IEEE Consumer Electronics Magazine - July 2016 - 53

What Is the Specification? (LIDAR Example)
* System Requirements Drive Component Requirements
* System Requirements Not Well Defined in Initial Stage
* Application: Map Environment/Avoid Collisior
* Range: 100-400 m
* Range Accuracy: 2-10 cm
* FOV Horizontal: 24-360°
* FOV Vertical: 6-20°
* Angular Resolution: 0.3-30°
* Operating Conditions: -40-125°C
* Packaging/Mounting: Small/Should Not be Noticeable/
Should be Robust for Usage and Service
* SOP: One to Five Years
* Test Specifications/Regulation: Not Available Yet
* Price: US$
* Takeaways
* Manufacturers Developing Modular Designs-Meet
High/Low End of Spec
* Road Map from NHTSA/OEM/Tier 1s Can Speed Up
Innovation Efforts
FIGURE 6. The system specification requirements for scanning
LIDAR can be confusing.

▼

These systems are believed to have the cleanest signal
and noise ratio to date and generally provide 360° HFOV.
The challenges are size and cost. There is also some lingering doubt about the need for self-calibration as the
motor bearings wear.
Microelectromechanical system (MEMS) mirror: A MEMS
mirror is used to scan the FOV with the laser beam, after it
has been collimated and circularized to a round shape. The

detector side is typically an APD array. MEMS is a proven
technology in commercial use. The LIDAR application of
MEMS is under development by a number of companies.
The attractiveness of this concept is the small form factor
and potential ability to reach lower cost with use of proven
technology. This will need to be tested by the market when
it becomes available. A concept for such a LIDAR is
shown in Figure 7.
▼ Optical phased array (OPA): Similar to the MEMS scanning
concept, an OPA is used instead of a MEMS mirror to scan
the FOV. OPA is a comparatively new technology in relation
to MEMS. Quanergy (Sunnyvale, California) showed a form
factor for an OPA LIDAR at the 2016 CES [1].
The next few years will be competitive for these different
technologies as they carve out their niche in the scanning
LIDAR market. A number of nonautomotive markets also
have high interest in LIDAR technology, such as drones, mining, and military.

LASER/EMITTER CONSIDERATIONS
Ideally one would like to realize a high signal-to-noise ratio
by blasting out as much laser power as possible at the object
to be detected; however, this would not be safe for the
human eye. Lasers with wavelengths between 400 and 1,400 nm
can reach the retina and create permanent damage if the
exposure time and power density are above acceptable eye
safe limits. Lasers above 1,400 nm are typically more expensive, though safer for the eye at higher power limits. The
wavelength of choice is currently 905 nm, as these lasers are
comparatively economical and are able to achieve the
desired range with a low duty cycle. They are also available
in various packages and power levels from multiple suppliers. Pulsewidth is another key performance criterion for the

Receiver Channel

Transmission Channel

Laser

LIDAR Controller Chip
(ADC, GHz Sampling,
TDC, Signal Processing,
Data Compression,
Communication)

Laser Driver

MEMS Driver ASIC

Transimpedance Amplifiers

MEMS Mirror

APD Sensor Array

Sensor Inputs
Data Fusion Module
(Object Detection, Tracking,
Identification, and
Classification)

ADAS System/
Active Safety Control

FIGURE 7. An artist's impression of a LIDAR sensor. (Courtesy of Innoluce, Nijmegen, The Netherlands.)

JULY 2016

IEEE Consumer Electronics Magazine

Table of Contents for the Digital Edition of IEEE Consumer Electronics Magazine - July 2016