Sense and Avoid Sensor Selection

Originally unmanned systems were developed for government and military use. However, in recent decades, there has been a significant increase of small unmanned aerial systems (sUAS) becoming available commercially for a variety uses including: agriculture, infrastructure inspection, real estate, movie production, and hobbyist activities. With this sudden increase of availability, there has also been an increase of inexperienced operators. The development of sense and avoid systems not only protects the system, but also the public from potential incidents. These systems not only assist operators with avoiding obstacles, but allow the system to autonomously operate to avoid potential collisions when flying a predesignated route. This paper will discuss a commercially available sense and avoid system developed for a sUAS. It will give a detailed explanation of the system including how it operates, cost, weight, and power requirements.

The Guidance is a sense and avoid system developed by DJI in 2015 (Snow, 2016). Developed originally for the Matrice 100 platform, the Guidance was later incorporated into the Phantom 4 and later the Matrice 600 series sUAS (Snow, 2016). The Guidance uses a combination of five sets of ultrasonic sensors and stereo cameras to detect objects up to 65 feet away from the vehicle, including objects difficult to detect such as trees and grass (DJI, n.d.a; DJI, n.d.b). The Guidance allows sUAS to become a high-precision vision positioning system without the need of a Global Positioning System (GPS), with an accuracy within five centimeters (DJI, n.d.b). The Guidance has an effective sensor range of 0.2 meters to 20 meters and a velocity detection range within 0.04 meters per second from 2 meters of the ground (DJI, n.d.b). This allows the Guidance to maintain a safe predesignated distance from obstacles automatically, without the assistance of the operator (Snow, 2015).

The Guidance Kit from DJI comes with several components including: one Guidance Core, five Guidance Sensors, five VBUS cables (standard) to connect the sensors to the core, one VBUS cable (long) as a spare, and one CAN-Bus cable to connect the Guidance Core to the flight control system (DJI Store, n.d.). The kit also comes with one micro-USB cable, USB cable extender and one UART cable to allow the system to be connected to other computer systems when necessary (DJI Store, n.d.). The total weight of the system is approximately 337 grams which broken down is 64 grams for the Guidance Core, 215 grams for the five sensors sets, and 58 grams for the five VBUS cables (DJI, n.d.c). The system has a maximum power consumption level of 12 watts, which includes operating all five sensors simultaneously (n.d.c). The Guidance is available for purchase from the DJI store for $999 on its own (DJI Store, n.d.a). The Phantom 4 includes the Guidance within its onboard systems, but the Matrice does not come with the Guidance system equipped (Snow, 2016). In order to add the Guidance to the Matrice a Guidance Connector kit is needed which costs an additional $79 (DJI Store, n.d.a; DJI, n.d.b).

This system is an ideal choice for several reasons. One of the most significant reasons is that it can ensure precision position information without the need of a GPS. This means it can act as a redundant sensor in case of a GPS failure onboard the vehicle. The system can also be put onboard any sUAS with USB and UART connection ports according to an article from Unmanned Aerial Online and the DJI website (Lillian, 2015; DJI, n.d.c). This means that any operator wanting to design their own system can put the Guidance onto their vehicle. Another benefit to the system is the weight, which allows it to be within the payload requirements for many sUAS without making additional changes to the payload or battery components.

References

DJI. (n.d.a) Guidance. DJI. Retrieved from http://www.dji.com/guidance

DJI. (n.d.b) Guidance Features. DJI. Retrieved from http://www.dji.com/guidance/features#sub-feature

DJI. (n.d.c) Guidance SPECS. DJI. Retrieved from http://www.dji.com/guidance/info#specs

DJI Store. (n.d.a) Guidance. DJI Store. Retrieved from http://store.dji.com/product/guidance?site=brandsite&from=buy_now_bottom

DJI Store. (n.d.b). Matrice 100 – Guidance Connector Kit. DJI Store. Retrieved from http://store.dji.com/product/matrice-100-guidance-connector-kit

Lillian, B. (2015, June 8). DJI Unveils M100 Drone, Collision Avoidance System. Unmanned Aerial Online. Retrieved from https://unmanned-aerial.com/dji-unveils-m100-drone-collision-avoidance-system

Snow, C. (2016, September 22). Sense and Avoid for Drones is No Easy Feat. Skylogic Research Drone Analyst. Retrieved from http://droneanalyst.com/2016/09/22/sense-and-avoid-for-drones-is-no-easy-feat/

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