The Cricket Indoor Location System: An NMS Project @ MIT LCS Page 1

http://nms.lcs.mit.edu/projects/cricket/ 27.05.2004 12:38:12

The Cricket Indoor Location System

overview - cricket project descriptiontechnology - how it works?

results - how well cricket works?applications - what can you do with cricket?

download - the software you needpeople - who are we?papers - cricket documents

data - collection of some raw cricket dataacknowledgments - who sponsors cricket?

Overview

Cricket is indoor location system for pervasive computing environments, such as those envisioned byMIT's Project Oxygen. These environments take advantage of emerging network-enabled devices andthe promise of ubiquitous network connectivity.

Note: This overview discusses Cricket v1. We have recently completed the design of Cricket v2, whichis substantially more accurate than v1, has better energy consumption properties, has a new softwarestack based on TinyOS, has better support for continuous object tracking, and which will becommercially available in early 2004 (per current plan). We haven't had time to finish thedocumentation of Cricket v2 yet, but it will be available soon along with the software and hardwaredesign.

A compelling set of applications in pervasive environments are context-aware, being able to discoverthe external context in which they run and adapt accordingly. An important example of context islocation, such as the position (in some coordinate system) of a device or user, the geographic space inwhich a device or user is (e.g., the room or portion of a room), and the orientation of a device withinsome coordinate system.

Knowledge of location in the form of coordinate position, spatial resolution, and orientation (a.k.a."directionality" or "heading") enables a wide variety of pervasive computing applications such asresource discovery, "point-and-use" interfaces, navigation, and augmented reality.

While location information in outdoor environments may be obtained via the Global PositioningSystem or using the cellular infrastructure (with the emerging E-911 services) augmented with amagnetic compass, such capabilities are unavailable in indoor environments or around tall buildingswhere line-of-sight to GPS satellites is usually unavailable. We assert that location-aware applicationsinside buildings, such as offices (and campuses), shopping malls, airports, homes, etc. has the potentialto fundamentally change the way we interact with our immediate environment where computingelements will be "ubiquitous" or "pervasive".

Doonesbury, August 22 2001.

Obtaining location information for applications in an indoor environment in an unobstrusive andprivate manner is a challenging task. Indoor environments are harsher than outdoor ones in theirtreatment of radio signals because of multipath effects and dead spots inside buildings. A traditionalmagnetic compass doesn't work well in many buildings with computers and monitors because of EMinterference. User-privacy concerns are an important consideration in the successful deployment ofthese applications, especially if the users of the system are to extend beyond the researchers whodevelop the technology. The administration of the hardware and software infrastructure used for thismust be minimal because of the large number (potentially over several thousand in a typical building)of devices and networked services that need this information.

Technology

Cricket uses a combination of RF and ultrasound technologies to provide a location-support service tousers and applications. Wall- and ceiling-mounted beacons are spread through the building, publishinginformation on an RF signal operating in the 418 MHz AM band. With each RF advertisement, thebeacon transmits a concurrent ultrasonic pulse. Listeners attached to devices and mobiles listen for RFsignals, and upon receipt of the first few bits, listen for the corresponding ultrasonic pulse. When thispulse arrives, they obtain a distance estimate for the corresponding beacon. The listeners runmaximum-likelihood estimators to correlate RF and ultrasound samples (the latter are simple pulseswith no data encoded on them) and to pick the best one. Even in the presence of several competingbeacons vying for attention, our goal is to accurately pinpoint the right one within a small number ofseconds.

The Cricket Compass provides position (x,y,z coordinate) information and orientation (the direction atwhich the device is pointing) information.This is what the Cricket v1 beacon (left) and listener (right) look like. (They're actually about the samesize.)

This is Cricket v2 RS-232 (left) and Compact Flash edition (right).

Results

Cricket uses active beacons and passive listeners, which has two significant benefits. First, it is not atracking system where a centralized controller or database receives transmissions from users anddevices and tracks them. Second, it scales well as the number of devices increases; a system withactive transmitters attached to devices wouldn't scale particularly well with the density of instrumenteddevices. Third, its decentralized architecture makes it easy to deploy. This does not mean it is hard tomanage; a centralized front-end allows easy management and control.

Cricket can estimate position to a few centimeters of accuracy and angles to within 3-5 degrees of thetrue value. It can determine which space a device is in by detecting boundaries to within about 2 feet. These combined capabilities are better than other available location systems that we know of.

We've been deploying Cricket. Here's a picture of its deployment on the 5th floor of MIT's LCS at 200Tech Square (click on it for a bigger image).

Applications

Stream-Migration Demo Video (18MB)An Oxygen Scenario (9MB)Indoor Navigation (27MB)

BeaconFinderStream MigrationViewfinderPeopleFinderCricketNav

Download

Cricket Setup Notes

Cricket Software/Design Distribution The Cricket distribution is available for free. Please registeryour name, email, and affiliation to obtain the proper login and password to access the distribution.

Cricket people

Faculty:

Hari BalakrishnanSeth TellerErik Demaine

Research Staff

Michel GoraczkoKen SteeleDorothy Curtis

Graduate Students

Bodhi PriyanthaRoshan BaligaAllen MiuKevin WangKyle Jamieson

Undergraduate Students

Adam SmithMike Whitaker

Former Students

Anit Chakraborty (MEng)Albert Lin (UROP)Nikos Michalakis (MEng)Jorge Rafael Nogueras (SM)

Papers

Nissanka B. Priyantha, Anit Chakraborty, Hari Balakrishnan, The Cricket Location-Supportsystem, Proc. 6th ACM MOBICOM, Boston, MA, August 2000.This is the original Cricket paper describing our first prototype and algorithms.

Nissanka B. Priyantha, Allen Miu, Hari Balakrishnan, Seth Teller, The Cricket Compass forContext-Aware Mobile Applications, Proc. 7th ACM MOBICOM, Rome, Italy, July 2001.This paper describes how Cricket can be enhanced to provide orientation information, in additionto space and position coordinates.

Seth Teller, Kevin Chen, Hari Balakrishnan, Pervasive Pose-Aware Applications andInfrastructure, IEEE Computer Graphics and Applications, May/June 2003.This paper describes early experience with some applications of the Cricket compass (done withtwo or more "standard" Crickets, rather than with an integrated compass device). This paperdescribes the lessons learned from Cricket v1 and how Cricket v2's design builds on theselessons.

Nissanka B. Priyantha, Hari Balakrishnan, Erik Demaine, Seth Teller, Anchor-Free DistributedLocalization in Sensor Networks, LCS Tech. Report #892.

Seth Teller, Jiawen Chen, Hari Balakrishnan, Pervasive Pose-Aware Applications andInfrastructure, IEEE CG&A, July/August 2003.

Hari Balakrishnan, Roshan Baliga, Dorothy Curtis, Michel Goraczko, Allen Miu, Nissanka B.Priyantha, Adam Smith, Ken Steele, Seth Teller, Kevin Wang, Lessons from Developing andDeploying the Cricket Indoor Location System, November 2003. (Preprint.)

Adam Smith, Hari Balakrishnan, Michel Goraczko, Nissanka Priyantha,Tracking MovingDevices with the Cricket Location System, June 2004.

Theses

Nissanka Bodhi Priyantha,Providing Precise Indoor Location Information to Mobile DevicesSM Thesis, Massachusetts Institute of Technology, January 2001. [Postscript (1.21 MB)](54 pages) Nikolaos Michalakis,Location-aware Access Control for Pervasive Computing EnvironmentsM. Eng. Thesis, Massachusetts Institute of Technology, February 2003. [PS (749 KB)][PDF (1.1 MB)] (73 pages)

Allen K. L. Miu,Design and Implementation of an Indoor Mobile Navigation SystemSM Thesis, Massachusetts Institute of Technology, Jan 2002. [Postscript (3.8 MB)] [ps.gz(459 KB)] [PDF (1.9 MB)] (60 pages)Winner of a Masterworks Award, May 2002. Jorge Rafael Nogueras,A Stream Redirection Architecture for Pervasive Computing EnvironmentsSM Thesis, Massachusetts Institute of Technology, May 2001. [PDF(577 KB)] (70 pages)Winner of a Masterworks Award, May 2001. Anit Chakraborty,A Distributed Architecture for Mobile, Location-Dependent ApplicationsM. Eng. Thesis, Massachusetts Institute of Technology, May 2000. [PDF (656KB)] (58pages)

Experimental Data

Cricket v1 Data

Some experiments conducted using the original version of Cricket.

Distance Measurements (zip file 180 kB)Positioning Measurements (zip file 900kB) See detailed experiment description in Design andImplementation of an Indoor Mobile Navigation System

Cricket v2 Data

Some experiments conducted using the second version of Cricket.

Mobile Positioning Measurements (zip file 310 kB)

Acknowledgments

Cricket is funded by:

NTT Inc. under the NTT-MIT research collaboration;Acer Inc., Delta Electronics Inc., HP Corp., NTT Inc., Nokia Research Center, and PhilipsResearch under the MIT Project Oxygen partnership and the National Science Foundationsupport for The Scalable Location Aware Monitoring Project. We are grateful to these sponsors.Analog Devices, Inc., for their kind donation of electronic components and sensor devices.

NMS Home People Publications Software

CSAIL E E C S M I T

M. I. T. Computer Science and Artificial Intelligence Laboratory · 32 Vassar Street · Cambridge, MA 02139 · USA

If you're looking for a tiny computer for robotics applications, please visit Crickets: Tiny Computers for Big Ideas,which is a project led by Fred Martin at the MIT Media Laboratory.