Sense and Avoid Sensors for sUAV

Detect, Sense and Avoid for sUAV
Small UAS of the size 55-lbs provides to consumers opportunities ranging from indoor to outdoor applications, such as aerial video-photography, land mapping, and surveying, or delivering packages. The payload size, weight, and power (SWaP) is an essential constraint that forces designers to miniaturize cooperative and non-cooperative sensors needed for sense and avoid (SAA) functionality. Compact, lightweight and low-cost sensors such as the Industrial Millimeter-wave (mmWave) Sensor offers the mean to detect, sense and avoid objects that are threats or targets.
Industrial mmWave Technical Specifications and Operations
Texas Instrument (TI) millimeter wave (mmWave) sensor, integrates RF processing, calibration, high-speed ADC, microcontroller (MCU), digital signal processing (DSP) and memory on a single complementary metal-oxide semiconductor (CMOS) monolithic chip, which accurately reports range, velocity and angle between the sensors and objects around the drone (TI, n.d.) This contactless technology operates in the spectrum ranging from 30 GHz to 300 GHz using small wavelengths that can penetrate things such as plastic, drywall, clothing, and function correctly in a rainy, dusty, foggy, and snowy environment (TI, n.d.). For example, The TI (n.d.) document describes the IWR1642 as being highly integrated and built on RFCMOS technology operating in 76- to an 81-GHz frequency band. The devices have a closed-loop PLL for precise and linear chirp synthesis, includes a built-in radio processor (BIST) for RF calibration and safety monitoring. The devices have a very small-form-factor, low power consumption, and are highly accurate. The single radar chip features FMCW transceiver, built-in calibration and self-test, a 1.5MB memory chip and power management encompassing the following:
– Built-in LDO Network for Enhanced PSRR
 – I/Os Support Dual Voltage 3.3 V/1.8 V (TI, n.d.).
 IWR1642 use for displacement sensing, traffic monitoring, proximity sensing and motion detection in sUAV facilitates objects detection, sense, and avoidance. 
Ground-Water Proximity and Object Detection and Avoidance
Landing a UAV is one of the most critical navigation phases that mmWave intelligent operation can detect the ground or water proximity and abort the landing in case of water proximity. The IWR evaluation module (EVM) can achieve 2-cm of accuracy with an altitude range from the ground to 40 m, at speed from hover to exceeding 25 cm per second (TI Marketing, 2017). A speedy data processing to detect and avoid obstacles in the air is necessary as the UAV navigates at high speed. TI Marketing (2017) reports:
At the core of an intelligent sense-and-avoid operation is a drone’s ability to detect possible obstructions that it will encounter in its line of flight, which could result in total loss or damage to the platform, negatively impacting productivity. Beyond the ability of mmWave sensors to detect objects in conditions without regard to lighting, smoke, dust or fog, they are uniquely positioned to identify objects that are difficult using other sensor technologies.
Conclusion

As the computer chip sensor industry continues to evolve, the miniaturization of highly intelligent single radar chip sensors provides the sUAV the opportunity to implement detect, sense and avoid (DSA) that would almost be very difficult to achieve. Cooperative technologies such as traffic alert and collision avoidance (TCAS) and the automatic defender surveillance-broadcast are too big and complicated to fit in a 55-lbs UAV that mmWave offers the best alternative.

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