Method for realizing high-precision and long-range ultrasonic distance measurement
By using the low sampling rate mode in the ultrasonic ranging system to initially determine the target object and switch to the high sampling rate mode for accuracy position determination, combined with hardware circuit preprocessing, the problems of large amount of computing and limited resources in the existing technology are solved, and the High-precision, long-range ultrasonic ranging.
Patent Information
- Application Number
- CN202310819112.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-05
- Publication Date
- 2025-01-07
AI Technical Summary
When the existing ultrasonic ranging method achieves high precision and long range, it has large calculation volume, high storage capacity and processing speed requirements, making it difficult to achieve efficient echo delay estimation on processors with limited resources.
The low sampling rate mode is used to determine whether the target object exists or not, and switch to the high sampling rate mode within the determined position range for secondary sampling and cross-correlation processing, and combine the hardware circuit to perform echo signal preprocessing to reduce the system's storage capacity and Dependence on processing speed.
It realizes high-precision and long-range ultrasonic ranging, reduces the processor's storage capacity and processing speed requirements, and improves the system's anti-interference ability and resource utilization efficiency.
Smart Images
Figure CN119270278A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an ultrasonic distance measurement method, and in particular to an ultrasonic distance measurement method based on echo time delay estimation. Background Art
[0002] As a typical non-contact measurement method, ultrasonic ranging is widely used in many occasions such as industrial automatic control, construction engineering measurement and robot visual recognition. Compared with other methods, such as laser ranging and microwave ranging, the propagation speed of sound waves in the air is much lower than that of light and radio waves, and the requirements for time measurement accuracy are much lower than those of laser ranging and microwave ranging systems. Therefore, the ultrasonic ranging system circuit is easy to implement, simple in structure, low in cost, and ultrasonic waves are not affected by factors such as smoke and air visibility during propagation.
[0003] At present, the ultrasonic ranging delay estimation methods include threshold method, cross-correlation method, frequency domain phase detection method and time-frequency analysis method. Among them, the threshold method is simple and practical, with good real-time performance, but poor anti-interference ability, and cannot accurately determine the time when the echo front appears, making it difficult to obtain high precision. The frequency domain phase detection method and the time-frequency analysis method have large computational complexity, high requirements for the storage capacity of the measurement system, and low practicality. The cross-correlation law is an algorithm suitable for low signal-to-noise ratio signals and low sampling rates, and is widely used. However, the conventional cross-correlation method directly processes the sampled data as samples. When the measurement distance is far, the data to be processed is huge, and the storage capacity and processing speed of the processor are very high. It is difficult to achieve high-precision and long-range comprehensive performance on a processor with limited resources. This invention patent proposes a new method for ultrasonic ranging that realizes high-precision and long-range echo delay estimation in response to the above technical bottlenecks. Summary of the invention
[0004] The technical problem to be solved by the present invention is to propose an ultrasonic ranging method for realizing high-precision and long-range echo delay estimation.
[0005] The technical method of the present invention for solving the above technical problem is as follows: first, when the distance between the detected target object X and the ultrasonic ranging system A is unknown, the ultrasonic ranging system A first uses a low sampling rate mode to complete echo sampling under a large range and cross-correlation processing with a standard signal, so as to determine whether the detected target object X exists.
[0006] Secondly, if there is no detected target object X, the system continues to work in the low sampling rate mode; if there is a detected target object X, the current low-precision position of the detected target object X can be preliminarily determined.
[0007] Again, within a certain range before and after the position X of the detected target object, switch to a higher sampling rate mode; further, the higher sampling rate mode is determined according to the accuracy requirements and the processor storage capacity;
[0008] After switching modes, secondary sampling of the same echo and cross-correlation processing with the standard signal are completed, thereby determining the high-precision position of the detected target X.
[0009] Finally, if the position of the detected target object X deviates from the maximum detection range when working in the high sampling rate mode, the ultrasonic ranging system A switches to the low sampling rate mode and re-detects the position of the detected target object X until it is determined that the detected target object X exists in the maximum ultrasonic detection range supported by the current ultrasonic ranging system A.
[0010] The beneficial effects of the present invention are: high-precision, long-range echo time delay estimation ultrasonic ranging can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 The present invention is a flowchart of an implementation of a high-precision, long-range ultrasonic ranging method. Implementation
[0012] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0013] Preconditions of this embodiment: Considering the comprehensive performance of the ultrasonic ranging system, including but not limited to accuracy, range, anti-interference, etc., the present invention adopts an implementation method based on pseudo-random binary sequence, i.e., m-code autocorrelation, to realize ultrasonic echo delay estimation. The storage capacity of the processor of the ultrasonic ranging system A is generally small and the processing speed is also limited. In order to reduce the dependence of the ultrasonic measurement system on storage capacity and processing speed, the embodiment of the present invention can firstly realize the pre-processing of the echo signal envelope detection and low-pass filtering through the hardware circuit of the ultrasonic ranging system A.
[0014] like Figure 1 As shown, a high-precision, long-range ultrasonic ranging method comprises the following steps:
[0015] Step 1, the ultrasonic ranging system A is powered on, initialized, and parameters are loaded; after the system is powered on, the same initialization action is performed. After initialization, it is decided to use the system default parameters or load the system parameters from the EEPROM according to the needs.
[0016] Step 2: Ultrasonic ranging system A transmits m code.
[0017] Step 3, the ultrasonic ranging system A samples and stores data at a low speed; the ultrasonic ranging system first uses a low sampling rate fLS Collect echo signals at a large range and perform cross-correlation processing with standard signals at a low sampling rate to determine whether there is a target object;
[0018] Furthermore, whether the target object exists is determined by whether the cross-correlation function is greater than a preset threshold.
[0019] Step 4: The ultrasonic ranging system A calculates the measurement distance.
[0020] Step 5: The ultrasonic ranging system A determines whether there is a target; if there is no target, it continues to use a low sampling rate. f LS Detect the target object; if there is a detected target object X, the low-precision position L of the target object can be preliminarily determined.
[0021] Step 6, the ultrasonic ranging system A samples and stores data at high speed; within a certain range [Ld*M, L+d*M] before and after the position X of the detected target, where M is the storage capacity of the system, it switches to a higher sampling rate c / 2d, collects the same echo signal, and performs cross-correlation processing with the standard signal at the high sampling rate, thereby determining the high-precision position L of the target.
[0022] Step 7, the ultrasonic distance measurement system A calculates the temperature correction of the measured distance.
[0023] Step 8: The ultrasonic ranging system A determines whether the target object is within the range. If the position of the detected target object X deviates from the detection range [Ld*M, L+d*M] in the high sampling rate mode, the system switches to the low sampling rate mode. f LS Work and re-detect the position of the target.
[0024] Step 9: The ultrasonic ranging system A outputs the X distance of the detected target object.
[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for achieving high-precision, long-range ultrasonic ranging, characterized in that: The following steps are involved: Step 1: Use the low sampling rate mode to complete the echo sampling under a large range and the cross-correlation processing with the standard signal to determine whether the detected target exists; Step 2: If there is a detected target, preliminarily determine the current low-precision position of the detected target; Step 3: Switch to a higher sampling rate mode within a certain range before and after the position of the detected target; Step 4: After switching modes, the same echo is resampled and cross-correlated with the standard signal to determine the high-precision position of the detected target.
2. A method for realizing high-precision and long-range ultrasonic ranging according to claim 1, characterized in that: The step 1 determines whether there is a target object by determining whether the cross-correlation function is greater than a preset threshold.
3. The method for realizing high-precision and long-range ultrasonic ranging according to claim 1, characterized in that: In the process of determining whether there is a detected target object in step 1, if there is no detected target object, the ultrasonic ranging system continues to operate in a low sampling rate mode.
4. The method for realizing high-precision and long-range ultrasonic ranging according to claim 1, characterized in that: In the step three, the range before and after the position of the detected target object is [Ld*M, L+d*M], where M is the storage capacity of the system; the higher sampling rate when switching to the higher sampling rate mode is c / 2d.
5. The method for realizing high-precision and long-range ultrasonic ranging according to claim 1, characterized in that: The step 4 determines the high-precision position of the detected object, and the ultrasonic ranging system A calculates the temperature correction of the measured distance and determines whether the detected object is within the range.
6. The method for realizing high-precision and long-range ultrasonic ranging according to claim 1, characterized in that: The step 4 determines the high-precision position of the target object. If the position of the detected target object deviates from the maximum detection range when working in the high sampling rate mode, the ultrasonic ranging system switches to the low sampling rate mode and re-detects the position of the detected target object until it is determined that the detected target object exists in the maximum ultrasonic detection range supported by the current ultrasonic ranging system.