High Precision GNSS in Automotive Jonathan Auld, VP Engineering and Safety 6, March, 2018
2 Global OEM Positioning Solutions and Services for Land, Sea, and Air.
GNSS in Automotive Today Today the primary use case is positioning in navigation Single frequency and at least 2 constellations Narrowband RF and Antennas Accuracy - meter level Primarily pseudorange based positioning techniques, with some carrier phase assistance. No functional safety standards No safety data provided on the output solution Built to automotive manufacturing standards 3
Performance of GNSS in Automotive today Single frequency, automotive receiver Open sky environment 4.0 m separation 4
GNSS for Autonomous Vehicles Lane level accuracy - 3D centimeter to decimeter absolute positioning Multi-frequency, Multi-constellation receiver and antenna Improves overall accuracy Increases available measurements High availability through sensor fusion with IMU and other sensors Functional Safety ISO26262 Development at ASIL B 5
Moving from meter to centimeter level position Receiver Hardware Differences More constellations More frequencies And signals Increased bandwidth 6
Moving from meter to centimeter level position Algorithmic Differences Code ~293 m Carrier ~19 cm Software to process additional signals More sophisticated error detection and management Using carrier phase for positioning 7
Moving from meter to centimeter level position Correction Services clock, orbit, ionosphere Global and High accuracy SBAS (e.g. EGNOS) 8
Nearly 30 years experience in high precision GNSS Numerous autonomous applications already use GNSS 9
10 Hexagon s PI Global Correction Network Provides clock and orbit corrections for land, airborne and near shore applications Operational in the market for nearly 30 years Corrections delivered over L-band or IP Redundant infrastructure 10
Higher Density Station Coverage for Improved Regional Performance North America 1300+ STNs Europe 2500+ STNs Russia 350+ STNs Regional coverage typically near urban centers and along main transport corridors Rapid Expansion possible as needed. Australia 600+ STNs 11
Global and Regional Coverage for Optimal Performance GNSS Satellites Geo Satellites Customer Comms Hub Hexagon Corrections Processor Global Network + Regional Network Delivers service levels from 1cm to 50 cm accuracy throughout entire coverage area Meets requirement for cm level accuracy in <1 minute (TerraStar Fast) Corrections can be received through same antenna as GNSS signals or over IP/Cellular Designed with functional safety, reliability and availability for 24/7/365 all weather operations 12
Performance of GNSS Possible in Automotive today Single Frequency Automotive receiver NovAtel corrections Open sky environment 0.9 m separation over 9 laps 13
Comparison of the GNSS Performance Possible in Automotive Today Automotive Today L1 Automotive with Corrections L1/L2 Automotive with Corrections 14
Moving from meter to centimeter level position - Availability Sensor Fusion Increasing availability GNSS signals are challenged by trees and blocked by tunnels, buildings Add 6-axis IMU, wheel speed sensor, to bridge temporary GNSS outages 15 GNSS navigation
Moving from meter to centimeter level position Summarizing Performance Improvements Feature Added Ability Resulting improvement Enhanced hardware Receive additional signals and frequencies Accuracy meter sub-meter Corrections services Satellite error information Accuracy sub-meter decimeter Advanced algorithms Carrier phase positioning Accuracy decimeter centimeter Sensor Fusion Navigate during GNSS outages Availability non-open sky environments 95% 99% 16
Technologies are complementary GNSS/INS is an established synergy Other AD/ADAS sensors are complementary with GNSS Rural, highway Few features; LIDAR, cameras, map matching struggle GNSS works extremely well Dense urban environments GNSS struggles Many targets for LIDAR, cameras, map matching 17
Accuracy isn t enough we need Safety and Authentication Accuracy evaluated at 68%, 95%, or 99% For safety of life, that s not good enough Need to ensure no failures at 99.999999% Automotive requirements supporting this: ISO/TS16949 Corporate Process APSICE Level 3 Software development process maturity ISO26262 ASIL B Functional Safety Design Assurance Interference and Spoofing are growing concerns GNSS Signals and Corrections Authentication is required Have these topics been addressed in other segments yet? 18
Moving Beyond Aviation Hexagon PI has extensive safety of life experience in aviation and marine Some of this experience is directly applicable to automotive, e.g. satellite failures Some other errors have changed Carrier phase positioning Different algorithms require different approach to safety Corrections can protect against some failures but corrections are also a potential failure source Local environment Obstructions and signal blockages Multipath Sensor fusion Many complementary sensors are available Less focus on continuity 19
Integrity Services in High Precision Applications Aviation industry has a long history of high integrity GNSS Concepts of Protection Levels, Threat Models, Integrity Risk, Advanced RAIM Systems must be designed to keep integrity risk very low, less than 10-7 / hr Since 2016 Hexagon has been working with Stanford University and Illinois Institute of Technology to analyze the integrity case for automotive PPP positioning techniques 20
Building Blocks for High Precision GNSS GNSS Signals multi constellation and multi frequencies, solution availability and accuracy Receivers Optimization of cost/weight/size/ performance Antenna Critical to accuracy and often neglected Corrections Standalone GNSS does not achieve sub meter level Sensor Fusion Motion and environmental sensing offsets GNSS limitations 21 Integrity Ensuring reliability of output solution for safety applications Algorithms Generating high precision positions and trajectory data
Hexagon-PI Solution Portfolio Corrections Services TerraStar/Veripos PPP network, SmartNet RTK network New fast-converge PPP Corrections Service with RIM High Precision Automotive Positioning Multi-constellation & single-, dual-, & multi-frequency GNSS positioning Precise Positioning algorithms: RTK, PPP, DGPS, SBAS GNSS Integrity for Automotive GNSS Authentication for Automotive GNSS/INS Fusion + Dead Reckoning Reference Design and Integration Services GNSS Chipsets, GNSS antennas, Augmentation Sensors, Processing Subsystems ISO26262 ASIL + ASPICE Certification Package Lifecycle Engineering Services 22