JPH0557688U - Laser range finder - Google Patents

Abstract

(57) [Abstract] [Purpose] A / D conversion is performed with high resolution only in the temporal vicinity of the target prediction distance obtained with low resolution, and the target distance is obtained from the temporal position of the peak value of the received signal, resulting in high accuracy and small size. To obtain a laser distance measuring device that can measure distance with memory capacity. [Structure] Based on the contents of the first range memory 4 recording the presence or absence of the echo signal 10 at a constant time interval, the distance calculator 5
The target distance is calculated by the prediction filter 15, the target distance is predicted by the prediction filter 15, and the received signal in the temporal vicinity is converted by the A / D converter 12 into digital data at a time interval shorter than that of the first range memory 5, and the second The distance is recorded in the range memory 16 and the distance is calculated with high accuracy from the address of the peak value of the received signal by the distance calculator.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a laser distance measuring device capable of measuring a distance to a target with high accuracy by obtaining a temporal position of a peak of a received signal from the target.

[0002]

[Prior Art]

 FIG. 2 shows the configuration of a conventional laser range finder, where 1 is a laser transmitter, 2 is a receiver, 3 is a threshold value processor, 4 is a first range memory, 5 is a distance calculator, 6 is a transmitted pulse laser beam, 7 is a start pulse, 8 is reflected light from a target, 9 is a received signal which is photoelectrically converted and amplified, 10 is an echo signal, and 11 is data of the first range memory 4. In the figure, when the transmission pulse laser beam 6 is emitted from the laser transmitter 1, a start pulse 7 indicating that the transmission pulse laser beam 6 is emitted is output. When the start pulse 7 is output, the first range memory 4 starts recording the presence / absence of an echo signal at regular time intervals. When the reflected light 8 from the target is input to the receiver 2, it is photoelectrically converted, amplified, thresholded by the threshold processor 3, and recorded as an echo signal 10 in the first range memory 4. The address of the first range memory 4 corresponds to the distance, and the distance calculator 5 checks at which address of the first range memory 4 the echo signal 10 is recorded and calculates the distance value.

[0003]

[Problems to be solved by the device]

 In the conventional device, the received signal is thresholded as described above, so even if the resolution is increased by narrowing the time interval for recording in the first range memory, the threshold is exceeded depending on the strength of the received signal. There was a problem that the time changed and an error occurred. Further, if the time interval for recording in the first range memory is narrowed, there is a problem that a large memory capacity is required.

The present invention has been made in order to solve such a problem, and an object thereof is to obtain a laser distance measuring device capable of measuring a target with high accuracy and a relatively small memory capacity.

[0005]

[Means for Solving the Problems]

 The laser range finder according to this invention is An A / D converter for A / D converting the reception signal at a time interval shorter than the time interval at which the first range memory records the presence or absence of an echo signal; Address corresponds to distance, A second range memory that records the output of the A / D converter at the same time interval as the A / D converter at each address, A calculator for calculating a distance from the contents of the first range memory and the second range memory to a target; A prediction filter for predicting the position of the moving target based on the distance calculated from the contents of the first range memory, A gate timing generator that generates a gate timing corresponding to the target predicted position, A gate generator for generating a gate signal for limiting the operations of the A / D converter and the second range memory at the gate timing is used.

[0006]

[Action]

 In this invention, the target is measured using a range memory with a low resolution, the target position is predicted from this distance by a prediction filter, and after the predicted position converges, high resolution is achieved in the temporal vicinity of the predicted position. Since the received signal is A / D converted and the temporal position of the peak value is obtained, distance measurement can be performed with high accuracy and with a relatively small memory capacity.

[0007]

【Example】

 FIG. 1 is a diagram showing an embodiment of the configuration according to the present invention, in which 12 is an A / D converter, 13 is a gate generator, 14 is a gate timing generator, 15 is a prediction filter, and 16 is a second range memory. , 17 is the target distance, 18 is the target predicted distance, 19 is the gate timing signal, 20 is the gate signal, 21 is the data after A / D conversion of the received signal, and 22 is the contents of the second range memory. In the figure, first, as the first step, the target distance 17 is obtained from the contents of the first range memory 4 as in the conventional case. Next, as the second step, the target predicted distance 18 is calculated from the target distance 17 calculated in the first step by using the prediction filter 15. As the third step, the first step and the second step are repeated until the target predicted distance 18 converges, and as the fourth step, the gate timing signal 19 indicating the temporal vicinity of the converged target predicted distance 18 is supplied to the gate timing generator 14 And the gate generator 13 generates a gate signal 20 covering the temporal vicinity of the target predicted distance 18. While the gate signal 20 is being generated, the received signal 9 is A / D converted by the A / D converter 12 at a time interval narrower than the time interval for recording the presence or absence of the echo signal 10 in the first range memory 4, The target distance is obtained from the address of the peak value of the received signal 9 recorded in the second range memory 16 by the distance calculator 5 by recording the distance in the second range memory 16. By repeating all steps except the third step as the fifth step, it is possible to measure the target with high accuracy regardless of whether it is a moving target or a fixed target with a relatively small memory capacity.

[0008]

[Effect of the device]

 As described above, according to the present invention, the target distance is measured using the range memory with low resolution, the target position is predicted by the prediction filter from this distance, and after the predicted position converges, the target position is estimated in the temporal vicinity of the predicted position. Since the received signal is A / D converted with high resolution to determine the temporal position of the peak value, it is possible to measure distance with high accuracy and with a relatively small memory capacity regardless of the strength of the received signal.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the configuration of the present invention.

FIG. 2 is a diagram showing a configuration of a conventional laser distance measuring device of this type.

[Explanation of symbols]

 1 Laser Transmitter 2 Receiver 3 Threshold Processor 4 First Range Memory 5 Distance Calculator 6 Transmitted Pulse Laser Light 7 Start Pulse 8 Reflected Light From Target 9 Received Signal Amplified by Photoelectric Conversion 10 Echo Signal 11th Contents of the range memory 1 12 A / D converter 13 Gate generator 14 Gate timing generator 15 Prediction filter 16 Second range memory 17 Target distance 18 Target predicted distance 19 Gate timing signal 20 Gate signal 21 Received signal A / D Data after conversion 22 Contents of second range memory

Claims (1)

[Scope of utility model registration request] 1. A distance measuring device for measuring a distance from a time difference between the emission of pulsed laser light to a target, the reception of the reflected light, and the reception of an echo from the emission of the pulsed laser light. A laser transmitter that emits light, a receiver that receives the reflected light from the target, converts it to an electric signal and amplifies it, and the address corresponds to the distance, and at the same time when the pulse laser light is emitted, the echo signal of each address A first range memory that starts recording presence / absence, an A / D converter that A / D-converts a received signal at a time interval shorter than a time interval when the first range memory records the presence or absence of an echo signal, and an address are Corresponding to the distance, the output of the A / D converter is recorded at each address at the same time interval as the A / D converter.
A range memory, a calculator for calculating the distance from the contents of the first range memory and the second range memory to the target, and a target for movement based on the distance calculated from the contents of the first range memory. A prediction filter for predicting a distance, a gate timing generator for generating a gate timing corresponding to a target predicted distance temporal position, a gate signal for limiting the operations of the A / D converter and the second range memory are provided. A laser range finder having a gate generator that generates at the gate timing.