An arrangement for performing position determination.

(54)

INVENTOR INVENTOR

REPRESENTATIVE TITLE

Mikael Hertzman, Sollentuna SE, Olle Engdahl, Enebyberg SE, Lars at surveying and / or (56) (57)

Geotronics AB, Box 64 182 11 Danderyd SE Rudolf Wiklund, Täby SE, Leif Andersson, Täby SE, Ericsson, Täby SE H Albihns patent agency AB Arrangement to be used for deployment work

CALLED PUBLICATIONS:

SE A 8107684-6 (G01C 1/00), SE B 442 557 (G01S 17/66), DE A 3 324 489 (G01C 3/30), US A 3 865 491 (356-152) SUMMARY: The invention relates to a arrangements for use in surveying and / or launching work. The arrangement has a measuring station (1) with an instrument which is rotatable with motors for targeting a target unit. The arrangement further has a target unit (2) movable by an operator, which with the target unit marks the measurement and / or release points. A benchmark arrangement is indicated by an indicator arrangement (7) on the measuring station when the instrument is directed to the target unit (2). The arrangement assumes a target search mode when the indicator arrangement (7) does not indicate the target cursor arrangement, and assumes a target tracking mode when the indicator arrangement indicates the target cursor arrangement. The target marker arrangement comprises a combination of a first and a second target marker unit. The first comprises a light source (8) located on the target unit (2) directed to the measuring station (1), emitted light beam can be indicated by the indicator arrangement (7) on the measuring station. The second target marker unit comprises a light source (9) located on the measuring station (1), a reflector (11) located on the target unit (2) and the indicator arrangement (7) on the measuring station.

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The numbers in brackets indicate international identification code, INID code. Letters in clamps indicate international document code.

500 856

The present invention relates to an arrangement of the kind set forth in the preamble of claim 1.

In geodesin, it is known technique to measure distances and angles using electro-optic methods to determine the position of measuring points in a current coordinate system. According to a commonly used method, an electro-optic distance measuring instrument (EDM) emits a modulated infrared light beam, which is reflected against a cube corner prism located at the target point and for measurement. The reflected light is received and phase detected, the distance being determined with high accuracy. Vertical angle and horizontal direction to the target point can also be determined by electrical or electro-optic path. It is known technique to have the measuring instrument make repeated measurements and continuously determine the position of a moving target, where the measuring instrument is manually directed to the target.

It is also known technology to have a measuring instrument automatically follow a target by means of a servo drive, which is controlled by a signal transmitted from or reflected against the target.

The object of the invention is to provide a simple and reliable arrangement which, after a measuring instrument has found alignment to a target point, quickly and safely follows the target point whether it is near or far away from the measuring instrument.

This object is achieved with an arrangement according to the invention which has obtained the features of claim 1. Further features of the invention are set forth in the other claims.

The invention thus comprises an arrangement which allows the instrument itself to search for the target point after call and then locks in on the target and follows any movements thereon. The measuring instrument is preferably based on an existing so-called total station, e.g. of the brand Geodimeter®, which measures distances and angles as above. The setting event is

500 856 so depleted that the entire measurement operation with the alignment of the instrument, the start of the measurement, data storage and calculations can easily be completed by a single person, who works with a unit located at the target point. So far, the measurement has to be carried out with a person who has taken care of the measuring instrument and data recording, and a person who has placed a reflector unit on the measuring point. A further advantage of the new procedure is precisely that it is controlled from the actual target point, where important information is available and where decisions are made during the measurement and that the target tracking becomes independent of whether the target unit is near or far from the measuring station.

The invention is described in more detail below with reference to the accompanying drawings, in which: Fig. 1 is a block diagram of one embodiment of the control arrangement included in the invention; Fig. 2 shows a measuring arrangement in work in nature; Fig. 3 is a perspective view of an embodiment. Figure 4 shows another embodiment of part of the arrangement of Figure 1; Figure 5 shows a first embodiment of a detector; and Figure i shows a second embodiment of a detector. .

The invention comprises a measuring instrument unit 1 and a measuring unit 2. As shown in the block diagram of Fig. 1, the measuring instrument unit is provided with two servomotors 3 and 4, each with drive 5 and 5 respectively. 6 for rotation in horizontal and vertical joints. A detector unit 7 is designed to recognize and position a signal emitted from a light emitter 8 at the target unit. The detector unit 7 is also designed to recognize a light signal emitted from a light transmitter 9 located on the measuring instrument unit and reflected against a reflector 11 located at the target unit. A control unit 12 at the measuring instrument unit 1 is connected to a light detector 7 via a conversion unit 13 and receives signals suitable for evaluating the direction of the target, which signals together with the detector's design will be described in more detail below. The measuring unit 2 and the measuring instrument unit 1 are each provided with antenna 15 and 15 respectively. 16 and communication unit 27, 17. The reference 10 in Fig. 3 is a telescope which can be used for manual alignment in cases where

500 856 is desired, and thus does not refer to a unit which falls within the concept of the invention itself.

Instead of -To have a single detector 7 indicating both the light -from the light emitter 8 and from the light emitter 9, the detector 7 may be adapted to detect the light from the transmitter 9_? and another detector unit (not shown) arranged to detect the light from the light emitter 8. The light emitters 8 and 9 can e.g. transmit light within different wavelength ranges and the detectors be provided with light filters adapted to the transmitters 8 and 9 respectively wavelength ranges.

In the embodiment of Fig. 2, the target unit 2 is shown to comprise a rod 20 provided with the antenna 15 and a directional means with a binoculars 21 provided with a vertical angle sensor 22 of the type which automatically emits an electric signal indicating the angular position of the binoculars relative to the vertical. A pendulum-type vertical angle sensor has this feature. Vertical angle sensor 22 is coupled to a control box 23 located on the rod comprising a control unit coupled to a keyboard 25 (see FIG. 1) maneuverable by an operator 26 at rod 20. The operator aligns binoculars 21 with the measuring instrument of the measuring instrument unit and presses a key either at the target means 21, 22 or the box 23, when he thinks the alignment is the right one. The control unit is thus given an indication of reading the vertical angle sensor and issuing a control signal. The digital angle sensor signal is transmitted to the communication unit 27. This can e.g. consist of a radio unit with circuits for modulation and transmission, for example on radius frequency, of angular information and synchronization and control1 signals for transmission via the antenna 15. Other types of transmission arrangements are also conceivable, e.g. transmission via microwave link.

A communication unit 17 (FIG. 1) for receiving and demodulating the signal from the antenna 16 is coupled to the controller 12. This receives the angle information and calculates the vertical angle corresponding to the angle value from the sensor 22 to which the instrument system optical system is to be directed. receiving signal from the light transmitter 8 or reflector 11. This angle becomes 200 gon (180) minus the angle value from the transducer 22. The control unit controls with information from vertical angle Ϋ

500 856 sensor IS (with digitally transmitted signal) via drive unit 5 servomotor 3 to the calculated angle. Adjustment need only be done with such precision that the signal from the light transmitter S or reflector 11 falls within the opening angle of the detector 7. It then controls the drive unit 6 to control the servo motor 4 to rotate the instrument horizontally, while simultaneously reading a horizontal angle sensor 19 with digitally transmitted signal.

The unit 8 of the target unit 2, which emits a light signal, is shown in Fig. 2 located on the directional unit 21, 22, but it may as well be located directly on the rod 20. Preferably the unit 8 comprises an IR diode. The detector 7 of the measuring instrument unit 1 may, in a practical design, have an optical field of view of some or some degrees. The light signal unit 8 may have a scattering angle 1 of about ten degrees. These values ​​are approximate. The values ​​are completely dependent on the range required by the system, ie the practical applications into which the system will be deployed.

Instead of a light transmitting unit 8 located on the rod, the rod may have a reflector and the instrument unit has a light transmitting unit 9 which emits a light signal reflected by the reflector and received by the detector. Both units can also be present at the same time.

Thus, in order for the instrument unit 1 to search and find the target unit, it is oriented vertically to the angle corresponding to the angle from the aiming means 21, 22 as described above. Thus, it only needs to be rotated by the servo drive in a plane around its vertical axis and the instrument unit is rotated by the servo drive around the horizontal until the detector unit 7 perceives the control signal from the light transmitting unit 8 or reflected signal from the unit 11, and the servo drive in the hor in horizontal direction is stopped. If the rotation occurs rapidly, the instrument unit passes the target, but its position can be detected by the controller 12, which first stops and then turns back the unit 1 with the target. Thereafter, the control unit 12 switches to target tracking mode and controls in the Continuation unit 1's servomotors 3 and 4 in a manner that will be described below so that the target is followed.

500 856

As shown in the block diagram of Fig. 4, another way of reducing the search sector and thus the search time is to provide the target means 21, 22 of the target unit 2 with a horizontal directional sensor 28 of e.g. digital compass type. When the target device's directional means is directed at the instrument unit, the compass provides information about the relative direction relative to the north direction of the compass. This measurement value is transmitted via the communication link 15, 16 as well as the command signal and the vertical angle to the instrument unit 1. In the i -fig. 4 The embodiment shown is vertical angular sensor 22 ', which provides digital output, and horizontal directional sensor 28 is connected directly to the control unit 30, which via a communication unit 29 feeds the indicated values ​​to the antenna 15.

The horizontal direction measurement circuit of the instrument unit 1 is regularly related to the north direction of the operator in the instrument set-up, so that in the instrument control unit 12, preferably included as a program in the normal calculating computer of the instrument, the direction to the target can be calculated. The instrument unit now has information on both at what vertical angle and horizontal angle it can locate the target unit and is then aligned so that its detector unit 7 receives control signal from the target unit light transmitter 8 or reflector 11.

In terms of experience, the vertical angle can be determined with greater accuracy than the horizontal direction. The compass display can be disturbed by metal objects in the environment, which give measurement errors, but the compass does however provide information that allows the search to be limited to a limited sector in the horizontal plane. This can significantly reduce the time for searching.

However, there are methods to get an exact horizontal angle measurement from the target unit 2. These are relatively complicated and therefore more expensive than the simple variant described above. If both exact vertical angle measurement and horizontal angle measurement are performed in the target unit, the measurement station is controlled directly with the data transmitted from the target unit.

The described search method can thus utilize both information about the host in the cold angle and the hor in the sonal direction, as shown in fig.

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4th It is, of course, also possible to use only horizontal orientation in the method, set the instrument in the specified horizontal direction and rotate the instrument in vertical direction to search the light transmitter 8 or 9, 11.

There is also another possibility to limit the search angle in the horizontal plane by aiming the instrument unit 1 at portions of the terrain and determining the directions which limit the area of ​​interest to be measured. In each search for a release point, which the instrument unit thereafter does, search only needs to be done within the horizontal angular area defined by the arrangement. Because the instrument does not have to search over a full lap, the setting becomes fast.

When the light detector 7 has indicated signal from the light emitter 8 or the reflector 11, the controller 12 goes into target tracking mode, ie, switches to a program screen to power the setting of the instrument system's optical system towards the target. Two main applications can be distinguished, namely measurement and positioning of fixed targets, and measurement and positioning of moving targets. In the first case of fixed targets, the instrument unit shall lock onto the target unit 2, which is positioned at the current point and leveled, after which distance and angles are measured and the position calculated. When measuring against moving targets, e.g. when launching in construction or hydrography measurements, the instrument unit 1 must follow the movement of the target unit 2 and deliver measurement values ​​from repeated distance and angle measurements, so that the position relative to the desired can be calculated by the instrument's computer, and the information is delivered to an exposer or a vehicle, such as a boat, depending on what applies in the present case. With today's measuring equipment, about 3 position values ​​per second can be given.

Several partially contradictory requirements are placed on a practical system as described above. Measurements must be able to take place both near and far. Moderate requirements for alignment accuracy must be set for the target unit, especially during operator movement during measurement. There are known systems for tracking, which operate under certain conditions. Such a system

500 856 utilizes a rotating modulation in the periphery around the instrument's own measuring beam and is described in Swedish Patent No. 8402723-4. This system -While works perfectly satisfactory but is relatively expensive to put into equipment for launching purposes etc.

According to the invention, the tracking system has been designed so that accurate measurement is allowed, while at the same time simplifying the operator's operation at both short and long distances. The device can be built up with a so-called active system, or with a so-called passive, or both of these methods can be used to optimize the function. By active or passive system is meant that the target unit 2 is active or passive as a transmitter.

The active system comprises the light emitter 8, which cooperates with the light detector 7. According to the preferred embodiment, the light emitter 8 is an IR-type LED, which is directed at the instrument unit 1. Its lobe angle, i.e. scattering of the light, can in practice be e.g. ± 10 gon to achieve a range of a few hundred meters at normal sensitivity and signal-to-noise ratio for existing detector material. This means that the operator must direct the target unit 2 within approx. + 10 gon to the instrument unit 1.

The active system is advantageously used in relatively short distances as this can be arranged parallax-free, since it allows a good point definition, ie the illuminating point to which the instrument unit is directed can be given a small extent.

In the detector unit 7 of the instrument unit 1, the received light is focused on a semiconductor type detector. Two embodiments of this detector are shown in Figures 5 and 6. The detector in Figure 5 is formed with a number of segments 31, 32, 33, 34 to determine the position of the incident light. At least three segments are needed to detect deviations in both lateral and vertical directions, but the easiest is to use four segments as in Fig. 5. Each segment is divided into sectors, e.g. 32a, 32b, 32c for the sector 32, radially outside each other for the control unit 12 to be able to determine the degree of outward deviation. Once the target tracking is established and the incident light is kept centered on the central part of the detector, the outer segments 32c and others can. coupled

500 856 away. Then a better signal-to-noise ratio is obtained. An error signal is generated, which is a measurement of the alignment error of the instrument unit against the target unit and used by the controller 12 to power the instrument unit 1 against the target unit 2 so that the light signal of the light emitter 8 should fall as centrally as possible on the light detector 7.

The detector in -Fig. 6 is shown square, but can also be rectangular, and comprises four internal detector units 35 - 38 assembled around a central point C and surrounded on the outside by each external detector unit 39 - 42. In this type of detector, the control unit 12 also controls the instrument unit 1 against the target unit. , so that the light signal of the 1 transmitter 8 falls as centrally as possible on the detector.

The unit 13 in Fig. 1 is designed to detect the segment and sector within the segment hit by the light and output a signal to the controller indicating this.

In the passive system, the light emitter 9, preferably a light emitting diode, is used on the instrument unit 1. The light of the light emitter 9 is reflected against the in this case passive unit cube corner prism 11 on the target unit 2. The prism reflects the light within a space angle of about 25 gon, as determined in the no-directional requirement. . The transmitter diode 9 in this case may have a narrow lobe, which gives longer reach.

Thus, the advantages of the passive system are to be able to be used at long distances and to be relatively insensitive to the alignment, since the transmitted and received beam are almost parallel to each other within a large space-angle range, as the reflections on the target unit 2 take place against a cube corner prism.

The passive and active system can also be used simultaneously. The light of the transmitter diodes 8 and 9 can be modulated at different frequencies and the same detector 7, as shown in Fig. 1, can be used, since then the two control signals can be selected from the detector's output signals. Thus, both systems are not used simultaneously in and for the control, but a comparison and discrimination of one system is ongoing. The advantage of using

500 856 both systems at the same time -For detection, you are almost certain to have encountered a correct target when signal is present simultaneously from both systems. As a result, reflections from sources other than the target unit 2 can be excluded.

Preferably, the radiation is received from the radiation sources 8 and 9 on the same detector. For example, since the radiation source 1s 8 and 9 are modulated at different frequencies, their outputs from the detector 7 can be distinguished. During the target search mode, the light from the light emitter 8 is preferably used for indication. It is far more difficult to find a reflex from a reflector than the light from a separate light emitter at the target point, although it is also possible to use as a complement or alternative the system 9, 11, 7 also for the target search operation. Thus, during the target search mode, the modulation frequency in the signals from the detector 7 arising from the modulation of radiation source 9 is preferably written. Only signals from the detector 7 parts emanating from incident light from the radiation source 8 are fed to the controller by the transducer and the scrambler 13. As soon as a portion of the detector 7 has emitted an indication signal, the control and calculation unit 12 receives an indication that it is time to switch to målföljningsmod.

During the target tracking mode, signals from the detector 7 originating from one or both radiation sources are fed to the controller 12. This individually indicates the hit points of the light detector by the radiation from the light sources 8 and 9. It uses the directional signals from the light source 8 to continuously control the instrument's motors 3 and 4 for alignment with the target, if the indicated difference in hit point exceeds a predetermined value, e.g. lies within different segments of the sectors horizontally upwards or downwards, which implies troublesome parallax for the passive system. Otherwise, the directional signal obtained from the passive system for this control is utilized.

Many modifications are possible within the scope of the invention. For example, the whorls specified in the text in Zone 1a and the vertical directions may be interchanged.

500 856