Opto-Electronic Distance Module Pulse Compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional surveying devices face challenges in miniaturization, complexity, and usability while maintaining sensitivity and accuracy for long-range distance measurements, particularly due to the limitations of laser diodes with low peak power and the bulkiness of high-power laser arrangements.
Innovation Solution
An opto-electronic distance measuring module utilizing a spatial single-mode laser diode or low-power fiber laser that emits a finite emission code sequence of pulses, combined with a cross-correlation processing method to achieve high-speed and long-range distance measurements, effectively compressing energy into a single intense peak with low residual sidelobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-power laser arrangements are used for long-range distance measurements, then measurement precision and range are improved, but device weight, volume, and complexity increase
Solution Approach 1:
The patent transforms the optical signal parameters by applying pulse compression through cross-correlation processing. The received pulse signal is correlated with a reference signal to compress the pulse width and increase peak power, thereby improving distance measurement precision without requiring high-power laser hardware
Solution Approach 2:
The patent replaces the mechanical/optical approach of using high-power laser hardware with a signal processing approach. Instead of increasing laser power physically, the system uses digital cross-correlation to achieve pulse compression and enhance signal quality, substituting complex optical hardware with computational methods
2Measurement precision
If high-power laser arrangements are used for long-range distance measurements, then measurement precision and range are improved, but device weight and size increase
Solution Approach 1:
The patent changes the signal parameters through pulse compression in the time domain. By correlating the received signal with a reference signal, the system compresses the pulse width and concentrates energy, achieving higher effective signal strength without increasing the physical laser power or device weight
3Device complexity
If laser diodes with low peak power are used, then device size and power consumption are reduced, but measurement precision and range deteriorate
Solution Approach 1:
The patent employs periodic pulse transmission from the laser diode, where sequences of pulses are emitted at regular intervals. This periodic action allows the use of low-power diodes while maintaining measurement capability through accumulation and compression of signal energy over multiple pulses
Solution Approach 2:
The patent compensates for the low peak power of laser diodes by transforming the signal parameters through cross-correlation pulse compression. The system processes the temporal structure of the received pulses to concentrate energy and enhance the effective signal strength, thereby achieving precision comparable to high-power systems
4Productivity
If high measurement rates are achieved, then productivity is improved, but signal quality and measurement precision deteriorate
Solution Approach 1:
The patent uses periodic pulse transmission with coded modulation at high rates. By assigning unique codes to different pulses and using cross-correlation to decode them, the system maintains high measurement rates while preserving signal quality through the periodic structure and signal processing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables high-resolution, low-background distance measurements at high speeds, achieving measurement rates of several million points per second with reduced power consumption and increased device mobility, while maintaining accuracy and simplifying device design.
Implementation Method 1
an emission unit with a laser diode, e.g. a spatial single-mode laser diode, or a low power fiber laser, and configured to provide for emission of light pulses by the laser diode or the low power fiber laser
Implementation Method 2
The target object to be measured in the surveying, construction, or mapping process reflects a portion of the emitted radiation back to the device, where it is received and converted into an electrical signal for distance determination
Implementation Method 3
cross-correlation processing method to achieve high-speed and long-range distance measurements, effectively compressing energy into a single intense peak with low residual sidelobes
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to an opto-electronic distance measuring module and a surveying device (1) comprising the opto-electronic distance measuring module. The opto-electronic distance measuring module comprises a laser diode or a low power fiber laser as emission unit of a distance measuring beam (15), wherein a finite emission code sequence (16, 16') with N chips (17) is emitted and cross-correlated with a reference signal (30) for generating a compressed pulse (35, 36, 37). In order to provide sufficient pulse compression and accurate timing of the compressed pulse (35, 36, 37), the reference signal (30) is configured to have a number of chips (17) larger than N and is formed by reference signal components (33, 33') which take up a bipolar shape of expected receiver output signal components which can be assigned to respective light pulses (18) of the emission code sequence (16, 16').