Determining a location and aligning a sensor

Abstract

The invention relates to a method (100) in which information concerning the shape of an environment is acquired (102) by means of a sensor (10). Furthermore, a location and orientation of the sensor (10) are determined based on a comparison of the acquired (102) information concerning the shape of the environment with previously known topographical data (104).

Description

The invention relates to a method, a mobile device for carrying out the method, a computer program and a computer-readable medium.Mobile sensor systems for airspace monitoring and / or defense often require accurate knowledge of their location as well as alignment of an associated sensor. Up to now, information of a satellite-assisted navigation system and / or of an inertial navigation system has been used for this purpose. In satellite-based navigation systems, such as a global navigation satellite system, the location and orientation of the sensor may be determined based on signals transmitted and provided by the satellites. An accuracy of the location and of the alignment is generally dependent on a visibility of the satellites and a relative arrangement of the satellites with respect to one another. A method for satellite-assisted determination of a vehicle position is known, for example, from the publication DE 10 2018 205 430 A1. However, the signals transmitted by the satellites can easily be disturbed since they are often only very weak. Therefore, for example, interference transmitters are used, by means of which the signals of the satellites are superimposed or a reception of these signals is prevented. As a result, an incorrect location and an incorrect orientation are often determined or a determination of the location or the orientation on the basis of the satellite-based navigation system is even made impossible. Additionally or alternatively, inertial navigation systems are therefore provided for the purpose of ascertaining the location and the orientation of the sensor. Although this can generally prevent an accuracy of the location and the alignment from being impaired with the aid of external interference transmitters, inertial navigation systems require a predetermined settling time in order to achieve a required accuracy for ascertaining the location and the alignment. Moreover, in inertial navigation systems, an accuracy usually varies depending on a latitude. In the region around the equator, there is a greatest accuracy. In the direction of the poles, on the other hand, the accuracy decreases with increasing latitude. Furthermore, it is possible to determine the location and the orientation of the sensor under consideration using a magnetic compass. Due to the comparatively low accuracy, however, this procedure is only selected in the event of a strong fault or a failure of the inertial navigation system and / or of the satellite-based navigation system. A position determination device is known from the publication DE 10 2016 101 455 A1, by means of which a location can be determined independently of satellite-based navigation systems by using an earth surface model database. Furthermore, the publication DE 102011 119 762 A1 describes a method for the high-precision position determination of a motor vehicle, which method can also be used in areas in which satellite-based systems do not function or only function to a limited extent.An object of the invention is to provide an improved method for determining a location and an orientation of a sensor.This object is achieved by a method having the features of independent claim 1.Furthermore, the object of the invention is to specify a mobile device for carrying out the method.This object is achieved by a device having the features of the subordinate present claim.Furthermore, the invention is based on the objects of providing a computer program and a computer-readable medium.These objects are achieved by a computer program having the features of the subordinate claim 15 and by a computer-readable medium having the features of the subordinate claim 15.Advantageous refinements are the subject matter of dependent dependent claims in each case.The method according to the invention provides that information relating to a shape of an environment is detected by means of the sensor. Furthermore, a location and an orientation of the sensor are determined on the basis of a comparison of the acquired information relating to the shape of the environment with previously known topographical data. Expediently, this is a computer-implemented method.In the present context, topographical data are intended to be understood as meaning data in the sense of topography as a subregion of cartography, which data are usually based on a detailed measurement, representation and / or description of a geographical surface. By means of topographical data, it is possible, for example, to identify a relief of a geographical surface, water bodies and / or traffic routes located thereon, and also fouling. Expediently, the sensor is configured to acquire information relating to a direction, a distance, a type and / or a position of an object. Data based on an electro-optical distance measurement and / or a radio-assisted localization are preferably recorded by means of the sensor. By way of example, the sensor can be embodied as a radar or a lidar.Matching with previously known topographical data enables a rapid determination of the location and the orientation of the sensor. An influence of external sources of interference on an accuracy of the location and the alignment of the sensor can be minimized. In the individual application, such as, for example, in ground-bound air repulsion, radar systems can thereby be made ready for use quickly and reliably. If necessary, ready-to-use of the sensor can be restored quickly after a change in location and / or orientation. This enables a reliable defense of an air space and a rapid perception and reconnaissance of hostile targets.An advantageous further development provides that a height profile of the environment is detected by means of the sensor as the information relating to the shape of the environment. The location and the orientation of the sensor are then determined on the basis of a comparison of the detected height profile with previously known topographical data stored in a digital surface model.In the context of the present invention, a digital surface model is to be understood to mean a digital model which is produced on the basis of measured topographical data and which maps a height profile of at least part of an earth's surface together with objects located thereon, such as a construction, roads, bodies of water and / or a fouling. Digital surface models are usually based on digital terrain models which are based exclusively on data relating to a height profile of a terrain of at least part of the earth's surface.The use of previously known digital surface models enables the method to be carried out in a cost-effective and reliable manner. Moreover, high-resolution and high-accuracy digital surface models can be used in order to keep an error in the determination of the location and the determination of the alignment of the sensor small.In a further advantageous development, a digital model is created on the basis of the information regarding the shape of the environment detected by means of the sensor. The location and the orientation of the sensor are then determined on the basis of a comparison of the created digital model with the previously known digital surface model. This allows a rapid and time-efficient adjustment to be made. Furthermore, the location and the alignment of the sensor can be determined with a high accuracy in this way in a cost-effective manner. Furthermore, the matching can be carried out on the basis of an iterative procedure, in which a match of the digital model with the previously known digital surface model can be reliably found. If there is a sufficiently good agreement, the alignment and the location of the sensor can be determined easily and cost-effectively. In the preferred application, computer-implemented pattern recognition algorithms are used for efficiently carrying out the method. As a result, a comparison of the created digital model with the predefined digital surface model can be accelerated.The information concerning the shape of the environment is preferably obtained from disturbance data detected by means of the sensor. Information relating to an environment that has already been detected by means of the sensor but has not yet been used can be used for the purpose of establishing ready-to-use of the sensor. This makes it possible to provide an efficient and cost-effective method.In the present context, the mentioned interference data is preferably the data detected by the sensor, which data differ from a target object of interest or generally make detection of the target object difficult. Interference data can therefore relate, for example, to reflections, echoes, data generated by multiple propagation and / or data generated on the basis of Doppler effects. In the preferred application, the disturbance data are acquired in such a way that information relating to a distance, a position and / or a relative solid angle with respect to the sensor of reflections in three-dimensional space is acquired. Information relating to the shape of the environment is preferably obtained from disturbance data which are based, for example, on reflections from fouling, water bodies and / or geological elevations or depressions.An advantageous variant provides that the information relating to the shape of the environment is obtained from the captured disturbance data in such a way that moving objects are first extracted from this disturbance data. Using suitable filters, moving objects can be extracted at low cost. This leaves stationary or supposedly static objects, on the basis of which the shape of the environment can be quickly determined. In this way, meteorological effects, such as precipitation, wind or reflection effects at varying air pressure differences, can also be extracted at low cost. The aforementioned digital model relating to the shape of the environment can then be created. In the preferred application, the method is carried out in a stationary operating state of a mobile sensor.Furthermore, the method provides that a plurality of digital models are successively created on the basis of the information regarding the shape of the environment detected by means of the sensor. On the basis of a comparison of the plurality of digital models mentioned, information relating to a classification of a terrain type, slow-moving objects, objects moving out of coverage within a field of view of the sensor and / or multipath propagation is determined. As a result, a quality of the digital model can be continuously improved. Further information concerning, for example, applied hostile forces or slowly moving objects, such as helicopters, can be understood quickly and reliably. This makes it possible to obtain further information from the disturbance data beyond the shape of the environment. In this way, the sensor and at least the tactics associated therewith can be protected, for example, from a mischief attack. Furthermore, in the preferred application, it can be detected whether the sensor itself is the target for attack.The location and the orientation of the sensor are preferably additionally determined on the basis of information from a satellite-based navigation system and / or an inertial navigation system. An accuracy of a determination of the location and of the alignment of the sensor can thereby be further improved. Errors which arise within the scope of the mentioned comparison during the determination of the location and the alignment can in the preferred case be reduced on the basis of the information of the satellite-based navigation system and / or of the inertial navigation system.In an advantageous variant embodiment, it is provided that information relating to an accuracy of a location determined by means of the global satellite-based navigation system and / or by means of the inertial navigation system and alignment of the sensor is determined with the aid of the location determined on the basis of the aforementioned comparison and the alignment of the sensor determined thereby. In addition to conventional methods for the purpose of determining an accuracy of data based on a satellite-based navigation system, which are based, for example, on a number of available satellites, a relative position of the satellites with respect to one another and / or a signal-to-noise ratio relating to a received signal, the location determined by means of the aforementioned matching and the orientation of the sensor determined thereby can be used. In a preferred application, it is thereby possible to identify interference transmitters or interference signals and, if appropriate, to filter incorrect information. It is also conceivable that this recognition is given to further sensors and / or further units in order to prevent an erroneous determination of the location or an erroneous determination of an alignment. Furthermore, an accuracy of the inertial navigation system can thereby be determined in an improved manner. An influence of a latitude, a possible drift behavior of the inertial navigation system and / or a spread of measurement values of the inertial navigation system can be recognized quickly and reliably. Thereby, the accuracy of the inertial navigation system can be obtained with high reliability. A correction requirement can therefore be recognized quickly and, if appropriate, a corresponding correction can be carried out.A further advantageous variant provides that a determination of the location and the orientation of the sensor is carried out on the basis of information relating to the accuracy of the location determined by means of the satellite-based navigation system, by means of the inertial navigation system and / or on the basis of the aforementioned comparison of the information detected by means of the sensor relating to the shape of the environment with previously known topological data in each case and the orientation of the sensor determined in this way. Such information, which is occupied with a high level of uncertainty, can be ignored or can be used only with a low weighting for the purpose of determining the location and the alignment. For example, it can thereby be established whether signals of a satellite-assisted navigation system are disturbed or manipulated. Manipulated signals can therefore be ignored in a simple manner when determining the location or the alignment. Further, an increased weight may be associated with a measurement of the inertial navigation system at low latitude locations compared to higher latitude locations.Moreover, an advantageous development provides that a radar is provided as the sensor, which is used when monitoring and / or defense a predetermined air space. Required change in location or a change in an orientation of the radar can be carried out quickly and cost-effectively on the basis of the method according to the invention. A range of vision of the radar can be quickly and reliably aligned with a predicted trajectory of a target object. Furthermore, in a reliable and reliable manner, the radar can be ready for use for monitoring and defense of the predetermined air space. In the individual application, an absolute error can be estimated on the basis of a digital surface model for an air target measurement. With the aid of knowledge of the absolute error, improved control of a sensor-effector system in which the sensor is incorporated can be achieved. Furthermore, drift effects of a radar can be quickly detected and optionally corrected.The sensor is advantageously designed as a mobile sensor, the location and orientation of which is determined in a stationary operating state. A change between different steady-state operating states can be carried out quickly and reliably. In various steady-state operating states, a location and / or the orientation of the sensor can be changed in each case. Such changes can be determined quickly in order to achieve reliable readiness for use. Furthermore, various disturbing influences can be easily detected and uncovered. As a result, objects of interest can be located and tracked with a high accuracy by means of the sensor. In the preferred application, an air space can thereby be efficiently and resource-savingly revised. In addition, a high probability of interception for a sensor-effector system can thereby be provided. Hostile movements can be understood and / or elucidated reliably and quickly. Furthermore, a detection of the sensor can be made more difficult with the aid of a change in location.By means of the mobile device according to the invention, the method according to the invention is carried out in a stationary operating state of the mobile device.The mobile device according to the invention has a sensor which is configured to monitor an air space. The mobile device can be made ready for use at low cost after a change in location or a change in orientation. In this case, a new location and / or a new alignment can be determined with a high accuracy quickly and with low cost. Time-consuming and possibly highly uncertain determinations of the location and the alignment of an offset sensor can be dispensed with. In the individual application, it is possible to react quickly to an hostile attack. For example, the sensor can be brought into registration for a short time. Furthermore, an explanation of the mobile device can be avoided by displacing it at regular intervals. As a result, it is nevertheless possible to restore ready-to-use of the mobile device in a quick and reliable manner. In the preferred application, a sensor-effector system with a high probability of interception and a low probability of failure can be realized in this way.In an advantageous development, it is provided that the mobile device is designed as a mobile radar system for monitoring the air space using a radar sensor. Hostile objects within the air space to be monitored can be detected and located quickly and with high accuracy. Sensor-effector systems can be used to support hostile objects with high reliability and high probability of detection by means of the mobile device.Moreover, the invention provides a computer program which, when executed, causes the mobile device according to the invention to perform the method according to the invention.The invention further provides a computer readable medium. This device has instructions which cause the mobile device according to the invention to carry out the method according to the invention.The computer-readable medium can be, for example, a CD-ROM, a DVD, a USB or flash memory or a non-physical medium, such as a data stream and / or a digital carrier signal.The description thus far of advantageous embodiments of the invention contains numerous features which are reproduced in part in a plurality in a few dependent claims. However, the features can also be considered individually and combined to form meaningful further combinations, in particular in the case of references from claims, such that a single feature of a dependent claim can be combined with a single, multiple or all features of another dependent claim. In addition, these features can be combined both with the method according to the invention and with the system according to the invention according to the respectively independent claims. Thus, method features are also to be seen as being expressed in terms of the subject matter as properties of the corresponding device unit, and functional device features are also to be seen as corresponding method features.The above-described properties, features and advantages of this invention and the manner in which these are achieved become clearer and more clearly comprehensible in conjunction with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawings. The exemplary embodiments serve to explain the invention and do not restrict the invention to the combination of features specified therein, nor with respect to functional features. Furthermore, features suitable for this purpose of each exemplary embodiment can also be considered explicitly isolated, removed from one exemplary embodiment, introduced into another exemplary embodiment for supplementing the same and / or combined with any of the claims. The figures are schematic representations which are not true to scale.The following are shown: FIG. 1 shows an illustration of an example of the method according to the invention for determining a location and an orientation of a sensor on the basis of a schematic flow diagram; FIG. 2 shows an exemplary embodiment of the mobile device according to the invention, which is exemplarily embodied as a mobile radar system.FIG. 1 shows an example of a method 100 by means of which a location and an orientation of a sensor 10 are determined 104.The example of method 100 described here provides that information relating to a shape of an environment is detected 102 by means of sensor 10. By way of example, the sensor 10 mentioned is embodied as a radar 10. In order to acquire 102 information relating to the shape of the environment, a so-called clutter map is created in the example of the method 100 described here. For example, disturbance data is acquired 110 with a lowered viewing direction of the radar 10. Disturbance data is usually unwanted, but can be used in the present case to acquire 102 information relating to a shape of the environment. The clutter map has information about captured 102 reflections, which relate, for example, to an angle, a distance, a position and / or a signal-to-noise ratio of each reflection. Furthermore, the example of method 100 described here provides that information relating to a height profile of the environment is obtained 108 from the 110 disturbance data acquired by means of radar 10. For this purpose, moving objects are extracted 112 from the detected disturbance data 110 in the present case by way of example. This extraction is preferably carried out with the aid of suitable filters. This makes it possible to extract 112 aircraft, cars, helicopters or other moving objects from the acquired 110 disturbance data in a simple manner.In a preferred embodiment, the example of method 100 described in the present case provides that a digital model is created 106 on the basis of the 102 information relating to the shape of the environment acquired by means of radar 10. In the present context, the captured 110 and filtered disturbance data are used for this purpose in order to generate 106 a digital model of an elevation profile of the environment.By way of example, in the present case, the location and the orientation of the radar 10 are determined 104 with the aid of a comparison of the created 106 digital model with a previously known digital surface model. A previously known digital height model is preferably used as a previously known digital surface model. The digital height model is, for example, a so-called "digital elevation model", which is therefore known under the abbreviation DEM. The previously known topographical data stored in the digital surface model are then matched to the captured 102 information relating to the height profile of the environment. Such matching is preferably performed using computer-implemented pattern recognition algorithms. In this way, a correspondence between the acquired information 102 and the previously known data can be ascertained 104 quickly. Alternatively or additionally, the created 106 digital model can be iteratively examined for matches with the previously known digital surface model.A preferred embodiment provides that a plurality of digital models are created 106 successively on the basis of the information regarding the shape of the environment acquired 102 by means of the radar 10. These multiple digital models may be used to improve accuracy of the location and orientation of the radar 10. Furthermore, the plurality of digital models can be used to determine 114 information relating to a classification of a terrain type, slow-moving objects, objects moving out of coverage within a field of view of the radar 10, and / or multipath propagation. In a simple manner, additional information can thereby be obtained on the basis of the determined 102 information relating to the shape of the environment. This can improve a quality of the created 106 digital model. Furthermore, safety of the radar 10 can be enhanced using the additional information. For example, slowly moving helicopters or hostile forces acting from a arrest can be understood to be rapid and reliable. Furthermore, objects moving below a usual range of vision of the radar 10 can be understood as appropriate.Furthermore, the example of method 100 described here provides that the location and the orientation of radar 10 are additionally ascertained 104 on the basis of information from a satellite-based navigation system and on the basis of information from an inertial navigation system. In this way, an accuracy in determining 118 the location and orientation of the radar 10 may be improved. In the preferred application, information regarding an accuracy of the location determined on the basis of the aforementioned comparison and the orientation of the radar 10 is determined 116.For this purpose, errors in the digital height profile, systematic angle errors and errors in a position angle determination of the radar 10 and errors which are caused by the aforementioned alignment itself can be taken into account by way of example. Knowing the accuracy of the 104 location determined on the basis of the aforementioned comparison and the orientation of the radar 10 makes it possible to control effectors of a sensor-effector system, not shown in more detail, by means of the radar 10 in an improved manner. For example, a probability of interception of an object 102 detected by the radar 10 can be improved taking into account the mentioned accuracy.Furthermore, the example of method 100 described here provides that information relating to an accuracy of a location determined 104 in each case by means of the satellite-based navigation system and by means of the inertial navigation system and the orientation of radar 10 is determined 116 in a manner known to the person skilled in the art. In addition, the example of method 100 described in the present case provides that the 104 location ascertained on the basis of the comparison of the acquired 102 information with the previously known topographical data and the orientation of radar 10 are used for the purpose of ascertaining 116 the information relating to the accuracy of the location ascertained in each case by means of the satellite-based navigation system and by means of the inertial navigation system and the orientation of radar 10. External disturbing influences or drift effects can thereby be quickly uncovered. These disturbing influences and uncertainties are preferably taken into account before a determination 116 of information concerning the accuracy of the global satellite-based navigation system as well as of the inertial navigation system.Then, it is provided that for ascertaining 104 the location and the orientation of the radar 10, a determination of the location and the orientation of the radar 10 is carried out 118 on the basis of the information regarding the accuracy of the location and the orientation of the radar 10 ascertained by means of the satellite-based navigation system, the location and the orientation of the radar 10 ascertained on the basis of the aforementioned comparison. For this purpose, information ascertained 104 in each case relating to the location and the orientation of the radar 10 are preferably weighted on the basis of the respectively assigned accuracy. Information regarding the location and the orientation of the radar 10 which is occupied with high uncertainties can be ignored in this way or can be included only with a low weight in the determination 118 of the location and the orientation of the radar 10. This makes it possible to determine 118 the location and the orientation of the radar 10 quickly, at low cost and with a high accuracy.In a preferred application, the radar 10 is used in monitoring and / or defense of a predetermined air space. By way of example, the sensor 10 embodied as a radar 10 can be used in a mobile radar system 12 of a sensor-effector system, not shown in detail, in order to control effectors quickly and reliably toward a target object to be controlled. This makes it possible to understand and track target objects to be controlled in a simple and reliable manner. Furthermore, a trajectory of a target object to be controlled can be predicted with an improved quality. The predetermined air space is preferably monitored and / or attenuated by means of the mobile radar system 12 in a stationary operating state. In this stationary operating state, the location and the orientation of the radar 10 of the mobile radar system 12 are determined 104 in the manner described above. This makes it possible to adapt the location and / or the orientation of the mobile radar system 12 as required. For various stationary operating states, the location and / or the alignment can then be determined 118 quickly and cost-effectively. In particular, this enables a high operational readiness of the radar 10, which can be restored quickly as required.FIG. 2 shows a schematic illustration of a mobile radar system 12 for monitoring an airspace with a radar 10.The exemplary embodiment of the mobile radar system 12 described in the present case is configured to carry out the example of the method 100 described in connection with FIG. 1 in various stationary operating states 14, 16.FIG. 2 illustrates by way of example the exemplary embodiment of the mobile radar system 12 with the radar 10 in a first stationary operating state 14. Due to a changing deployment scenario, mobile radar system 12 has to be moved from first stationary operating state 14 into a second stationary operating state 16, for example. In the second operating state 16, both the location and the orientation of the radar 10 of the mobile radar system 12 differ in comparison to the first stationary operating state 14. Moreover, the orientation of a field of view of the radar 10 is changed and exemplarily rotated relative to the first stationary operating state 14. Preferably, based on the example of method 100 described in connection with FIG. 1, the location and the orientation of radar 10 of mobile radar system 12 in second stationary operating state 16 are then ascertained 104. This enables the mobile radar system 12 to be restored to ready for use quickly and reliably.List of reference characters100 Method 102 Environment capture 104 Location and orientation determine 106 Digital model generate 108 Information from disturbance data obtain 110 Disturbance data capture 112 Moving objects extract 114 Information determine 116 Accuracy determine 118 Determination perform 10 Sensor / radar 12 Mobile device / mobile radar system 14 First stationary operating state 16 Second stationary operating state

Claims

Method (100), in which - information relating to a shape of an environment is detected (102) by means of a sensor (10); - a location and an orientation of the sensor (10) are determined (104) on the basis of a comparison of the detected (102) information relating to the shape of the environment with previously known topographical data; - a plurality of digital models are successively created (106) on the basis of the information relating to the shape of the environment detected by means of the sensor (10); - information relating to a classification of a terrain type, slow-moving objects, objects moving out of a coverage within a field of view of the sensor (10) and / or a multipath propagation is determined (114) on the basis of a comparison of the said plurality of digital models.Method (100) according to Claim 1, in which - a height profile of the environment is detected (102) by means of the sensor (10) as information relating to the shape of the environment; - the location and the orientation of the sensor (10) are determined (104) on the basis of a comparison of the detected (102) information relating to the shape of the environment with previously known topographical data stored in a digital surface model.Method (100) according to Claim 1 or 2, in which - a digital model is created (106) on the basis of the information relating to the shape of the environment, which information is captured by means of the sensor (10); - the location and the orientation of the sensor (10) are determined (104) on the basis of a comparison of the created (106) digital model with a previously known digital surface model.Method (100) according to one of the preceding claims, in which the information relating to the shape of the environment is obtained (108) from disturbance data detected (110) by means of the sensor (10).Method (100) according to Claim 4, in which the information relating to the shape of the environment is obtained (108) from the disturbance data detected (110) by means of the sensor (10) in such a way that moving objects are first extracted (112) from this disturbance data.Method (100) according to one of the preceding claims, in which the location and the orientation of the sensor (10) are additionally determined (104) on the basis of information from a satellite-based navigation system and / or an inertial navigation system.Method (100) according to Claim 6, in which information relating to an accuracy of a location determined by means of the global satellite-based navigation system and / or the inertial navigation system and an orientation of the sensor (10) is determined (116) with the aid of the location determined (104) on the basis of the aforementioned comparison and the orientation of the sensor (10).Method (100) according to Claim 6 or 7, in which a determination of the location and the orientation of the sensor (10) is carried out (118) on the basis of the information relating to the accuracy of the location determined by means of the satellite-based navigation system, by means of the inertial navigation system and / or the location determined (104) on the basis of the aforementioned comparison and the orientation of the sensor (10).Method (100) according to one of the preceding claims, in which a radar (10) is provided as the sensor (10), which radar is used in monitoring and / or defense of a predetermined air space.Method (100) according to one of the preceding claims, in which the sensor (10) is designed as a mobile sensor (10), the location and orientation of which is determined (104) in a stationary operating state.Mobile device (12) for monitoring an air space, having a sensor (10) which is configured to carry out the method (100) according to one of the preceding claims in a stationary operating state (14, 16).Mobile device (12) according to Claim 11, characterized in that the mobile device (12) is designed as a mobile radar system (12) for monitoring the air space using a radar (10).A computer program which, when executed, causes the mobile device (12) according to any one of claims 11 or 12 to perform the method (100) according to any one of claims 1 to 10.A computer readable medium comprising instructions that cause the mobile device (12) of any one of claims 11 or 12 to perform the method (100) of any one of claims 1 to 10.

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