Pulsed Laser Emitter and Detector Timing for Remote Sensing
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Solution Overview
Problem
Active remote sensing devices face challenges in optimizing eye-safety, signal-to-background ratio, and power consumption, particularly due to limitations in laser power emission and receiver sensitivity, which restrict their performance in environmental and regulatory contexts.
Innovation Solution
A method and device that adjust the laser emitter and detector operation by setting a target integration time, translating it into a reduced time and corresponding power increase factor, activating them for a specific duration, and then deactivating them, with a subsequent off-time to optimize optical budget and power consumption, while maintaining eye-safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the laser emitter power is increased to improve signal-to-background ratio, then the signal contributions are enhanced, but eye-safety regulations are violated
Solution Approach 1:
The patent applies periodic pulsed operation of the laser emitter and detector, where both are activated only during specific time windows (τp) within a larger integration period (tp), followed by off-periods. This periodic activation allows the system to achieve high peak power during the active phase for improved signal-to-background ratio, while maintaining low average power to comply with eye-safety regulations. The duty cycle is controlled by the ratio of active time to total period.
2Reliability
If the detector is kept active continuously to maintain sensitivity, then the detection capability is preserved, but the power consumption increases
Solution Approach 1:
The detector is activated periodically in sync with the laser emitter, only during the time window τp when signal acquisition is needed, and deactivated during the remaining period. This periodic operation maintains detection sensitivity during active phases while significantly reducing average power consumption compared to continuous operation. The detector can be quickly reactivated for the next measurement cycle.
Solution Approach 2:
The system performs preliminary setup and calibration during off-periods when the detector is inactive, preparing the detection system for the upcoming active phase. This allows the detector to be fully ready for high-sensitivity measurement when activated, without requiring continuous power consumption for maintenance.
3Measurement precision
If the integration time is increased to improve signal accumulation, then the measurement accuracy is enhanced, but the total measurement time increases
Solution Approach 1:
The system uses periodic pulsed measurement cycles where the laser and detector are activated for a short duration τp repeated N times within the total integration time tp. This allows signal accumulation over the full integration period while maintaining fast measurement cycles. The periodic structure enables parallel signal accumulation across multiple pulses, improving accuracy without linearly increasing measurement time.
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 enhances the signal-to-background ratio and reduces power consumption by efficiently utilizing the available optical budget, achieving improved performance within the constraints of eye-safety regulations and environmental conditions.
Implementation Method 1
a laser emitter (11)
Implementation Method 2
a photo-sensitive detector (12)
Data Source
AI summary
The invention relates to a method of an optimal arrangement in time of a laser emitter and a detector for a remote sensing application, comprising: —setting a target time unit integration time tp; —translating said time unit integration time into a reduced time τp and its corresponding power increase factor η−1; —activating both the laser emitter, with a power output corrected by η−1, and the detector for a duration of τp; —deactivating the emitter and detector after duration τp; —keep emitter and detector off for the subsequent duration toff=tp−τp.The invention further relates to a device implementing said method.