Tracking Laser Rangefinder With Fast-Scan Mirror for Low Latency
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Solution Overview
Problem
Existing rangefinder technologies, such as LiDAR, are unsuitable for applications requiring fast response times or low latency, particularly when detecting and tracking fast-moving objects, as they suffer from latency issues and noise susceptibility, limiting their effectiveness in environments with high noise levels and fast-moving targets.
Innovation Solution
A tracking laser rangefinder (T-LRF) device that uses a fast-scan mirror and sensor to detect and track objects in real-time, combined with digital signal processing to filter noise and increase signal-to-noise ratio, and a controller to determine angles and range, allowing for high-speed operation and accurate tracking of fast-moving objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If existing rangefinder technologies (LiDAR) are used, then range measurement capability is provided, but response time is slow and latency is high
Solution Approach 1:
The patent replaces traditional mechanical scanning systems with a fast-scan mirror system that uses electromagnetic actuation (voice coil or piezoelectric) to achieve much faster mirror deflection speeds. This substitution of mechanical inertia-based scanning with electromagnetic field-based control enables response times in the microsecond range, directly resolving the slow response time and high latency issues of conventional LiDAR systems.
Solution Approach 2:
The patent changes key operational parameters including laser pulse width (shortened to sub-nanosecond durations), mirror scan frequency (increased to kHz range), and detector integration time (optimized to match pulse width). These parameter changes enable the system to capture and process returning photons within microseconds, dramatically improving response time and reducing latency compared to traditional systems.
2Speed
If fast-scan mirror is used to improve tracking speed, then response time improves, but noise susceptibility increases
Solution Approach 1:
The patent employs periodic pulsed laser emission synchronized with the fast-scan mirror's periodic scanning motion. By emitting laser pulses at specific intervals that match the mirror's scan cycle, the system creates predictable timing windows for detecting returning photons. This periodic action allows the detector to integrate signals only during expected return windows, filtering out random noise that does not coincide with the periodic pulse pattern.
Solution Approach 2:
The patent implements feedback control where the actual position of the fast-scan mirror is continuously monitored and fed back to the controller. This feedback enables the system to dynamically adjust the timing and positioning of laser pulses and detector integration windows to compensate for any deviations in mirror motion. The feedback mechanism ensures that even at high scan speeds, the system maintains precise synchronization, preventing noise from corrupting the measurement signals.
3Measurement precision
If light is concentrated onto a small spot to improve range performance, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent designs the fast-scan mirror system to serve multiple functions simultaneously: it acts as both the beam steering element for directing laser pulses and as part of the returning light collection path. The same mirror that deflects outgoing pulses also reflects returning photons onto the detector. This multi-functionality eliminates the need for separate steering and collection optics, concentrating the optical path through a single critical element while maintaining high measurement precision.
Solution Approach 2:
The patent introduces a beam splitter as an intermediary optical element that mediates between the laser source and the fast-scan mirror system. The beam splitter separates the outgoing laser path from the returning photon path, allowing both to share common optical components without interference. This intermediary enables the concentration of light onto a small detector spot while using relatively simple optical components, avoiding the need for complex multi-element optical systems.
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 T-LRF device achieves improved range performance and accuracy by concentrating light onto a small spot, filtering noise, and using high-speed digital signal processing to track objects in real-time, overcoming limitations of existing technologies.
Implementation Method 1
a laser source arranged to generate and emit a laser pulse
Implementation Method 2
a fast-scan mirror arranged to deflect and steer the laser pulse
Implementation Method 3
a sensor arranged to receive a reflection of the laser pulse from the object
Data Source
AI summary
A tracker laser rangefinder for detecting, targeting, locating or tracking an object in real time in a field of view, including a laser source arranged to generate and emit a laser at a first time in response to a laser trigger signal; a fast-scan mirror arranged to deflect and steer the laser to an object in a scan plane; a sensor arranged to receive a reflection of the laser from the object at a second time and output a return laser detection signal; and a controller arranged to receive the return laser detection signal and determine a first angle, a second angle and a range to the object. The angles can be based on a position of the fast-scan mirror and the range can be calculated based on a period of time.