JPS60157063A - Laser distance measuring device - Google Patents

Abstract

PURPOSE:To remove an error due to atmospheric propagation by measuring time intervals between two signals corresponding to two pulse laser light beams, and two stop signals of reflected light, and correcting the time between the 1st start signal and stop signal. CONSTITUTION:Reflected light 9 of two pulse laser light beams 7' of a laser oscillator 1 from a target body (not shown in figure) is converted photoelectrically by a stop pulse detector 10, and the time interval (t) between the 1st and the 2nd reflected pulses is calculated by a counter B27 by passing the signal of a reference clock generator 12 through a count gate B25. The time interval T between the 1st and the 2nd start pulses of the oscillator 1 is counted and calculated by a counter A26 through the count gate A24, and the time interval T0 between the 1st start pulse and the 1st reflected pulse is counted and calculated by a counter 14 through a count gate 13. Then, an arithmetic circuit 28 compares the time intervals T and (t) with each other to calculated the error due to atmospheric propagation and then correct the time interval T0.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a laser distance measuring device that measures the distance to an arbitrary target object using pulsed laser light.

[Prior art]

FIG. 1 is a block diagram showing a conventional laser distance measuring device of this type. In the figure, (1) is a laser oscillator that oscillates a pulsed laser beam, and (2) is a charging voltage (4) for driving the laser oscillator (1) according to an external ranging start command (3).
, an oscillation controller that provides a high-voltage pulse (5), and (6) a transmission optical system that enlarges and transmits the pulsed laser light (7) generated from the laser oscillator (1) and irradiates it onto an arbitrary target object (not shown). system, (8) is the reflected laser beam from the target object (
9) is the receiving optical system that focuses the light, α is the receiving optical system (8)
A stop pulse detector photoelectrically converts the light guided from the laser oscillator to obtain a stop pulse that ends the distance measurement. Start pulse detection i, (1 is a reference clock generator that generates a reference clock signal for distance measurement, α Enoki is a reference clock generator that generates a reference clock signal for distance measurement, and α Enoki is a reference clock generator that generates a reference clock signal for distance measurement. A count gate for passing signals, α4 is a counter for calculating the distance by counting the number of reference clock signals that have passed through the count gate aυ.

Appointment! A display 9 displays the distance to the target object obtained by the counter I.

Figure 2 is a diagram showing the configuration of the laser oscillator (11) in the conventional device. In Figure 2, ae is the output mirror, aη is the Nd:YAG
The rod, side is a flash lamp, al is a dye Q switch, an is a total reflection prism, nari is a trigger wire, g4 is a charging capacitor, and (c) is a choke coil.

After storing a predetermined charging voltage (4) in the charging capacitor (2), when a predetermined high voltage pulse (5) is applied to the trigger wire Q〃, the flash lamp (+8) emits light and its light energy becomes 11 (1: YAG Absorbed into the rod α force.

So-called optical pumping is performed, and light travels back and forth within a resonator consisting of an output mirror ae and a total reflection prism (towards).
When it exceeds a predetermined light level, the two-dye Q-switch I
is activated to generate a so-called giant pulse laser beam with a high peak value.

Normally, in order to generate a single pulsed laser beam from the laser oscillator (1), the voltage stored in the charging capacitor is controlled.

By the way, if you improve the distance measurement accuracy by increasing the frequency of the reference clock signal using the conventional device described above, for example, the fluctuations that occur when the pulsed laser beam propagates through the atmosphere and the refractive index change will be reduced. It becomes necessary to remove distance measurement errors caused by fluctuations. In particular, when measuring long distances of several tens of kilometers or more with an accuracy of several α, sufficient consideration must be given to the distance measurement error that occurs during atmospheric propagation.

Generally, due to the nonlinear effect of the dye Q switch αη in the laser oscillator (1), when the input energy of the flash lamp Qf9 is increased beyond the value that generates a single pulse laser beam, two pulse laser beams are generated. It has been known.

[Summary of the invention]

The present invention provides a laser distance measuring device that uses the above two pulsed laser beams to eliminate distance measurement errors caused by atmospheric propagation.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a configuration diagram of a laser distance measuring device showing an embodiment of the present invention. In FIG. 2, (!) to (al, +51. +6),
(8) to a rise are the same as those shown in FIG. Furthermore, the configuration of the laser oscillator (11) in the figure is also the same as that shown in FIG.

Charge 1 input to laser oscillator (1)! The voltage (4') is set to a value that causes the laser oscillator (1) to generate two pulsed laser beams (7).

(Foundation) is Count Gate A, @ is Count Gate B.

(c) is a counter A, (5) is a counter B, and (c) is an arithmetic circuit.

Count gate A (goods) and count gate B (c) have the same functions as currant game) OJ.
), the counter B@ has the same '+s capability as the counter.

This invention will be explained in detail using FIG. 4.

In the figure, the horizontal axis indicates time.

In the figure, 01 is the start signal output from the start pulse detector (111), and the above two pulsed laser beams (7'
) and includes a first start pulse (a) and a second start pulse (b).

Count gate A (2) receives the first start pulse (a
) and the second start pulse (b), the count gate signal 1 (C) is generated in synchronization with the rising timing of the second start pulse (b),
The reference clock signal from the reference clock generator (L side) is passed through only during this period and is output to the counter A@.

Counter A (c) counts the number of the reference clock signals and first start pulses (a), ! : Calculate the time interval T of the second start pulse. OI/a is a stop signal output from the stop pulse detector, and the two pulsed laser beams (7') generated by the laser oscillator (1) are
), the first reflected pulse (cl), the II2 reflected pulse (
Contains rus (e).

Count gate B (c) is the above count gate Ac! 4
The counter B@ operates in the same manner as above to generate the count gate signal 2(f), and the counter B@ calculates the time interval t between the first reflected pulse (d) and the fs2 reflected pulse (e). - 10,000, count gate a rises at the rising edge of count gate signal 1 (C) and count gate signal 2 (f).
b)) and generate the first start pulse at the counter ←
) and the first reflected pulse (d).

The time TO corresponding to the distance to the target and the time t between the two reflected pulses (d) and (θ) mentioned above both include errors caused by atmospheric propagation.

Generally, the time interval between two pulsed laser beams (7') is 1
1 hour TO and 1
The errors included in Vc can be considered to be the same.

On the other hand, the time T calculated by the counter A@ does not include the error due to atmospheric propagation, so it is calculated by the arithmetic circuit.

By calculating the error associated with atmospheric propagation 9 from the comparison of the times T and t and correcting the 2-hour TO, it is possible to measure the distance to the target without including the error.

If the target is moving1, for example, its speed is 360 per second.
If the interval between m and z pulsed laser beams is 20XIO-6 seconds, the first reflected pulse ((1) and the second reflected pulse (e)
Since the time interval difference corresponds to a distance of 7.2 m, if the aim is to achieve an accuracy of 1α or less, it is necessary to make the interval between the two pulsed laser beams as small as possible.

〔Effect of the invention〕

As described above, by using the present invention, it is possible to realize a submerged laser distance measuring device that can accurately measure distances while eliminating many errors that occur during propagation in the atmosphere.

Although the example shows a method of using three counters, it is not necessary to measure the times T, t, and 'ro at the same time. It goes without saying that it can be achieved by

[Brief explanation of drawings]

#! Figure 1 is a #Ig diagram showing a conventional laser distance measuring device. FIG. 2 is a block diagram of the laser oscillator shown in FIG. FIG. 3 is a configuration diagram of a laser distance measuring device showing an embodiment of the present invention, and FIG. 4 is an operation diagram illustrating the operation of the bridge shown in FIG. 3. In the figure, (1) is a laser oscillator, (2) is an oscillation controller, and (3) is a laser oscillator.
J is distance measurement start command, +41 (4 is photoelectric voltage, (5 is
) is a high-voltage pulse, (6) is a transmission optical system, (7) (7'
) is pulsed laser light. (8) is the receiving optical system, (9) is the reflected laser beam, Q1 is the stop pulse detector, (IO is the start pulse detector,
a is the reference clock generator, (III is the count gate, Q4 is the counter, Q9 is the display, cm is the output mirror, aη is Nd: YAG rod, cod is the flash lamp, a → is the dye q switch, Kankozen reflective prism,
aI) is the trigger wire, Shisha charging capacitor, Q3 is the choke coil, 94 is the count gate A, @ is the current count gate) B, (c) is the counter A, @Kana counter B,
@ is the arithmetic circuit, @ is the start signal, and (to) is the stop signal. (a) is the first start pulse, ψ) is the second start pulse, and (C) is the count gate signal 1. ←) is the first reflected pulse, (e) is the second reflected pulse, and (f) is the count gate signal 2. (g) is the count gate signal 3. In addition, the same or equivalent parts in FIG. 1 are indicated by the same reference numerals. Agent Masuo Oiwa Figure 1 Figure 2

Claims (1)

[Claims] A laser oscillator that generates two pulsed laser beams, a transmitting optical system that transmits the pulsed laser beam toward a target, and a receiver that receives the reflected laser beam from the target of the pulsed laser beam. and a stop pulse detector that photoelectrically converts the reflected laser light guided from the receiving optical system to generate a stop signal. A start pulse detector that receives a portion of the pulsed laser beam and photoelectrically converts it to generate a start signal to start distance measurement; a reference clock generator that generates a reference clock signal for distance measurement; and a reference clock generator that counts the reference clock. In a laser distance measuring device equipped with a counter that displays the measured distance and a display that displays the measured distance. The time between the two start signals corresponding to the two pulsed laser beams and the time between the two stop signals generated in the reflected light from the target are compared and calculated. a first arithmetic means for measuring the difference; and a first arithmetic means for subtracting the value obtained by the first arithmetic means from the time between the first start signal and the first stop signal of each of the two start signals and the two stop signals. 1. A laser distance measuring device comprising: 2 calculating means.