Using radar to predict radar and fall accidents


Researchers at Chalmers University of Technology in Sweden have developed a method for predicting fall accidents and cognitive illnesses such as Alzheimer’s disease by reading a person’s walking pattern with the aid of a radar sensor.

The small sensor can be attached to furniture, walls and ceilings, both in the home and in a healthcare setting. “Our method is both precise and easy to use. It can help healthcare staff to carry out a more reliable risk analysis and tailor interventions to achieve a significant effect early on. Hopefully it can help to solve a growing challenge for society,” says Xuezhi Zeng, who is a researcher in biomedical electromagnetics at Chalmers University of Technology. 

The researchers published their findings in the journal Sensors.

portrait of Xuezhi Zeng

Fall accidents and cognitive illnesses such as Alzheimer’s disease are increasing as the population ages. Preventive measures are helpful and can reduce both suffering and costs. In Sweden around 100,000 people aged 65 or over have such bad falls each year that they need to seek medical care, with 70,000 of them needing to be admitted to hospital. Approximately 1,000 elderly people die each year due to fall accidents. This situation is not unique to Sweden. For example, in the USA it is estimated that 3 million elderly people seek care in an emergency department due to fall accidents each year. The new method devised by the Chalmers’ researchers uses a small radar sensor to acquire real-time, high-resolution reading of a person’s walking pattern, especially the time required to take a step. 

“It is the variation in step times that is the key. A healthy person normally has a regular gait. But a person at risk of fall accidents often has a large variation in step times. For example, the first step may take a second whereas the second may take two seconds,” says Zeng. 

It can be used without invading people’s privacy and integrity, and without the feeling of monitoring that something such as a camera would giveXuezhi Zeng

A product containing the sensor is no larger than a fire alarm and could be used within the healthcare system, in the home or in care environments for the elderly in order to identify risks. Preventive measures such as physiotherapy, tailored training or the adaptation of furnishing in the home can be implemented in order to prevent fall accidents, thus avoiding both suffering and costly hospital care. Apart from being easy to use, another advantage of the method is that it collects data without filming. “This means that it can be used without invading people’s privacy and integrity, and without the feeling of monitoring that something such as a camera would give,” says Zeng. 

Also, with cognitive illnesses such as Alzheimer’s, an increase in step time variability is often an early symptom. Alzheimer’s disease is one of the most common causes of dementia in the world, and it is difficult to detect at an early stage. Here too, the method could be beneficial as an aid to making an early diagnosis, and contribute to preventive measures and an improved quality of life. 

The method is based on an off-the shelf radar sensor and therefore a commercial development is feasible in the near future. In the short term, Zeng hopes that it can be used by the elderly at home and provide healthcare staff with objective and valuable decision support data. She also hopes that in the future the method can facilitate clinical research in the elderly and establish more connections between a change in gait and the development of other illnesses. 

Source: Chalmers University of Technology

Can this radar spot a missing plane?


Research team test photonics-based coherent radar system
The new laser system could send live cockpit video as well as pinpoint a plane’s precise location

As the search for the missing Malaysia Airlines flight intensifies, a new advanced radar system has been unveiled by scientists. But could it spot the plane?

The world’s first photonic radar was tested at Pisa Airport in Italy and achieved “world-class” performance, according to an independent expert.

It uses lasers to produce high fidelity signals that pinpoint planes precisely.

But there are doubts over its range, say researchers in Nature journal.

Could it really have followed flight MH370 as it veered off its route from Kuala Lumpur to Beijing – possibly travelling far out over the southern Indian Ocean where search teams are now investigating sightings of possible debris?

Today’s radar networks track planes via a combination of ground stations and satellites – as this guide explains.

Normal aircraft tracking

Graphic: How planes can be tracked

The new PhoDiR (Photonics-based fully digital radar) system is a working prototype for next-generation radars – designed to let pilots and air traffic control exchange far more information in a single signal.

Photonic systems promise:

  • Higher precision – less noise (interference) in the radar transmission
  • Higher bandwidth – able to transmit cockpit data (eg critical flight systems) as well as location data, simultaneously
  • Greater flexibility – more frequencies available
  • Smaller antennas – cheaper, lighter and more portable

PhoDiR was developed by Paolo Ghelfi and colleagues at Italy’s National Laboratory of Photonic Networks.

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One could imagine transmitting live streaming video from the cockpit together with the radar data”

Dr Paolo Ghelfi National Laboratory of Photonic Networks, Italy

To test their radar, they put it on the roof of their lab – and pointed it at planes taking off from nearby Pisa Airport.

“It was even more precise than we expected. We detected airplanes much farther away than we expected, with even higher precision,” he told BBC Radio 4’s Inside Science.

“We’re still trying to find out exactly how much better it is than conventional radar. It’s only a prototype – we don’t have clear numbers yet.”

The compact system could potentially be installed on aircraft, and has a very large bandwidth – allowing pilots to transmit detailed information directly to ground stations within range.

“In future, we imagine a system on an airplane that can scan objects around but also communicate what’s happening in the cockpit – what has been said, movements in the airplane, everything,” Dr Ghelfi told BBC News.

“One could imagine transmitting live streaming video, together with the radar surveillance data. The advantage would be that a single system can do the entire job, instead of multiple systems.”

Map of MH370 information

Experts say photonic radar can overcome some of the limitations of current electronic systems.

A laser produces a finely-tuned digital signature, which is converted into a radio frequency wave and transmitted from the radar antenna.

The returning wave is also converted via laser into a digital signal free from “jitter”.

“Because the light is very precise, so is the radio frequency signal,” said Prof David Stupples, an expert on radar systems at City University in London.

“Currently we produce the carrier wave using electronics. But then you’ve got to transport it up to the radar head through expensive, heavy cabling – and this creates noise in the system.

“But if you use light – with fibre optics – it is cheaper, lighter and crucially – it has less interference. It’s very accurate.”

The BBC’s Richard Westcott takes a look at the gadgets used to track a plane in flight

Jason McKinney, of the US Naval Research Laboratory, said the performance of the system’s transmitter and return signal converter were “world-class with respect to those of other photonics-based devices”.

“These elements… are appealing components for future frequency-agile, software-defined radar architectures,” he wrote in a commentary in Nature.

The main limitation on the system, he says, is range. It’s not clear how a photonic ground radar could cover any greater swathe of ocean than current coastal stations.

Dr Ghelfi agrees. “Over oceans you might still depend on satellite capacity,” he told BBC News.

And for this reason, the missing Malaysia Airlines flight MH370 would likely evade PhoDiR too – assuming it has taken a path across the Indian Ocean.

Rather than hunting planes over seas, the new system would be much more useful over land – benefiting European air traffic control for instance, the researchers suggest.

In highly-congested airspaces – such as above London’s Heathrow Airport – pilots will know precisely how much breathing space they have.

But the photonic system could also have applications beyond air traffic control.

It could be used more widely in surveillance and wireless communications. Dr Stupples even suggests it could help motorway drivers to avoid collisions in fast-moving traffic.

“We are putting all these radar systems into a single small chip – low-cost with multiple functionalities,” said Dr Ghelfi.

“But it will not be something that you will see right away – we are in the range of years and not of months.”

Dolphin-inspired bomb radar tested.


A dolphin
Dolphins send out signals in pairs to help target prey

British engineers have taken inspiration from dolphins for a new type of radar that could help detect roadside bombs more easily.

The device sends out two pulses instead of one, mimicking how dolphins pinpoint their prey.

The twin inverted pulse radar (TWIPR) can distinguish between the electronics at the heart of an explosive and other “clutter” such as pipes or nails.

Experts said the system “showed promise”.

The radar device has been developed by a team led by Prof Tim Leighton, of the University of Southampton, and scientists from University College, London.

Strong signal

Prof Leighton took his inspiration from the way dolphins are able to process their sonar signals to pinpoint prey in bubbly water.

Some dolphins blow bubble nets around schools of fish to force them to cluster together.

Their sonar would not work if they could not distinguish the fish from the bubbles.

He wanted to see if the same technique would work with radio waves, and so developed a system that also sent out pulses in pairs.

Traditional radar typically sends out just one pulse.

The device his team came up with was just 2cm in size and cost less than £1 to put together.

The second pulse has the reverse polarity of the first.

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Any technology that increases the probability of detecting IEDs [improvised explosive device] or buried earthquake victims while reducing false alarms will undoubtedly save lives”

Gary Kemp Cambridge Consultants

This means that if it hits an electronic device, it turns the pulse into a positive, which in turn gives off a very strong signal.

In tests the team applied the radar pulses to an antenna typical of the circuitry used in explosive devices, which was surrounded by “clutter” metals.

The antenna showed up 100,000 times more powerfully than the other metal “clutter”.

Animal super-senses

Such a device could also be extremely helpful in finding surveillance device as well as bombs, the team said.

It could even help locate people buried after an avalanche or earthquake by detecting their mobile phones.

“Such technology could also be extended to other radiations, such as magnetic resonance imaging (MRI) and light detection and ranging (Lidar)… offering the possibility of early fire detection systems,” said Prof Leighton.

Gary Kemp, programme director at technology consultancy Cambridge Consultants, said that the system “shows promise”.

He said: “We continue to take inspiration from the many animal super-senses found in nature, whether from the sophisticated echolocation techniques used by bats and cetaceans or the remarkable chemical detection ability of dogs and bees.

“Any technology that increases the probability of detecting IEDs [improvised explosive device] or buried earthquake victims while reducing false alarms will undoubtedly save lives,” he added.