Multi-Emitter Laser Remote Sensing with Periodic Pulsed Emission
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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 emitter power and detector sensitivity, which restrict the effectiveness of remote sensing applications.
Innovation Solution
A method involving multiple independent laser emitters and a photo-sensitive detector, where the emission duration is reduced to increase peak power while maintaining constant average power, with a logic circuit controlling the emitters and detector to optimize eye-safety and signal detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the laser emitter power is increased to improve signal detection, then the signal-to-background ratio is improved, but eye-safety is compromised
Solution Approach 1:
The patent applies periodic pulsed emission instead of continuous wave emission. The laser emits short pulses at controlled repetition rates, allowing the peak power during pulses to be high for good signal detection, while the average power remains low to satisfy eye-safety regulations. The duty cycle is optimized to balance signal quality and safety requirements.
Solution Approach 2:
The patent changes the temporal parameters of laser emission by adjusting pulse width, pulse repetition frequency, and duty cycle. By optimizing these parameters, the system achieves high peak power for improved signal-to-background ratio while maintaining average power within eye-safety limits. The detector integration time is also synchronized with pulse parameters to maximize signal capture.
2Measurement precision
If the emission duration is reduced to increase peak power, then the signal-to-background ratio is improved, but the power consumption of the detector increases
Solution Approach 1:
The detector operates in synchronized periodic mode, activating only during the laser pulse windows and remaining inactive between pulses. This reduces the detector's average power consumption while ensuring it captures all signal photons during the active emission periods. The integration time is precisely matched to the pulse duration to optimize signal capture without continuous operation.
3Productivity
If multiple emitters are used to increase the number of measurements per unit time, then productivity is improved, but the device complexity increases
Solution Approach 1:
The patent divides the measurement task across multiple independent laser emitters, each operating at reduced power and emitting at different time slots or wavelengths. This segmentation allows parallel or sequential measurements without requiring a single high-power emitter, thereby increasing overall productivity while keeping individual emitter complexity manageable. The system coordinates multiple simple units rather than one complex high-power unit.
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, allowing for more measurements per unit time while adhering to eye-safety regulations.
Implementation Method 1
A method involving multiple independent laser emitters and a photo-sensitive detector, where the emission duration is reduced to increase peak power while maintaining constant average power
Implementation Method 2
A method involving multiple independent laser emitters and a photo-sensitive detector
Data Source
AI summary
The invention relates to a method of an optimal arrangement in time and space of nsrc multiple laser emitters 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; —repeating for every emitter k of said plurality of nsrc emitters the steps of: —waiting for a given offset duration toffset,k; —activating both the laser emitter k, with a power output corrected by η−1, and the detector for a duration of τp; —deactivating said emitter k and detector after duration τp; —flagging emitter k to be kept off for the subsequent duration toff=tp−τp. The invention further relates to a device implementing said method.