Survey Target Detection Using Asynchronous Light Cycles

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Solution Overview

Problem

Conventional target detection methods in surveying systems require synchronization of clocks between the surveying instrument and the target, leading to inefficiencies and potential synchronization failures, especially when multiple targets are present, increasing the time required to find a specific target.

Innovation Solution

A target detection method that utilizes targets emitting identification light at different cycles, allowing the surveying instrument to receive and process these lights asynchronously, eliminating the need for synchronized clocks by setting the light reception cycle based on a selection signal, and using arithmetic processing to identify the target.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If clock synchronization is implemented between surveying instrument and target, then accurate direction determination is achieved, but device complexity and synchronization failure risk increase

Engineering Contradiction:
Improvedirection determination accuracyVSAvoidclock synchronization system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the clock synchronization requirement from the system by using asynchronous light emission at different cycles. Each target emits light independently without needing to synchronize with the surveying instrument, eliminating the complex clock synchronization subsystem while maintaining measurement capability through cycle-based identification.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs periodic light emission at different cycles for each target. Targets emit identification light at distinct periodic intervals (e.g., 10ms, 20ms, 30ms), allowing the surveying instrument to identify specific targets by detecting their unique emission cycles without requiring clock synchronization between devices.

Inventive Principle:
Principle #19Periodic action

2Reliability

If entire area is searched to find specific target, then target detection is performed, but detection time increases and other targets may be detected

Engineering Contradiction:
Improvetarget detection accuracyVSAvoidtarget search time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The surveying instrument performs periodic scanning at different time points corresponding to different target emission cycles. By timing the scanning to match when specific targets emit light, the system can selectively detect desired targets without searching the entire area continuously, reducing search time while maintaining detection accuracy.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses feedback from detected light pulses to identify which targets are present and their emission cycles. This feedback mechanism allows the instrument to adaptively adjust scanning timing and focus on specific targets, reducing unnecessary area searches and improving detection efficiency.

Inventive Principle:
Principle #23Feedback

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

Enables efficient and reliable detection of a target without clock synchronization, even when targets are close to each other, by distinguishing identification lights based on their unique emission cycles.

Implementation Method 1

the plurality of targets emitting identification light in different cycles

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

a light receiving unit that receives the identification light

Methodology Applied
Scientific EffectLight reception: Photoelectric Effect

Data Source

PatentEP4692721A1Method for detecting target in surveying system
Publication Date: 2026.02.11 TOPCON CORPORATION
  • EP4692721A1 patent drawingFigure 1
  • EP4692721A1 patent drawingFigure 2
  • EP4692721A1 patent drawingFigure 3A~3B

AI summary

Provided is a method of identifying and detecting one selected target in a survey system in which a plurality of targets are present for one surveying instrument. Light emission cycles T1, T2, and T3 of pieces of identification light of respective optical transmitters of a plurality of targets are different from each other, a light reception cycle TA of an optical receiver of the surveying instrument is set to be equal to a light emission cycle of identification light of a selected target, and each time the identification light of the selected target is received, the identification light is accumulated and amplified, and an amplified signal is identified to detect the selected target.