SU1374049A1 - Light range finder with active reflector - Google Patents

Abstract

This invention relates to a geodetic instrument. The purpose of the invention is to improve the accuracy and performance of measurements. The signal from the output of the detector 5 through the amplifier 12 and the adder 13 is fed to the input of the generator 3. If the modulation frequency and phase of the incoming signal do not coincide with the same parameters of the generator 3, an error signal appears at the output of the detector 5, tuning the frequency of the generator 3 to exactly match with the received. This is the initial capture frequency. After the capture mode is established, the reference oscillation at the input of the detector 14 appears, due to the presence of the phase shifter 15, in phase with the received signal. At the output of the detector 14, a constant maximum voltage is released. It acts on indicator 16, which serves to estimate the level of a signal coming from a distance. In the absence or breakdown of the capture, there will be only a variable beat voltage at the output, to which the indicator 16 does not respond. I il. tc (L

Description

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The invention relates to geodetic instrumentation, in particular to devices for measuring distances using electromagnetic waves.

The purpose of the invention is to increase the accuracy and performance of measurements.

The drawing shows a range station.

The device contains a source of light 1, a modulator 2, a voltage controlled oscillator 3 of scale frequency, an adjustable phase shifter 4, a synchronous detector 5, an indicator 6. phases, an optical calibration line 7-7, an integrator 8, a switch 9

modes of operation Range finder - Active, reflector, signal 10 that goes a distance, coming from a di-. stations 1I signal, amplifier 12, adder 13, second synchronous detector 14, second phase shifter, 15, providing a fixed phase shift by 90, the second indicator 16 is a capture indicator.

The device works in two modes.

In the Range Finder mode, the switch 9 is open. Light from the source

I is modulated in the modulator 2 by the scale frequency of the generator 3. The modulated luminous flux 10 is distant. At the other end of the measured line there is a reflector - passive or active. Reflected from a passive reflector or re-emitted active, the luminous flux

I1 enters the photodetector (not shown) and then in the form of an electrical signal to the synchronous detector 5.

The reference signal is fed to the synchronous detector from generator 3 through the phase shifter 4. Using the phase shifter 4, the output signal of the detector 5 is set to zero, the phase indicator 6 is observed, i.e. The device works like a normal light range finder. An optical calibration line 7-7 is used to determine the zero reference, and measurements at other fixed scale frequencies are used to resolve the multi-value.

In active reflector mode, the switch 9 is closed. The generator 3 is switched to an external voltage control mode. The signal from the output of the phase detector 5 through the amplifier 12 and the adder 13 is fed to the control input of the generator 3. If the modulation frequency and phase of the incoming signal from the distance of the signal do not coincide with the logical parameters of the signal of the generator 3, the output of the detector 5 appears an error signal that tunes the frequency of the oscillator 3 to exactly match the received one. Thus, an initial frequency acquisition is performed. The capture band is determined by the gain in the loop of phase locking, i.e. gain and bandwidth of the amplifier 12.

For this, it can be made wide enough to compensate for the inaccuracy of the installation of large-scale frequencies of p, Vuh stations.

The residual phase error leads to the appearance of a constant voltage at the output of the phase detector 5. This voltage is accumulated by the integrator 8 and through the adder 13 also goes to the control input of the generator 3. The ideal integrator reduces the residual phase error to zero. A real integrator, performed, for example, on an operational amplifier with a gain factor K, reduces

0 residual phase error K times, i.e. reduces it to a negligible value. After testing the residual phase error, the incoming and reference signals at the inputs of phase detector 5 have a constant phase shift of 90, which is required for normal operation of the active reflector.

The capture indication is carried out

0 as follows.

After the acquisition mode has been established, the reference oscillation at the input of the second phase detector 14 appears due to the presence of the phase shifter 15,

5 common mode with received signal. At the output of the detector 14 under these conditions, a constant maximum voltage is detected. It affects indicator 16 which can

0 serve, for example, a pointer device or a LED, and the indicator indicates the presence of a grip. In the absence or breakdown of the capture at the output of the detector 14, there will be only a variable beat stress, to which the indicator does not respond. Indicator 16 also serves to estimate the level of a signal coming from a distance, which is important when operating at large distances.

313740494

Claims (1)

The invention claims an adder, a second synchronous detector, a light range finder with an active reflector, a second phase shifter and a second a telem containing a light source, a mo-indicator, an amplifier and an adder; a sodulator; a large-scale generator are often connected in series and switched on you, adjustable phase shifter, sync-between synchronous detector and control detector, connected to sync-kic input of generator, second input The rony detector indicator and the integrator are connected to the output of the integrator, optical calibration LED, synchronous signaling inputs and mode switch, JQtectors are interconnected, based on the fact that the signals are connected through the second phase rotation to increase accuracy and and the second indicator is connected to water ,. it is equipped with an amplifier, the output of the second phase shifter.