These MEMS devices are positioned for applications that require greater accuracy, reliability and control, including vehicle navigation systems and drone navigation

By Brian Santo, contributing writer

Anticipating that vehicle navigation
systems could get far more sophisticated to support safe semi-autonomous and
fully autonomous driving, STMicroelectronics Inc. announced a high-performance 6-axis
inertial sensor for the automotive market. Thales, meanwhile, introduced a new 6-axis
inertial motion sensor for a set of other high-performance applications that
include drone navigation, robotic control, camera/antenna platform
stabilization and augmented/virtual reality (AR / VR). These devices are more properly described as a 3-axis
accelerometer combined with a 3-axis angular-rate sensor (essentially a
gyroscope).

The automotive market has been using a
variety of motion sensors for some time now, but almost never for navigation. They’ve
been used for things such as airbag deployment systems, which are triggered by
simple 1- or 2-axis detectors that are more than adequate to sense the abrupt
deceleration associated with collisions.

Autonomous vehicles will, of course,
have on-board sensing. It looks likely that some, if not all, may end up also
relying on GPS for geo-positional data. There is growing expectation that, in
cities at least, autonomous vehicles are likely to be connected to local 5G
wireless networks that will exchange environmental data, which will be used by
the vehicles’ navigation systems. But exactly how all semi-autonomous and autonomous
vehicles will be equipped for safe navigation is still up in the air.

GPS cannot be relied on everywhere,
including urban canyons, tunnels, covered roadways, parking
garages, or dense forests, ST points out, which is one of the reasons it is
proposing the use of 6-axis motion sensors in combination with dead-reckoning
algorithms to calculate precise position from sensor data should satellite
signals be blocked. ST’s new ASM330LHH 6-axis
inertial sensor will also enable telematics services such as e-tolling,
tele-diagnostics, and e-Call assistance.

The company claims the forthcoming ASM330LHH will have the lowest
power consumption in its class, with features for optimizing power management
if battery operation comes into play. It is built using ST’s proprietary ThELMA
(Thick Epitaxy Layer for Micro-gyroscopes and Accelerometers) MEMS process
technology. The
accelerometer can scale up to ±16 g, while the gyroscope has a range from ±125
to ±4,000 degrees per second (dps). ST said the device will operate across
a temperature range of -40 to +105 °C.

 

STMicroelectronic’s
ASM330LHH 6-axis inertial sensor

Engineering samples will be available for evaluation by Q3 2018,
followed by volume in Q4. Budgetary pricing starts at $5.00 for orders of 1,000
pieces. Reference designs, as well as ST’s Teseo satellite-positioning modules
and related software are available. The dead-reckoning algorithm included with
the Teseo III GNSS-receiver chipset already supports the ASM330LHH for
autonomous navigation applications, the company said.

Separately, Thales announced a new version of its 6-axis motion
detectors, which the company categorizes as inertial measurement units (IMUs).
The new NavChip2 IMU comes in a small and easily mountable package (12.5 x 24.5 x 5.4 mm) and was designed to exhibit low power
dissipation, which the company said makes it especially suitable for
applications such as drone navigation, robotic control, camera/antenna platform
stabilization, and AR / VR. Thales caters to the defense and aeronautics
industries. 

Thales describes the NavChip2 as a
“very low drift” IMU with an acceleration range of ±16 g and a full scale angular rate of ±2,000 dps. The
company claims it exhibits “exceptionally
quiet acceleration noise performance.” Power consumption is a 135 mW. The temperature range is -40°C to +85°C. The NavChip2
unit price is $450 in small quantities. Evaluation units are available from
stock.

Several other companies including InvenSense
(owned by TDK since 2016) and NXP also compete in the 6-axis motion sensor
market.

TDK InvenSense has a line of 6-axis sensors, aimed at applications such as navigation,
imaging, and augmented reality. It already has one such device which, like ST,
is aimed at the automotive market. The IAM-20680 6-axis MotionTracking device combines a 3-axis
gyroscope and a 3-axis accelerometer in a 3-mm x 3-mm x 0.75-mm
(16-pin LGA) package. As of this
writing, the company’s website notes the IAM-20680 is sampling. The MEMS
inertial sensors can be used in several automotive subsystems, including
navigation/dead reckoning, infotainment, telematics, advanced driver assistance
systems (ADAS), theft detection, e911 location, and driver
facing camera image stabilization.

The sensors that NXP Semiconductors currently
has designated for the automotive market include 1- and 2-axis MEMS accelerometers used for traditional applications which,
beyond airbag systems, include electronic stability control, electric parking
brake and tilt angle measurement solutions. NXP does offer 6-axis sensors. The company’s
current list of applications for those include augmented
reality, e-readers, medical applications, home appliances, portable navigation
devices, smartphones, and tablets – but not vehicle navigation systems.