RU2563332C2 - Navigation method for autonomous unmanned underwater vehicle - Google Patents

Abstract

FIELD: physics, navigation.

SUBSTANCE: invention relates to navigation and can be used in navigation systems of autonomous unmanned underwater vehicles. The method includes determining location coordinates on underwater landmarks by measuring the bottom topography using on-board acoustic equipment; forming a regular grid of points of measured depths and comparing the obtained depth values with reference depth values, where when determining location coordinates on underwater landmarks the sinking speed of the autonomous unmanned underwater vehicle is determined using a log for measuring the speed of the autonomous unmanned underwater vehicle relative to the water surface. The method includes measuring hydrological parameters using side-looking sonar, a profile recorder, temperature and electrical conductivity measuring devices, and sound speed in the marine environment; from the measured depths, reconstructing the topography of the area by constructing Kronrod-Rib trees when comparing measured depth values with reference values. If critical depth coordinates match, said coordinates are used to adjust the inertial navigation system of the autonomous unmanned underwater vehicle.

EFFECT: low labour costs when performing underwater work using autonomous unmanned underwater vehicles.

3 dwg

Description

The invention relates to the field of navigation, and more particularly to methods of navigation of autonomous uninhabited underwater vehicles (AUVs) as components of an integrated search and rescue system designed to perform work on the shelf in high latitudes.

In the well-known navigation systems of the underwater autonomous uninhabited apparatus, the problems of bringing and docking under water are solved in the presence of acoustic (Allen B., Austin T., Forrester N. et al. Autonomous Docking Demonstrations with Enhanced REMUS Technology // Proc. Of OCEANS'06 MTS / IEEE. Boston, MA, 18-21 September, 2006. USA CD-ROM. ISBN 1-4244-0115-1. Utley C, Lee H. Signal Processing Algorithms for High-Precision Three-Dimensional Navigation and Guidance of Unmanned Undersea Vehicles (UUV) // Proc. Of OCEANS'06 MTS / IEEE. Boston, MA, September 18-21, 2006. USA CD-ROM. ISBN 1-4244-0115-1. Grant M. de Goede, Donald Norris. Recovering Unmanned Undersea Vehicles With a Homing and Docking Sonar // Proc. Of OCEANS 2005 MTS / IEEE. Washington, DC, USA, 18-23 September 2005. USA CD-ROM. ISBN 0-933957-33-5. [1-3 ]) or visual (optical contact in the near cast zone (Inzartsev A.V., Matvienko Yu.V., Pavin A.M., Vaulin Yu.V., Scherbatyuk A.Ph. Algorithms of Autonomous Docking System Operation for Long Term AUV // Proc. of 14th Int. Symp on Unmanned Untethered Submersible Technology (UUST05), Durham, New Hampshire, USA, August 21-24, 2005. Vaulin Yu.V., Inzartsev A.B., Matvienko A.B., Pavin A.M., Scherbatyuk A.F. Investigation of the operation of elements of a system for bringing an autonomous uninhabited underwater vehicle // Mater, Int. scientific and technical conf. "Technical problems of the development of the oceans." Vladivostok, September 14-17, 2005. Vladivostok: Dalnauka, 2005, pp. 40-45 [4, 5]). When operating the AUV with great autonomy and range, it is necessary to ensure the return of the AUV to the supply vessel after a long mission. Under these conditions, it is important to organize the AUV in the near zone, taking into account the fact that the accumulating errors of autonomous on-board navigation can be hundreds and thousands of meters.

One of the solutions to this problem is associated with bringing the device to a sonar beacon, made in the form of a towed antenna or towed antenna module, which is part of the ship's sonar navigation system (HANS) (Kiselev L.V., Inzartsev A.V., Matvienko Yu. V., Vaulin Yu.V. Navigation and control in the underwater space // Mechatronics, Automation, Management, 2004. No. 11, p. 35-42 [6]). This approach does not require installation of additional equipment on the device, but is reduced to modifying the control system software using the data from the HANS receivers available on board. However, the use of a supply vessel with a towed antenna module to perform research and survey work using measuring equipment installed on the underwater vehicle practically excludes the use of underwater vehicles in the presence of solid ice or drift ice, i.e. in arctic areas.

There is also a method of navigating an underwater vehicle (A.M. Pavin. Automatic reduction of an autonomous underwater robot to a sonar beacon // Underwater Research and Robotics. 2008, No. 5 (1), p. 32-38. [7]), which is implemented as follows way. Navigation aids are installed on the underwater vehicle, which include an onboard autonomous navigation system that provides coordinates based on dead reckoning; sonar and satellite navigation systems, allowing to determine the local or absolute coordinates of the autonomous AUV and the supporting vessel.

A dead reckoning system that uses information from navigation and flight sensors, depth gauges, components of translational and angular speeds, course angles, roll and trim, gives an accumulating error of the order of several tens of meters per hour of operation, depending on the type of speed meter used (Doppler or relative lag).

Similarly, the task of navigating underwater objects is also solved in well-known technical solutions (patents RU 2119172 C1, 09.20.1998 [8], RU 2084923 C1, 07.20.1997 [9], RU 52197 U1, 03/10/2006 [10], RU 102814 U1, 03/10/2011 [11], EP 1275012 B1, 01/15/2003 [12], US 20110051555 A1, 03/03/2011 [13], RU No. 2460043 C1, 08/27/2012 [14], RU No. 2456634 C1, 07/20/2012 [ fifteen]).

An increase in the signal-to-noise ratio is achieved in two ways: by increasing the signal power and reducing the noise level. As a rule, piezoelectric radiating elements operating at the limit of radiated power are used in the sources of the analyzed sound signals for UHF antennas, so the only way to amplify the signal is to increase its energy by increasing the duration. An increase in the duration in the tonal mode leads to a decrease in the accuracy of measuring the traveltime of the wave, and thereby to a deterioration in the characteristics of navigation as a whole. The only real way to increase the signal energy without compromising the resolution of the system in range is to use complex signals. Such systems are known, for example, of the "POSIDONIA" type from IXSEA OCEANO. However, the use of complex signals requires, on the one hand, a significant increase in processor performance in transponders and an onboard antenna, and on the other hand, it shortens the life of acoustic transponders in standalone mode with a fixed resource of power sources.

The ambient noise at the receiving point has complex frequency and spatial spectra, and its effective level can be reduced by limiting the sensitivity of the receivers in areas that do not contain useful information. The limitation of sensitivity in the frequency domain is achieved by optimal filtering of signals, the limitation of sensitivity in the spatial region by passive or active beamforming. Passive formation is achieved by the use of reflective and damping elements in the antenna structure, which attenuate sound waves from undesirable directions. This method is used in most known UKB systems and is very effective and relatively cheap, but it does not allow to narrow the spatial spectrum of the analyzed signal and to achieve the lowest possible noise level. Active directivity is achieved by using multi-element phased arrays and is used, for example, in the Kongsberg HIPAP-500 system. This method of generating a reception diagram gives the best results, however, implementing antennas of this type is a very difficult and expensive task. So, in the HIPAP-500 system, hundreds of independent receiving channels are used, through which synchronized reception and real-time processing of incoming information is carried out.

Known navigation methods [1-15] AUVs include determining the location (coordinates) of the defendant beacons, and are weighed down by the need to install the defendant beacons, their binding to the installation site. The implementation of these works is burdened by significant labor costs and not in all cases allows you to achieve the desired result.

There are also known methods for navigating underwater vehicles (TERCOM (Terrain Contour Matching) navigation system britannica.com> EBehecked / topic / 587825 / Tercom [16]) along the bottom topography.

In autonomous navigation of a moving underwater vehicle, control actions are formed according to the feedback principle in the form of functions of the measured values. While moving in the coordinate numbering system - in the inertial navigation system (ANN), built on gyroscopes and accelerometers, large errors accumulate, so the realized trajectory can significantly differ from the true one.

An effective means of correcting accumulated errors is the use of bottom topography information observed during movement.

All existing methods for navigating underwater vehicles along the topography of the bottom have a common core. It consists in the following. Reference depths are available. They represent a reference regular grid of depth points obtained from preliminary measurements of the bottom topography. During navigation, the underwater vehicle measures the bottom topography of the onboard acoustic equipment, forms a regular grid of points of the measured depths, and then compares the obtained depth values with the reference ones.

For all existing methods, the general principle of comparison methods is the correlation-extreme approach, which is based on the search for the extremum of some functional for comparing the obtained bottom topography measurements with a priori (reference) information about it stored in the memory of the onboard computing device.

The classical correlation processing algorithm for assessing the similarity of the measured depths on board the underwater vehicle with the reference ones is based on the calculation of the cross-correlation function with the subsequent search for its maximum:

$$K(p,q)=\frac{\mathrm{one}}{NM}{\displaystyle \sum _{x=0}^{N-\mathrm{one}}{\displaystyle \sum _{y=0}^{M-\mathrm{one}}{f}_{sh}(x,y)f_{th}(x+p,y+q)},(\mathrm{one})}$$

where x, y are the planned coordinates of the navigation area, f _sh (x, y), f _th (x, y) are the regular grids of the reference and current depth measurements, p, q are the linear values of the possible offset of the depth grid of the current measurements, N, M - the number of columns and rows in the grid.

The TERCOM system is based on the following principle: the geographical position of any point on the earth's surface (the bottom of the sea) is uniquely described using vertical depth profiles. Such a system also requires preliminary mapping of the surface profiles of the bottom topography of the area over which the underwater vehicle will be used. Predefined terrain relief data is stored digitally in the on-board storage device. During swimming, the TERCOM system measures the vertical profile of the bottom topography along the true flight path using an echo sounder. Subtracting the current depth measured by the pressure sensor, the system determines the profile of the bottom topography along the swimming path and organizes a search in the memory of the calculator for the most “similar”, pre-stored profile with known coordinates.

It is obvious that all existing correlation-extreme navigation systems, without exception, are sensitive to mutual geometric distortions, that is, to mutual rotation, shift and zooming. Indeed, the underwater vehicle can not absolutely accurately and constantly follow in a certain direction and at a constant level from the sea surface. Therefore, it is fundamentally impossible to coordinate the direction of the reference depth grid and the direction of navigation, as well as to withstand the coordination of the spatial scales of depth measurements. All this significantly limits the accuracy of these methods. In addition, the correlation coefficient, being an integral parameter, does not make it possible to distinguish trajectories with close values of the correlation coefficients.

The objective of the proposed technical solution is to reduce labor costs in the production of underwater operations using AUV.

The problem is solved due to the fact that in the method of navigation of an autonomous uninhabited underwater vehicle, which includes determining the coordinates of the place by underwater landmarks by measuring the bottom topography of onboard acoustic equipment, forming a regular grid of points of measured depths and comparing the obtained depths with reference depths, in which, when determining location coordinates using underwater landmarks determine the speed of immersion of an autonomous uninhabited underwater vehicle through a lag for measuring speed the autonomous uninhabited underwater vehicle relative to the water surface, which is made in the form of an induction meter for the longitudinal and transverse components of the velocity and drift angle and is additionally equipped with n receiving sensors located in the bow and stern parts of the autonomous uninhabited underwater vehicle body, perform measurements of hydrological parameters using a side-scan sonar , profilograph, temperature and electrical conductivity meters, and sound velocity in the marine environment, as measured to the depths, the terrain is restored by building the Kronrod-Riba trees, when comparing the measured depths with the reference values, with the coordinates of the critical depths coinciding, they are introduced to adjust the inertial navigation system of the autonomous uninhabited underwater vehicle.

The essence of the proposed technical solution is illustrated by drawings (Fig. 1-3).

FIG. 1. The principle of operation of the TERCOM system.

FIG. 2. The navigation system of an autonomous uninhabited underwater vehicle 1, which includes blocks of a hydroacoustic telecontrol and communication system 2, navigation and flight sensors 3, a local area network 4, a hydroacoustic Doppler lag 5 for measuring the speed of an autonomous uninhabited underwater vehicle relative to the seabed, lag 6 for measurement speeds of an autonomous uninhabited underwater vehicle relative to the water surface, inertial navigation system 7, magnetic compass 8, gyrocompass 9, depth gauge 10, a steering system 11 of the steering mechanisms 12, and also an autonomous uninhabited underwater vehicle equipped with equipment for performing hydrological research, including a side-scan sonar 13, a profiler 14, meters 15 for temperature and electrical conductivity of the marine environment, cameras 16, a mobile meter 17 for the speed of sound, electronic cartographic navigation information system 18 and video plotter 19, multipath echo sounder 20.

Lag 6 for measuring the speed of an autonomous uninhabited underwater vehicle relative to the water surface is made in the form of an induction meter for the longitudinal and transverse components of the velocity and angle of drift and is additionally equipped with n receiving sensors located in the fore and aft parts of the body of an autonomous uninhabited underwater apparatus for determining the immersion speed of an autonomous uninhabited underwater apparatus.

The gyrocompass 9 is made in the form of an adjustable gyrocompass built on the basis of a dynamically tuned gyroscope and quartz accelerometers.

Inertial navigation system 7 is built on the basis of a precision gyro with an electrostatic suspension of the rotor.

Multipath echo sounder 20 is used to measure depths in a certain band at the swimming course of the underwater vehicle.

FIG. 3. The Kronrod-Rib-21 graph for functions of types 22 and 23. Embedding of the Kronrod-Rib-21 graph in the plane 24 of the contour drawing of the function, points (I, H, J) are maxima, points (D, A, D, L) are minima , points (F, E, C, K) are saddles.

The identified problems in the task of navigating the relief can be eliminated by using the structure of the bottom topography discretely describing the cartographic representation of the bottom topography. This structure arises provided that the bottom topography surface can be interpreted as a smooth two-dimensional function for which there are only isolated simple critical points: minima, maxima, and saddle points (Yu.N. Zhukov, Mathematical tools for describing the cartographic representation of the Earth's relief // Navigation and Hydrography , 2011, No. 32, pp. 60-69 [17]).

In geomorphology, these terms correspond to the geographical concepts of the top of the mountain, the position of the maximum of the depression and the pass. The indicated critical points are ordered in a special way. This ordering allows critical points to be organized in the form of a special graph called the Kronrod-Reeb tree. An illustrative example of this structure is presented in figure 3.

With this method of describing the topography of the bottom, the position of the underwater object is determined by the degree of similarity of the two structures of the Kronrod-Riba trees. One tree is a reference tree, the other is being built aboard an underwater vehicle. In this case, the coordinates of the location of critical points, their depth and the presence of edges of bonds between them are compared.

The main advantage of using this method is that in this case it is only necessary to compare point objects (their coordinates and depths) with each other. These objects are insignificant; they represent natural features of the relief surface. And most importantly, it is obvious that in this case there are completely no problems inherent in traditional methods with the spatial orientation of the underwater vehicle and the various spatial scales of depth measurements.

The method is implemented as follows.

When conducting research, for example, in the water area where an underwater business object is located, before launching the AUV in the inertial navigation system 7 of the autonomous uninhabited underwater vehicle 1, the coordinates of the place of its immersion are entered, digital maps of the bottom topography, critical points are loaded into the electronic cartographic navigation information system 18 (mountains, hollows and passes) containing reference trees of Kronrod-Riba.

According to a predetermined program, swimming and measurement of hydrological parameters are performed by means of equipment for performing hydrological studies, including side-scan sonar 13, profilograph 14, temperature and conductivity meters 15 of the marine environment, cameras 16, and a mobile sound velocity meter 17.

Swimming is performed using information from navigation and flight sensors 3, sonar Doppler lag 5, lag 6 for measuring the speed of an autonomous uninhabited underwater vehicle relative to the water surface, inertial navigation system 7, magnetic compass 8, gyrocompass 9, depth gauge 10, steering control system 11 mechanisms 12. In this case, by means of a multi-beam echo sounder 20 and a video plotter 19, a bathymetric survey is performed. Based on the measured depths, the terrain is restored with the construction of the Kronrod-Riba trees and compared with reference values. When the coordinates of the critical points are entered, they are introduced to adjust the inertial navigation system 7.

In the proposed method for navigating an autonomous uninhabited underwater vehicle, by comparing two representations of the bottom topography (reference and directly measured) for the task of navigating the underwater vehicle, in contrast to traditional methods, the comparison is carried out between regular arrays of depth points representing a continuous surface of the bottom topography. The principal feature of the proposed method is a discrete representation of the surface of the bottom topography in the form of a special structure. In this case, errors due to yaw at the direction of movement of the underwater vehicle and the different scale of the reference and measured data on the topography of the bottom are eliminated.

The implementation of the method is not of technical complexity, since the method can be implemented on a standard ship equipment.

Information sources

1. Allen B., Austin T., Forrester N. et al. Autonomous Docking Demonstrations with Enhanced REMUS Technology // Proc. of OCEANS'06 MTS / IEEE. Boston, MA, 18-21 September, 2006. USA CD-ROM. ISBN 1-4244-0115-1.

2. Utley C, Lee H. Signal Processing Algorithms for High-Precision Three-Dimensional Navigation and Guidance of Unmanned Undersea Vehicles (UUV) // Proc. of OCEANS'06 MTS / IEEE. Boston, MA, 18-21 September, 2006. USA CD-ROM. ISBN 1-4244-0115-1.

3. Grant M. de Goede, Donald Norris. Recovering Unmanned Undersea Vehicles With a Homing and Docking Sonar // Proc. of OCEANS 2005 MTS / IEEE. Washington, D.C., USA, September 18-23, 2005. USA CD-ROM. ISBN 0-933957-33-5.

4. Inzartsev A.V., Matvienko Yu.V., Pavin A.M., Vaulin Yu.V., Scherbatyuk A.Ph. Algorithms of Autonomous Docking System Operation for Long Term AUV // Proc. of 14th Int. Symp on Unmanned Untethered Submersible Technology (UUST05), Durham, New Hampshire, USA, August 21-24, 2005.

5. Vaulin Yu.V., Inzartsev A.B., Matvienko A.B., Pavin A.M., Scherbatyuk A.F. Investigation of the operation of elements of a system for bringing an autonomous uninhabited underwater vehicle // Mater, Int. scientific and technical conf. "Technical problems of the development of the oceans." Vladivostok, September 14-17, 2005. Vladivostok: Dalnauka, 2005, pp. 40-45.

6. Kiselev L.V., Inzartsev A.V., Matvienko Yu.V., Vaulin Yu.V. Navigation and control in the underwater space // Mechatronics, automation, control. 2004. No. 11, p. 35-42.

7. A.M. Pavin. Automatic reduction of an autonomous underwater robot to a sonar beacon // Underwater research and robotics. 2008, No. 5 (1), p. 32-38.

8. Patent RU No. 2119172 C1, 09/20/1998.

9. Patent RU No. 2084923 C1, 07.20.1997.

10. Patent RU No. 52197 U1, 03/10/2006.

11. Patent RU No. 102814 U1, 03/10/2011.

12. EP patent No. 1275012 B1, 01/15/2003.

13. Application US No. 201110051555 A1, 03.03.2011.

14. Patent RU No. 2460043 C1, 08.27.2012.

15. Patent RU No. 2456634 C1, July 20, 2012.

16. TERCOM system (britannica.com> EBehecked / topic / 587825 / Tercom).

17. Zhukov Yu.N. Mathematical tools for describing the cartographic display of the Earth's relief // Navigation and Hydrography, 2011, No. 32, p.60-69.

Claims (1)

A method of navigating an autonomous uninhabited underwater vehicle, including determining the coordinates of a place by underwater landmarks, by measuring the bottom topography of onboard acoustic equipment, forming a regular grid of points of measured depths and comparing the obtained depths with reference depths, characterized in that when determining the coordinates of a place using underwater landmarks, immersion speed of an autonomous uninhabited underwater vehicle through a lag for measuring the speed of an autonomous uninhabited submarine relative to the water surface, which is made in the form of an induction meter of the longitudinal and transverse components of the velocity and angle of drift and is additionally equipped with n receiving sensors located in the fore and aft parts of the body of an autonomous uninhabited underwater vehicle, perform measurements of hydrological parameters using a side-scan sonar, profiler, measuring instruments for temperature and electrical conductivity and sound velocity in the marine environment, restore the topography of the places by measured depths By constructing the Kronrod-Riba trees, when comparing the measured depths with the reference values when the coordinates of the critical depths coincide, they are introduced to adjust the inertial navigation system of the autonomous uninhabited underwater vehicle.

Images