Sense and Avoid Sensor Selection

The sensors on an Unmanned Aerial System (sUAS) must meet several key criteria to be effective and practical. These sensors must be small in size, lightweight, and consume a minimal amount of power. All of these factors directly impact flight duration, one of the most important attributes for sUAS. In addition, a sense and avoid sensor must provide a wide field of view and high resolution at distances that provide coverage at maximum flight speeds.

A commercially available sensor suitable for this application is the μSharp – 360°, a miniature microwave radar sensor built specifically for UAV sense and avoid applications. Aerotenna went with a radar-based sensor due to the limitations of optical, LIDAR, and ultrasonic sensors (Aerotenna, 2016). Optical sensors are capable of very high resolution images but struggle in extreme or changing lighting conditions (Wilkinson, 2017). LIDAR sensors, although very high and detailed in resolution, are typically very expensive, heavy, and fragile due to their mechanically rotating lasers (Wilkinson, 2017). Ultrasonic sensors have numerous benefits but can have distorted readings due to density, consistency, and material.

      Aerotenna. (2016). μSharp – 360° microwave radar antenna.

The μSharp – 360° is a powerful sensor for its size. It provides 360-degree coverage without blind spots, scanning at 90 Hz at an accuracy of up to 5cm range (Aerotenna, 2016). The benefits of using a microwave radar is reliable performance in various weather and light conditions. A radar system works by sends out radio waves that bounce off of surfaces within range. The waves bounce back as echoes and the response time is used to calculate the distance from the object.

The μSharp – 360° weighs in a 243 grams (8.57 ounces) with dimensions of 115mm by 115mm by 67mm (Aerotenna, 2018) which can be mounted onto a professional 6 rotor professional sUAS such as the DJI Matrice Pro 600. This sensor can be purchased for $2,499 (Aerotenna, 2018), an acceptable price when looking at the DJI Matrice Pro 600 which costs $4,999 before the addition of a gimbal and camera (DJI, 2018a). The sensor uses a 5V DC, 500 mA power input and consumes 2.5w (Aerotenna, 2017). Unlike sense and avoid sensors on other aircraft like the DJI Phantom 4 Pro, the μSharp – 360° can detect objects at a minimum range of 0.5 meters (1.6 feet) to a maximum range of 40 meters (131.2 feet) (Aerotenna, 2017). The Phantom 4 Pro’s infrared sensing system is only capable of detecting objects at a maximum distance of 7 meters (23 feet) (DJI, 2018b).

This sensor can be used on any sUAS which has room for external sensors, both in physical space and connectivity. The weight capacity of the aircraft must also be considered as this sensor weights 8.57 ounces, a number too large for smaller consumer UAS. A larger sUAS such as the Matrice 600 would have no issue with the added weight. The UAS can have any number of rotors (4, 6 or 8) as long as the weight can be supported safely.

References

Aerotenna. (2016, October 3). Aerotenna Releases 360° Sense-and-Avoid Radar, Advances Drones Closer to Autonomous Flight [Blog post]. Retrieved from Aerotenna website at https://aerotenna.com/aerotenna-releases-360-sense-avoid-radar-advances-drones-closer-autonomous-flight/

Aerotenna. (2018). μSharp – 360° Sense-and-Avoid Radar [Product page]. Retrieved from Aerotenna website at https://aerotenna.com/shop/%CE%BCsharp-360-sense-avoid-radar/

Aerotenna. (2017). μSharp ​– ​360° Sense-and-Avoid ​Radar Product Overview. Retrieved from Aerotenna website at https://aerotenna.com/datasheets/AerotennauSharp360Datasheet.pdf

DJI. (2018a). Matrice 600 Pro [Product page]. Retrieved from DJI Store website at https://store.dji.com/product/matrice-600-pro

DJI. (2018b). Phantom 4 Pro Specs [Product page]. Retrieved from DJI website at https://www.dji.com/phantom-4-pro/info#specs

Wilkinson, J. (2017, January 27). LiDAR Sensors in Drones and UAVs - Accurate Obstacle Detection in Any Environment [Interview]. Retrieved from AZO Sensors website at https://www.azosensors.com/article.aspx?ArticleID=737