CN210690814U

CN210690814U - High-order amplification-fitting time discrimination circuit of pulse laser radar

Info

Publication number: CN210690814U
Application number: CN201921183034.3U
Authority: CN
Inventors: 周国清; 黄伟; 周祥; 谭逸之
Original assignee: Guilin University of Technology
Current assignee: Guilin University of Technology
Priority date: 2019-07-25
Filing date: 2019-07-25
Publication date: 2020-06-05
Anticipated expiration: 2029-07-25

Abstract

The utility model discloses a pulse laser radar's high order is enlarged-identification circuit at fitting moment, including filter circuit, controlled gain amplifier circuit, high-speed sampling circuit and controller, among the filter circuit, input pulse signal carries out filtering and output. The controlled gain amplifying circuit realizes different gains for the filtering output signal under the control signal of the controller and outputs the signals; the high-speed sampling circuit samples gain output signals and transmits the signals to the controller; the controller controls the states of the controlled gain amplification circuit and the high-speed sampling circuit to realize data transmission; the input end of the filter circuit is used for inputting pulse signals, and the output end of the filter circuit is connected with the input end of the controlled gain amplification circuit. The output end of the controlled gain amplification circuit is connected with the input end of the high-speed sampling circuit; the input end of the controller is connected with a time zero signal and a high-speed sampling signal, and the output signal of the controller is the identified laser echo time. The utility model discloses effectively eliminate the timing point drift error that echo signal rising edge and noise disturbance arouse, improve constantly and distinguish the precision.

Description

High-order amplification-fitting time discrimination circuit of pulse laser radar

Technical Field

The utility model relates to a laser radar field, in particular to high accuracy is discrimination circuit constantly is applied to the laser surveying field.

Background

Lidar is used as a core sensor of a plurality of intelligent devices in the 21 st century, and has been widely applied to the fields of service, safety, entertainment, industrial and laboratory measurement and the like. In order to realize high-precision measurement of the laser radar, the time identification technology in a receiving circuit of the laser radar is an effective way.

The time discrimination circuit determines the time when the echo signal reaches the laser radar receiver. In the conventional time discrimination, the error of the rising edge time discrimination method and the high-pass capacitance resistance method is large, and the time distance from a timing point to the actual starting point of an echo signal is respectively determined by a threshold level and a first zero-crossing point of the signal. Since the starting point of the rising edge of the echo pulse signal is different depending on the magnitude of the comparator reference threshold, the stop time is different, and since the trigger signal at the stop time is effectively generated only when the comparator reference threshold is set to be greater than the threshold level due to the presence of noise, there is a large margin of error between the minimum threshold level and the threshold level at which the signal peak point is located, and the minimum error is the case when the minimum set threshold level is present. The arrival time of the echo signal in the high-pass capacitance-resistance time identification method depends on the position of a zero-crossing point of the echo signal after differential processing, the position of a first-order zero-crossing point generally corresponds to the time of a first peak point, the error is equivalent to the time of a rising edge, and theoretically, the error has a larger reducible interval. In order to simultaneously solve the problems of low echo signal strength and timing drift error caused by noise, it is necessary to improve the time discrimination circuit.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a pulse laser radar's high order is enlarged-circuit is distinguished constantly in fitting can effectively eliminate because of the timing point drift that echo signal intensity is low and the noise arouses, compression timing error improves the precision of distinguishing constantly to further effectively improve pulse laser surveying's precision.

In order to realize the purpose of the utility model, the following technical scheme is adopted to realize: a high-order amplification-fitting time discrimination circuit of a pulse laser radar. The device comprises a filter circuit, a controlled gain amplification circuit, a high-speed sampling circuit and a controller, wherein in the filter circuit, an input pulse signal is filtered and output; the controlled gain amplifying circuit realizes different gains for the filtering output signal under the control signal of the controller and outputs the signals; the high-speed sampling circuit samples the gain output signal and transmits the signal to the controller; the controller controls the working states of the controlled gain amplification circuit and the high-speed sampling circuit and realizes data transmission; the input end of the filter circuit is used for inputting pulse signals, and the output end of the filter circuit is connected with the input end of the controlled gain amplification circuit; the output end of the controlled gain amplification circuit is connected with the input end of the high-speed sampling circuit; the input end of the controller is connected with a time zero signal and a high-speed sampling signal, and the output signal of the controller is the identified laser echo time.

The utility model has the advantages that: the high-order amplification-fitting time discrimination circuit adopting the pulse laser radar comprises a filter circuit, a controlled gain amplification circuit, a high-speed sampling circuit and a controller which are combined, wherein the filter circuit carries out denoising operation aiming at noise contained in an echo signal, so that the quality of a target signal is improved; the controlled gain amplifying circuit amplifies and outputs the filtering output signal by different times to generate required signal rising edge information; the high-speed sampling circuit samples and acquires digital information of an echo signal; the controller processes the sampling data, controls the amplification factor of the controlled gain amplification circuit and the sampling parameter of the high-speed sampling circuit, and simplifies the structural design of the circuit; on one hand, the filter circuit eliminates noise signals except laser echo pulse signals, so that the time discrimination operation is not influenced by noise; on the other hand, the controller is combined with the controlled gain amplification circuit and the high-speed sampling circuit, so that data such as pulse width, rising edge time and the like of an echo signal can be effectively acquired, and the sampled data is digitally processed in the controller through a software algorithm, so that hardware errors caused by processing of an analog circuit can be eliminated; the utility model discloses be suitable for the detection under low energy pulse signal and the adverse circumstances, can eliminate the timing error that low energy and noise disturbance arouse.

Drawings

Fig. 1 is a schematic diagram of the present invention.

Fig. 2 is a signal processing analysis diagram of the high-order amplification-fitting time discrimination circuit of the present invention.

Detailed Description

The following describes the embodiments of the present invention with reference to the accompanying drawings.

Example (b):

with reference to fig. 1, a high-order amplification-fitting time discrimination circuit for a pulse laser radar includes a filter circuit, a controlled gain amplification circuit, a high-speed sampling circuit, and a controller, wherein an input pulse signal is filtered and output in the filter circuit; the controlled gain amplifying circuit realizes different gains for the filtering output signal under the control signal of the controller and outputs the signals; the high-speed sampling circuit samples the gain output signal and transmits the signal to the controller; the controller controls the working states of the controlled gain amplification circuit and the high-speed sampling circuit and realizes data transmission; the input end of the filter circuit is used for inputting pulse signals, and the output end of the filter circuit is connected with the input end of the controlled gain amplification circuit; the output end of the controlled gain amplification circuit is connected with the input end of the high-speed sampling circuit; the input end of the controller is connected with a time zero signal and a high-speed sampling signal, and the output signal of the controller is the identified laser echo time.

With reference to fig. 1, the filter circuit includes resistors R1 and R2, capacitors C1 and C2, a first terminal of the capacitor C1 is used as a signal input, a second terminal of the capacitor C1 is connected to first terminals of the resistors R1 and R2, a second terminal of the resistor R2 is connected to a first terminal of the capacitor C2 and an input terminal of the controlled gain amplifier circuit, and second terminals of the resistor R1 and the capacitor C2 are both grounded; the control input end of the controlled gain amplification circuit is connected with the controller, the output end of the controlled gain amplification circuit is connected with the high-speed sampling circuit, and the high-speed sampling circuit is connected with the controller; the input end of the controller is connected with the time zero point signal, and the output end of the controller outputs the timing point information.

With reference to fig. 1, the filter circuit is a band-pass filter composed of capacitance resistors, so as to realize frequency selection operation of signals, the working states of the controlled gain amplification circuit and the high-speed sampling circuit are controlled by the controller, the controller controls the signal amplification times of the controlled gain amplification circuit, the controller controls the sampling frequency and sampling digit related parameters of the high-speed sampling circuit, the controller receives pulse signal sampling data and performs software data processing, and the controller calculates and outputs timing point position information by combining an input time zero signal and the software processing data.

With reference to fig. 2, the peak value of the echo signal is obtained by the high-speed sampling circuit and sent to the controller, the threshold is set to be a fixed value, and each pulse sampling signal is rapidly compared, and corresponding timing point information is obtained; all timing information is sent to the controller and a plurality of time intervals are generated. In a controller, drawing all information of peak points and corresponding time points in MATLAB software, and then finding out a functional relation of the peak points and the corresponding time points; by the mechanism of data post-processing, the timing point is infinitely close to the starting point of the rising edge of the received signal.

In connection with fig. 2, the peak value of the original received signal is set to a₀Corresponding timing point is t₀Amplification factor is G₁、G₂、G₃、…、G_nThe peak of the signal amplified step by step is A₁、A₂、A₃、…、A_nCorresponding to a timing point of t₁、t₂、t₃、…、t_n. Then, the matrix between the signal and the corresponding timing point information is defined as the peak value of the signal under different amplification factors

In the above relationship, the amplification factor is calculated starting from the second measurement. In addition, the calculated amplification factor for each stage is compared to the first measured peak magnitude. The crossing point of the rising edge and the threshold value is continuously moved forward (t) along with the gradual increase of the received pulse signal₀>t₁>t₂>t₃>…>t_n). Theoretically, as the rising edge gradually increases, the rising edge tends to be vertical, and the minimum timing point is located at the rising edge and V_thAt the intersection of (a) and (b).

With reference to fig. 2, the minimum drift is derived from the matrix X by analyzing the inter-relationship between the drift error and the amplification factor and the peak of the received signalAnd (4) error. In the controller, a power approximation function model is called by a CFTOOL tool box of MATLAB software, and the general formula used is f ═ a.x^b+ c, where f is the timing point, x is the peak of the sampled pulse signal, a is the weight of the argument x, b is the power of the argument x, and c is the compensation constant. By choosing the values of a, b and c reasonably, the timing points of matrix X fall exactly on the same curve. The final actual curve function can be considered as a functional relationship of different timing points corresponding to all peaks and amplification factors, and the timing point at which the minimum time discrimination error is obtained can be calculated from the fitted function.

Claims

1. A high-order amplification-fitting time discrimination circuit of a pulse laser radar comprises a filter circuit, a controlled gain amplification circuit, a high-speed sampling circuit and a controller, and is characterized in that in the filter circuit, a pulse signal is input for filtering and output; the controlled gain amplifying circuit realizes different gains for the filtering output signal under the control signal of the controller and outputs the signals; the high-speed sampling circuit samples the gain output signal and transmits the signal to the controller; the controller controls the working states of the controlled gain amplification circuit and the high-speed sampling circuit and realizes data transmission, and the output signal of the controller is the identified laser echo time; the input end of the filter circuit is used for inputting pulse signals, and the output end of the filter circuit is connected with the input end of the controlled gain amplification circuit.

2. The high-order amplification-fitting time discrimination circuit of the pulse laser radar as claimed in claim 1, wherein the filter circuit comprises resistors R1 and R2, capacitors C1 and C2, a first terminal of the capacitor C1 is used as a signal input, a second terminal of the capacitor C1 is connected to first terminals of resistors R1 and R2, respectively, a second terminal of the resistor R2 is connected to a first terminal of the capacitor C2 and an input terminal of the controlled gain amplification circuit, and second terminals of the resistor R1 and the capacitor C2 are both grounded; the control input end of the controlled gain amplification circuit is connected with the controller, the output end of the controlled gain amplification circuit is connected with the high-speed sampling circuit, and the high-speed sampling circuit is connected with the controller; the input end of the controller is connected with the time zero point signal, and the output end of the controller outputs the timing point information.

3. The circuit according to claim 2, wherein the filter circuit comprises a band-pass filter formed by a capacitor resistor, and the circuit is configured to perform frequency-selective operation of signals, the operating states of the controlled gain amplifier circuit and the high-speed sampling circuit are controlled by the controller, the controller controls the signal amplification factor of the controlled gain amplifier circuit, the controller controls the sampling frequency and sampling bit number related parameters of the high-speed sampling circuit, the controller receives the pulse signal sampling data and performs software data processing, and the controller calculates and outputs timing point position information by combining an input time zero signal and software processing data.