Mar 25 2020
10:30 am - 11:30 am
Advanced Sensor Topics
Track Names: ADVANCED SENSOR TOPICS, Wednesday 10:30 - 11:30
Session Date: Mar 25 2020 10:30 am - 11:30 am
High Performance Unmanned Aerial Vehicle LiDAR
10:30 AM - 10:45 AM
Motivation: In precision agriculture LiDAR data is a key sensing modality providing valuable insight into crop yields and overall health. The large scale of tree nut groves, citrus groves and forestry operations combined with the requirement to provide timely information to customers makes an airborne LiDAR the most economical solution. Problem statement: Widespread adoption of LiDAR is hindered by the high cost of the LiDAR and INS/GPS systems currently available. In addition, current systems are primarily intended for mapping rather than a foliage penetrating (FOPEN) LiDAR optimized for imaging beneath dense canopies. FOPEN LiDAR allows measurement of tree topology, crop yield estimation while also imaging the surrounding topography. Collecting this data would be time consuming and prohibitively expensive without the use of LiDAR. Approach: A compact airborne LiDAR based on lessons learned during the DARPA Jigsaw FOPEN Lidar program has been designed. Development is based on a phased approach using function over form Engineering Demonstration Units (EDUs) to rapidly test various system configurations. Results: A LiDAR with 1x16 detector array, 100kHz laser and dual wedge prism scanner has been developed. Phase I is complete with an EDU operating at 1.6MSs. The Phase II flight EDU is nearing completion and will fly in the 4th quarter of 2019. A Phase III prototype with 1x128 array operating at ≥12.8MSs will be competed in 2020. Conclusions: Airborne LiDAR systems designed for mapping applications are not well suited to precision agriculture due to their limited FOPEN capability and high cost. A cost effective LiDAR design optimized for FOPEN capable of being deployed on small drones allows widespread use of LiDAR in precision agriculture and forestry.
Unique Scanning Scheme for High-Precision UAV LiDAR Acquisition
10:45 AM - 11:00 AM
In the last few years, LIDAR acquisition from medium-scaled unmanned aerial vehicles has found growing fields of applications by providing dense point clouds with high precision and impressive accuracy. Such employed LIDAR instruments have evolved significantly with respect to measurement speed and thus acquisition efficiency. Recent examples include LIDAR instruments with up to 1.5 million laser pulses per second on the ground, perfectly suited for operation from fast-flying fixed-wing platforms. However, it is not only the achievable point density on the ground that counts, but also the diversity of angles of incidence of the measurement beams with respect to the targets. Especially in corridor mapping with a single flight line over e.g. a power line, the acquisition of data on vertical structures like pylons is essential. We discuss a scanning scheme novel to UAV-based laser scanning which is especially suited for corridor mapping from UAV platforms. We illustrate the achievable distribution of the measurements on the ground for typical scenarios with emphasis on the distribution of the angles of incidence of the measurement beams on the objects providing an enhanced completeness of data acquired.
RIEGL Laser Measurement Systems GmbH
Design Trade-Offs in Selecting a Lidar System for UAV Operations
11:00 AM - 11:15 AM
Regulatory changes allowing for the commercial operation of unmanned aerial vehicles (UAVs) in the national air space are driving a rapid increase in the use of such platforms for survey and mapping applications. The increasing availability of off-the-shelf UAV platforms at prices that are affordable for survey firms allows for the profitable deployment of UAVs on small projects or at an increased frequency than would be achievable or cost-effective using traditional manned platforms. Initial UAV mapping projects were done primarily using digital cameras for image capture and structure from motion (SfM) techniques for product generation. As the commercial use of UAVs has expended, the demand to add lidar payloads on specific projects has increased rapidly. Designing a lidar payload for a UAV involves making tradeoffs in price, performance, size and weight of the lidar subsystem to fit the overall design goals for the payload. There are a range of lidar systems available from commercial vendors that fit the category of ?UAV lidars?. They can be classified into one of two categories for purposes of this analysis; automotive-class lidars and survey-grade lidars. The price/performance differences between the two class are significant while the price/performance difference between system within the same class are harder to quantify. We assessed the commercially available lidar system during the deign of our True View 410 lidar sensor, ultimately choosing the Quanergy M8 Ultra. In this paper we will present the results of our analysis on the strengths and weaknesses of each lidar system and the price/performance trade-offs considered during the design phase. We will present a roadmap and basic decision tree for determining the class and type of lidar best suited for common survey and mapping applications.
GeoCue Group, Inc.
Q&A and panel discussions with session presenters
11:15 AM - 11:30 AM
There will be a 15 minute Q&A /panel discussion with the presenters of the Advanced Sensor Topics session.