Millimetre Wave Radar: A New Skyline for Autonomous UAS
By: James Henderson
Consultant, Antennas & Propagation
23rd August 2017
When people talk about what technology is going to be available in the future, most 10-year-olds will imagine a world where we’re all flying around with jet packs on our backs, or being waited on by Humanoid robots. But as an engineer involved in cutting-edge technology, I like to think about a more realistic short-term answer to such a question.
One of the biggest developments over the past decade has been in enabling the autonomy of road vehicles and, whilst various technology companies are promising self-driving cars in the near future, the smaller step of driver aids has become the norm for modern cars. As with most large scale industry advances where huge sums of money are invested in their development, new technologies often open up opportunities to other industries.
This has certainly been the case with the development of cheap millimetre wave (mm-wave) devices. These have come off the back of automotive radar modules for adaptive cruise control and automatic braking assistance. But rather than looking for large vehicles in lanes on the motorway, there are many alternative applications for a mm-wave radar sensor, both for use in civil and military scenarios.
For me, the futuristic application which this enables is that Unmanned Aerial Systems (UAS) could soon be the common method for automatically delivering all manner of items. From completing takeaway meal orders to medi-kit drops for personnel on the front line – I may not be alone in having this vision but I can say that I’ve played a part in their development.
However, enabling the ability of autonomous flight for small UAS is not a trivial task. There are many difficulties involved with allowing swarms of UAS to safely navigate through the concrete jungle of an urban environment. They would need to avoid buildings, power lines, trees, and potentially other UAS on different errands.
This is especially difficult in a military context, where the environment could be hostile, complex and contested. Operations can take place day, night and in all weather conditions – this would be the case for the last mile resupply requirement (as stated in this most recent Defence and Security Accelerator competition).
For both scenarios, this requires a 3-dimensional situational awareness by detecting small objects, potentially out to hundreds of metres with a level of positional accuracy to allow a fast moving UAS to navigate through a cluttered environment. In this scenario, a low size, weight and power sensor is critical to its success, and pushing radar to operate at mm-wave frequencies could be the solution.
More often than not, radio engineers choose to go up in frequency to utilise the large amounts of available bandwidth, particularly for communication systems where users are demanding ever increasing data rates, but for this application, there’s another advantage. For high definition radar to achieve small angular resolution, the antenna needs to be large with respect to the wavelength. Therefore, increasing the frequency (which will reduce the wavelength) allows us to keep the same resolution in a smaller size.
At Plextek, we have been capitalising on the small wavelength of these mm-wave devices to design a complete radar front end on a single 10 x 10 cm circuit board. This minimises size and weight, but also system complexity, where transmit and receive antennas are inherently aligned on a flat panel.
There are many difficulties with working at higher mm-wave frequencies which primarily come from the increased precision required in every aspect of the design, as well as handling the higher loss associated with high-frequency systems. But the extra effort required is sure to be worth it if it means the Poppadoms in my Indian take away are still warm when they arrive cradled underneath an autonomous UAS. Or those vital supplies are delivered efficiently to personnel engaged in combat operations to maintain operational tempo and enable successful mission outcomes.
When people talk about what technology is going to be available in the future, most 10-year-olds will imagine a world where we’re all flying around with jet packs on our backs, or being waited on by Humanoid robots. But as an engineer involved in cutting-edge technology, I like to think about a more realistic short-term answer to such a question.
One of the biggest developments over the past decade has been in enabling the autonomy of road vehicles and, whilst various technology companies are promising self-driving cars in the near future, the smaller step of driver aids has become the norm for modern cars. As with most large scale industry advances where huge sums of money are invested in their development, new technologies often open up opportunities to other industries.
This has certainly been the case with the development of cheap millimetre wave (mm-wave) devices. These have come off the back of automotive radar modules for adaptive cruise control and automatic braking assistance. But rather than looking for large vehicles in lanes on the motorway, there are many alternative applications for a mm-wave radar sensor, both for use in civil and military scenarios.
For me, the futuristic application which this enables is that Unmanned Aerial Systems (UAS) could soon be the common method for automatically delivering all manner of items. From completing takeaway meal orders to medi-kit drops for personnel on the front line – I may not be alone in having this vision but I can say that I’ve played a part in their development.
However, enabling the ability of autonomous flight for small UAS is not a trivial task. There are many difficulties involved with allowing swarms of UAS to safely navigate through the concrete jungle of an urban environment. They would need to avoid buildings, power lines, trees, and potentially other UAS on different errands.
This is especially difficult in a military context, where the environment could be hostile, complex and contested. Operations can take place day, night and in all weather conditions – this would be the case for the last mile resupply requirement (as stated in this most recent Defence and Security Accelerator competition).
For both scenarios, this requires a 3-dimensional situational awareness by detecting small objects, potentially out to hundreds of metres with a level of positional accuracy to allow a fast moving UAS to navigate through a cluttered environment. In this scenario, a low size, weight and power sensor is critical to its success, and pushing radar to operate at mm-wave frequencies could be the solution.
More often than not, radio engineers choose to go up in frequency to utilise the large amounts of available bandwidth, particularly for communication systems where users are demanding ever increasing data rates, but for this application, there’s another advantage. For high definition radar to achieve small angular resolution, the antenna needs to be large with respect to the wavelength. Therefore, increasing the frequency (which will reduce the wavelength) allows us to keep the same resolution in a smaller size.
At Plextek, we have been capitalising on the small wavelength of these mm-wave devices to design a complete radar front end on a single 10 x 10 cm circuit board. This minimises size and weight, but also system complexity, where transmit and receive antennas are inherently aligned on a flat panel.
There are many difficulties with working at higher mm-wave frequencies which primarily come from the increased precision required in every aspect of the design, as well as handling the higher loss associated with high-frequency systems. But the extra effort required is sure to be worth it if it means the Poppadoms in my Indian take away are still warm when they arrive cradled underneath an autonomous UAS. Or those vital supplies are delivered efficiently to personnel engaged in combat operations to maintain operational tempo and enable successful mission outcomes.
