Improving Pedestrian Tracking Accuracy With A Low-cost IMU .
Improving Pedestrian Tracking Accuracy With aLow-cost IMU Through the Use of Tightlycoupled L1 GPSStanley Radzevicius, W. Todd Faulkner, David W.A. TaylorENSCO, Inc.WPI PPL Workshop 2010August 2, 2010
IntroductionTracking first responders requires navigation in GPSimpaired environments.Unobstructed GPSCoverage GapsIMU is self contained and provides good short-termnavigation, but errors increase with time.GPS requires sky view, suffers from multipath, and can bejammed but provides meter-level accuracy whenavailable.Integrating GPS extends tracking capability of standaloneboot-mounted IMU/compass mission time in GPSimpaired environments.GPS-Denied2 2010 ENSCO, Inc. All rights reserved.
Boot-mounted IMU and CompassPush-OffSwing Heel-StrikeStanceZUPTUnaided inertial navigation position errors grow as time cubed with gyro biases.Through an extended Kalman filter (EKF),1. Zero-velocity updates (ZUPTs) constrain position errors.2. Heading updates using filtered compass data constrain heading errors; updatesare typically available even in magnetically complex indoor environments.Positioning accuracy of a few meters for up to 15 minutes.3 2010 ENSCO, Inc. All rights reserved.
Why integrate GPS with a boot-mounted IMU?Complementary errors:GPS position errors are larger but do notgrow with time.Inertial navigation position errors are moreaccurate over short periods of time butdrift over long periods.Initialization:GPS provides an initial absolute positionestimate and can be used to estimateinertial heading, magnetometer and IMUerrors, especially accelerometer biases,as the operator walks.GPS Measurement Filtering:Inertial position estimates help reject poorGPS data.4 2010 ENSCO, Inc. All rights reserved.
Loosely Coupled GPS/IMU: Two Separate EKFsIMUSensorGPSSensorPseudoranges& DopplerGPSKalmanFilterError States:3 Position3 VelocityClock BiasClock DriftIncremental Angle& VelocityPositionVelocityInertialNavigation &KalmanFilterPositionVelocityAttitudeError States:3 Position3 Velocity3 Attitude3 Gyro Bias3 Acc Bias5 2010 ENSCO, Inc. All rights reserved.
Tightly Coupled GPS/IMU: Single EKFGPSSensorPseudoranges& DopplerIMUSensorIncremental Angle& VelocityGPS/IMUInertialNavigation &Kalman FilterError States3 Position3 Velocity3 Attitude3 Gyro Bias3 Acc BiasClock BiasClock DriftPositionVelocityAttitude6 2010 ENSCO, Inc. All rights reserved.
Why use a tightly coupled approach?Chi-square goodness of fit (Χ2) test checks for outlier measurements.Loosely coupled approach: GPS position estimates input to theinertial EKF may be based on correlated pseudorange errors; Χ2 testaccepts/rejects a position measurement, even if based on a singlebad pseudorange.Tightly-coupled approach: Χ2 test accepts/rejects each pseudorangemeasurement independently (it may reject a single bad pseudorangemeasurement while accepting adjacent measurements). Thisapproach also allows integration of sparse pseudorangemeasurements that are discarded in loosely coupled approach.7 2010 ENSCO, Inc. All rights reserved.
System ComponentsExperimental Hardwareu-blox 5 GPS receiverand u-blox GPS antennaMEMSense nIMU 1200IMU & CompassSize: 0.8 cubic inchesWeight: 1 ouncePower: 1 WGyro Bias Instability: 70 /hr8 2010 ENSCO, Inc. All rights reserved.
GPS/Boot-mounted IMU Test ResultsOperator walking for over an hour andcovering multiple miles.GPS coverage environments:1. Unobstructed with continuous GPScoverage2. Obstructed environment withintermittent GPS coverage3. GPS-denied indoor environment –primarily inertial navigation solutionPosition results overlaid on Google Earthimagery for ground truth.9 2010 ENSCO, Inc. All rights reserved.
Indoor/Outdoor Walk (65 minutes, 2.75 miles)Multipath & partiallyGPS-denied0.5 milesMultipath reflectorsIntermittent dropouts 2010 ENSCO, Inc. All rights reserved.
Indoor/Outdoor Walk: GPS OnlyLoss of GPSPoor Indoor NavigationLarge GPSErrors11 2010 ENSCO, Inc. All rights reserved.
Indoor/Outdoor Walk: Tightly Coupled GPS/IMUGPS Multipath ErrorsGreatly ReducedGood Indoor Navigation12 2010 ENSCO, Inc. All rights reserved.
Indoor/Outdoor Tightly Coupled GPS/INSNavigation: Short SegmentGPS OnlyGPS/IMUExit BuildingEnter Building13 2010 ENSCO, Inc. All rights reserved.
70 Minute Walk Under Tree Canopy4.5 mile walk around lakeTree Canopy for 75% of walkOnly lost GPS for 5 minutes14 2010 ENSCO, Inc. All rights reserved.
Canopy Walk: GPS Only Solution7-10 satellites availableexcept for 5 minuteperiod where nosatellites were visible.15 2010 ENSCO, Inc. All rights reserved.
Real time Processing: IMU Bridges 5-minute GPS GapRed GPSGreen Tightly coupled GPS/IMUBlack line Trail location in imageryUsing only the boot-mounted IMU,position estimation remainsconsistent with overheadimagery of the trail after loss ofGPS for 5 minutes.200 m16 2010 ENSCO, Inc. All rights reserved.
IMU bridges 30-minute GPS GapEnd of GPS outageRed GPSBlue GPS/IMU solutionStart of GPS outageReal-time position error based on imagery after 30 minutes without GPS(covering 1.75 miles) is 15 meters17 2010 ENSCO, Inc. All rights reserved.
ConclusionsTracking first responder for extended periods of timewithout GPS is feasible using a boot-mounted IMUand compass.However, even sparse GPS data in a GPS/IMUsystem provides:Initialization of position, heading and IMU sensorerrors for inertial navigationCorrection of long-term inertial navigation errors18 2010 ENSCO, Inc. All rights reserved.
Todd Faulknerfaulkner.todd@ensco.comDavid W.A. Taylor, PhDtaylor.david@ensco.comgeonav.ensco.com
Low-cost IMU Through the Use of Tightly-coupled L1 GPS Stanley Radzevicius, W. Todd Faulkner, David W.A. Taylor . approach also allows integration of sparse pseudorange measurements that are discarded in loosely coupled approach. 7 . Indoor/Outdoor Tightly Coupled GPS/INS Navigation: Short Segment Enter Building Exit Building GPS Only GPS .
East Cesar Chavez Neighborhood Plan Implementation Tracking Chart 9/1/2020 42 Make existing pedestrian-lighted signals and crosswalks on Cesar Chavez safer by encouraging pedestrian traffic to use the south side in the short term. In the long term, improve the north side with pedestrian lights and a pedestrian island. 33 Austin Transportation
Bicycle and Pedestrian Design Guide. Where there is a discrepancy between content in this Part 800 and the Oregon Bicycle and Pedestrian Design Guide, this Part 800 takes precedence. The Oregon Bicycle and Pedestrian Design Guide is for use by local agencies to develop their standard of practice for the bicycle and pedestrian realms.
STRATEGIES TO IMPROVE TRACKING ACCURACY this paper: Three strategies for improving heliostat tracking are discussed in Mark Position Adjust or "Bias": Use tracking accuracy data to calculate a change in the heliostat azimuth and elevation encoder reference or "mark" positions to minimize the time-variant tracking errors.
This paper describes a simple pedestrian detection system for monocular NIR image. The algorithm consists of four modules: Image capture, segmentation, tracking, warning and display. Pedestrian detection system will aid the driver about pedestrian on the road both in day and night time with the help of a camera and its display .
Object tracking is the process of nding any object of interest in the video to get the useful information by keeping tracking track of its orientation, motion and occlusion etc. Detail description of object tracking methods which are discussed below. Commonly used object tracking methods are point tracking, kernel tracking and silhouette .
2. Deploy common tracking technology and open network connectivity: Ensure tracking across the entire logistics chain despite the numerous hand-offs 3. Automate data capture: Improve data accuracy and timeliness, reduce tracking labor 4. Create a closed-loop process for reusing tracking tags: Reduce tracking costs and improve sustainability
signs), and TURNING TRAFFIC MUST YIELD TO PEDESTRIANS signs R10-15. 11.3 Pedestrian Signals Extensive guidance and standards for pedestrian signal warrants are provided in the MD-MUTCD, and are not duplicated in this Chapter. Pedestrian signals must be designed to meet SHA’s current Accessibility Policy & Guidelines for
The checklists contained herein are based on ADA compliance requirements for permanent pedestrian facilities. The checklists are a tool for personnel to use in determining compliance of pedestrian facility features. Personnel must verify that contract compliance of pedestrian facilities has been obtained.
