Development of long-range, high ranging resolution and crosstalk-free LiDAR by FMCW method

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04501
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21030:Measurement engineering-related
• Research Institution: Kanazawa University
• Principal Investigator: Iiyama Koichi 金沢大学, フロンティア工学系, 教授 (90202837)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 光干渉計測 / FMCW法 / LiDAR / 距離計測 / 物体形状計測

Outline of Final Research Achievements

We have developed FMCW LiDAR using a high-coherence laser diode as an optical frequency-swept laser source. The nonlinearity in the optical frequency sweep is cancelled by utilizing the k-sampling method. We have successfully profiled structures inside a building in our campus up to 200 m distant. The repetition frequency of the optical frequency sweep was increased up to 30 kHz for fast measurement, and the measurement time of about 3 sec was realized. However, the nonlinearity in the optical frequency sweep cannot be perfectly cancelled by the k-sampling method for fast measurement situation. To overcome the problem, we slightly distorted the modulation signal for optical frequency sweep to improve the linearity of the optical frequency sweep. As a result, accurate profiling can be realized even when fast repetition frequency of the optical frequency sweep.

Free Research Field

光電子計測工学

Academic Significance and Societal Importance of the Research Achievements

FMCW LiDARは光の干渉を利用することから，外部光が非常に強い環境においても，安定した計測が可能である。また，干渉を利用することで高感度であり，レーザ光パワーが現行のToF法の100分の1以下の低パワーでも距離測定が可能である。これらのことから，屋外における測量，自動運転自動車などにおけるレーザレーダへの安全な適用が可能である。また，遠方の構造物までの距離を持続的に測定することで，構造物の揺れの検知も可能であり，構造物の健康診断や破壊予測など，防災分野への適用も可能である。