autonomous cars: radar, lidar, stereo cameras -...
TRANSCRIPT
2 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Role of Cameras in Automotives
� Camera module market ~$25B in 2015, expected to double by 2025 (Yole)� Machine Vision integration with multiple sensors for ADAS and partial
autonomous driving� Disadvantages of cameras
• Environmental conditions can introduce problems• Difficulty in detecting non- illuminated and varying lighting conditions• Computer vision limitations for reliable detection
3 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
CMOS image sensors for Automotive are quite different from Consumer Electronics
Source: Yole
� Improved Low light sensitivity by larger pixel size� Lower resolution (it’s not about Mega pixels)� Fast response time (significantly faster than smartphone cameras
� Packaging Differences• Embedded logic in image sensor package• Ceramic packages for higher functional safety requirements
4 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Challenges� Fast image acquisition� Stereo camera for depth and distance of the object in image plane� High resolution AND high speed
• Resolution: greater than 1k x 1k pixels, aim for 4k x 4k• Frame rate: 60 fps and higher for shorter reaction time
� Zoom into image area for a greater detail � Efficient image processing for real-time analysis� Wider field of view than radar or laser systems
5 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Cameras in Current Cars (Bosch)
� Bosch‘s mono and stereo camera system: smallest currently available in the market. Has a 50-degree horizontal field of view for 50m distance.
Bosch’s stereo camera system
6 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Cameras in Current Cars (Panasonic)
� Stacked CMOS imaging chip and processing electronics in one package� Compact enough to fit within rearview mirror assembly or behind the windshield� Low cost high resolution cameras, but limited speed� High speed cameras limited resolution� Circuits for efficient image processing for real-time analysis� Can be implemented with multiple units for stereo vision
Panasonic CMOS 34227 Sensor
7 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Prior Work at GT: 1st CIS DEMONSTRATOR on LOW COST 3D GLASS PACKAGE
� 100um Thin Glass Substrate
� Wafer Level Camera on Top Side
� Thin Logic Emulator IC on bottom side
� Solder reflow at chip level
� Passed initial tests at Georgia Tech
� <1mm total thickness (3x reduction from
PWB integration)
� 10x higher I/Os for integrating multiple
sensors, logic, memory etc.
8 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Thermal Control Using Glass Package� Glass limits lateral thermal spreading by design� Junction temperatures can be reduced by vertical copper vias� Heating of image sensor with IC stacking or silicon interposers
Without copper With copper
Glass
38C 58C 48C 50C
49.1C 49.4C 49.1C 49.4C
Silicon10mm x 10mm Test Chipon Glass or Si Interposer
10 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Why RADAR in NAE?
• Above functions Require radar sensors due to their robustness in varying environmental conditions like rain, dust, or sunlight
(J. Hasch, "Driving towards 2020: Automotive radar technology trends," Microwaves for Intelligent Mobility (ICMIM), 2015 IEEE MTT-S International Conference on, Heidelberg, 2015, pp. 1-4.)
Roadmap for driver assistance functions
• Short, Medium and Long Range RADAR Modules
Critical to Fully Autonomous Driving
11IEEE-CPMT Workshop – Autonomous Cars
Automotive RADAR – Brief Intro
• Basic Architecture and Requirements- Frequency Modulated Continuous Wave (FMCW) Doppler Radar- 76 GHz – 81 GHz- Severe Environment Conditions- Long Term Reliability
Many challenges to device and design !!
TxRx
fr
Freq
uenc
y
fb
fd
fb fd
fr
Transmit FMCW Signal76-81 GHz
Compare Received Signal with Transmitted Signal to Extract
Distance and Velocity
PROF. JOHN CRESSLER
12 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Automotive RADAR Evolution
1999 Mercedes-Benz • First manufacturer to use radar
for autonomous cruise control (ACC) system in S-class
Active Components Evolution
Pack
agin
g Ev
olut
ion
GaAs Technology
• Discrete semiconductor components ÆMMIC blocks or even complete
transceiver circuits
Silicon-based SiGe technology• Improved RF performance at high freq.• Destined to be the mainstream
semiconductor technology millimeter-wave
(J. Hasch, E. Topak, R. Schnabel, T. Zwick, R. Weigel and C. Waldschmidt, "Millimeter-Wave Technology for Automotive Radar Sensors in the 77 GHz Frequency Band," in IEEE Transactions on Microwave Theory and Techniques, vol. 60, no. 3, pp. 845-860, March 2012.)
Chip on board wire bonding
Flip chip mounting on substrate
eWLB (embedded wafer level
BGA) package
Evolution of SiGe Device Technology
Courtesy of P. Chevalier
13 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Challenges in Automotive RADARPackage Challenges
� Low losses and reflections chip to substrateTransition
� Thermal dissipation� High Reliability� Low cost
• Generation of sufficient output power at high frequency
• LNA demonstration
Device Challenges
• No LNA: High NF → Low SNR → Lowmaximum detecting range of system
77GHz 4-channel automotive radar transceiver chip specification
(H. P. Forstner et al., "A 77GHz 4-channel automotive radar transceiver in SiGe," Radio Frequency Integrated Circuits Symposium, 2008. RFIC 2008. IEEE, Atlanta, GA, 2008, pp. 233-236. )
14 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Status of Automotive RADAR Products
Bosch LRR3 Sensor• SiGe MMICs instead of Gunn oscillators and discrete mixer diodes • Size and package complexity reduction
Bosch LRR3 SensorBosch LRR2 Sensor
15 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Latest Automotive RADAR Products
Bosch Mid Range Radar (MRR) Sensor• Frequency band 76-77 GHz• Distance range up to 160 meters • Integrates two electronic boards and STMicroelectronics devices• RF board with Hybrid PTFE/FR4 substrate and equipped with planar antennas• Infineon 77GHZ SiGe Monolithic Microwave Integrated Circuits (MMIC) used as High-Freqency
transmitter and receiver
16 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Recent Automotive RADAR Packaging Technologies Infineon RRN7745P & RTN7735P eWLB Fan-out Package - 77GHz Radar Dies
The radar receiver die is packaged in an eWLB (embeddedWafer Level BGA) package, Fan-Out technology fromInfineon.
Back view
Die3mm x 3mm
Package cross-section
17IEEE-CPMT Workshop – Autonomous Cars
Proposed High Linearity Low Noise RX
Block Diagram
�One of the first Radar modules to integrate LNA in front end
�Leading Edge SiGe Receiver9 Employ Advanced SiGe Node
9 Use Novel Circuit Design
9 Incorporate High Gain High Linearity
LNA
� Current Design Phase
9 LNA layout modificationPROF. JOHN CRESSLER
18IEEE-CPMT Workshop – Autonomous Cars
Proposed High-Linearity LNA
9 IBM 9HP 90nm technology9 3 cascaded cascode stages9 Fully differential to improve CMRR9 Input transformer balun:
- Provide RF ESD protection and differential signal
9 Inter-stage matching with transformers9 Variable gain
- Improve input P1dB
Area: 0.6mm x 1 mmVCC: 2.5V
IN
OUT
VCC
VB1_13
VB2_13
VB1_2
VB2_2
GND
GND
GND
PROF. JOHN CRESSLER
19IEEE-CPMT Workshop – Autonomous Cars
LNA Initial Design and Simulation� Transistor Sizing: 6um, 8um, 10um Simulation Results
S-param
NF
P1dB
Gain 17.3 dBNF 6.221 dB3dB Freq 56GHz-94GHzDC Power 91.5 mWInput P1dB -14.5 dBm
PROF. JOHN CRESSLER
IEEE-CPMT Workshop – Autonomous CarsSlide 20
CONFIDENTIAL
GT Program Focus� The research objective is to design and demonstrate an ultra miniaturized low cost
integrated 77GHz radar & high speed camera module applying the most advancedpanel-level glass fan-out (PGFO) packaging technologies to the following parameters:
77 GHz Radar Chip
Processor
Image sensor
Antenna Incident light
Glass
Cover glass
Active area Camera ModuleRadar Module
Properties Objectives Prior Art
Integrated Module
Package type GFO FO-WLP/ CeramicCost <1x 1.2x
Reliability AEC Q100 Grade 1 AEC Q100 Grade 3Thickness < 300 um > 500 um
RadarNoise Figure 6-7 dB > 20 dB
Gain 15 dB < 15 dBAntennas Integrated in package Integrated in PCB
CameraData Rate ~ 1 Gbps <1 Gb/s
Response time < 1 ms >1 ms
22 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Why Lidar for Automotive ?
� Cameras and radar cannot ensure 100 % safety� Radars provide no object detection� Cameras depend on environmental conditions.� Lidar enables high precision detection in real time � Time of Flight lasers in Lidar are the most accurate for real time and
long range detection.
23 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Basics of Lidar
Fired Laser Pulses
Reflected Laser Pulses
Starting a timer when the pulse goes out and stopping by the reflected pulse
24 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Challenges
� Cost reduction (see figure)� Miniaturization for easy integration in car body� High aperture angle – number of channels � Reliability by application of solid state lidar
25 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Lidar Products
� Velodyne lidar system VLP-16• Range: 100 m, • Power consumption: ~8 W, • Weight: 830 grams, • Footprint:~Ø103 mm x 72 mm,• 16 channels, ~300,000
points/sec, • 360° horizontal field of view,
30° vertical field• Accuracy: +/- 3 cm (typical)• Rotating mirror inside
assembly,• Laser: Class 1 – 903 nm
wavelength
26 | IEEE-CPMT Workshop – Autonomous Cars Prof. Rao R. Tummala
Lidar Products
� Quanergy Solid-state LIDAR system• Field of view is 120 degrees both horizontally and vertically. • The minimum range is 10 cm, and the maximum range is at least
150 m at 8 percent reflectivity. • At 100 meters, the distance accuracy is +/- 5 cm, and the
minimum spot size is just 9 cm.
Small (9 cm x 6 cm x 6 cm), no moving parts