Exploratory Advanced Research . . . Next Generation Transportation Solutions

Lane-Level Vehicle Positioning

Integrating Diverse Systems for Precision and Reliability

widely available technologies to augment an integrated navigation system.”

Exploring Viable Approaches

In phase I, now completed, the project’s task 

was to compare the capabilities—accuracy, reliability, availability, continuity—and deployment 

costs of candidate approaches, addressing 

these questions: 

•	 Which aiding sensors are feasible for automotive applications, now and in the future? 

What advancements are required to alter this

assessment?

•	 Which combinations of feasible sensors can

achieve the lane-level positional accuracy, 

availability, and continuity specifications?

•	 How do the successful sensor combinations

compare from the cost perspectives of roadway infrastructure and vehicle-based equipment?

Candidate approaches considered in terms 

of their accuracy, vehicle cost, roadway cost, 

and advances they may require included the following technologies:

•	 Global Positioning System: GPS, differential

GPS, carrier phase differential (CPD) GPS.

•	 Terrestrial radio: Pseudolites (local, groundbased transceivers that can substitute for 

GPS), cell phones (time of arrival, time distance of arrival), digital TV, radio (AM analog,

FM analog, digital), packet radio.

•	 Feature-based technology: Vision, RADAR,

LIDAR.

Based on their evaluation, the investigators 

selected (1) FM and digital TV radio navigation

methods and (2) vision, LIDAR, and RADAR for

further exploration and testing in phase II of the 

study. These approaches will serve as integrated

adjuncts to the primary, dual system: inertial 

navigation aided by CPDGPS. CPDGPS provides

the centimeter-level precision necessary for automated highway systems by referencing the 

high-frequency carrier signal to provide position 

The Exploratory Advanced Research Program Fact Sheet

The Vehicle Positioning Challenge

Integrated global positioning system/inertial 

navigation system (GPS/INS) technology, the

backbone of vehicle positioning systems, cannot provide the precision and reliability needed 

for vehicle-based, lane-level positioning in all 

driving environments at all times—INS or encoder based navigation systems tend to accrue error unless corrected and GPS signals are blocked

by obstacles. Feature-based technologies—camera, LIDAR, and RADAR, often used to augment

GPS/INS, succeed only where detectable structural features are found. To access critical positioning data in any location, at any time, regardless of weather and visibility, the next generation 

of vehicle positioning systems will need to integrate data from satellites, terrestrial radio signals, and feature-based sensors. 

“Manufacturer and university research groups

are pursuing data fusing solutions independently,” 

says Jim Arnold of FHWA, “but a low-cost, publicsector solution could advance the availability of 

a robust lane-positioning architecture nationwide. 

This 3-year EAR Program study is investigating

Fusion of data from several sources 

could deliver the highly accurate, 

real-time positioning information that 

new driver assistance applications 

require. Investigating that promise is 

the task of an Exploratory Advanced

Research (EAR) Program project,

“Innovative Approaches for Next

Generation Vehicle Positioning,” at

the University of California at Riverside, 

funded by the Federal Highway

Administration (FHWA) in 2009.
corrections in real time. The

phase II work is following a 

three-step approach:

• Integrated (or aided) navigation system fuses asynchronous, possibly latent, data 

from a diversity of sensors to 

reliably estimate vehicle state. 

• High-rate sensor readings are

integrated through a model 

of a moving vehicle to produce a continuously available 

vehicle state estimate.

• Integrated errors from highrate sensors are corrected 

from a diversity of aiding 

sensors. 

The researchers plan to develop and evaluate prototype 

integrated positioning systems. For sufficiently 

advanced systems, they will conduct field tests 

and propose a full-scale deployment plan.

Moving Forward

The experience and products obtained through

the successful completion of this project will 

speed the development of vehicle positioning 

systems and further the maturity of the Connected 

Vehicle Program, in which FHWA participates.

Many driver-assistance applications targeting

roadway safety and mobility (with reduced energy use and emissions) will benefit, and much

will be learned about the strengths and limitations of sensors, components, algorithms, and 

strategies. 

Cross-cutting in nature, the project’s findings 

will be of interest to other Federal agencies and 

to automotive manufacturers. “If successful, this 

project could provide a major step forward in realizing the safety and mobility benefits of intelligent transportation systems,” says Arnold.

What Is the Exploratory 

Advanced Research Program?

FHWA’s Exploratory Advanced Research

(EAR) Program focuses on long-term,

high-risk research with a high payoff

potential. The program addresses underlying gaps faced by applied highway 

research programs, anticipates emerging issues with national implications, and 

reflects broad transportation industry 

goals and objectives. 

To learn more about the EAR Program, visit the Exploratory Advanced

Research Web site at www.fhwa.dot.gov/

advancedresearch. The site features information on research solicitations, updates 

on ongoing research, links to published 

materials, summaries of past EAR Program events, and details on upcoming 

events. For additional information, contact 

David Kuehn at FHWA, 202-493-3414

(email: david.kuehn@dot.gov), or Terry

Halkyard at FHWA, 202-493-3467 (email:

terry.halkyard@dot.gov).

Lane-Level Vehicle Positioning

Integrating Diverse Systems for Precision and Reliability

Publication No. 

FHWA-HRT-13-059

HRTM-30/04-13(1M)E

Photo credit, page 1: 

© Shutterstock.com/

Zsolt Biczo

Photo credit, page 2:

© Center for Environmental 

Research and Technology

Feature-based mapping 

and positioning sensor suite 

showing a GPS/IMU (inertial

measurement unit) box and

a forward-looking camera 

for positioning, and a 

360-degree camera and

Velodyne® LIDAR for

mapping.

GPS/IMU

CAMERAS:

Positioning

Mapping

Mapping LIDAR

Learn More

For more information on this project, contact 

Jim Arnold, FHWA Office of Operations Research and Development, at 202-366-8422

(email: james.a.arnold@dot.gov).