CN113391324A

CN113391324A - Target distance positioning system and positioning method

Info

Publication number: CN113391324A
Application number: CN202110718451.9A
Authority: CN
Inventors: 付永杰; 曹向宇; 高川; 白旭; 于东钰
Original assignee: Institute Of Metrology And Measurement Of People's Liberation Army 92493
Current assignee: Institute Of Metrology And Measurement Of People's Liberation Army 92493
Priority date: 2021-06-28
Filing date: 2021-06-28
Publication date: 2021-09-14
Anticipated expiration: 2041-06-28
Also published as: CN113391324B

Abstract

The invention discloses a target distance positioning system, which comprises an emitting optical module, a receiving optical module, a detector and a controller, wherein the controller controls a laser to emit laser, the laser irradiates a target after passing through the emitting optical module, and enters the detector after passing through the receiving optical module after being emitted by the target; the controller starts the delay control circuit at the same time, the delay control circuit is respectively connected with the high-speed acquisition and target information processing unit and the gain control circuit through signals, and the gain control circuit is connected with the detector through signals. According to the target distance positioning system and method, the echo on the surface of the medium is used as the reference time point to detect the target distance, so that the problem of cross-medium distance measurement can be solved, and the optical path is simplified.

Description

Target distance positioning system and positioning method

Technical Field

The invention relates to a target distance positioning system and a positioning method, and belongs to the field of laser metering.

Background

The laser ranging is mainly divided into two types, namely pulse type laser ranging and phase type laser ranging. The pulse laser ranging is used for calculating the distance of a target by calculating the flight time of a laser pulse in space, and the flight time of the laser pulse in space is calculated by calculating the time difference between an echo signal exceeding a certain intensity threshold and the emission of the laser pulse in a circuit. The pulse laser ranging method comprises the steps of controlling a laser to emit a laser pulse through an electric signal processing and overall control measuring unit, starting timing by taking laser pulse emitting time as a reference until the laser pulse reflected by a target is received by a laser pulse receiving device, generating a signal with the pulse larger than a set threshold value in a circuit, ending timing, and calculating the target distance according to the measured time.

At present, the laser range finder is positioned by adding a beam splitter and a detector inside the range finder to record initial time. This increases the size of the rangefinder and the complexity of the system. When the existing distance measuring machine is used for measuring distance across media, the backward reflection of laser pulses on the surface of the media is strong, and the intensity of echo signals may be higher than that of target echo signals, so that the distance measurement is invalid.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention provides a target distance positioning system and a positioning method, which can detect the target distance by using the echo on the surface of a medium as a reference time point, solve the problem of cross-medium distance measurement and simplify the optical path.

The technical scheme is as follows: in order to solve the technical problem, the target distance positioning system comprises an emitting optical module, a receiving optical module, a detector and a controller, wherein the controller controls a laser to emit laser, the laser irradiates a target after passing through the emitting optical module, and enters the detector after passing through the receiving optical module after being emitted by the target; the controller starts the delay control circuit at the same time, the delay control circuit is respectively connected with the high-speed acquisition and target information processing unit and the gain control circuit through signals, and the gain control circuit is connected with the detector through signals.

A positioning method of a target distance positioning system comprises the following steps:

step 1: the controller controls the laser to emit a nanosecond pulse, and the nanosecond pulse is irradiated on a target through the emission optical module;

step 2: the controller controls the high-speed acquisition and target information processing unit to start acquiring data by using the high-precision delay signal generator, and controls the gain of the detector at the same time, so that the gain of the detector at the echo time of the surface of the medium is accurately lower, and then the detector is quickly recovered to be normal;

and step 3: the target echo signal is received by the receiving optical module and converged on the detector, and the output signal of the detector is amplified by the signal processing circuit;

and 4, step 4: acquiring the amplified signal by using an acquisition circuit with tau as a sampling time interval to obtain a signal sequence x (kg tau), wherein k is 1, 2, 3 and 4 … … … which are kth sampling points of the acquisition circuit;

and 5: fitting the collected signal sequence x (kg tau) according to a formula (1);

in the formula, A, alpha is a fitting coefficient, h and x are the propagation distances of light in two media, the two media are a medium where a distance measuring machine is located and a medium where a target object is located, and the included angle between theta incident light and the normal line of the target surface is formed;

and 5: subtracting the fitted curve from the signal sequence x (kg τ) to eliminate the inherent trend of the signal sequence;

step 6: obtaining a threshold value according to the effect of the practical application scene of the system, and regarding the point of the signal greater than the threshold value as a target signal;

and 7: according to the first point k obtained in step 6₁A point returned to the surface of the medium, a second point k₂As a return point of the target, Δ k ═ k₁-k₂；

And 8: calculating the distance of the target according to the formula (2);

wherein: l is the distance between the target and the surface of the medium, C is the speed of light 3X 10⁸m/s, τ is the sampling time interval.

Has the advantages that: the target distance positioning system and method of the invention utilize a detector with controllable gain and echo on the surface of the medium as a reference time point to detect the target distance, can solve the problem of cross-medium distance measurement and simplify the light path

Drawings

FIG. 1 is a schematic diagram of the system of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1, the target distance positioning system of the present invention includes an emitting optical module 2, a receiving optical module 5, a detector 4 and a controller, wherein the controller controls the laser 1 to emit laser, the laser irradiates a target after passing through the emitting optical module 2, the laser enters the detector 4 after passing through the receiving optical module 5 after being emitted by the target, the detector 4 is in signal connection with a signal processing circuit 3, and the signal processing circuit 3 is sequentially connected with a high-speed acquisition and target information processing unit 8; the controller starts a delay control circuit 7 at the same time, the delay control circuit 7 is respectively in signal connection with a high-speed acquisition and target information processing unit 8 and a gain control circuit 6, and the gain control circuit 6 is in signal connection with the detector 4.

Taking the example that the detector 4 is a hamamatsu photomultiplier for detecting underwater targets in the air, the positioning method of the target distance positioning system comprises the following steps:

step 1: controlling a laser 1 to emit a nanosecond pulse, and irradiating the nanosecond pulse onto a target through emission optics;

step 2: controlling a high-speed acquisition and target information processing unit 8 to start acquiring data by using a high-precision delay signal generator, and simultaneously controlling a photomultiplier high-voltage power supply network to generate a pulse high voltage of 500ns, wherein the rising edge time of the pulse high voltage is 50ns, and adjusting the delay time to make 30% of the rising edge be echo signals reflected by the water surface;

and step 3: the target echo signal is received by receiving optics and converged on a detector 4, and the output signal of the detector 4 is amplified by a signal processing circuit 3;

and 4, step 4: acquiring the amplified signal by using an acquisition circuit with a sampling time interval of 1ns to obtain a signal sequence x (kg τ), wherein k is 1, 2, 3 and 4 … … which is the kth sampling point of the acquisition circuit;

in the formula, A and alpha are fitting coefficients, h and x are propagation distances of light in two media, and theta incident light forms an included angle with a normal line of a target surface.

step 6: the threshold value of the system is 5 mV.

And 7: and 6, the first point obtained in the step 6 is the 328 th sampled point which is the water surface echo signal, and the second point is the 659 th sampled point which is the return point of the target. K is₁-k₂＝331

And 8: calculating the distance of the target according to the formula (2);

The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.

Claims

1. A target range locating system, characterized by: the device comprises a transmitting optical module, a receiving optical module, a detector and a controller, wherein the controller controls a laser to transmit laser, the laser irradiates a target after passing through the transmitting optical module, and enters the detector after passing through the receiving optical module after being transmitted by the target; the controller starts the delay control circuit at the same time, the delay control circuit is respectively connected with the high-speed acquisition and target information processing unit and the gain control circuit through signals, and the gain control circuit is connected with the detector through signals.

2. A positioning method using the object distance positioning system according to claim 1, characterized by comprising the steps of:

and 4, step 4: acquiring the amplified signal by using an acquisition circuit with tau as a sampling time interval to obtain a signal sequence x (kg tau), wherein k is 1, 2, 3 and 4 … …, which is the kth sampling point of the acquisition circuit;

in the formula, A, alpha is a fitting coefficient, h and x are the propagation distances of light in two media, and theta incident light forms an included angle with a normal line of a target surface;

step 6: setting a threshold value according to the effect of the practical application scene of the system, and regarding the point of the signal greater than the threshold value as a target signal;

And 8: calculating the distance of the target according to the formula (2);