Array Coherent Ranging Chip for Extended LiDAR Distance
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Solution Overview
Problem
LiDAR systems face limitations in ranging distance and interference resistance, particularly due to the time-of-flight method's short range and susceptibility to environmental interference.
Innovation Solution
An array coherent ranging chip with a modulated light source unit, on-chip emission unit, and reception array that generates and splits light beams for multi-angle signal processing, using reference and reflected signals to enhance ranging accuracy and resistance to ambient light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the time-of-flight method is used for ranging, then the system structure is simple, but the ranging distance is short and interference resistance is poor
Solution Approach 1:
The patent changes the fundamental measurement parameter from time-of-flight to phase difference of coherent light waves. By using coherent detection and measuring the phase shift of modulated light signals, the system achieves much longer ranging distances and better interference resistance while maintaining a relatively compact structure through integrated photonic circuits.
Solution Approach 2:
The patent replaces mechanical scanning systems (such as rotating mirrors or moving parts) with optical phased arrays and integrated photonic beam steering mechanisms. This substitution eliminates mechanical complexity while enabling long-range coherent detection through phase-controlled light manipulation.
2Adaptability or versatility
If flashes with wide-emission-angle light source are used to implement multi-angle emissions simultaneously, then the field-of-view is enlarged, but the emitting power within unit angle is limited and ranging distance is restricted
Solution Approach 1:
The patent segments the light emission into multiple discrete angular channels using an optical phased array or beam splitting network. Each reception unit corresponds to a specific angle and processes signals independently, allowing the system to maintain high power concentration in each angular direction while covering a wide total field-of-view through parallel multi-angle detection.
3Loss of information
If sensors are used to detect reflected light at multiple angles, then multi-angle signal information is obtained, but environmental light interference causes sensor saturation and reduces identification capability
Solution Approach 1:
The patent converts the harmful effect of environmental light into a beneficial filtering mechanism by using coherent detection. The system detects only light signals that are coherent with the transmitted reference signal (same frequency and phase relationship), automatically rejecting incoherent ambient light. This coherent correlation technique transforms potential interference into a selective advantage, allowing clear signal extraction even in bright environments.
Solution Approach 2:
The patent implements a feedback mechanism where the transmitted modulated light signal serves as a reference for the received signal. By comparing the phase and frequency of the returned signal against the known reference signal, the system can distinguish weak reflected signals from strong ambient light through correlation detection, effectively suppressing environmental interference.
4Reliability
If coherent detection with reference light is used, then interference resistance is improved and ranging distance is extended, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into integrated photonic circuits and chip-scale devices. The coherent detection system, including light sources, modulators, beam splitters, and detectors, is integrated onto a single chip or compact module. This integration maintains the high interference resistance and long ranging distance of coherent detection while dramatically reducing overall device complexity and size.
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 extends ranging distance, improves interference resistance, and enables high-speed data collection by using coherent detection and parallel processing of multi-angle signals, resulting in a compact, reliable, and cost-effective LiDAR system.
Implementation Method 1
coherent detection, and according to the different laser modulation methods, there are several relatively common solutions such as the frequency modulated continuous wave (FMCW) and the chirped amplitude modulation (CAM)
Implementation Method 2
irradiating the signal light onto a target object at a preset divergence angle so as to have the signal light reflected to form multi-angle signal light
Implementation Method 3
coherent detection, and according to the different laser modulation methods, there are several relatively common solutions such as the frequency modulated continuous wave (FMCW) and the chirped amplitude modulation (CAM)
Data Source
AI summary
Disclosed by the present application are an array coherent ranging chip and a system thereof. The chip includes a modulated light source unit (101), an on-chip emission unit (102) and a reception array (103). The modulated light source unit (101) is used for generating a modulated light beam and splitting the modulated light beam into signal light and reference light, and then outputting the signal light and the reference light. The on-chip emission unit (102) is used for irradiating the signal light onto a target object at a preset divergence angle so as to have the signal light reflected to form multi-angle signal light. The reception array (103) is used for receiving the reference light and the multi-angle signal light and respectively performing conversion and detection on both the reference light and the signal light of each angle so as to obtain a plurality of ranging signals. The present application implements the laser ranging by employing the form of a chip, whereof the structure is compact, the reliability is high, and the cost in ranging is reduced. In a way of coherent ranging that employs reference signal and reflected signal at the same time, the choice of a proper reference power can implement the control on signal amplitude, thereby the range of ranging is able to be extended, which provides the effect of ambient light interference resistance, and enables parallel processing of data on multiple pixels by receiving multi-angle reflected lights at the same time.