JPH04283684A - Optoelectronic distance meter - Google Patents

Abstract

PURPOSE:To execute measurement of distance accurately by a method wherein a time mark signal is generated when a light intensity modulation output is emitted, a time interval thereof is measured, while the own speed is detected, and a distance resolution is selected on the basis of a speed signal. CONSTITUTION:A phasemeter 15 measures a phase difference between the phase of an emission light emitted from a light intensity modulation circuit 14 to a target and turning to be a reference signal and the phase of a reflected light from the target which enters a demodulation circuit 13, and the data thus obtained are sent to CPU 16 and converted into distance data. Moreover, the CPU 16 selects a distance resolution on the basis of own speed signal data from an own speed detecting circuit 18 and sends a signal thereof to the phase- meter 15. Besides, a time mark circuit 11 generates a time mark signal at the time when the light emission from the circuit 14 is started, and sends it to a light emission interval measuring circuit 19. A time interval thereof is measured therein and the data thereon are sent to the CPU 16. The CPU 16 calculates the speed of the target from these time data, the distance data obtained from the phase difference and the own speed data and displays it in a display device 17.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light wave ranging device used to measure, for example, the distance to a stationary object, the distance to a moving object, and the speed of a moving object.

0002

2. Description of the Related Art Conventionally, this type of light wave distance measuring device, that is, a distance measuring device that electrically measures the distance to an object using light waves, has a configuration as shown in FIG. 2, for example. There is something.

[0003] In such a conventional light wave distance measuring device, a signal from a light intensity modulation circuit 1 is obtained as a modulation signal by a reference oscillator 2, and the light intensity modulation circuit 1 modulates the light intensity based on this signal. Light (outgoing light) L-1 is projected onto a target object (object to be measured).

[0004] Then, the reflected light L-2 that is reflected back from the emitted light L-1 projected onto the target by the light intensity modulation circuit 1 is demodulated by the demodulation circuit 5, and modulated with this demodulated signal. The frequency of the signal is converted by mixers 4 and 6 using a local oscillation signal generated by a local oscillator 3.

[0005] The phase difference between the respective frequency-converted signals is measured by a phase meter 7, and the distance to the target is determined by calculation.

[0006]

[Problem to be Solved by the Invention] However, in most of the conventional light wave distance measuring devices described above, measurements are made while both the main body of the device and the target are stationary, and the distance between them is constant. Since there is no need to obtain time and speed information such as how long the device was at the measured distance or position, and at what speed they were moving relative to each other, measurements can be made when the main body of the device and the target are moving relative to each other. Not suitable for distance.

[0007]

OBJECTS OF THE INVENTION An object of the present invention is to provide a light wave distance measuring device that can accurately measure the distance between the main body of the device and an object to be measured even when they are moving relative to each other. be.

[0008]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a light-wave distance measuring device that calculates distance from a phase difference between a reference signal and a signal reflected by a distance-measuring object. time mark signal generating means for generating a time mark signal at a time equal to the time when the modulated output is emitted;
A measuring means for measuring the time interval of the time mark signal generated by the time mark signal generating means, a self speed detecting means for detecting the self speed of the device body, and a self speed signal detected by the self speed detecting means. The configuration includes means for selecting a distance resolution according to the following.

[0009]

[Operation] That is, the present invention generates a time mark signal at a time equal to the time when the light intensity modulated output is emitted by the time mark signal generating means, measures the time interval of this time mark signal, and measures the self-speed Since the distance resolution is selected based on the self-speed signal of the main body of the device detected by the detection means, the time mark signal and self-speed signal are transmitted when the moving object to be measured is at the measured position. By doing this, accurate distance information can be obtained.

[0010] Also, since a time mark signal is generated at a time equal to the time when the light intensity modulation output is emitted, and time interval information is obtained by measuring the time interval of this time mark signal. From this time interval information, distance information, and self-speed information of the main body of the device, speed information of the object to be ranged is obtained.

[0011] Therefore, since the speed information of the moving object can be obtained by the time mark signal and self-speed signal that can correspond to the distance data obtained by measuring the distance to the moving object, the main body of the apparatus and the object to be measured are To accurately measure the distance between an object and a distance object even when the two objects are moving relative to each other.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIG.

FIG. 1 is a block diagram showing the overall circuit configuration of a light wave ranging device according to the present invention, in which 11 is a time mark circuit, 12 is an optical path monitoring circuit, 13 is a demodulation circuit, and 14 is a light intensity modulation circuit. , 15 is a phase meter, 16 is a central processing unit (CPU), 17 is a display, 18 is a self-speed detection circuit for detecting the self-speed of the apparatus main body, and 19 is a light emission interval measuring circuit.

The phase meter 15 is connected to the light intensity modulation circuit 14.
Measure the phase difference between the phase of the emitted light L-1 that is emitted from the target object (the object to be measured) that serves as a reference signal, and the phase of the reflected light L-2 from the target that enters the demodulation circuit 13. The data on this phase difference is then sent to the CPU 16.

The CPU 16 calculates data on the phase difference and converts it into distance data, and also receives the self-speed signal of the main body of the device from the self-speed detection circuit 18.
The resolution from the phase meter 15 is selected based on the data of this self-speed signal, and the selected signal is sent to the phase meter 15.

On the other hand, the optical path monitoring circuit 12 detects the output light L-1.
A large change in the reflected light L-2 that affects the phase difference data, such as a blockage of the phase difference optical path with the target object, is detected from the information on the reflected light L-2 and the information on the reflected light L-2.

Further, the time mark circuit 11 generates a time mark signal at the time when the light intensity modulation circuit 14 starts outputting the light output, that is, at a time equal to the time when the light intensity modulation output is output, and transmits the output to the light. It is designed to be sent to the light emitting interval measuring circuit 19, and this light emitting interval measuring circuit 19
measures the time interval of the time mark signal and sends this time data to the CPU 16.

That is, the CPU 16 calculates the difference between the time data obtained by measuring the time interval of the time mark signal by the light emission interval measuring circuit 19 and the distance data calculated and converted based on the phase difference data. The speed of the target object can be calculated from the self-speed data of the main body of the device and displayed on the display 17.

[0019]

Effects of the Invention As is clear from the above explanation, the present invention generates a time mark signal at a time equal to the time when the optical output is emitted to a moving object to be measured. Since the absolute speed can be obtained from the difference between the interval and distance data, and the self-speed of the device itself is detected, it is easy to select the distance resolution suitable for the self-speed. Even when the device main body and the object to be measured are moving relative to each other, the distance between the two can be accurately measured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the overall circuit configuration of an embodiment of a light wave distance measuring device according to the present invention.

FIG. 2 is a block diagram of the overall circuit configuration of a conventional light wave distance measuring device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11... Time mark circuit, 12... Optical path monitoring circuit, 13... Demodulation circuit, 14... Light intensity modulation circuit, 1
5... Phase meter, 16... CPU, 17... Display unit, 18... Self-speed detection circuit, 19... Light emission interval measurement circuit, L-1... Emitted light, L- 2...Reflected light.

Claims (1)

[Claims] Claim 1: In a light wave distance measuring device that determines distance from a phase difference between a reference signal and a signal reflected by a distance measurement object, a time mark signal is generated at a time equal to the time when a light intensity modulated output is emitted. A time mark signal generating means, a measuring means for measuring the time interval of the time mark signals generated by the time mark signal generating means, a self speed detecting means for detecting the self speed of the apparatus main body, and a self speed detecting means for detecting the self speed of the apparatus main body. 1. A light wave distance measuring device comprising means for selecting a distance resolution based on a self-speed signal detected by a self-speed signal.