Sensor-based rider assistance systems are about to get serious

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It’s only been a year since the first radar-equipped bikes started to reach customers but already there are new companies starting to supply the tech.

Over the next couple of years radar is set to become the must-have tech on bikes and with fresh faces like Israel’s Vayyar coming into the market, the scene is set for a tech tussle that will encourage rapid improvement.

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While Bosch supplied the first front and rear-facing radars fitted to production bikes, with Ducati, BMW, KTM and Kawasaki adopting the German kit, we’re already seeing more firms getting in on the action.

New radar systems from Vayyar are on the way

Triumph’s new Tiger 1200 GT Explorer and Rally Explorer have rear-facing radars supplied by Continental, and as we reported last year, Piaggio are set to reveal their first bikes using Vayyar’s radars.

Vayyar’s kit is somewhat different from the Bosch system that’s laid the template so far and is described by the firm as ‘4D’ – it uses far more antennae than a normal radar, generating a high-resolution 3D ‘point cloud’ image of the world around it and using Doppler analysis, the measurement of distortion in the reflected radar waves caused by movement, to establish the relative velocity of objects it detects.

The greater number of antennae means the Vayyar radars have a 170-degree field of view both horizontally and vertically, which is significantly wider than the radar cone of more traditional systems.

The vertical coverage and wide field of view are particularly useful on bikes as it means the sensor won’t lose track of an object as you tip into a corner.

Piaggio look set to use Vayyar tech

The system also claims a much longer range than the market-leading Bosch radar, with Vayyar’s system picking up targets as far as 300m away, compared to 160m for the Bosch front radar. That’s potentially important, as bikes can’t use the sort of automated emergency braking systems seen in radar-assisted cars.

Motorcycle brake-assist can’t be aggressive, as it might throw the rider off, so being able to spot potential dangers at a greater distance and provide warnings or automated assistance earlier is a valuable benefit.

Vayyar say the system, with both front and rear radars, can support blind spot detection, lane change assist, adaptive cruise control, front and rear collision warning and rider brake assist and costs the same as existing radars (for reference, the Bosch front radar option on BMW’s R1250RT costs £500).

Radar technology explored

Vayyar say their software can support blind spot detection

Long vision Up to 300 metres – vital for brake-assist or early warning systems so as not to cause panic reactions from riders.

Wide angle Around 170-degrees of coverage per radar, both horizontally and vertically, means two units (one front, one rear) give nearly 360-degree coverage.

More antennae There are up to 48 antenae rather than the seven in most automotive radars – using WiFi-style MIMO (Multiple Input, Multiple Output) technology to track multiple targets, and Doppler analysis to work out their velocity and direction of movement.

Small but affordable Safety kit is no good if it’s only fitted to the most expensive, unattainable bikes, but Vayyar say their radars are low-cost and small enough to be fitted unobtrusively and affordably, even on scooters.

Staying on target Current radars like the Bosch MRR (Mid-Range Radar) monitor up to 32 objects but Vayyar say their system can keep track of an unlimited number of targets.

Piaggio’s active radar tech to make your bike stand out to autonomous cars

First published on 3 February 2022 by Ben Purvis

Piaggio radar reflector technology is on the way

When cats arch their backs, elephants spread their ears, frogs puff up their throats or cobras spread their hoods they’re all doing one thing: making themselves look bigger than they really are. And that’s precisely what motorcycles of the future may try to do when mingling with autonomous cars.

Since radar is the dominant technology being used in driver assistance systems and for the sensor arrays of the next generation of self-driving cars, the trick will be to give bikes a larger radar cross-section than they really have, allowing them to be sensed at a greater distance.

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It’s a topic that’s become hotter than ever. The Law Commission – the independent statutory body that makes sure our laws are up-to-date and recommends reforms – has now published its report on automated vehicles, recommending the creation of an Automated Vehicle Act that would shift the accountability for accidents from the driver to the manufacturer of the vehicle when in self-driving mode.

New technology could make riders more visible to other road users

But whoever the blame lies with, if you’re the rider who’s been hit because a car’s radar system didn’t spot you soon enough, you’re coming off worse.

Research has, unsurprisingly, shown that ADAS (advanced driver assistance systems) don’t spot smaller vehicles as easily as larger ones.

A project by Dynamic Research Inc in 2016 showed bikes were inadequately detected in 40% of trials. That’s improving, with Euro NCAP now adding specific tests for ADAS to see how well they spot bikes, but even so motorcycle ‘visibility’ to radar remains a concern. That’s where the idea of appearing bigger comes into play.

Both Suzuki and BMW have filed patents for passive radar reflectors in the last year or so (see below) – simple, cheap, reflective arrays that can be mounted on bikes to bounce back radar waves more effectively. Now Piaggio has filed a patent for its own take on the idea, but it’s opting for an active radar reflector.

Piaggio have opted to keep their reflector equipment simple

Both active and passive reflectors are already well-established in the maritime sector. On boats, active radar reflectors have the advantage of being smaller and operating over longer ranges than passive ones, and the same is likely to apply on bikes.

Piaggio’s design features two small reflectors – one front, one rear – to receive radar waves, amplify those signals and then transmit them back at their source.

The patent suggests they would be fitted inside the head- and tail-lights, where there’s already an electrical supply.

While an active reflector would probably cost more than the passive reflectors, Piaggio’s is a simple design that seems unlikely to be expensive and has the advantage of being able to be completely hidden.

Radar reflectors explored

Piaggio radar reflector equipment revealed in patents

Return to sender Once the receiving antenna (marked 52 in the drawings) picks up a radar signal – from a car’s front radar or its blind spot radar, for instance – it sends that through the amplifier (54) and into the transmitting antenna (53) to fire back a strong reflection.

Dial up the accuracy In the most basic version, the chip (56) controls the how much the signal is amplified, but Piaggio also suggests more advanced reflectors including a signal modulator (59) to compensate for delays introduced by the electronics and make sure the bike’s radar ‘blip’ appears in the right place.

Doing the full 360° The reflectors in the patent transmit a beam that covers between 15° and 45° vertically and between 120° and 160° horizontally, so having two wouldn’t quite create a 360° circle around the bike. However, Piaggio’s patent says more reflectors – one on each side, for instance – could be used if that proves necessary.

Keeping it simple There are only five components in the simplest form of the active radar reflector: a receiving antenna, an amplifier, a control chip, a voltage regulator and a transmitting antenna.

Adding extra info Piaggio also suggest the return signal could be encoded with additional information that the ADAS system of the car could interpret. For instance, it could tell the car what type of vehicle its radar is detecting, or even whether you’re braking. The most advanced version also incorporates a second amplifier.

Hidden radar tech: 2022 Kawasaki H2 SX has sensor in numberplate bracket

First published on 12 November 2021 by Ben Purvis

Kawasaki H2 SX spyshot rear

In just a couple of weeks’ time Kawasaki will pull the wraps off the second-generation of the supercharged Ninja H2 SX and introduce an array of new technology in the process. Among that kit will be radar to monitor traffic both ahead and behind.

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The fact Kawasaki are adopting the Bosch-developed radar isn’t a surprise. Spy pictures of the next-gen H2 SX emerged in February, showing an opening for a front-facing radar sensor, and now new patents show a rear sensor too.

The Bosch kit is already available on the Ducati Multistrada V4 S, while KTM’s 1290 Adventure S and BMW’s R1250RT can both be bought with the front radar only. However, Kawasaki appear to have solved the problem of hiding the radar sensors, which are all left on display in rival machines.

Radars work by transmitting electromagnetic waves and picking up their echoes when they bounce off an object. That poses a problem when it comes to hiding the transmitters and sensors, requiring the use of ‘radar invisible’ materials that allow the waves to travel through. Although many cars already use these materials – usually thin, smooth plastic – so far none of the bikes with radars have done so.

Kawasaki H2 SX spied in testing

When the spy pictures of next year’s H2 SX appeared, it was clear there was a space for a front radar under the headlight, although it looked to be blanked off and some thought it meant there wasn’t going to be a radar fitted or that it might be an optional extra.

Recently type-approval documents for next year’s H2 SX show that it has the same 197hp supercharged 998cc four as the current model, but that it’s about 4kg heavier than the H2 SX SE+, at 266kg wet, and 40mm longer at 2175mm, despite carrying over the old bike’s 1480mm wheelbase.

The spy pictures show that the extra length comes in an extended number plate bracket, and it turns out that’s the secret to hiding the rear-facing radar. Kawasaki’s new patent shows exactly the same hanger and reveals that it’s made of three separate components – with the outer section being a thin, radar-invisible cover that hides both the structural part and the electronics within.

A patent drawing of Kawasaki's hidden radar system

If Kawasaki have solved the problem of hiding the radar units, then the blank cover panel under the spied prototype’s headlight is also likely to be made of the same material to make sure the radar itself is hidden from view yet still able to operate.

The patent also reveals that the company are working on other rear radar mounting systems. Most notably, one of the images very clearly shows the rear of the Z900RS but with a sensor hiding where the rear reflector is mounted on the current version.

As on cars, radars on bikes are likely to proliferate fast, so within a few years they’re likely to be as commonplace as traction control systems and TFT dashboards on today’s models.

Piaggio scoot into the radar age: Tie-in with Israeli-based Vayyar promises entire radar safety system by next year

First published on 25 August 2021 by Ben Purvis

Vespa e-Gita

Radars are fast becoming the ‘next big thing’ with companies all over the world rushing to develop bike-mounted sensors for adaptive cruise control and collision warning systems.

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This year has seen the first showroom-ready, radar-equipped bikes, with optional systems on the Ducati Multistrada V4 S and BMW’s latest R1250RT, and a standard front radar on KTM’s 1290 Super Adventure S.

All those bikes use the same sensors and electronics, made by Bosch and derived from long-established components developed for use in cars.

Other firms including Honda, Harley-Davidson, Indian and Yamaha are working on bike-mounted radar but have yet to reveal whether they’re adopting the Bosch kit.

How the system would work

Piaggio, however, have decided not to follow the Bosch route, instead teaming-up with Israeli- based radar specialists Vayyar with the intention of developing a system that’s not limited to high-end, high-priced motorcycles but can also be applied to scooters.

The first Piaggio Group bikes and scooters with the system are expected to launch in 2022, and the firm intend to offer the setup to other companies in the future. Piaggio envisage using the radars for blind spot detection, lane change assist and forward collision warning systems.

The dominant Bosch radar sensor is the firm’s ‘Mid Range Radar’ (MRR), a 70mm x 60mm x 30mm box that operates at the 76-77GHz frequency range and weighs 190g. It has a range of up to 160 metres and has a field of view that can be adjusted depending on the situation, from as wide as +/- 42° at close range (12m), narrowing to +/- 6° at 160m.


In comparison, Vayyar’s design is a ‘Radar on Chip’ (RoC) setup, designed to be relatively cheap and compact, with a particularly wide field of view, while promising a range of “over 100 metres” in Piaggio’s application. It uses ‘MiMo’ (multiple input, multiple output) technology, as used in WiFi systems, and operates in 60-64GHz and 76-81GHz ranges.

The system is being developed by Piaggio Fast Forward (PFF), the Italian firm’s robotics subsidiary, based in Boston. PFF’s initial production offering, Gita, is a $3250 luggage-carrying robot that’s designed to trundle along behind its owner, lugging up to 40lb of weight for up to 20 miles. The idea is to get people to walk instead of using cars for short journeys.

PFF intends to use Vayyar’s radars on robots like this by the end of 2021, even before the equipment is carried over to bikes. Ilan Hayat, Director of Business Development at Vayyar Imaging, said: “Motorcycle riders are among the most vulnerable road users, and this is a big step forward in reducing their risk of collision.”

BMW look to nautical tech to make bikes more visible to vehicle radar

First published on 23 March by Ben Purvis

New technology could make bikes more visible to radar systems

‘Be Safe, Be Seen’ is a message that’s been hammered home to motorcyclists but the growing reliance on high-tech safety systems in cars means simply being visible to the human eye might not be enough.

Radar is only just starting to appear on the most high-end of bikes, but the tech has been available in cars for years. Initially restricted to luxury vehicles, it is very much entering the mainstream, allowing a huge number of road users to offload some of the stress of keeping a careful eye on their surroundings.

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It’s not necessarily a bad thing. Radar can ‘see’ through fog and spray and won’t be distracted by changing the radio station. But the tech has downsides, particularly when it comes to bikes, as their small size and plastic bodywork means they’re far less effective than cars at reflecting radar waves.

The reflectors could make seeing bikes easier

The problem has existed at sea for years, where small, fibreglass boats are just as invisible to nautical radar as motorcycles can be to automotive ones, so BMW have looked to the solutions used at sea for inspiration.

As seen in a newly published patent application, BMW’s idea is to fit small reflectors on the extremities of a bike – notably the bars and the ends of the axles – to bounce radar waves back at the system which emitted them.

These reflectors are simply miniaturised versions of nautical reflectors seen on the mast of a yacht. They work on the principle of corner reflection. By putting reflective surfaces together at 90-degree angles to each other, forming a spherical array of three-sided open boxes, you create a device that will reflect radar waves directly back at their source, whatever angle they come from. It’s a simple, passive solution to the radar visibility problem.

Radar systems have been used at sea to help smaller boats

Bike firms are acutely aware that as motorists become increasingly reliant on systems such as radar, it’s important to make sure that bikes aren’t forgotten. BMW recently expanded their commitment to the Connected Motorcycle Consortium, a multi-manufacturer group, also including Honda, KTM, Yamaha Suzuki and Triumph, which is developing a host of systems focused on the idea of vehicles communicating between themselves and being ‘aware’ of the other vehicles in their surroundings.

The patent shows how even cheap, passive components that could easily be retrofitted to any bike could play a role in achieving that target.

Radar technology explored

Small reflectors could be fitted on the bars

Bar-mounted By fitting four or six radar reflectors – on the ends of the bars and the bike’s axles – its ‘visibility’ to radar is vastly increased

Double benefit As a useful side-effect of their position on a bike’s extremities, BMW’s patent says the reflectors double as sacrificial, impact-absorbing bar and axle protectors

Metallic coating: BMW’s patent says the reflectors can be made of metal or, to save weight, be plastic or carbon-fibre with a metallic coating

Harder to spot Bikes are harder than cars for radars to see. In the words of BMW’s patent “Due to of the narrow cross-section these vehicles have a small backscatter area… This makes it difficult and/or delays the detection of vehicles.”

A marine radar reflector

Size matters Existing marine radar reflectors are at least a foot in diameter due to the type of radar they need to reflect. The bike-mounted versions can fortunately get away with being much smaller and still reflect the radars used on cars

Suzuki system BMW aren’t alone in thinking along these lines: Suzuki have also filed a patent application for a very similar radar reflector system

On the radar: How Battle of Britain technology is appearing on 2021’s motorcycles

First published on 12 November, 2020 by Ben Purvis

The system emits a fan-shaped signal of high-frequency radio waves and senses their reflections

Acronyms have long been a familiar way for bike firms to crow about tech but long before terms like SRAD or DCT became familiar on two wheels the term RADAR – RAdio Direction And Ranging – had been coined.

Dating back to the 1930s and famously used by the RAF to fend off the Luftwaffe, radar’s use has spread from the military to civilian world and now is finding its way into vast numbers of cars and, from 2021, motorcycles.

Why? To let bikes fitted with the systems build a real-time picture of their surroundings, monitoring other vehicles in the vicinity and enabling technologies including Adaptive Cruise Control (ACC) and blind-spot monitoring.

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The radar sensors are made up of two main components: a transmitter and a receiver. The transmitter emits high-frequency radio wave ‘chirps’ in the 77GHz spectrum along a focused, fan shaped pattern.

These waves bounce off anything they hit inside that area, reflecting back to the receiver. By measuring those reflections – their width, the direction they came from and the time it took for them to return – the radar ‘sees’ objects, including registering how fast they’re moving and in what direction.

The Bosch-developed radar sensors that are first to appear on in motorcycles – with Ducati’s Multistrada V4 and BMW’s R1250RT having the system as an option in 2021 – can ‘see’ around 120 metres in front of the bike with a field of view of about 60 degrees. The Ducati also gets a rear radar with a shorter range to monitor vehicles approaching from behind.

The radar sensors themselves are just part of the system, though. The picture they build is useless without the ability to interpret it, and that requires all the information that’s become available to motorcycle computer systems in recent years thanks to inertial measurement units, so the bike knows how fast it’s going, its lean angle and rate of acceleration – allowing it to compare those with the objects the radar senses to tell how they’re moving in relation to the bike.

The systems only work with a specific speed range – between 30kmh and 160kmh. Because they are set not to turn on at lower speeds, they can be programmed to ignore stationary objects such as lamp posts or parked cars that might otherwise interrupt or confuse the system.

Close cooperation between the radars, IMU, ABS system and electronic throttles means that when the ACC is engaged a bike fitted with the system can maintain a constant distance – selected by the rider – from the vehicle ahead, accelerating and braking (gently) to keep pace with it and return to the preselected cruising speed when the road ahead is clear.

Because so much of the kit needed for ACC is already in many modern bikes, the system isn’t a vast additional expense. BMW’s front-only radar is a £500 add-on for the R1250RT, while Ducati’s front-and-rear system adds around £700 although it can only be had with £1250-worth of other kit at the moment, making it a £1950 option.

Rear radar will also feature on motorcycles

Radar technology explored:

  • Display and controls Buttons on the left-hand bar controls let you activate the ACC system and select the distance you want to keep from vehicles ahead, shown on the dash.
  • Rear radar Bosch’s rear radar is smaller than the front one, with less range, and monitors blind spots. Unlike ultrasonic blind spot monitors (as on BMW’s C650 scooter), the radar monitors the speed differential from vehicles approaching from behind. It activates with the indicators, illuminating warning lights in the appropriate mirror if there’s a vehicle in the blind spot.
  • ACC computer Bosch’s system merges this with the ABS computer, which is already connected to the IMU, speed sensors and the electronic throttle.
  • IMU Needed so fan-shaped radar signal doesn’t pick up the road surface when you turn into a corner. The radar range is also reduced when you lean over, so the system is programmed not to accelerate if the vehicle in front drops out of its field during a corner.
  • Front radar Emits a fan-shaped signal of high-frequency radio waves and senses their reflections. Multiple measurements every second mean that interference, for instance from other bikes or cars with similar radars, can be filtered out.

Keep your distance: BMW to launch radar-guided cruise control

First published on October 16, 2020 by Ben Clarke

BMW will put radar cruise control on bikes in 2021

BMW have joined the list of manufacturers working to release a radar-guided cruise control function for motorcycles. Following Ducati’s announcement that they will be first to market and spyshots showing a similar system used by KTM and BMW themselves, the Bavarian brand have released details of how their system will work.

The Active Cruise Control (ACC) system has been developed with Bosch and will allow the rider to set not only a cruising speed but also a distance from the vehicle ahead, which is detected using a radar sensor at the front of the bike.

The radar unit uses this information, plus yaw rate and current vehicle speed to calculate the likely path the motorcycle will take in the next 100m and then, if necessary, modulate speed.

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A required adjustment is sent via the bike’s CAN bus to the ABS, which can add revs to the engine or apply the brakes depending on what is needed.

Both the distance to the car in front and maximum vehicle speed can be set in three stages at the touch of a button and will be displayed on the dash. ACC features two riding modes, comfortable or dynamic, which alter how aggressively the bike accelerates and decelerates.

Radar technology will feature on bikes in 2021

The system also incorporates ‘curve speed control’, which manages your speed in a turn to maintain a ‘comfortable lean angle’. As you lean further, the bike limits its interventions to avoid unsettling the rider.

This feature will also prevent unexpected acceleration while you are leaning in a bend if, for example, the radar loses sight of the vehicle ahead (BMW say the radar’s capability is limited while you’re cornering).

The system doesn’t respond to stationary vehicles, either, so if you are approaching the back of a queue of traffic you have to do your own braking.

Expect BMW R1250RT models to feature the tech in 2021

If the system is unable to operate, a symbol on the dash will let you know that you are in full control of your bike. There is also a second warning to let you know you are in a situation where emergency braking may be necessary because the braking capabilities of the system are limited for safety reasons.

BMW say that the rider will take an active role in the effectiveness of ACC by riding in the centre of their lane, making lane changes and overtakes clear (the system reacts to the use of indicators) and adopting a calm riding style.

BMW haven’t confirmed when the system will arrive, how much it will cost or which models will receive this technology but mock-up images from BMW feature their touring K1600GT model.

Watch our video review of the existing BMW R1250RT below:

Ben Purvis

By Ben Purvis