the use of lidar technology in autonomous cruise control systems for ...

Conference Session C10Paper #3124THE USE OF LIDAR TECHNOLOGY IN AUTONOMOUS CRUISE CONTROLSYSTEMS FOR AUTOMOBILESGreg Jakubiec,(gjj6@pitt.edu, Vidic, 2:00), Brendan Mullinix, (bdm39@pitt.edu, 0012, Budny, 4:00)Abstract- This paper is concerned with the topic of“LiDAR”, or Light Detection and Ranging technology, andits specific usage in autonomous or “self-driving” cruisecontrol systems for automobiles. LiDAR is a high techremote sensing technology that makes use of lasers toanalyze and map various objects and landscapes. LiDARworks by emitting infrared, ultraviolet, or visible light at anobject, and then measuring how quickly the light returns tothe source, as well as measuring other disturbances in thelaser as it returns to the LiDAR source.LiDAR technology is similar to radar and sonartechnology, and is often called “laser radar”, althoughLiDAR is technically not a radar system; it relies on laserlight instead of radio or microwaves, or sound waves likesonar. LiDAR, however, is able to provide much faster andmore detailed, as well as higher resolution readings thanradar systems.While LiDAR has a multitude of innovative and usefulapplications for society, we are particularly concerned withits use in remote sensing in autonomous automobiles. LiDARallows automobiles to create extremely detailed, highdefinition maps of their surroundings in real time. Computersystems connected to the LiDAR systems then analyze thisinformation to direct the car as safely and efficiently aspossible, avoiding obstacles and collisions and obeyingother regulations and rules.In this paper, we will explain how the electrical, as wellas computer and mechanical, technology behind theoperation and utilization of LiDAR systems work inautonomous automobiles, for driving and parking them. Wewill also detail and explain why autonomous cars withLiDAR systems will improve the quality of life of those whodrive and use them, as well as society as a whole. We willalso discuss the potential future of LiDAR technology andautonomous automobiles s well as research and explore thepotential ethical complications of the use of autonomousautomobilesKey Words - Grid-Based Processing, Laser, LiDAR, Multi-Level Fusion, Obstacle Maps, Radar, Road-Edge Detection.that interact with their surroundings and then bounce back tothe recording device, the major differences being in thetypes of waves. Radar and sonar, however, both have largeflaws that LiDAR does not, as we will explain in more detaillater. To summarize for the time being, however, LiDARprovides a much more accurate map of the surroundingenvironment, and is able to scan much larger distance andranges than radar systems. LiDAR was created to detectobjects for collision avoidance, and mapping, and has amultitude of other applications in science and engineering,such as astronomy, geology, mapping at the atomic level,navigation, and urban planning. [1]. A major use of LiDARtechnology is as a type of scanning and navigation system inautonomous automobiles, which greatly improves theaccuracy and precision of the functions of these automobiles,making them safer and more efficient.FIGURE 1Velodyne HD LiDAR [2]HOW LIDAR WORKSWHAT IS LIDAR?LiDAR, short for Light Detection and Ranging, is a laserbased 3-D scanning system, similar in basic function tosonar and radar. Sonar, radar and LiDAR all send out wavesThe LiDAR device shoots out rapid bursts of invisiblelaser light in all directions, in a very similar fashion to sonarwith sound waves, or radar with radio waves. The lighttravels towards whatever object is in its path, and thenrebounds back towards the device. Receivers on the deviceUniversity Of PittsburghSwanson School of Engineering 1 April 13, 2013

Gregory JakubiecBrendan MullinixEach LiDAR device contains one scanner for each laser.In the case of the Velodyne HD system, 64 lasers andscanners are used [2].Positioning SystemsA key part of creating a detailed map of the environmentis knowing where the LiDAR device is actually located inthe larger environment, on a global level. LiDAR alone isable to scan every aspect of its surroundings, but without aprecise reading of its own location, accurate maps cannot becreated. This is done by Global Positioning System (GPS).GPS is a satellite-based navigation system [6], created by theUS government. The GPS satellites send information abouttheir location, in relation to the GPS device, and the positionon the ground is then calculated. GPS systems allow theLIDAR system to keep track of its exact location at alltimes. This enables it to create highly detailed images of thecorrect location, and connect these scanned images to abroader geographic location.around this by only searching for “Doppler-shifted” [8]Signals. This again works against the goal of mapping theentire environment, as the radar beam is “tightly focused”[8] on one area. This is where LiDAR excels. It is able tomap entire areas very quickly and accurately. The lasersused do not encounter the same interference, so there can beno mistakes in measuring the distance to objectsUSES OF LIDAR TECHNOLOGYAlthough LiDAR did not become commerciallysuccessful until the late 1970’s the current number of usesfor LiDAR technology systems are great.Mapping/CartographyThe use of LiDAR scanning has been implemented inthe creation of maps used alongside aerial photography [1].LiDAR can assist in creating 3-D representations of allenvironments.WHY LIDAR?Now that we know how LiDAR works, the main questionis: why is it better than already existing technology such asradar and sonar? Radar and sonar had both been around fordecades before LiDAR gained popularity.The major problems with sonar are relativelystraightforward. First of all, sonar makes use of sound wavesas opposed to radio or light waves, which travel muchslower, as the speed of light is magnitudes faster than that ofsound. Light travels at approximately 29980000 m/s, whilesound only travels at approximately 343 m/s (in air at roomtemperature) [7]. This leads to a much lower frequency ofmeasurements being taken, and therefore a much lowerdegree of accuracy.Radar, although much more accurate than sonar, still fallsshort of LiDAR in many aspects. A major differencebetween the two is the way radar detects objects. The radardevice sends out radio waves that bounce off objects andreturn to the receiver. Radio waves are the largest in theelectromagnetic spectrum, ranging from 1cm to 1000m.They are also silent, invisible, and easily detectable. Theradar set measures the time it takes for the echo to arrive,and also measures the Doppler Effect which allows radar todirectly measure velocities (this is one of the few advantagesradar does have over LiDAR) [8].The problem with radar, however, is that there are manymore opportunities for interference. When used on theground the returning echo could be from any object such astrees, people, and animals, not just cars. This would beuseful, but the many returning radio waves make it difficultto differentiate between objects. Some have found a wayUrban planningLiDAR is used to create “Digital Surface Models” [1] ofthe surface of the planet. Digital surface models are used inconjunction with city planners to create models of theproposed area.Navigation“LiDAR is becoming more and more popular as aguidance system for autonomous vehicles” [1]. BecauseLiDAR uses high-speed pulses of laser light, data isprovided in real-time [1]. This is the most attractive featureof LiDAR when used in autonomous vehicles. The real-timedata feedback allows collision detection, and navigation likeno other device.Military and law enforcementOne of the most well-known uses of LiDAR is in Policespeed scanners. It has started to replace radar traffic gunsbecause it has more accuracy, and does not face the sameinterference problems. LiDAR is also being used in theautonomy of robots and UAV drones for the military.3

Gregory JakubiecBrendan MullinixLIDAR IN AUTOMOBILESThe direct application of LiDAR systems that we aremost concerned with is its use in self-driving automobiles.Autonomous cars that utilize LiDAR generally have multipleLiDAR devices onboard, in addition to various otherimportant devices used to sense their surroundings, such asradar, cameras and video systems. They also carry complexcomputer processing systems that analyze the data. It shouldbe noted that LiDAR can’t effectively navigate anautonomous car by itself. It must work in conjunction withvarious other devices, such as cameras and radar systems, aswell as advanced computer hardware and software.There have been multiple specific methods of analyzingand utilizing the LiDAR data that have been experimentedwith, although the majority of them are heavily based on theconcept of grid based processing (which will itself later beexplained in much greater detail), in order to mapenvironments in real time.FIGURE 4LiDAR and Radar IntegrationIn addition to LiDAR, many cars also have radar systemsonboard. Although LiDAR can take measurements acrosslarger ranges and distances, as well as operate much better ininclement weather, radar is able to provide the vehicle withmore detailed information, due to the Doppler Effect.LiDAR technology is our main focus, although radar doeshave its place in autonomous cars as well, and is not to beforgotten. The most efficient autonomous car should utilizeboth [5].When used to operate automobiles, LiDAR andtraditional radar both serve their respective purposes. Inorder for a LiDAR machine to measure velocity, forinstance, it must take different distance measurements atdifferent times, and use them to compute the velocity of theobject being tracked. This leads to a relatively inaccuratevalue of velocity, which in turn leads to an inaccurate valueof acceleration. Radar, however, makes use of the DopplerEffect, which allows systems to measure the disturbances inthe frequency of the return signal, which correspond directlyto velocity of the point being measured. [5]Although LiDAR may not provide as accurate velocityinformation as radar systems, it does operate at much largerranges and fields of view. This is essential to a vehiclemoving through curves and around corners at high speeds[5]. The most efficient autonomous navigation system is onethat utilizes both LiDAR and radar in harmony, covering theweaknesses and exploiting the strengths of both systems.Below is a diagram of one example of an autonomous carsystems utilizing multiple types of sensing technology tonavigate.Diagram of Radar, and Ultrasonic collision detector sensorson a vehicle. [4]Grid Based ProcessingThere have been multiple methods of analyzing andutilizing the LiDAR data that have been experimented with,although the majority of them are heavily based on theconcept of grid based processing.Grid based processing is a general technique used inautonomous cars to map their environments. The basic ideaof this type of data processing is that very small amounts ofdata are each stored in very specific “locations”,corresponding to their actual physical locations, within agigantic grid. This allows the system to quickly andefficiently locate and analyze whatever specific data may berelevant at the current moment, and then update all of it inreal time.The environment around the car is divided up into smallsections of grid within the computing system. The LiDARand radar systems then collect data about each piece of thisgrid, returning it to the analysis software. Using the responsefrom the different systems, a probability is determined for aspecific grid square to be occupied, and assigned to thatspot. With each of these small grid spaces being extremelysmall, a large grid environment is formed [9]. Conclusionscan then be made by the computer regarding the shapes andtextures of objects by analyzing the similarities anddifferences of clusters of grid squares to each other, andsubsequently what types of objects they are most likely tobe. This information is then used to navigate the careffectively throughout this constantly changing grid.4

Gregory JakubiecBrendan Mullinixcars. “Something similar to this happened after the ThreeMile Island and Chernobyl accidents with the nuclearindustry, and it has only recently partly recovered from thosedisasters” [13]. An event such as these would set theautonomous automobile industry back decades, andpotentially destroy any chances it had at large scaleimplementation.Although the majority of relevant ethical concerns regardautonomous automobiles specifically, LiDAR also carriespotential ethical problems in and of itself. For instance,many people are likely to be anxious of the widespread useof laser technology due to fears of lasers harming humanbeings or the environment [1]. These fears are unfounded,however, as the lasers utilized in these use a wavelength andfrequency that has been tested and proven to be safe forhumans and not damage eyes or other bodily functions.In order to successfully integrate these machines into oursociety without dissent, it must be made sure that any and allof the devices used are safe to humans, through extensiveresearch and testing They should also be integrated intowidespread use fairly slowly, so that society can adapt totheir use as should occur naturally.Although LiDAR and autonomous cars do have theirethical complications for society, they are of a magnitudethat can be overcome over time through responsible use ofthese systems. After all, the initial advent of cars themselvesmet plenty of dissent from the public, and now a majority ofAmerican families own vehicles, or at least make use ofpublic transportation, and it has led to a far more advancedand efficient society, as will LiDAR and self-driving cars inyears to come.Pre-Crash SystemsOne important part of autonomous, as well as semiautonomousvehicle systems is pre-crash systems. These aresystems that are implemented in the event of an impendingcrash to minimize the damage caused, and therefore helpmake these cars safer, for passengers that may ride in them,as well as decreasing the likelihood of accidents betweennon-passenger cars. These are already being used in userdriven cars that are currently on the road in order tominimize injuries and fatalities to the passengers.Basically, the vehicle sense when an emergency is aboutto occur through LiDAR and radar and activates anemergency reaction sequence. The vehicle will thenautomatically react by tightening seatbelts, adjusting headrestraints, and deploying airbags early, in order to protect allonboard passengers. It will also activate emergency steeringand braking, as fast as physically possible, to avoidoncoming collisions, and set off emergency signals [9]. Thisis one major aspect of what makes self-driving cars saferthan human driven cars. Humans will often panic duringemergency situations, whereas autonomous cars canconsistently act as logically as possible and do whatever ispossible to avoid an accident, or at least minimize thedamage caused by one.THE FUTURE OF LIDAR ANDAUTONOMOUS AUTOMOBILESJudging by the current state of autonomous automobiletechnology, self-driving cars are a very real possibility forthe relatively near future. Although still being heavilyrefined and researched, the required technology is certainlyin existence. Google has successfully created a small groupof functioning semi-autonomous cars, which have driven atotal of around 140,000 miles around California, although allof these are done with a driver who can take control ifnecessary. “Cars are approaching the point that smartphoneplatforms had reached just before the introduction of theApple iPhone and the Motorola Android” [4].Implementation of self-driving vehicles into things such asthe shipping business, would completely automate truckdriving, eliminating human error and decreasing excesspollution. This will also allow for things to be shipped muchcheaper, as drivers would not be utilized, but rather a smallgroup of technicians to service the vehicles.In California, a bill was signed into law by GovernorJerry Brown on September 25, 2012 that will legally allowautonomous cars to travel on public roads along with userdriven cars, once they have been certified as safe [12].Sergey Brian, of Google has also said that it would take“fewer years than he had fingers on his right hand” for thesecars to become available to the general public, although theyare likely to be very expensive at first [12].With advancements and promises such as thesehappening outside of the science and engineering world, aswell the technological advances that continue to occurwithin the software and operation of autonomousautomobiles and their use of LiDAR systems, it likely willnot be very long before we begin to see these cars on theroad alongside our own.REFERENCES[1] (2012). “How does LIDAR Work?” LIDAR-UK.(Online article). http://www.lidar-uk.com/how-lidar-works/[2] (2012). “HD-64e.” Velodyne LIDAR. (Online article).http://velodynelidar.com/lidar/hdlproducts/hdl64e.aspx[3] (2012). “LIDAR Overview.” Washington.edu. (Onlinearticle).http://forsys.cfr.washington.edu/JFSP06/lidar_technology.htm[4] M. Conner. (2011). “Automobile sensors may usher inself driving cars.” EDN Network. (Online article).http://www.edn.com/design/automotive/4368069/Automobil7

Gregory JakubiecBrendan Mullinixe-sensors-may-usher-in-self-driving-cars[5] G¨ohring, Daniel, Wang, Miao, Schn¨urmacher, Micheal,Ganjineh, Tinosch. (2011). “Radar/Lidar Sensor Fusion forCar-Following on Highways” 5th International Conferenceon Automation, Robotics and Applications (ConferencePaper).http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6144918[6] (2013). “What is GPS?” Garmin.http://www8.garmin.com/aboutGPS/[7] Halliday, Resnick, Walker. (2012). “Fundamentals ofPhysics” Department of Physics and Astronomy Universityof Pittsburgh. (Textbook)[8] Kaydee. (2011). “Self-Driving Cars: Here Sooner ThanYou Think, Courtesy of Google?” Engineering Ethics Blog.(Online Blog Article).http://engineeringethicsblog.blogspot.com/2011/08/selfdriving-cars-here-sooner-than-you.html[9] Lindner, Philipp and Wanielik, Gerd. (2009). “3DLiDAR Processing for Vehicle Safety and EnvironmentRecognition.” (Online article).http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4938725[10] Peterson, Kevin, Ziglar, Jason,and Rybski, Paul E..(2008). “Fast Feature Detection and Stochastic ParameterEstimation of Road Shape using Multiple LIDAR” TheRobotics Institute, Carnegie Mellon University (ConferencePaper).http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4651161[11] (2012). “Moral Machines.” The New Yorker. (Onlinearticle).http://www.newyorker.com/online/blogs/newsdesk/2012/11/google-driverless-car-morality.html[12] Stiller, Christoph, and Ziegler, Julius. (2012). “9 thInternational Multi-conference on Systems, Signals, andDevices” (Conference Paper).http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6198130[13] Thompson, Iain. (2012). “Google PromisesAutonomous Cars for all within 5 Years” (Online NewsArticle).http://www.theregister.co.uk/2012/09/25/google_automatic_cars_legal/Research & Development Division Automotive Research &Testing Center (Conference Paper).http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5514860(2012). “Google’s Self-Driving Car with Blind Driver”.Universal Design Style (Online Article)http://www.universaldesignstyle.com/wpcontent/uploads/2012/04/01458sz1i28643900.jpgLardinois, Frederic (2012). “Google’s Self-Driving CarsComplete 300K Miles Without Accident, Ready ForCommuting” Tech Crunch. (Online Article).http://techcrunch.com/2012/08/07/google-cars-300000-miles-without-accident/Moras, Julien, Cherfaoui, V´eronique and Bonnifait.,Phillipe. (2011). “A lidar Perception Scheme for IntelligentVehicle Navigation” 2010 11th Int. Conf. Control,Automation, Robotics and Vision (Conference Paper).http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5707962(2012). “LIDAR Boosts Brain Power for Self-Driving Cars.”Earth Imaging Journal. (Online article).http://eijournal.com/lidar-solutions-showcase/lidar-boostsbrain-power-for-self-driving-cars(2012). “User’s Manual and Programming Guide.” (Onlinearticle) http://velodynelidar.com/lidar/products/manual/63-HDL64ES2h%20HDL-64E%20S2%20CD%20HDL-64E%20S2%20Users%20Manual.pdfACKNOWLEDGMENTSWe would like to thank our co-chair, Traci Smith, forhelping us write and revise our paper and pointing us in theright direction. We also would like to thank Red Bull, forhelping us to stay awake for the long hours required to writethis paper.[14] (sustainability)http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4534692ADDITIONAL SOURCESChan Wei Hsu, Tsung Hua Hsu, Chun Hsiung Chen andYung Yuan Kuo. (2010). “A Path Planning Achievement ofCar Following in Motion Control via LiDAR Sensing.”8