Rangefinding Instrument Combining Pulse and Phase Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser rangefinders face challenges in achieving high accuracy due to ambiguity in phase-based systems and difficulty in distinguishing targets from interfering debris, while pulse-based systems require complex timing circuitry and calibration.
Innovation Solution
A system and method combining pulse and continuous wave signal generating and processing techniques, allowing for accurate distance measurement independent of range and capable of distinguishing targets from interference, by using a distance computing circuit to determine range based on time of flight and phase shift of signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase-based continuous wave techniques are used, then measurement precision is improved with simpler electronics, but device complexity increases due to frequency multiplication and signal processing requirements
Solution Approach 1:
The patent segments the distance measurement task into two independent parts: a pulse-based system handles the unambiguous range determination (resolving the phase ambiguity problem), while a phase-based system handles the high-precision measurement within that range. This segmentation allows each system to operate independently with optimized circuitry, avoiding the need for complex frequency multiplication while maintaining both accuracy and simplicity.
2Reliability
If pulse-based laser systems are used, then reliability is improved by distinguishing targets from debris, but device complexity increases due to complicated timing circuitry
Solution Approach 1:
The patent divides the ranging function into two segments: pulse-based measurement for reliable target discrimination and unambiguous range determination, and phase-based measurement for high-precision distance within the unambiguous range. This segmentation allows the system to achieve reliable target discrimination without requiring overly complex timing circuitry, as the pulse-based system only needs to determine when the pulse was sent and received, not continuously track phase information.
3Measurement precision
If phase-based systems operate at higher frequencies, then measurement precision is improved, but the unambiguous range decreases
Solution Approach 1:
The patent segments the measurement task by using pulse-based systems to establish a large unambiguous range (independent of frequency), and phase-based systems operating at high frequencies to provide precise measurement within that established range. This segmentation resolves the contradiction by decoupling the unambiguous range determination from the high-frequency phase measurement, allowing both long range and high precision simultaneously.
Solution Approach 2:
The patent introduces a dimensional separation between two measurement approaches: pulse-based measurement provides the temporal dimension for unambiguous range determination, while phase-based measurement provides the angular/fine-position dimension for high-precision measurement within the unambiguous range. This dimensional separation allows the system to achieve both long unambiguous range and high measurement precision without compromise.
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
The solution provides a compact, low-cost, and highly accurate rangefinding instrument that compensates for the disadvantages of both pulse-based and phase-based systems, maintaining accuracy even in dusty or industrial environments.
Implementation Method 1
a time of flight measurement technique to compute the distance to a particular target based on the time it takes for a transmitted pulse to reach the target and be reflected back therefrom
Implementation Method 2
the phase of the backscatter signal that is reflected back therefrom is determined
Implementation Method 3
a transmitted pulse to reach the target and be reflected back therefrom
Data Source
AI summary
A system and method for a rangefinding instrument incorporating pulse and continuous wave signal generating and processing techniques for increased distance measurement accuracy. The use of the former technique effectively solves the ambiguity issues inherent in the latter while allowing for relatively simple circuit implementations. Thus, a potentially more accurate phase-based distance measurement technique can be utilized which is also completely independent of the maximum range to the target.