Autonomous Vehicle Engineering - July 2022 - 6

Cover Story
also relies on the fact that more than 99% of voxels are
simply free space. This reduces the data rate to between
one-hundredth and one-tenth the rate without AN
while continually monitoring the entire space.
Based on sensitivity analyses, we conclude that
with AN, human-driven and autonomous vehicles
must be able to sense the environment at a peak rate
on the order of 100 x 1012
bits/s (100 Tb/sec) to handle
a surge of sensor data in the worst conditions. This is
at least 98% less than the 7 Pb/sec rate without AN.
In addition to reducing the required data rate,
AN can obtain the same performance as conventional
radar algorithms using just 1/50th
of the transmit
power, yielding much higher resolution and many
more hits on targets. Conventional automotive radars
can barely detect a pedestrian up to 100 meters away,
but with AN and multiband radar, it is possible to see
a pedestrian in rain, snow, fog and darkness in excess
of 500 meters (1,640 ft)5
.
Fig. 2: Requirements flow-down for zero roadway deaths.
Cameras can't find these objects no matter how fast
they can sample.
Enter the Atomic Norm
Any sensor system that physically scans the entire
coverage volume will require an incredibly large data
rate to reconstruct scenes soon enough, clear enough
and far enough to eliminate preventable roadway deaths
under worst conditions. No current system comes close.
Fortunately, a mathematical framework exists
that, when combined with advanced sensors and
system-on-a-chip (SoC) technology, allows the
massive data rate requirement for scene reconstruction
to be addressed and human-driven and autonomous
vehicles to sense well enough to eradicate preventable
roadway deaths. Called the Atomic Norm (AN), this
method is based on compressed sensing (CS) which
reduces the number of measurements required to
maintain a certain level of performance and was developed
to improve magnetic resonance imaging (MRI)4
.
AN uses much wider beams and better computation
to allow each voxel to be interrogated individually. It
What's needed to sense 100 Tb/s?
Fig. 2 shows how the requirement of zero roadway
deaths flows down to specify requirements for sensing
and how meeting sensing requirements flows up to
enable other system requirements. Our premise is that
100% awareness of what is in the environment at all
times is required to enable zero preventable roadway
deaths, and by sensing and processing around 100 Tb/s
in worst conditions, higher-level system requirements
will be easier to meet. To do this, the Atomic Norm
must be combined with multi-band radar, solid state
lidar, SoC processors and digital maps.
Different radar bands complement each other by
having different propagation and reflection properties
- higher bands have better resolution and lower
bands have longer range (especially in adverse weather
conditions) and can go through and bend around
objects. Because objects reflect differently at different
frequency bands, one can use different radar responses
to determine the constituent material of different
targets (e.g., metal vs. soft tissue). This means the radar
must use causal inference and reasoning to interpret
the multi-spectral response from the environment.
Solid-state lidar has precise scanning repeatability
advantages and avoids moving parts. Along
6 July 2022
AUTONOMOUS VEHICLE ENGINEERING
NPS
Autonomous Vehicle Engineering - July 2022

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