UAS Sensor Placement

Unmanned Aircraft System Sensor Placement

Mark C. Hardy

Embry Riddle University

Unmanned aircraft systems (UAS) have the potential to serve in a multitude of civilian roles impacting a large number of industries. As UAS mission sets have developed, so too have the electronic sensor technologies necessary to support new mission requirements. Ideally, new sensor technology would be coupled with new UAS platforms designed specifically for a particular sensor and its mission. However, given the range of unmanned aircraft currently available, it is commonplace for new sensor payloads to be designed for integration with UAS platforms already in service. One key consideration of the platform selection and integration design process is the placement and positioning of the sensor payload on the UAS airframe to optimize sensor performance (Austin, 2010).  

The Flying-Cam 3.0 SARAH and its sensor payload was designed to conduct high resolution aerial video/photography and in October of 2014, Flying-Cam Inc. was granted an exemption by the Federal Aviation Administration (FAA) for use in video production on closed sets within the United States. Prior to that the 3.0 SARAH had been used abroad to conduct high definition cinematography (Flying-Cam, 2014).

The 3.0 SARAH is an electric-powered twin engine UAS in a conventional single-rotor helicopter configuration.  The 3.0 SARAH’s effectiveness for conducting the aerial video/photography mission can be attributed to the forward looking “Gyro Head 3.0” gimbal system which is prominently mounted to the device’s nose section. The Gyro Head 3.0 utilizes a high grade inertial measuring unit (IMU), along with the attitude and heading reference system (AHRS), to provide automatic horizon leveling and stabilization even in high wind conditions. The Gyro Head 3.0 is capable of a 90 degree up tilt and a -110 degree down tilt at a maximum rate of 60 degrees per second. Flying-Cam’s Body Pan system employs the 3.0 SARAH’s gyro stabilized direct drive tail rotor to provide a full 360 degree unobstructed azimuth pan capability by yawing the entire aircraft at a maximum rate of 120 degrees per second (Flying-Cam, 2014).

The 3.0 SARAH and the Gyro Head 3.0 can accommodate a wide array of non-dispensable electro-optical payloads capable of capturing high resolution still imagery and high definition video (Austin, 2010; Flying-Cam, 2014). The 3.0 SARAH’s conventional single main rotor helicopter configuration combined with the Gyro Head 3.0’s forward placement provides the system with an unobstructed field of view throughout the vast majority of the Gyro Head 3.0’s specified range of motion. Operation of the system is further aided by the 3.0 SARAH’s computer assisted piloting (CAP) software which allows missions to be pre-programmed and flown autonomously. Additionally, the system’s versatility can be further enhanced by selection of an optional all-weather performance package (Flying-Cam, 2014).

While the 3.0 SARAH and its systems are clearly suited to collect aerial imagery, the Storm Racing Drone (SRD) was built for speed and performance for the task of first person view (FPV) multi-rotor racing. Many FPV multi-rotor racing enthusiasts prefer to build their own racing UAS utilizing customizable kits. However, the SRD is an off the shelf FPV quad-copter racer built on a lightweight but highly durable carbon fiber frame.

The SRD utilizes four 2204 brushless electric motors to power its tri-blade rotors which provide exceptional acceleration and maneuverability. The entire system is powered by an 11.1 volt, 1500 milliamp lithium polymer battery giving the SRD approximately 5-8 minutes of racing endurance (Helipal, 2015).

The SRD radio control system operates at 2.4 gigahertz while the FPV system transmits at 5.8 gigahertz. Both systems offer sub channels to allow multiple UASs to operate on the same frequency in close proximity. The SRD is equipped with a forward looking camera which is mounted on top of the SRD’s main support frame and located within the protective equipment bay to prevent damage in the event of a crash. The FPV camera is positioned in a fixed-mount and provides a 110 degree field of view for the operator. The camera’s forward looking fixed position is essential in the high speed FPV environment allowing the operator to quickly and accurately determine the aircraft’s spatial orientation. The SRD’s relatively low resolution camera system allows for low latency video data transfer which lends well to the FPV experience (Helipal, 2015).

The aforementioned aircraft are equipped with sensor payloads which are ideally positioned on their respective UAS platforms to perform their specific missions. The 3.0 SARAH equipped with the forward mounted Gyro Head 3.0 offers a system capable of supporting a range of high grade camera systems while providing the requisite unobstructed field of view to collect studio quality aerial imagery. The SRD, designed for the multi-rotor FPV racing enthusiast, does not necessitate a high quality imaging system or an adjustable field of view. The SRD’s mission allows for a lower resolution video system with a fixed mount system that can transmit data to the operator’s FPV receiver in real time for enhanced spatial orientation.

References

Austin, R. (2010). Payload Types. Unmanned Aircraft Systems-UAV Design, Development, and Deployment  (pp.127-141). Retrieved from http://site.ebrary.com.ezproxy.libproxy.db.erau.edu/lib/erau/reader.action?docID=10380998

Flying-Cam Inc. (2014). Flying-Cam 3.0 SARAH. Retrieved from http://www.flying-cam.com/en/products.php?product=2

Flying-Cam Inc. (2014, October 15). Official FAA Approval for Flying-cam 3.0 SARAH. Retrieved from http://www.flying-cam.com/en/news.php?id=133

Helipal (2015). Storm Racing Drone. Retrieved from http://www.helipal.com/storm-racing-drone-rtf-type-a.html