Is Your Drone Flying Blind?
Spend a few days at a drone conference and two things rapidly become clear. First, from the technical programs, we hear a lot about promising developments in spatial awareness sensors, collision avoidance solutions, and research projects related to SLAM (Simultaneous Location and Mapping). Second, a tour of the main UAV vendors on the show floor rapidly indicates that these solutions are not quite ready for prime time.
Clearly, a gap exists between the immediate needs of this booming industry for efficient spatial awareness sensing and the solutions that are readily available.
Interestingly, the challenges related to commercial drones’ awareness of their immediate environment are quite similar between the entry-level $1500 quadcopter and the $50,000 fully loaded customized UAV. Here are three of these key challenges and how optical detection and ranging can help.
Take-off, hovering and landing
In order to take off gracefully in a vertical direction, have the ability to hover in place while awaiting a pilot’s instructions, and avoid hitting the ground upon landing, UAVs rely on information from GPS and pressure sensors located outdoors. This may become problematic when navigating in urban canyons and inside structures as well as during indoor operations. To assist in these situations, some vendors provide ultrasound (SONAR) sensors that will give you a height above ground level (AGL) of up to about 5 to 6 m. The SONAR is sometimes coupled with an optical flow camera, which can survey the ground and ensure lateral stability.
Many vendors now opt for an optical altimeter for its precise distance measurement to the ground as well as the superior distance range provided compared with ultrasonic sensors. This range will typically vary with the optical power of the light source: eye-safe power sources, such as LED and Class 1 lasers are favored over more powerful lasers, which may face safety restrictions. Highly optimized optical range finders, such as the LeddarOne, are being implemented in new generations of commercial drones.
Indoor navigation and 360° collision avoidance
Indoor navigation, rendering GPS and pressure sensors ineffective, is one of the main challenges faced by today’s UAVs. Imagine flying into a building damaged by an earthquake or navigating in sewer lines or inside a hydro dam turbine! Sensors capable of providing information about the drone’s immediate surroundings, including accurate distance information, enable the development of new navigation algorithms for safe and even automated flights. The drone then becomes aware of its position and any obstacles along the way.
Camera vision solutions are promising, but still immature, complex and processor-intensive. Sonars or infrared sensors are just too basic and lack in range. The use of a multi-segment optical sensing solution, enabled by Leddar technology, provides new capabilities in terms of multiple and precise distance measurements as well as obstacle detection. Using one or multiple wide fields-of-view, Leddar sensors on a drone allows for enhanced spatial awareness of up to 360°. Moreover, Leddar’s ultra-efficient onboard processing provides highly reliable positioning data with optimized power consumption and minimizes external processing requirements.
Structural inspection navigation
The use of UAVs for the inspection of a variety of structures, including buildings, bridges, dams, wind turbines, cell towers, and even large airplanes, is a rapidly growing field. Yet, existing drone sensors are still unable to provide sufficiently reliable positioning information to ensure precise and safe navigation in proximity of these structures.
Systematically navigating a pre-set inspection route while maintaining a safe, specific distance from the structure may prove to be a challenging and sometimes risky venture. Here again, the multi-segment Leddar optical sensor module, providing a wide range of field-of-views options, may just be the perfect solution.
Installed pointing forward, the Leddar sensor enables safe navigation by measuring critical UAV position information with regards to the structure and detecting obstacles entering its field of view.
Optical sensing technologies for drones: It’s just the beginning
With the exponential popularity of drones of all types roaming our cities, industrial complexes, and countryside, the quest to provide the best possible safety and navigation tools is ongoing. In the long term, we can expect a combination of on-board sensors working together with live, two-way communication systems that provide both airspace restriction information and real-time aircraft positioning data (from drones to commercial jetliners). Together, they will ensure secure, responsible UAV operation by both hobbyists and professional pilots.
It is generally accepted that full-blown detection and communication systems sanctioned by aviation authorities for mid-air collision avoidance will likely take time to develop and become commercially available. In the meantime, innovative sensor technologies, such as Leddar, either used by themselves or in a combined “sensor fusion” solution with other onboard navigational tools or camera vision systems, can indeed provide efficient, value-added detection capabilities that will make a significant difference in today’s UAV capabilities.