Tracking device and method for calibrating a tracking device

p0001Locating device and method for calibrating a locating device

p0002The invention relates to a locating device, in particular a handheld locating device, for detecting enclosed in a medium objects according to the preamble of claim 1. The invention further relates to a method for calibrating a measuring device, in particular for the calibration of a hand held measuring apparatus for detecting in a medium enclosed objects.

p0003State of the art

p0004Tracking devices for detecting objects enclosed in a medium are widely used in the field of crafts and interior construction, for example, to locate electrical cables or water pipes. In addition to the concrete realization of the actual measuring function is the operation of the device is crucial for the quality of the measurement results. A high quality from the technology meter can reach only a small measuring performance in practice in the field, when the user is operated incorrectly, or go out in the operation of the device of false assumptions

p0005When locating devices, which are typically used for search of lines, pipes,

p0006Metal studs or wooden beams are used in walls, ceilings and floors, various types of devices to hand the Deteklionsmethode used can be distinguished.

p0007So inductive devices are known, for example, which generate a magnetic field which is disturbed by entrapped metallic objects. The thus modified magnetic field is measured by a detector having one or more coils, so that the position of the enclosed, metallic object can be located by shifting or method of locating device on the surface of the object enclosing medium. A disadvantage of detectors of this type that only metals can be detected.

p0008A second class of tracking devices, which can be described as a capacitive device, are actively building on an existing instrument in the measuring capacitor, an electric field in which the through objects in the medium, such as a wall a ceiling or a floor are included, is disturbed. Such field penetrates but not very far into the examined medium. Therefore, these devices are used mainly as "studfinder" because they can locate wooden beams in particular, which are hidden behind wall coverings, such as plasterboard or paneling.

p0009Furthermore known are mains voltage detectors, the capacitive, but passively, ie capture without generating an own electric field, the AC field of a power voltage line and thus the position and route can show active electrical wires in walls.

p0010From recently Hochfiequenzdetektoren are known which generate a measuring capacitor, a high frequency electromagnetic field which can deeply emdringen in a subject to be examined medium. When crossing the surface of the medium under investigation are internal material changes, as caused for example by an enclosed object, detected by a change in dielectric constant of the measuring capacitor and localized. Encoders of this type, it is irrelevant whether the objects of metal, plastics, gases or liquids consist or contain these. It is sufficient that the electrical properties of the enclosed object from those of the surrounding

p0011Medium, such as a wall material, differ. <

p0012Also known are radars that emit radar pulses which are reflected by hidden in a medium objects. By evaluating the reflected radar pulses statements about the enclosed in the medium

p0013Objects possible.

p0014is most of these Geräleklassen in common that they need to be calibrated to give a meaningful measurement result, especially when switching on and / or at regular intervals. This calibration is usually an internal electronic

p0015Calibration is carried out, which should take place in a situation in which there is no object to be searched in the vicinity of the sensor.

p0016For example, metal detection devices must be calibrated at a large distance to each located in the vicinity of metal. These holding down the device typically by the wall to be examined away into the air. After calibration, you can set up the device on the examined medium, such as a wall, a floor or ceiling to locate hidden objects. Besides the fact that such a calibration process is time consuming, resulting from the calibration process itself is a certain risk, since in case of a wrong performed

p0017Calibration also wrong to positive or false negative test results occur. Property damage or even personal injury may be the consequence of such Falschkalibration at worst.

p0018On the other hand, many capacitive locating devices in direct contact with the wall of the

p0019Meter to calibrate by a reference measurement.

ADVANTAGES OF THE INVENTION

p0021The locating device according to the invention for detecting objects enclosed in a medium has on the one hand means for the detection of objects enclosed in the medium. In addition to these means of detection has the locator means which make it possible to measure a predetermined distance of the locating device to a surface of a medium and thus to ensure that the device is either a necessary minimum distance to the medium complies or placed clearly on the surface of the medium is. With this second means, which form a distance sensor for the measuring device can thus be ensured that locating device of the present invention is arranged such that a reference measurement for calibrating the measuring instrument can be performed. Such reference measurements are carried out for example with inductive location sensors in air, it must also ensure that no object is sufficiently close yet to the detection unit for the localization of the enclosed objects. Such an article would falsify the performed calibration reference or baseline measurement, and thus lead to a false zero the meter. In particular, the locating device according to the invention by means of an enabling

p0022Wall distance sensors in this case ensuring required for a reference measurement of the minimum distance.

p0023On the other hand there gauges, such as the so-called capacitively operating "Studfinder" or beam detectors are calibrated by, on a wall to be examined , Must be placed at a point at which, however, no bar is. The thus measured pure wall signal then corresponds to the reference or calibration signal. In this case, the device should be located on the wall to make the wall contact safely. In this type of measuring devices of the machine predeterminable distance to a surface of a medium is thus equal to zero then. This special case of vanishing distance of the meter from the wall, can in certain applications of measuring instruments must be calibrated in the air, already be sufficient to signal to the meter and the users that under these conditions a calibration measurement for this particular instrument does not make sense, since error-prone.

p0024The features listed in the dependent claims, advantageous refinements of the locating device according to the invention as claimed in claim 1 are possible.

p0025In an advantageous embodiment of the locating device according to the invention, the second detection means, which provide for the distance sensor, a capacitive sensor. A sensor according to capacitive type is based on an electric or electromagnetic field between its electrodes. Changes in this field the surrounding medium, for example, in that the first forward-meter air approaches the wall, the result is due to the different

p0026Dielectric constant of introduced in the measuring range of the measuring capacitor medium, the electrical or electromagnetic field of the capacitor. Such field change is measurable. In a particularly advantageous embodiment of a locating device according to the invention the measuring capacitor, which is part of the first means can be used to

p0027Detecting objects enclosed in a medium, is simultaneously used as a distance sensor and thus also form the second detection means. can be realized by a corresponding Beschaltxmg the measuring capacitor for locating thus with the same components and the distance sensor. This allows advantageously a compact construction of the positioning device according to the invention. In this embodiment, the first and the second means are realized by the same component.

p0028In an alternative embodiment of the locating device according to the invention the second detection means, which form a distance sensor can be an optical sensor, comprise fixing the minimum distance of the measuring device according to the invention to the surface of a medium to be examined. In this case may function as sensor all types of optical detectors. For example, as known from the triangulation method, a focused light beam such as a laser light, the surface of a medium under investigation obliquely. A light-sensitive receiver, such as a CCD array, detects it at a defined angle, the light reflected from the wall irradiance This angle can be adjusted so that light emitted falls back only when wall contact of the measuring device to the receiver. In this case, could be detected by the distance sensor system according to the invention a direct wall contact.

p0029Alternative embodiments may provide that the wall light reflected back is received only at a certain minimum distance so that can be confirmed from the wall to be examined because of such a signal, the presence of a minimum distance. It is also possible, such a distance measurement is at least one ultrasonic signal using.

p0030In principle can be the distance sensor of the locating device according to the invention realized by mechanical methods. Here all types of mechanical contact detection by switching elements are possible. By placing the device on the wall or by the exceeding of a minimum distance the device from the

p0031Wall is taken into a switching element actuated automatically and thus received the undershooting of a minimum distance to the control and evaluation unit of the measuring device.

p0032All such embodiments of the inventive measuring device is common that the signals from the wall distance sensors are evaluated electronically or software technical means of locating device itself. Due to this additional information, a decision can then be made as to whether a calibration measurement must be performed or not this decision, for example, are automatically set in the control or evaluation unit of the measuring device. For example, also be informed of the users of the locating device according to the invention of a successful or failed calibration via display or sound signal. It can also be integrated into the locating device according to the invention an automatic transmission, which calibrates the machine if there is reasonable distance from the wall automatically. In such an embodiment, also results in the advantage that the measuring device immediately after turning on is already operational, as it has been independent, already carried out by the user of Kalibrierangsvorgang.

p0033That also claimed inventive method for calibrating a measuring device, in particular for calibrating a handheld locating device for

p0034Detecting objects enclosed in a medium has the advantage that the necessary calibration reference measurement of the measuring device is carried out only after the carrying out at least one measurement of a distance of the measuring device to a medium. In this way it is ensured by the inventive method that a correct reference measurement is carried out for calibration.

p0035In particular, such a reference measurement for calibration at certain measuring devices is not carried out if a predefinable minimum distance of the measuring device to the surface of a medium is fallen below, the presence of a medium at a distance from the measuring device, which is smaller than a predeterminable minimum distance, leads in these measuring instruments, such as inductive measuring an erroneous

p0036Calibration, and thus to an increased risk for a fine measurement. For example, in an inductive metal detection during calibration but a metallic object within reach of the positioning sensor of the measuring device, as this may cause the positioning sensor is not working at the object location or at worst an existing, object does not display.

p0037In addition, it is provided that the reference measurement for calibrating the measuring device is terminated if a predefinable minimum distance of the gauge to the surface of a medium is undershot during the reference measurement. In this way it is ensured in the process of the invention that an inventive locating device is not placed early example a wall.

p0038Advantageously, the inventive measuring device informs its users when a definable distance for the reference measurement for calibrating the measuring device below or exceeded. This may for example be realized by an optical indicator, possibly the display of the measuring device or also by an audible warning tone. Advantageously, the inventive method a reference measurement for calibrating the measuring device in the presence of a predetermined distance of the measuring device to a surface of a medium leads at least through autonomously and automatically. This means that locating device according to the invention is short for localizing an object enclosed in a medium available.

p0039The inventive method can thus also ensure in particular that the reference measurement is performed only during instrument calibration when the meter is on the surface of a medium to be measured. This

p0040Special case of vanishing predeterminable distance of the measuring instrument to a medium is used for example in capacitive locating devices advantageously use.

p0041Further advantages of locating device according to the invention and the invention

p0042Method for calibrating a measuring device are disclosed in the accompanying drawings and in the description.

p0043drawing

p0044In the drawing, exemplary embodiments of the locating device according to the invention are shown to be explained in more detail in the following description. The drawings, the description and the claims contain numerous features in combination. An artisan will also consider these features individually and combine them to form further reasonable combinations, which are therefore in this

p0045Text can also be viewed

p0046It shows:

p0047Fig. 1 shows an embodiment of a measuring instrument according to the invention in a simplified overall perspective view,

p00482 is a schematic sectional view of an alternative embodiment of an inventive measuring device in contact with the wall Fig. 3 is a schematic representation of the measuring apparatus according to Figure 2 in the case of a wall of a remote measuring device,

p0049Fig. 4 an alternative embodiment of a locating device according to the invention with a second embodiment of a distance sensor for bodies put on a wall gauge,

p0050FIG. 5 shows the instrument according to Figure 4 when there is a distance to the wall to be measured,

p0051FIG. 6 a further embodiment of an inventive measuring device with an alternative distance sensor in a sectional view at a mounted on a wall gauge,

p0052Fig. 7 shows the meter of FIG. 6 with a corresponding distance sensor in the wall remote meter.

p0053Description of Embodiments

p0054Fig. 1 shows a first embodiment of a locating device 10 according to the invention in a perspective overview. The locating device has a housing 12 which is formed of an upper and a lower half-shell 48 and 50 respectively. Inside the housing is at least one sensor, in the embodiment of FIG. 1, an inductive sensor, a coil system for metal detection, a signal generation and evaluation, as well as a power supply for example the batteries or

p0055Batteries, provided. The locating device according to FIG. 1 furthermore has a display 14 for was spending a correlated with the measurement signal Ausgäbesignals. The display 14, such as a segmented bar display or a graphical LCD display, it is the strength of the detected measurement signal is possible to represent.

p0056Furthermore locating device according to the invention has a control panel 16 with a series of controls 18 that allow, turn the unit on and off, for example, and optionally starting a measuring process. In the area below the control panel 16, the locating device of FIG. 1 has a region 20 which is formed in its shape and material design as a handle 22 for guiding the locating device according to the invention. By means of this handle 22 the locating device is guided with its bottom 30 on a surface of an object to be examined or a medium.

p0057On the handle 22 opposite side 28 of the locating device 10 has the meter on a housing opening penetrating 24th The opening 24 is formed by an inserted sleeve 26 into the housing 12 as well as the top and bottom of the housing of the meter. The opening 24 is arranged concentrically in a coil of the inductive sensor of the measuring device. In this manner, the location of the opening 24 in the measuring device, the center of the locating detector, so that the user corresponds to the same time the exact position of any detected object is displayed. In addition, the measuring device in addition to its top marking lines 52, via which the exact center of the opening 24, and thus the

p0058Position of an enclosed object can be located.

p0059In the application locating device according to the invention is guided with its bottom side 30 along the surface of a medium to be examined in FIG. 1. This also balls, rollers or other rolling elements can be provided, with which the device can then be moved over a wall, in other embodiments of a locating device according to the invention, for example. enclosed, metal objects can be located and brought by means of the display 14 to the user for information about the inductive sensor of the locating device while in the wall. The locating device according to the invention has in its interior at a distance sensor, which makes it possible to detect the contact of the instrument with the to be examined wall or falling below a predetermined minimum distance of the locating device according to the invention of the under investigation wall. Depending on the distance sensor used has locating device according to the invention to on its lower exit and Eintrittsöf ments for a measurement signal of the distance sensor on.

p0060Hereinafter, some possible embodiments of such a distance sensor system according to the invention are shown, but these are not to be regarded as limiting. FIG. 2 shows another embodiment of a locating device according to the invention in a schematic sectional drawing. The locating device 56 according to Figure 2 comprises a housing 60 in which a sensor is integrated not described in detail for the detection of objects enclosed in a medium. This sensor may be an inductive or capacitive sensor, a capacitive high-frequency sensor or a

p0061its radar sensor. In addition, the locating device 56 to a distance sensor 62nd For locating objects enclosed in a medium, the locating device 56 is performed 60 existing balls or rollers 64 via a surface 65 of a medium, in the embodiment of Fig. 2, a wall 66 by means of the unit or enclosure. An enclosed in the medium object would thereby by a corresponding

p0062Sensor located. In addition to the Completed position sensor enables the distance sensor 62 to detect the contact of the measuring device 56 with the wall 66 and ensure a predetermined minimum distance of the measuring device.

p0063The distance sensor 62 of the locating device according to the invention shown in FIG. 2 has a capacitive sensor 68, which can build up an electric or electromagnetic field between its two capacitor elements 70 and 72 by means of a corresponding control electronics of the device. The two electrodes of the measuring capacitor 75 can be composed of any conductive material in every conceivable configuration. Here, special mention should be metal, cables and coils.

p0064The generated by the measuring capacitor 75 field 74 of the locating device is dimensioned so that it at least partially penetrates for bodies put on the wall 66 meter into the wall.

p0065Located at -. As shown in Fig shown 3 - the locating device according to the invention 56 but removed with a minimum distance d from the wall 66, so the electric field reaches 74, the distance sensor 62 no longer or at a negligible share in the wall 66. Due to the different dielectric constant of the introduced into the field 74 medium the capacitance of the measuring capacitor 75 of the distance sensor system changes 62. Such a change of capacitance is measurable and can be used in a direct signal for determining the wall contact or to determine the presence of a minimum distance d from a wall will.

p0066Is locating device according to the invention, for example, a capacitive device or an RF detector so, with appropriate circuit of the apparatus of Measuring capacitor serving also be used as a capacitor 74 of the distance sensor 62, the localization of objects enclosed in a medium. In this case, it is possible advantageously to dispense with various sensors for locating enclosed objects and to Wandkontakt- or Wandnäherung, so that a compact and powerful

p0067Locating device can be realized

p0068The minimum distance d, to be detected by the distance sensor 62 may be determined empirically, for example in advance, so that a corresponding configuration and arrangement of the distance sensor 62 ensures that not only the

p0069Existence of a direct wall contact (see FIG. 2 shows), but also the undershooting of a minimum distance d (see. FIG. 3) can be reliably detected. Capacitive distance sensor systems as shown in FIG. 2 and shown in Fig. 3, but can be also in inductive measuring devices or for example integrate radars.

p0070Figure 4 and FIG. 5 show an alternative embodiment of a distance sensor for an inventive measuring device. The locating device 57 according to Figure 4 or FIG. 5 may be any locating device for detecting enclosed in a medium objects, such as an inductive device, a capacitive device, a mains voltage detector, a high-frequency detector or also a radar unit.

p0071The locating device 57 uses for its distance sensor 62 an optical sensor 80, which is shown in Figure 4 in a schematic way. The sensor 80 includes at least one light source 82, such as a laser or an LED as well as a correspondingly arranged light-sensitive receiver 84, such as a photodiode or a CCD element. The light emitted from the light source 82 light 83 is emitted by a Öffhung 86 in the housing base 30 of the measuring device 57 and reflected, in the case of a wall contact of the locating device 57 from the surface 65 of this wall 66th Light reflected from the wall 66 light passes through a corresponding opening 88 in the bottom 30 of the meter 57 back into the meter and falls there to the light-sensitive receiver 84th

p0072The light-sensitive receiver 84 is detected at a defined angle, the radiation intensity of the light reflected from the wall 66th It is set in the embodiment of Figures 4 and 5, the angle so that only reflected light wall contact in the receiver 84th If the locating device according to the invention 57, as shown in FIG. 5, from the surface 65 of the wall 66 and spaced apart, so the reflected light from the wall 66 of the optical sensor 80 is not reflected back to the receiver 84th In this way, can be evaluated by the receiver 84, for example, by the device's internal control and

p0073detecting evaluation unit of the locating device according to the invention the wall 57 Contact this unit reliably.

p0074For example, in the case of wall contact, as shown in Figure 4, a corresponding optical or acoustic signal is passed on to the user of the positioning device. This signal can be user specific instrument types thus point out that in this case a reference measurement for calibrating this meter is not displayed because the existing wall 66 would falsify the measurement results of the reference or baseline measurement. In the case of capacitive measurement devices, (d = 0) require a calibration on the wall, ie at a vanishing distance, the user can be notified by the signaling of the wall contact that he now just may make a Kaübrationsmessung.

p0075Instead of the optical signal it is also possible in alternative embodiments to use for example an ultrasonic signal for this type of distance sensor.

p0076FIGS. 6 and Fig. 7 show an alternative embodiment of an optical sensor 81 for a distance sensor 62 of a locating device according to the invention. The locating device 58, which may use one or more of the known detection method for locating an object enclosed in a medium, has a distance sensor 62 with focused optics. Here, a light source 90, such as a laser, a laser diode or an LED by a suitable optical system 92, which is represented by a schematic lens 94 in the example of Fig. 6 and 7, a sharp light-emitting point or a light bar or any other appropriate geometrical shape 96 thrown onto the surface 65 of a wall 66th

p0077This spot is 96 with increasing distance of the locating device 58 from the wall 66 increasingly blurred, since the corresponding figure of the optics requirements are 92 no longer met. This blurring is depicted on a wall 66 is evaluated by a corresponding Hchtempfindlichen detector in a suitable form. So can For example, depending on the used detector, the shape of the light signal, ie the shape of the light spot 96, the absolute brightness, and the brightness distribution can be evaluated over the area. By means of a receiving optics 100, which is shown in the embodiment of Figures 6 and 7 also simplified as the lens 102, the detection signal 104 is routed to the receiving detector 98 of the distance sensor 62 of the locating device 58th

p0078Thus, for., Via a stored in the evaluation and control unit of the locating device according to the invention characteristic for the light intensity on the receiving detector approximation of the locating device on a medium, as for example through the wall

p007966 is symbolized in the embodiments, are included and quantified. Falls below locating device according to the invention a minimum distance d from one medium, such as the wall 66, so for example, by the device's internal controller, the internal calibration procedure will be blocked and the device user by a signal, such as a visual or audible

p0080Strobe, are reminded that under the currently present operating conditions, a reference measurement for calibrating the measuring device can not be performed because this due to the existing medium (wall 66) would result in an incorrect measurement.

p0081On the other hand 'can in this way also be clearly detected whether that meter is placed on a wall, so that, for example, capacitive devices, a calibration measurement can be made.

p0082Thus locating device according to the invention enables a method for calibrating a measuring device in which a reference measurement for calibration of the device is carried out only after the carrying out at least one measurement to the detection of a distance d of the measuring device to a surface of a medium. In this way, for example to ensure that the reference measurement is not carried out for calibration of the measuring device, or is terminated if a predefinable

p0083Minimum distance of the measuring device to the surface of a medium is undershot or is undershot during the reference measurement. On the other hand it can also be ensured that a contact of the instrument with the surface of a medium is such that, for example, a reference measurement for capacitive measuring devices can be carried out. Advantageously may be automated such that distance sensor 62 of the measuring devices of the invention that is first automatically checked whether a predeterminable distance d is adhered to a medium, that is, whether, for example, the instantaneous distance D of the locating device is greater at a medium than the predetermined

p0084Minimum distance d, is then performed a reference measurement for calibrating the measuring device and then the successful calibration of the measuring device is shown for example in an optical display of the meter. A user of the locating device according to the invention can begin to detect embedded in a medium objects without need for complex manual calibration can be linked to the measurement.

p0085Besides the described automatic calibration process, more natural way can also be provided in the measuring devices of the invention, such a calibration mode under user control, for example by a key of a

p0086To activate the control panel.

p0087The locating device according to the invention and in particular the distance sensor of such a locating device is not limited to the issues identified in the embodiments forms. In particular, the distance sensor is not limited to a capacitive or optical method. Ultrasonic methods or Radar techniques may also be used. It can, for example, but also mechanical methods, ie all kinds used by mechanical contact detections, for example, switch to the distance sensor of the locating device according to the invention. For example, by placing the device on a wall, a corresponding

p0088Switches are actuated automatically and the shift and the concomitant wall contact is transmitted to the control and evaluation of the measuring device.

p0089The signals of the distance sensor will be no matter of what Wall distance sensors they come in individual cases, by electronic or software technical route from

p0090Locating device evaluated. For example, the control unit of the detection sensor for locating objects enclosed in a medium based on the signals of the distance sensor to decide whether should be calibrated under specific measurement conditions or not. For example, a measurement automation in locating device according to the invention can be integrated, which at the unit not existing wall contact, or a distance which is greater than a minimum distance, are automatically kahbriert. The user is under these conditions at any time an operational, ie calibrated measurement system.

p0091The erfϊndungsgemäße locating device is not limited to the use of an inductive or capacitive sensor for detecting objects enclosed in a medium. Rather, each one known and unknown locating device may be provided with a distance sensor according to the invention.

p0092The locating device according to the invention and the underlying hegende procedures are not limited to use in walls, ceilings and floors. These are to be regarded merely as a non-limiting selection to illustrate the operation.