information from the angular velocity sensors and linear acceleration sensors, according whereto the current parameters of movement of the AV are determined in flight by means of a computing apparatus, if the computing apparatus fails, the performance capacity of the system is restored. A one- or two-processor computer is used as a computing apparatus, equipped with a data storage module, an emergency restart apparatus and registers retaining the state thereof in the event of an emergency restart, resistant to external influences. The time parameters of the emergency restart are preset by means of said computing apparatus. When the current parameters are determined, the predicted motion parameters are calculated, stored in the data storage module. The predicted motion parameters are calculated using an extrapolating polynomial, the coefficients whereof are determined using the least-square method. In the event of a failure of the computing apparatus, an emergency restart thereof is executed, and to restore the current motion parameters, the data with the predicted values of the motion parameters is used.

EFFECT: increased reliability of operation of the navigation system of the aerial vehicle.

1 cl, 5 dwg

Description

The invention relates to the field of instrumentation and can be used in navigation systems for moving objects, for example, aircraft (AC).

In the process of operation, the navigation and automatic control system of a moving object - the aircraft can be exposed to influences leading to equipment failures and, as a result, loss of data on the parameters of the object's movement. Taking into account the specifics of the operation of strapdown navigation systems, the task of predicting the parameters of object movement (coordinates, speeds, parameters of angular orientation, etc.) for the time the navigation system is in an inoperative state is relevant. The operation of the strapdown inertial navigation system (SINS) is based on the processing of measurements of inertial sensors, such as accelerometers and angular velocity sensors (ADS), and obtaining results in the form of current motion parameters. Accelerometers measure the absolute apparent linear acceleration, ROS measure the absolute angular velocity. The motion parameters determined by the SINS are the aircraft velocity vector, position coordinates and the aircraft angular orientation in space. The principle of constructing inertial navigation systems is known and described in the technical literature [David N. Titterton and John L. Weston Strapdown Inertial Navigation Technology - 2 ⁿ edition / The Institution of Electrical Engeeners, 2004, Navigation of aircraft in near-earth space. Avgustov L.I., Babichenko A.V., Orekhov M.I., Sukhorukov S.Ya., Shkred V.K. Ed. G.I. Janjgava. - M .: "Nauchtekhlitizdat", 2015, 592 p.]. As a rule, the SINS includes an on-board computer and a block of sensitive elements (BCH). The BChE includes accelerometers and DUS. In the computer, under the control of the work program, an algorithm for processing data from accelerometers and DUS is implemented, and the current motion parameters are formed, while a procedure known as the initial exhibition is carried out to bring the SINS to its initial (initial) state. As a result of the initial alignment, the correct angular orientation of the aircraft relative to the coordinate system is determined, in which the current parameters of movement are determined, which makes it possible to correctly determine the remaining parameters of the movement (velocity and coordinates). The initial exhibition involves obtaining the necessary information from an external source and is an iterative process that ends when the exhibition error is reached, which ensures the required accuracy in determining the movement parameters. After the end of the exhibition, SINS performs an autonomous determination of the current parameters of the aircraft movement: orientation angles (yaw, pitch, roll), aircraft speeds. The process of determining the current motion parameters is iterative and uses the motion parameters obtained in the previous step. The SINS of the aircraft, which autonomously determines the current parameters of movement in flight, is deprived of additional information support from an external source, as it could be during an initial exhibition based on data from an external navigation system. In the event of a malfunction in the operation of the aircraft navigation equipment in flight, it is necessary to take measures to ensure the fastest possible restoration of the SINS performance.

From the prior art, a method for determining the spatial orientation and heading of an aircraft is known, described in the invention under the name "System for determining the spatial position of the course of an aircraft" [RF patent 2427799, G01C 21/00, publ. 08/27/2011], which uses information from angular velocity sensors and linear acceleration sensors, according to which the angles of orientation of the aircraft in space are determined in flight by means of a computing device; true values of angles according to information from the indicated sensors.

In this method, a three-component magnetometer is also used to determine the parameters of the aircraft movement in flight mode, and the orientation angles (roll, pitch and gyromagnetic heading) of the aircraft in space are determined. Also, using additional on-board equipment, converters and a logic device, the signal about the sign of the aircraft being on the ground or in flight is analyzed. In the case of a signal being on the ground, the system automatically switches to the initial alignment mode. In the case of a signal being in flight, the initial alignment is blocked and an accelerated angular alignment is performed using data on the displacement of zero signals of the angular velocity sensors recorded in advance in the storage device; the calculated magnetic heading and data from the acceleration sensors are also used.

The proposed method makes it possible to fend off malfunctions in the operation of the aircraft navigation and flight equipment both on the ground and in flight.

However, the disadvantages of this method are that such parameters of movement as: components of the speed of movement of the aircraft, coordinates of the aircraft in space (latitude, longitude, altitude) are not determined and not restored, which limits the scope of application, since it does not allow the use of this device in control systems autonomous unmanned aircraft, whose tasks include moving to a given point in space. In addition, the initial exhibition takes place on the ground, which excludes the possibility of using this method for aircraft in which the exhibition of inertial navigation systems is carried out in flight. The absence of an emergency restart system does not allow to restore operation in the event of a failure not associated with a short-term power failure, for example, when the on-board computer "hangs" due to external influences.

A known method for determining the spatial angle of the course of the aircraft [RF patent 2505786, IPC G01C 23/00, publ. October 27, 2014, bul. No. 3.], taken as a prototype and consisting in the fact that information from angular velocity sensors and linear acceleration sensors is used, according to the specified information in flight, by means of a computing device, the current parameters of the aircraft movement are determined, in case of a failure of the computing device, the system is restored.

In this method, to determine the spatial angle of the aircraft heading, a three-component magnetometer is used, as in the previous analogue. According to information from the angular velocity sensors and linear acceleration sensors and a three-component magnetometer, the true values of the aircraft orientation angles are determined. To counter a short-term power outage, a sign of the aircraft being on the ground or in flight is formed, and the calibration characteristics of the sensors are used, taking into account the change in the ambient temperature. The use of calibration characteristics increases the accuracy of determining the angle of the aircraft heading in comparison with the above analogue. If a short-term power outage occurred in flight during maneuvering, then the aircraft is brought to a horizontal rectilinear flight segment without acceleration and the accelerated correction mode is activated, in which the angles calculated from the information from the angular velocity sensor unit are matched with the angles calculated from the information from the unit linear acceleration sensors and a three-component magnetometer. The accelerated correction mode is activated by the aircraft pilot. The proposed method makes it possible to increase the accuracy of determining the orientation angles of the aircraft in comparison with the above-mentioned analogue, it makes it possible to get rid of the need to carry out the initial alignment mode if a system malfunction occurs in flight.

However, the prototype is also not without its drawbacks, the main of which is that to bring the navigation system into working condition, it is necessary to bring the aircraft into horizontal flight without acceleration and activate the accelerated correction mode with the participation of the pilot, which does not allow using this method on unmanned aircraft not equipped with an engine. , since in this case, the provision of horizontal flight of the aircraft without acceleration may be difficult or impossible, depending on the traffic conditions at the time of the failure. As in the previous method, the initial exhibition takes place on the ground, which excludes the possibility of using this method for aircraft powered in flight and which are forced to carry out the initial exhibition procedure in the air. As in the previous method, the absence of an emergency restart system does not allow to restore operation in the event of a failure that is not associated with a short-term power failure, for example, when the on-board computer "hangs" due to external influences. To carry out accelerated correction, the participation of the pilot is required, which limits the scope of this method and does not allow its use in unmanned aircraft.

The task and the technical result to be achieved by the present invention is to improve the reliability of the navigation system of the aircraft by restoring its operating state after a failure ("freezing") of the onboard computer due to external factors without removing power from the devices included in its composition.

The technical result is achieved by the fact that the method of restoring the operability of a strapdown inertial navigation system after a hardware failure, which consists in using information from angular velocity sensors and linear acceleration sensors, according to which the current parameters of the aircraft movement are determined in flight by means of a computing device, in case of a computing failure. the devices restore the system operability, according to the invention, a one- or two-processor computer is used as a computing device, equipped with a data storage module resistant to external factors, an emergency restart device and registers that retain their state during an emergency restart, preliminarily using the said computing device, time parameters are set emergency restart, when determining the current parameters, the predicted motion parameters are calculated, which are stored in the xp module data analysis, and the predicted motion parameters are calculated for the time the system is in an inoperative state using an extrapolating polynomial, the coefficients of which are determined using the least squares method, if the computing device fails, its emergency restart is performed, and to restore the current motion parameters, data with predicted parameter values are used movement.

The use as a computing device of a one- or two-processor computer equipped with a data storage module resistant to external influences and an emergency restart device provides a “reset” of the calculator without removing power after a hardware failure due to external factors.

The registers used in the processor calculator, which retain their state when the system is restarted, make it possible to identify the fact of an emergency restart and make a decision on the need to restore the current motion parameters.

Preliminary setting of temporary parameters of emergency restart by means of a computing device, and then calculation of predicted motion parameters when determining the current parameters and storing predicted motion parameters in the storage module, and calculating predicted motion parameters for the time the system is in an inoperative state using an extrapolating polynomial, the coefficients of which are determined from using the least squares method, it allows the system to be restored as quickly as possible by reading the current motion parameters from the storage module without performing an initial alignment or accelerated heading angle correction.

When the computing device fails, its emergency restart, after which the use of data with predicted values of the motion parameters to restore the current movement parameters makes it possible to obtain the current movement parameters as quickly as possible without conducting an initial alignment or accelerated heading angle correction.

The use of an independent power supply channel makes it possible to increase the reliability of the aircraft navigation system by restoring its operating state after a failure ("freezing") of the on-board computer due to external factors without removing power from the devices included in its composition, since it allows the on-board equipment to be "powered" when the power is disconnected from the aircraft power supply system and ensures the restoration of operability after a failure in the operation of the equipment involved in determining the current parameters of the aircraft movement.

The presence in the claimed invention of features that distinguish it from the prototype makes it possible to consider it as corresponding to the "novelty" condition.

New features have not been identified in technical solutions for a similar purpose. On this basis, it can be concluded that the claimed invention meets the condition "inventive step".

The invention is illustrated by drawings:

in fig. 1 shows a block diagram of the SINS, where above the arrow going from the BChE to the computer are the measurements of the inertial sensors (nx, ny, nz, wx, wy, wz) entering the computer for processing, and above the arrow going from the computer are the current parameters aircraft motions (Ψ, υ, γ, Vx, Vy, Vz, B, L, H), calculated by the computer.

in fig. 2 shows a diagram of information links of a two-processor computer;

in fig. 3 shows a diagram of data transfer between the master (MASTER) processor, the slave (SLAVE) processor and the storage module (arrows show the data transfer with the current motion parameters (Ψ, υ, γ, Vx, Vy, Vz, B, L, H) from the master to the slave processor and transfer of the predicted motion parameters (Ψ ^e , υ ^e , γ ^e , Vx ^e , Vy ^e , Vz ^e , V ^e , L ^e , N ^e ) from the slave processor to the storage module);

in fig. 4 is a diagram illustrating the simultaneous writing of a keyword to stateful registers and to a storage unit;

in fig. 3 shows the algorithm of the action program for the implementation of the proposed method.

The method of restoring the operability of a strapdown inertial navigation system (SINS) after a hardware failure is implemented as follows: information from angular velocity sensors and linear acceleration sensors is used, according to which the current parameters of the movement of the aircraft are determined in flight by means of a computing device; ... As a computing device, a one- or two-processor computer is used, equipped with a data storage module resistant to external influences, an emergency restart device and registers that retain their state during an emergency restart.

As a rule, the SINS (Fig. 1) includes a block of sensing elements 1 (BChE) and an onboard computer 2. In the case of using a computer with one processor, the current parameters of movement are calculated (angular orientation, components of the velocity vector and coordinates of the aircraft in space) and performing predictive extrapolation thereof, so as to obtain the predicted parameters at the time of the completion of the emergency restart of the system in the event of a failure. Consider the case of using a two-processor computer (Fig. 2-4). In this case, the first processor 3 plays the role of the master (MASTER) to ensure the regular operation of the SINS, namely, to calculate the current parameters of the aircraft movement (angular orientation, components of the velocity vector and coordinates of the aircraft in space). The second processor 4 acts as a slave (SLAVE) and is used to extrapolate the current motion parameters in such a way as to obtain the predicted parameters at the time of the emergency restart of the system in the event of a failure. The use of two processors makes it possible to "parallelize" the tasks of determining the current motion parameters and the tasks associated with calculating the predicted parameters. The two-processor computer is equipped with a data storage module 5, resistant to external influences, and an emergency restart device 6, which provides a “reset” of the computer without removing the power supply. The processors used in the one- and two-processor calculator are equipped with registers 7 and 7, 8, respectively, which retain their state when the system is restarted, but change it when the power is removed and applied, for example, as it is implemented in the SCRATCH-registers of the 5890BE1 processor [5890BE1T INTEGRAL CHART Notes on the use of YUKSU.431288.001D4]. Preliminarily, by means of the specified computing device, the time parameters of the emergency restart are set. When determining the current parameters, predicted motion parameters are calculated, which are stored in the data storage unit, and the predicted motion parameters are calculated for the time the system is in an inoperative state using an extrapolating polynomial, the coefficients of which are determined using the least squares method. If the computing device fails, its emergency restart is carried out, and data with predicted values of the movement parameters are used to restore the current motion parameters.

Predictive extrapolation is performed using a polynomial whose coefficients are determined using the least squares method (OLS). The general view of the polynomial is shown below:

ϕ (x) = a ₀ + a ₁ x + a ₂ x ² ... + a _n x ⁿ .

According to the OLS method, to find the coefficients of the polynomial a _{0 ...} a _n, it is necessary to minimize the functional

where: xi - empirical data (in our case, time);

y _i - empirical data associated with x _i (in our case, the motion parameters determined by the SINS algorithm).

To minimize, the derivative of the functional is taken and equated to zero. As a result, a system of equations is obtained, which in matrix form has the form:

Xa = Y.

The solution of this system with respect to the required coefficients is as follows:

a = X ^-1 Y,

where: X = Ф ^Т Ф - matrix of the system of equations,

Y = Ф ^T у,

- вектор эмпирических данных,

is a vector of empirical data,

- вектор эмпирических данных, связанных с х.

is a vector of empirical data associated with x.

The use of time values as empirical data x, at which the corresponding parameters of motion y were determined, leads to a degeneration of the matrix X, which in turn leads to large errors in determining the coefficients of the polynomial and, as a consequence, to an incorrect determination of the extrapolated parameter ϕ (x).

For SINS, which determines the parameters of motion with a given period, it is proposed, when constructing the system matrix, to replace the empirical data x with values x *, which are constants uniformly distributed both in the negative and in the positive region so that the condition number of the system matrix satisfies the condition:

1 <|| X || ₁ ⋅ || X ^-1 || ₁ <100,

|| X || ₁ ⋅ || X ^-1 || ₁ - condition number,

|| X || ₁ is the first norm of the matrix,

|| X ^-1 || ₁ is the first norm of the inverse matrix.

The fulfillment of this condition will indicate a good conditionality and the absence of degeneracy of the matrix of the system.

Since the components of the vector x * are constants, then, since the matrix of the system X is formed from the elements of the vector x *, it will also consist of constants. This, in turn, allows you to speed up the calculation of the coefficients of the polynomial.

и необходимо спрогнозировать пятое значение, то вектор эмпирических данных

обеспечит формирование обратной матрицы системы состоящей из констант, например для квадратичного полинома обратная матрица будет иметь вид:For example, if there are four measurements of any parameter

and it is necessary to predict the fifth value, then the empirical data vector

will provide the formation of the inverse matrix of a system consisting of constants, for example, for a quadratic polynomial, the inverse matrix will have the form:

а искомые коэффициенты полинома будут найдены, как

and the required coefficients of the polynomial will be found as

where: X11, X13, X22, X31, X33 - the corresponding elements of the matrix X ^-1 ,

Ф13, Ф23, Ф42, Ф32, Ф13, Ф23 - the corresponding elements of the matrix

In this case, when finding a forecast using the quadratic polynomial ϕ (x) = a ₀ + a ₁ x + a ₂ x ² , the coefficients of which were found in the above way, instead of the current value of x, the next value x * equidistant from the extreme value is substituted into the polynomial formula. For the given example, x * = 1.975.

The predicted parameters are stored in the data storage unit 5 (FIG. 3).

In the storage area of the key 10 of the storage module 5 and the registers 7, 8, which retain their state after restarting the processors 3, 4, a special keyword 9 is written (Fig. 4), which makes it possible to distinguish the emergency restart of the calculator from the power supply. The emergency restart device 6 provides a restart of the calculator 2 in the event of its "freezing".

Computer 2 is loaded with a program that operates on its resources - master 3 and slave 4 processors, emergency restart device 6 and data storage module 5.

The algorithm of the program implementation of the method (Fig. 5) contains two main functional branches, one of which implements the regular operation of the system before failure, and the second - emergency recovery of the current state. Applying power or resetting the calculator, including an emergency restart, force the algorithm to run from the very beginning. At the beginning of the operation, the algorithm analyzes the state of the registers 7, 8, which retain their state, and certain areas of the memory of the storage module 5, and establishes the fact that power is applied or an emergency restart. If it is established that an emergency restart was not carried out (the registers and special areas of memory of the data storage module do not match or do not contain special information corresponding to keyword 9), the algorithm initiates the start of regular operation of the system, generates keyword 9 and writes it to registers 7 , 8, preserving their state, and a special memory area 10 in the storage module 5. Then it proceeds to the sequential execution of the initial alignment, and then proceeds to the autonomous determination of the current movement parameters. In this case, the algorithm initializes the emergency restart timer in such a way as to ensure the restart of the calculator when the duration of the "hang" exceeds the specified time interval, for the same time interval the forecast of the motion parameters is determined. At the same time, the algorithm provides the formation of data in the storage module 5, reflecting the fact that the work was carried out in the mode of the initial exhibition or in the autonomous mode of SINS. In the SINS autonomous operation mode (after passing the initial alignment procedure), on the basis of the master processor 3, the current motion parameters are calculated, which are transmitted to the slave processor 4, where the predicted motion parameters are calculated by extrapolating the current parameters to the end of the computer restart. In case of establishing the fact that there was an emergency restart (coincidence of the key information of the registers and certain areas of the memory of the storage module), the algorithm initiates an emergency recovery of the system. Reads information from the storage module, with data on the operating mode of the SINS. If the SINS was not in the autonomous mode of determining the motion parameters, then the algorithm provides a repeated start of the standard work branch - it starts sequentially performing work in the mode of the initial alignment, after which it goes into autonomous mode. If at the time of the failure the computer was working off the autonomous mode, then the algorithm calculates the predicted motion parameters from memory, determines them as initial ones, and continues calculating the current motion parameters.

The use of an independent power supply channel makes it possible to increase the reliability of the aircraft navigation system, since it allows the on-board equipment to be "powered" when the power is disconnected from the aircraft power supply system and ensures the restoration of operability after a failure in the operation of the equipment involved in determining the current parameters of the aircraft movement, which is achieved by introducing the composition of the system of an independent power supply channel, for example, a battery with electrical isolation from the power supply circuits of the main power supply channel using diode decouples, in accordance with GOST R 54073-2017.

Thus, the proposed method increases the reliability of the navigation system for both manned and unmanned aircraft, since it allows the equipment to be "powered" when the power is disconnected from the aircraft power supply system and ensures the restoration of operability after a malfunction due to the influence of external factors of the equipment involved in determining the current aircraft motion parameters.

The presented information testifies to the fulfillment of the following set of conditions when using the claimed invention:

- the means embodying the claimed method in its implementation relates to the field of instrumentation and can be used in navigation systems for moving objects, for example, aircraft;

- increasing the reliability of the aircraft navigation system by restoring its operating state after a failure of the on-board computer due to external factors without removing power from the instruments included in its composition;

- for the proposed method in the form in which it is characterized in the claims, the possibility of its implementation is confirmed using the means and methods described in the application and known before the priority date.

Therefore, the claimed invention meets the condition of "industrial applicability".

Claims (1)

A method of restoring the operability of a strapdown inertial navigation system after a hardware failure, which consists in using information from angular velocity sensors and linear acceleration sensors, according to which the current parameters of the aircraft movement are determined in flight by means of a computing device; characterized in that a one- or two-processor computer is used as a computing device, equipped with a data storage module resistant to external influences, an emergency restart device and registers that retain their state during an emergency restart, preliminarily using the specified computing device, the time parameters of an emergency restart are set, when determining the current parameters, the predicted motion parameters are calculated, which are stored in the data storage unit, and the forecast is calculated the calculated motion parameters with the help of an extrapolating polynomial, the coefficients of which are determined using the least squares method, in case of a failure of the computing device, its emergency restart is carried out, and to restore the current motion parameters, data with the predicted values of the motion parameters are used.

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