RANGEFINDER FOR A SPYGLASS

Description

[0001] The invention relates to an electro-optical rangefinder and a method for measuring the distance of an object with an electro-optical rangefinder according to the preambles of claims 1, 15 and 18.

[0002] Electro-optical rangefinders for use in leisure activities or sporting activities are already known and can be designed as a stand-alone device or integrated into a binocular.

[0003] For example, document US 2020 / 077 075 discloses the monitoring of industrial environments in which humans and machines interact or come into close proximity. In particular, it describes systems and methods for monitoring work areas using 3D cameras. Their images also contain pixel-by-pixel distance values of surface points from objects in the monitored scene.

[0004] Document EP 2 378 245 discloses a binocular observation device or pair of binoculars with a laser rangefinder having a laser transmitter and a laser receiver, and with two optical beam paths. The two observation beam paths are each formed by an objective lens, an eyepiece, a focusing device, and a prism reversing system. Part of the optical path of the laser receiver is integrated into one of the optical beam paths.

[0005] Document EP 3 339 901 discloses a distance measurement method and an electronic laser distance measurement module for fast signal acquisition using an analog-to-digital converter. Conversion errors occurring during signal digitization are to be compensated for by varying the sampling times.

[0006] The object of the present invention is to provide a rangefinder and a method for measuring the distance of an object, which enables a greater range and more flexible use.

[0007] This object is achieved by a binocular telescope according to the claims.

[0008] The telescope generally comprises an electro-optical rangefinder with a transmitter and a transmission beam path and with a first receiver and a first receiver beam path, wherein the first receiver beam path runs at least partially in a first observation beam path of the telescope, and wherein a second receiver is formed with a second receiver beam path which is aligned parallel to the transmission beam path, and wherein the second receiver beam path is arranged at a distance from the first observation beam path of the telescope.

[0009] According to the invention, it is provided that the second receiver beam path runs at least partially in a second observation beam path of the telescope.

[0010] It is also advantageous if the transmit beam path runs at least partially in the first observation beam path of the telescope. These measures can ensure that the parallel alignment of the two observation beam paths, the two receiver beam paths, and the transmit beam path can be maintained more reliably. This also allows for less effort in adjusting the beam paths for parallelism during rangefinder manufacturing.

[0011] According to the invention in a first alternative it is further provided that the distance meter comprises evaluation electronics with an oscillator for generating a clock signal, with a first ADC (analog-digital converter) for the first receiver and with a second ADC for the second receiver.

[0012] According to this alternative, the first ADC is designed to generate digital values of a first intensity profile of reflected radiation IR1(t1 n ) detected by the first receiver at times t1 n determined by the clock signal, and the second ADC is designed to generate digital values of a second intensity profile of reflected radiation IR2(t2 n ) detected by the second receiver at times t2 n determined by the clock signal.

[0013] The feature of the rangefinder, according to which the evaluation electronics includes a phase shifter for generating a variable time difference Δt v between the times t1 n of activation of the first ADC and the times t2 n of activation of the second ADC, has the advantage that it synchronizes the two receivers and thus allows them to be effectively connected to form a single receiver.

[0014] The further development is also advantageous, whereby the phase shifter includes a phase-locked loop (PLL).

[0015] According to an alternative embodiment of the rangefinder, the phase shifter comprises a delay line with a defined line length.

[0016] Another advantageous embodiment of the rangefinder is one in which it is equipped with a control device with a processor, preferably an FPGA (Field Programmable Gate Array). A processor can be any electronic component that can be programmed and evaluate data, such as an ASIC, a microcontroller, a microprocessor, or a digital signal processor (DSP).

[0017] In an advantageous further development, the distance meter is designed with an operating terminal connected to the control device, wherein the operating terminal is suitable for selecting different operating modes.

[0018] It proves to be particularly advantageous if a first operating mode, in which the digital values of the detected radiation intensities of the two receivers are added in a synchronized manner to form a sum value, and a second operating mode, in which the sampling of the reflected radiation intensity by the two receivers takes place alternately, phase-shifted by half a period T, are designed.

[0019] According to a second alternative of the distance meter according to the invention, it is provided that it comprises evaluation electronics with an oscillator for generating a clock signal, with a summing amplifier for adding the measurement signals from the two receivers to a sum signal and with an ADC for converting the sum signal.

[0020] By further developing the rangefinder, in which a phase shifter is arranged between the first receiver and the summing amplifier, a reduction of measurement errors can be achieved.

[0021] Particularly advantageous is the design of the distance meter in which the phase shifter comprises a delay line with a defined line length.

[0022] Also disclosed is a method for measuring the distance of an object using an electro-optical rangefinder, wherein radiation is emitted by a transmitter and the radiation is directed onto the object through a transmission beam path, and wherein radiation reflected from the object is detected by a first receiver, and wherein a time-varying intensity profile of the reflected radiation IR1(t) detected by the first receiver is recorded, and wherein the distance of the object is calculated from a travel time of the radiation from the transmitter to the first receiver, and wherein radiation reflected from the object is detected by a second receiver and a time-varying intensity profile of the reflected radiation IR2(t) detected by the second receiver is recorded.A first ADC generates digital values of the first intensity curve IR1(t1 n ) from the first intensity curve IR1(t) at times t1 n determined by a clock signal. And a second ADC generates digital values of the second intensity curve IR2(t2 n ) from the second intensity curve IR2(t) at times t2 n determined by the clock signal, whereby the times t2 n are phase-shifted from the times t1 n by a time difference Δt, i.e. t2 = t1 + Δt, whereby the time difference Δt is made up of a system-dependent component Δt s and a variable component Δt v and thus Δt = Δt s + Δt v . The components Δt s and Δt v as well as Δt can assume both positive and negative values.

[0023] Particularly advantageous is the procedure according to which a value of the variable time difference Δt v is chosen to be so large that the times t1 n and t2 n each correspond to an identical time of the intensity curves of the reflected radiation IR1(t), IR2(t) at the first receiver and at the second receiver, and that subsequently the values of the first intensity curve IR1(t1 n ) and the values of the second intensity curve IR2(t2 n ) = IR2(t1 n ) are each added to one another.

[0024] According to an alternative procedure, a value of the variable time difference Δt v is chosen to be so large that the times t1 n and t2 n each correspond to times of the intensity curves of the reflected radiation IR1(t), IR2(t) at the first receiver and at the second receiver, which are phase-shifted from one another by the value of half a period T of the clock signal. Then, from the values of the first intensity curve IR1(t1 n ) and from the values of the second intensity curve IR2(t2 n ), an overall intensity curve IR(tn ) with twice the temporal resolution is formed in the form IR1(t1 n ), IR2(t1 n +T / 2), IR1(t1 n+1 ), IR2(t1 n+1 +T / 2), IR1(t1 n+2 ), IR2(t1 1+2 +T / 2), etc.

[0025] Finally, a method for measuring the distance of an object using an electro-optical rangefinder is disclosed, wherein radiation is emitted by a transmitter and the radiation is directed onto the object through a transmission beam path, and wherein radiation reflected from the object is detected by a first receiver, and wherein a time-varying intensity profile of the reflected radiation IR1(t) detected by the first receiver is recorded, and wherein the distance of the object is calculated from a travel time of the radiation from the transmitter to the first receiver.In this case, radiation reflected from the object is detected by a second receiver and a time-varying intensity profile of the reflected radiation IR2(t) detected by the second receiver is recorded, wherein measurement signals from the first receiver are phase-shifted by a variable time difference Δt v relative to measurement signals from the second receiver.

[0026] Particularly advantageous is the procedure in which a value of the variable time difference Δt v is chosen to be so large that times corresponding to the measurement signals IR1(t) and IR2(t) each correspond to an identical time of the intensity curves of the reflected radiation IR1(t), IR2(t) at the first receiver and at the second receiver, and that the measurement signals of the intensity curves of the reflected radiation IR1(t) and IR2(t) are then added to a sum signal by a summing amplifier.

[0027] For a better understanding of the invention, it is explained in more detail using the following figures.

[0028] They show in a highly simplified, schematic representation: Fig. 1 an electro-optical rangefinder in the form of a binocular; Fig. 2 a simplified circuit diagram of the control and evaluation unit of the rangefinder according to Fig. 1 ; Fig. 3 a schematic representation of the functional principle of electro-optical distance measurement; Fig. 4 a diagram of the radiation intensity curve of the emitted laser pulse and the reflected radiation pulse; Fig. 5 an enlarged section of the intensity curve of the reflected radiation pulse, according to Fig. 4 ; Fig. 6 a schematic representation of the digital measured values according to the first operating mode of the rangefinder; Fig. 7 a section of the intensity curve of the reflected radiation pulse, according to Fig. 4 , at double sampling rate; Fig. 8 a schematic representation of the digital measured values when operating with double sampling rate, according to Fig. 7 ; Fig. 9 an alternative embodiment of the rangefinder; Fig. 10 an alternative embodiment of the control and evaluation unit of the rangefinder; Fig. 11 a simplified representation of the control and evaluation unit of the rangefinder, according to Fig. 2 .

[0029] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these positional information must be applied analogously to the new position in the event of a change in position.

[0030] The Fig. 1 shows an electro-optical rangefinder 1 in the form of a binocular. This has a first observation beam path 2 in a first tube, which extends between an objective lens 3-1 and an eyepiece 4-1. Furthermore, an inversion system 5-1 formed by a prism system and a focusing lens 6-1 are arranged along the path of the observation beam path 2 in a manner known per se. A second observation beam path 7 formed in an analogous manner is provided parallel to the first observation beam path 2.

[0031] The electro-optical rangefinder 1 comprises a transmitter 8 and a first receiver 9, wherein a transmission beam path 10 of the transmitter 8 and a first receiver beam path 11 of the first receiver 9 extend at least partially within the first observation beam path 2. For this purpose, radiation emitted by the transmitter 8 is coupled into the first observation beam path 2 with the aid of a splitter prism 12 at an interface of the reversing system 5-1 in a manner known per se. This occurs in such a way that the radiation is emitted through the objective lens 3-1 toward a distant object. In the opposite direction, radiation reflected by the distant object then passes through the objective lens 3-1 into the first observation beam path 2 and is decoupled from the first observation beam path 2 at an interface of the reversing system 5-1. The radiation finally passes through the first receiver beam path 11 to the receiver 9, which detects the radiation.

[0032] According to this exemplary embodiment, the binocular or rangefinder 1 additionally has a second receiver 13, which is arranged in the second tube of the binocular and is coupled to the second observation beam path 7. In the same way as in the first observation beam path 2, radiation reflected from a distant object reaches the second receiver 13 through a second receiver beam path 14, with the radiation initially entering the second observation beam path 7 of the binocular through the objective 3-2 of the second tube. The reflected radiation is coupled out of the second observation beam path 7 at an interface of the inversion system 5-2.

[0033] The rangefinder 1 comprises a control and evaluation unit 15 for controlling the transmitter 8 and for detecting the measurement signals from the two receivers 9, 13.

[0034] The Fig. 2 shows the control and evaluation unit 15 of the distance meter 1 according to Fig. 1 , shown as a simplified circuit diagram. To measure the distance of a distant object, the control and evaluation unit 15 of the rangefinder 1 causes the emission of radiation from the transmitter 8 in the direction of the distant object. The distance is then calculated from the difference between the times of emission of the radiation and the arrival of the radiation reflected from the distant object at the receivers 9, 13 ( Fig.3, 4 ). For this purpose, the control and evaluation unit 15 comprises a control device 16, which controls the measurement sequence and performs the evaluation. Such a measurement process is initiated at the instigation of a user who, for this purpose, sights the object to be measured with the binoculars or with the rangefinder 1 and starts the measurement by pressing a corresponding switch.

[0035] According to this embodiment of the electro-optical rangefinder 1, the transmitter 8 is formed by a laser. The radiation from the transmitter 8 is emitted in the form of short laser pulses 24 ( Fig.3, 4 Avalanche photodiodes are provided as receivers 9, 13. The intensity profiles of the reflected radiation detected by these receivers 9, 13 are, after appropriate amplification (with amplifiers 17, 18), fed as analog measurement signals for digital evaluation by the control device 16. The radiation detected by the receivers 9, 13 naturally contains, in addition to the reflected radiation of the emitted laser pulses, also components of ambient light (reflected radiation pulse 25, Fig. 4 ), which cause a large amount of noise and complicate evaluation. With the help of a first ADC 19 and a second ADC 20 (ADC ... analog-to-digital converter), the analog measurement signals of the intensity curves from the receivers 9, 13 are converted into digital values or digital measurement data. For this purpose, the control and evaluation unit 15 of the rangefinder 1 comprises an oscillator 21 for generating a clock signal. This clock signal from the oscillator 21 determines discrete times at which the analog measurement signals from the receivers 9, 13 are sampled using the first ADC 19 and the second ADC 20.

[0036] By additionally using the second receiver 13 in the second tube of the binocular or the rangefinder 1, the advantage of an approximately twice as large effective reception area of the receivers 9, 13 can be achieved by summing their measurement signals from the reflected radiation. With the same power of the transmitter 8, this can result in a corresponding increase in the maximum range of the rangefinder 1. With regard to the possibility of correctly summing digital measurement data from the two analog-to-digital converters (first ADC 19, second ADC 20), possible differences in the signal propagation times to the two analog-to-digital converters must be taken into account. Such differences can arise, for example, from different cable lengths between the receivers 9, 13 and the respective analog-to-digital converters ADC 19, 20 in the control device 16.However, possible differences in the specific electronic components themselves must also be taken into account, such as the avalanche photodiodes of the receivers 9, 13 as well as the amplifiers 17, 18, which may have different time delays due to their design. This means that a digital value of the intensity of the reflected radiation IR1(t1 n ) generated by the first ADC 19 at a time t1 n predetermined by the clock signal of the oscillator 21 actually corresponds to an earlier time corresponding to the signal propagation time and / or due to different delays in the electronic components (resulting in a total system-related delay Δt s ) and is to be assigned to this earlier time. This also applies in the same way to a digital value of the intensity of the reflected radiation IR2(t2 n ) generated by the second ADC 20.

[0037] In the electro-optical rangefinder 1, the invention provides that the control device 16 comprises a phase shifter 22 for generating a variable time difference Δt v between the times t1 n of activation of the first ADC 19 and the times t2 n of activation of the second ADC 20. In this way, it can be achieved that digital values of the first ADC 19 and the second ADC 20 are each added to one another to form a sum value, which corresponds to the intensities of the reflected radiation detected by the first receiver 9 and the second receiver 13 at the same time.

[0038] The use of the phase shifter 22 to generate the variable time difference Δt v thus synchronizes the digital measurement signals received by the first receiver 9 and the second receiver 13. This prevents radiation intensity values detected at different times by the first receiver 9 and the second receiver 13 from being mistakenly added together to form a total value. Only then do the two receivers 9, 13 effectively function as a single receiver with a receiving area approximately twice as large.

[0039] To clarify this, reference is made to the Fig. 11 Reference is made to the components of the control and evaluation unit 16 of the distance meter 1 ( Fig. 2 ) corresponding times or intensities are provided. Using the notation Δt v for the variable time difference generated by the phase shifter 22 and Δt s for the system-related time delay, the relationships can be described as follows. If the intensities IR1(t1) and IR2(t2) are to be added together correctly, they should have been detected by the receivers 9, 13 at the same time, i.e. t2 = t1. Due to the system-related time delay Δt s, however, the intensity IR2(t2') for the second receiver 13 would now be at a different time t2' = t1 + Δt s . Taking into account the variable time difference Δt v generated by the phase shifter 22, the value of the time t2 is t2 = t2' + Δt v . This further results in t2 = t2' + Δt v = t1 + Δt s + Δt v .

[0040] Based on this relationship, in order to fulfill the condition t2 = t1, Δt v = -Δt s must hold. This expresses the fact that the system-related time delay Δt s is compensated by the variable time difference Δt v generated by the phase shifter 22, and thus Δt = 0.

[0041] According to a preferred embodiment of the electro-optical rangefinder 1, the control device 16 comprises a so-called FPGA (Field Programmable Gate Array). In addition to the control, the FPGA can also perform the evaluation of the measurement signals, including the calculation and display of the distance. A so-called phase-locked loop (PLL) is preferably used as the phase shifter 22. Alternatively, the phase shifter 22 can also be implemented as a digital PLL, abbreviated to DPLL. It is also possible for the PLL to be included in the FPGA. According to an alternative embodiment, the phase shifter 22 comprises a delay line.

[0042] The electro-optical rangefinder 1 comprising the first receiver 9 and the second receiver 13 is used to measure the distance of a distant object in such a way that the first ADC 19 generates digital values of the first intensity curve IR1(t1 n ) from the first intensity curve IR1(t) at times t1 n determined by the clock signal of the oscillator 21, and the second ADC 20 generates digital values of the second intensity curve IR2(t2 n ) from the second intensity curve IR2(t) at times t2 n determined by the clock signal, the times t1 n being phase-shifted from the times t2 n by a time difference Δt, the time difference Δt being made up of a system-dependent component Δt s and a variable component Δt v .The values of the first intensity curve IR1(t1 n ) and the values of the second intensity curve IR2(t2 n ) are recorded by the control device 16 and then each added to form a sum value. The digital data thus obtained of the time-varying intensity curve of the reflected radiation from the receivers 9, 13 then form the basis for calculating the distance from the radiation's travel time from the transmitter 8 to the receivers 9, 13. The recording and further processing of the digital measurement data and the subsequent calculation of the distance from this measurement data are carried out by the control device 16 based on corresponding programs stored in the control device 16.

[0043] In the described procedure according to the first embodiment, digital data of the detected radiation intensity are added at identical times to form a sum value. The temporal sequence of radiation intensity values IR1(t1 2 ), IR1(t1 n+1 ), IR1(t1 n+2 ), ..., also referred to as a digital signal vector, has a temporal resolution corresponding to a period T of the clock signal of the oscillator 21. This also applies analogously to the temporal sequence of the radiation intensity values IR2(t2 n ), IR2(t2 n+1 ), IR2(t2 n+2 ), ... of the second ADC 20. The same temporal resolution also has the sequence of the added intensity values of the summed digital signal vector IR1(t1 1 ) + IR2(t1 n ), IR1(t1 n+1 ) + IR2(t1 n+1 ), IR1(t1 n+2 ) + IR2(t1 n+2 ), etc.

[0044] According to an alternative embodiment of the electro-optical rangefinder 1, an additional phase shift of half a period T of the clock signal of the oscillator 21 is provided when generating the digital values of the intensity profile of the reflected radiation by the first ADC 19 and the second ADC 20. In contrast to the first described embodiment of the method, no addition of digital data from the first ADC 19 and the second ADC 20 takes place. Instead, the control device 16 forms a digital signal vector with twice the temporal resolution from the digital signal vectors of the first ADC 19 and the second ADC 20.This means that the times at which the digital values of the radiation intensities are sampled by the first ADC 19 and the second ADC 20 are interleaved by the phase shifter, resulting in a digital signal vector in the form IR1(t1n), IR2(t1n+T / 2), IR1(t1n+1), IR2(t1n+1+T / 2), IR1(t1n+2), IR2(t1n+2+T / 2), ... This thus contains a sequence of digital values of the radiation intensity detected by the first receiver 9 and the second receiver 13, with values from the first ADC 19 and the second ADC 20 alternating one after the other. In this way, the temporal intensity profile of the reflected radiation is effectively recorded at a sampling rate twice as high as the frequency of the clock signal from the oscillator 21. On the basis of the digital signal vector thus generated with double sampling rate, the control device 16 then calculates the value of the distance.

[0045] Again, taking into account the symbolic representation of Fig. 11 The formal relationships can be expressed as follows. The intensities IR1(t1) and IR2(t2) detected by the two receivers 9, 13 are assumed to have been recorded at times t1 and t2 which differ from one another by half the period T of the clock signal of the oscillator 21, i.e. t2 = t1 + T / 2, thus Δt = T / 2. Taking into account the system-related time delay Δt s and the variable time difference Δt v generated by the phase shifter 22, as already considered in the description of the first mode of operation, in this case one obtains t2 = t1 + Δt s + Δt v = t1 + T / 2.

[0046] This results in the value for the variable time difference to be generated by the phase shifter 22 being Δt v = T / 2 - Δt s .

[0047] According to a preferred embodiment of the electro-optical rangefinder 1, it is designed for the selective execution of different operating modes. For this purpose, the rangefinder 1 has a keyboard or operating terminal 23 that is connected to the control device 16. A user of the rangefinder 1 thus has the option of switching the rangefinder 1 back and forth between different operating modes by determining the execution of a corresponding program by the control device 16 via the keyboard 23.In addition to the previously described operating modes of the rangefinder 1, namely the one in which the digital values of the detected radiation intensities of the two receivers 9, 13 are added to form a total value, and the one in which the reflected radiation intensity is alternately sampled with a phase shift of half a period T, it is also possible to perform the distance measurement using only the second receiver 13 in the second observation beam path 7. This means that in this third operating mode of the rangefinder 1, the first receiver 9 in the first observation beam path 2 is deactivated and not used. This third operating mode of the rangefinder 1 proves particularly advantageous when measuring the distance of objects at a relatively short distance.So-called optical crosstalk, which can occur between the transmitter 8 and the first receiver 9, which are located in the same first observation beam path 2, is thereby avoided, which makes it easier to prevent incorrect measurements.

[0048] For the described electro-optical distance measurement, a plurality of laser pulses is preferably emitted by the transmitter 8. The laser pulses are emitted at a high frequency of, for example, 56 kHz. By summing the reflected radiation from many individual pulses, such as over 1024 individual measurements, the quality of the measurement signal is significantly improved and evaluation is facilitated. The evaluation is performed as with a measurement using a single pulse, but after summation and applied to the combined signal.

[0049] In the described embodiments, a frequency value of oscillator 21 of preferably 80 MHz is provided. According to this frequency, the reflected radiation or laser pulses are sampled with a temporal resolution of T = 12.5 ns.

[0050] Based on the Fig. 3 und 4 The basic operating principle of electro-optical distance measurement is briefly illustrated. An object (tree) located at a distance D is measured by the rangefinder 1 by the transmitter 8 emitting a laser pulse 24 through the transmission beam path 10 toward the object. A reflected radiation pulse 25, reflected by the laser pulse, then returns to the rangefinder 1 via the receiver beam path 11 and is detected by the receiver 9. The times of emission of the laser pulse 24 and reception of the reflected radiation pulse 25 determine a pulse transit time 26, the product of which with the speed of light is known to be equal to twice the value of the distance D of the object to be measured.

[0051] The Fig. 4 shows a diagram of the time course of the radiation intensity of the emitted laser pulse 24 and the reflected radiation pulse 25 in their temporal relationship to each other. As can be seen from the representation of the reflected radiation pulse 25 in the Fig. 4 As symbolically indicated, in addition to a portion of the radiation from the reflected laser pulse 24, this also contains components originating from natural ambient radiation as an interference signal. The end of the pulse propagation time 26 is therefore referred to a point in time in the region of the maximum intensity of the reflected radiation pulse 25. This relatively high proportion of interference signals in the intensity curve of the reflected radiation pulses 25 makes it necessary to repeat the measurement of the reflected radiation with a large number of laser pulses 24. By summing them accordingly over many individual measurements, the noise or the interference signal component can be reduced. In other words: The signal-to-noise ratio (SNR) in the measured intensity curve is thereby significantly increased.

[0052] The Fig. 5 shows a greatly enlarged section of the intensity curve of the reflected radiation pulse 25 in the area of the maximum of its intensity curve, according to Fig. 4 . On the curve of the reflected radiation pulse 25, points are highlighted by symbols, which correspond to a measurement by sampling with the analog-digital converters ADC 19 and ADC 20. Between measuring points of the first ADC 19 (symbol: circle) and measuring points of the second ADC 20 (symbol: triangle) there is a time interval equal to the time difference Δt s . This time difference Δt s corresponds to the time difference Δt s used in connection with the description of the Fig. 2 mentioned system-related difference in the signal propagation times between the two receivers 9, 13 and the respective analog-digital converters ADC 19, 20 of the rangefinder 1. In the case of the application of the first operating mode of the rangefinder 1, the phase shifter 22 generates a correspondingly large time difference Δt v , by means of which it is achieved that digital values of the first ADC 19 and the second ADC 20 can each be added together to form a sum value, which corresponds to the intensities of the reflected radiation detected by the first receiver 9 and the second receiver 13 at the same time. By means of the phase shifter 22, the Fig. 5 shown time intervals are thus reduced to zero. Furthermore, a time difference Δt can also be related to the period T of the clock signal of the oscillator 21, wherein a full phase duration or the period T corresponds to the full angle of 360°. A correction with the phase shifter 22 is preferably carried out when the phase shift corresponding to the time difference Δt s is greater than 10°, preferably when it is greater than 15°. In the case of a phase shift of less than 20°, compensation can also be omitted.

[0053] The Fig. 6 shows a schematic representation of the digital measured values of the reflected radiation pulse 25 in the operating mode of the rangefinder 1, in which the digital values of the detected radiation intensities of the two receivers 9, 13 are each added to a sum value. During sampling by the analog-digital converters ADC 19 and ADC 20, the generation of the time difference Δt v by the phase shifter 22 is taken into account ( Fig. 2 ). In the table according to Fig. 6 The first line, "DSV 1," symbolizes the digital signal vector of the first ADC 19 with the digitized radiation intensity values IR1(t 11 ), IR1(t 12 ), IR1(t 13 ), ...., and the second line, "DSV 2," symbolizes the signal vector of the second ADC 20 with the radiation intensity values IR2(t 21 ), IR2(t 22 ), IR2(t 23 ), .... Finally, the third line, "DSV SUM," shows the summed digital signal vector with the values IR(t 1 ), IR(t 2 ), IR(t 3 ), .... The time interval within each line, from measured value to measured value, corresponds to the clock signal of the oscillator 21, i.e., the period T.

[0054] As in Fig. 6 As shown, similarly measured and digitized intensity curves of many individual and successive pulse responses are summed to a sum signal vector before determining the pulse transit time 26 in order to average out the noise and increase the SNR.

[0055] The Fig. 7 shows a section of the intensity curve of the reflected radiation pulse 25, according to Fig. 4 , to illustrate the mode of operation of the rangefinder 1, in which the sampling of the reflected radiation pulses 25 with the first ADC 19 and the second ADC 20 takes place alternately, each phase-shifted by half a period T. In this mode of operation (according to the second embodiment of the electro-optical rangefinder 1), there are time intervals of the length of half a period T of the clock signal of the oscillator 21 between the times of sampling the digital values of the radiation intensities of the reflected radiation pulse 25. To illustrate this, digital data of the first ADC 19 are indicated by a circle symbol and digital data of the second ADC 20 by a triangle on the curve of the reflected radiation pulse 25.

[0056] The Fig. 8 shows a symbolic representation of the digital values or the digital signal vectors, as they are also shown in the Fig. 7 described situation corresponds to the second operating mode of the distance meter 1. In the tabular scheme, the first row shows the digital data (e.g. 8-bit values) of the measured values of the first digital signal vector "DSV 1" and the second row shows the digital data of the measured values of the second digital signal vector "DSV 2". The temporally alternating sequence of the values of the first digital signal vector DSV 1 and the values of the second digital signal vector DSV 2 is represented by a lateral offset between the first and second row in the Fig. 8 indicated. Finally, the control device 16 or the FPGA generates an entire digital signal vector "DSV," wherein the values of this digital signal vector DSV are formed by interleaving or nesting the values of the first and second digital signal vectors DSV 1 , DSV 2 . This resulting digital signal vector DSV corresponds to a measurement of the intensity profile of the reflected radiation pulse 25 at a sampling rate twice the frequency of the clock signal of the oscillator 21.

[0057] The method described above for improving the measured signal by summing many individual measurements is, of course, also possible in combination with the two new operating modes. This is done by first operating the two ADCs in the different operating modes as described, and then calculating the resulting individual DSVs ( Fig. 6 : DSV SUM or Fig. 8 : DSV) are summed again to form a new sum signal vector.

[0058] The Fig. 9 shows an alternative embodiment of the electro-optical rangefinder 1 in the form of a binocular. The first receiver beam path 11 of the first receiver 9 extends at least partially in the first observation beam path 2 of the first tube of the binocular, and analogously, the second receiver beam path 14 of the second receiver 13 extends at least partially in the second observation beam path 7 of the second tube of the binocular. According to this embodiment, the transmit beam path 10 of the transmitter 8 of the rangefinder 1 is arranged at a distance from the two observation beam paths 2, 7. According to the illustration in Fig. 9 The transmitter 8 is arranged approximately centrally between the two tubes of the binocular. Preferably, the transmitter 8 is arranged or aligned coaxially with a joint axis 27 of a joint bridge of the binocular. By means of beam splitters, such as boundary surfaces of the inversion systems 5-1, 5-2 acting as beam splitters, reflected radiation pulses 25 are decoupled from the observation beam paths 2, 7 and reach the receivers 9, 13, by which they are detected. Measurement signals from the receivers 9, 13 are finally further processed by the control and evaluation unit 15. With the rangefinder 1 according to the embodiment of the Fig. 9 It is possible to carry out measurements in the same way as described above as the first and second operating modes.

[0059] The Fig. 10 shows an alternative embodiment of the control and evaluation unit 15 of the distance meter 1, shown as a simplified circuit diagram. In the same way as in the embodiment described with reference to Fig. 2 As described above, intensity profiles of the reflected radiation or reflected radiation pulses 25 are detected by the receivers 9, 13. According to this exemplary embodiment of the rangefinder 1, the analog signals from the receivers 9, 13 are added to a summing signal after amplification (amplifiers 17, 18) by a summing amplifier 28. This analog summing signal is then converted into a digital signal by the ADC 19. In this exemplary embodiment of the electro-optical rangefinder, the phase shifter 22 is arranged between the first receiver 9 or the first amplifier 17 and the summing amplifier 28. The variable time difference Δt v generated by the phase shifter 22 thus also achieves synchronization of the analog measurement signals received by the first receiver 9 and the second receiver 13. The phase shifter 22 preferably comprises a delay line.

[0060] The embodiments show possible embodiments, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments with each other are also possible and this possibility of variation lies within the skill of the person skilled in the art in this technical field due to the teaching of technical action by means of the objective invention.

[0061] The scope of protection is determined by the claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the various embodiments shown and described may represent independent inventive solutions. The problem underlying these independent inventive solutions can be derived from the description.

[0062] All information on value ranges in this description is to be understood as including any and all sub-ranges thereof, e.g. the information 1 to 10 is to be understood as including all sub-ranges starting from the lower limit of 1 and the upper limit of 10, ie all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0063] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure, some elements have been shown out of scale and / or enlarged and / or reduced in size. Bezugszeichenaufstellung

[0064] 1 Rangefinder 2 Observation beam path 3 Objective lens 4 Eyepiece 5 Inverting system 6 Focusing lens 7 Observation beam path 8 Transmitter 9 First receiver 10 Transmitter beam path 11 First receiver beam path 12 Splitter prism 13 Second receiver 14 Second receiver beam path 15 Control and evaluation unit 16 Control device 17 Amplifier 18 Amplifier 19 First ADC 20 Second ADC 21 Oscillator 22 Phase shifter 23 Operator terminal 24 Laser pulse 25 Reflected radiation pulse 26 Pulse transit time 27 Articulated axis 28 Summating amplifier

Claims

1. A binocular with an electro-optical rangefinder (1) having a first observation beam path (2, 7) and a second observation beam path (2, 7) arranged at distance therefrom and approximately parallel thereto, - each having an eyepiece (4-1, 4-2), a prism erecting system (5-1, 5-2), a focusing lens (6-1, 6-2) and an objective lens (3-1, 3-2) - and having a transmitter (8) and a transmission beam path (10) and having a first receiver (9) and a first receiver beam path (11), - wherein the first receiver beam path (11) extends partially in the first observation beam path (2) of the binocular up to a boundary surface of the prism erecting system (5-1) and partially from the boundary surface of the prism erecting system (5-1) to the first receiver (9), - characterized in that a second receiver (13) with a second receiver beam path (14) is formed, - wherein the second receiver beam path (14) extends partially in the second observation beam path (7) of the binocular up to a boundary surface of the prism erecting system (5-2) and partially from the boundary surface of the prism erecting system (5-2) to the second receiver (13), - wherein the receivers (9, 13) are configured to detect a first intensity course IR1(t) and a second intensity course IR2(t), - and that a control and evaluation unit (15) with a first ADC (19), with a second ADC (20), with an oscillator (21) and with a phase shifter (22) is formed, - wherein the control and evaluation unit (15) is configured to calculate a summed value from digital values of the first intensity course IR1(t) and of the second intensity course IR2(t) generated by the first ADC (19) and by the second ADC (20) at points in time determined by the oscillator (21) with a clock signal, - and that the phase shifter (22) is configured to generate a variable time difference Δtv between a time t1n of activation of the first ADC (19) and a time t2n of activation of the second ADC (20) and thus to compensate for differences in the signal propagation times to the two ADCs (19, 20) and / or for time delays, - or that a control and evaluation unit (15) with a summing amplifier (28), with an ADC (19), with an oscillator (21) and with a phase shifter (22) is formed, - wherein the summing amplifier (28) is configured to add the first intensity course IR1(t) and the second intensity course IR2(t) to form a sum signal, - and wherein the ADC (19) is configured to generate digital values from the sum signal at points in time determined by the oscillator (21) with a clock signal, - and that the phase shifter (22) is arranged between the first receiver (9) and the summing amplifier (28) and is configured to generate a variable time difference Δtv for synchronizing the first intensity course IR1(t) and the second intensity course IR2(t).

2. The binocular according to claim 1, characterized in that the transmission beam path (10) extends at least partially in the first observation beam path (2) of the binocular.

3. The binocular according to claim 1 or 2, characterized in that the phase shifter (22) comprises a phase-locked loop, PLL.

4. The binocular according to one of the preceding claims, characterized in that the phase shifter (22) comprises a delay line with a defined line length.

5. The binocular according to one of the preceding claims, characterized in that a controller (16) having a processor, in particular having an FPGA, field programmable gate array, is formed in the rangefinder (1).

6. The binocular according to claim 5, characterized in that a first operating mode, in which the digital values of the detected radiation intensities of the two receivers (9, 13) are added to a summed value in a synchronized manner, and a second operating mode, in which sampling of the reflected radiation intensity by the two receivers (9, 13) is performed alternately shifted in phase by half a period T, are provided in the rangefinder (1).

7. The binocular according to claim 6, characterized in that an operator terminal (23) connected to the controller (16) is provided, wherein the operator terminal (23) is suitable for selecting different operating modes.