Tag: in-vehicle services

  • New Dawn for Driver Nav: GPS World Takes a Spin in the Audi A8L

    Today, some of the most exciting innovations in consumer electronics aren’t the ones in your living room or your office — they’re the ones inside your car. — Audi CEO Rupert Stadler

    While most automobile magazines do a great job of reviewing the performance of automobiles and trucks, they do not adequately address the vehicles’ GPS or positioning, navigation, and timing (PNT) capabilities, sensors, or electronics suites. Nor do they endeavor to fully grasp how these sensor suites, many enabled by GPS and other PNT devices, add to their safety, peace of mind, and overall situational awareness. My pick of the best automobile currently on the market for driver situational awareness is the 2011 Audi A8.

    Lest you think the choice was easy, it was not. For two years I drove more than 26 different candidate automobiles and I found myself repeatedly comparing them to the A8L. The Audi 8L is designated by its maker to premiere and test all electronic features — hardware and software, including situational awareness devices — that may eventually go into production on other Audi models.

    I noticed when I began testing automobiles that, on the high end, they were fairly uniform in performance. The majority of them went from 0 to 60 miles per hour (0 to 100 kilometers per hour) in less than five seconds. They all stopped or went from 60 to 0 in approximately 100 feet (30.48 meters), depending on the tires, weather, and road surface. They were all reasonably quiet and to some degree comfortable. The average fuel mileage varied from 15 to 27 miles per U.S. gallon, with the Audi A8L taking honors in this class. However, the models varied tremendously in their electronic sophistication, integration, and situational awareness: some vehicles kept the driver situationally aware, and some failed miserably at this critical task.

    I look not only at the electronics and how they are integrated, but also how easily and completely they inform the driver in all sorts of traffic and weather conditions. Do the windshield wipers activate automatically when it rains or you enter a fog bank? Does the navigation system automatically reroute you or at least offer that option when weather, accidents, or delays are encountered? Does the PNT system alert you in time to take evasive action in a potential dangerous situation? Does it present the mapping interface and alerts so that you are aware of your options both aurally and visually? Do you have to manually intervene or merely follow clear and precise directions?

    Every major automobile maker and dealer I spoke with said that the majority of serious buyers today look for performance and style as always — but those have become secondary to the options provided, mainly the electronic awareness, safety, and entertainment suites. Of course, makers and dealers also appreciate the fact that these options, while adding safety, convenience and awareness, also add — often significantly — to the bottom line, or the vehicle’s drive-away price. So, yes, situational awareness does come at a price and sometimes a steep one. However, if it gives you peace of mind, lower stress, and saves lives, it is hard to complain. One can certainly make the argument that all these devices should be available on all automobiles. As time goes by they will be, and at a lower price. For now, we pay a premium for them. But what price can you place on a human life? Rest assured, many of these features are potentially life-saving.

    Stealth GPS

    I want to alert you to a phenomenon some GPS subject matter experts and I discovered while researching for the Department of Defense. It surprised us, but in retrospect we have always suspected the phenomena existed; we have chosen to call it Stealth GPS.

    Stealth GPS exists in many military platforms today, and the practice now extends to the automotive industry as well. Basically, 90 percent of the more than 1 billion GPS users in the world use GPS for time or timing purposes and not for just position or navigational purposes. Obviously, in automobiles with very high-tech systems onboard, timing and synchronization are critical. Since GPS chips today are relatively inexpensive, they occasionally show up in unexpected places. No less than five major auto makers told us that every model they produce has a single and more likely multiple GPS chip(s) embedded somewhere in the electronic suites. These automobiles may or may not have a standalone GPS display, and it may not be obvious to the owner or even the mechanics that work on the vehicle, but GPS information, including timing data, is essential to proper vehicle operation.

    For example, on the Audi A8L the Quattro sensors measure tire adhesion or slip up to 100 times per second and report that information through the traction-control system’s electronics. This requires precision timing and a tightly integrated timing or synchronization system.

    Consider that GPS time is distributed freely around the world, and relatively cheap quartz crystal clocks can act to hold over precise GPS timing for a considerable period when the vehicle’s GPS antenna, also usually a stealth device, cannot see the sky. GPS chips in addition to position and navigation information may provide time of day to include day, month, year, hour, seconds, and divisions of seconds down to 1 x 10-14, along with altitude, attitude, heading, and velocity information, all independent of any other sensors on the car. As you will see, when GPS data are tightly integrated with other sensor data and display systems, the resulting displays and capabilities can be almost staggering in their versatility and ability to make the driver situationally aware.

    How many GPS chips, stealth or otherwise, does the Audi 8L carry? Frankly, I am not sure, and it’s just possible that neither is Audi; after all, some of them are likely very stealthy. But regardless of how many there are, they inform and enable a dizzying array of displays, capabilities, and overall situational awareness second to none.

    When I drove the A8L, every time I wanted a piece of information that the situation demanded, it always seemed to be readily available, and usually in more than one location. There is a pop-up full-color 8-inch display screen in the center console and a full color 7-inch display screen directly in front of the driver, between the speedometer and tachometer. The 7-inch screen is so well integrated that until information starts to appear, you never know it exists. I did not have to search or push buttons or pull levers — the information was simply there when I needed it.

    The Audi’s displays were the most intuitive I have experienced to date. So much so that after experiencing the Audi’s non-intrusive total situational awareness capabilities, they were subsequently conspicuously absent on any other vehicles I drove.

    The Audi A8L is available with all of what Car and Driver calls Audi’s latest “electronannies,” including a multimedia interface (MMI) and voice-controlled GPS display, which disappears when not in use or when the automobile is turned off. There is also active and adaptive cruise control with low-speed stop-and-go capability that will actually initiate and fully stop the vehicle if you are about to collide with an object, person, or another vehicle — and you fail to stop the car yourself.

    The A8L has

    • a blind-spot monitoring system;
    • a camera-enabled lane-assist mode that turns on above 40 miles per hour and warns you with a steering wheel vibration when you are wandering in your lane or about to intrude on another;
    • a night-vision system that displays yellow silhouettes for anything warm-blooded ahead, including pedestrians and those lovable but pesky Bambis lurking by the side of the road; when such creatures are directly in the car’s path, the alerts turn bright red.
    • a visual reverse navigator in the center pop-up that clearly displays the exact parking path the car will take depending on how you turn the wheel. The proximity sensors beep with increasing frequency as you near objects and turn to a solid tone when you are within four inches of the object. I parked the Audi A8L several times solely by monitoring the center display.

    While these wonders are merely enabled by GPS, the display screens in the vehicle are nothing short of amazing in their capability and versatility. The touch-screen color display can enable almost any feature of the automobile through a mere touch while many features are MMI- and/or voice-activated. You quickly learn, if your hands are occupied keeping you on the road, that you merely need to speak, and the Audi quickly obeys.

    Road Trip

    Before driving from Colorado Springs to Denver and back, I spent two very informative hours with the dealer staff going through the A8L’s features and capabilities. They do this with every prospective buyer — a good thing because the number of features can be daunting. But once you are actually driving, everything seems intuitive and, most important, non-distracting. I never once had to hunt for switches or buttons, because if you can’t remember, just use the audio system and tell the Audi what you want or need.

    On the open road, I headed north to Denver. I set my destination merely by asking aloud for the Denver airport; the system immediately gave me a choice of the three airports in and around Denver, and I selected one. I could have looked up all airports within 100 miles, or put in the address if I knew it, or just browsed local transportation options, or even input the coordinates if I had them.

    The center display always gave me the speed limit of the road I was traveling; it allows you to set a warning if you exceed that speed by your choice of number. The car is so quiet, there are no audible clues as to your actual velocity. If there had been any speed cameras on I-25, the Audi would have warned me about them as well.

    The car always displayed the next three turns in blocks that clearly gave the mileage to the turn, the direction and degrees of the turn, and the name of the exit and road to turn onto. A mile before each exit, the navigation system displayed all its amenities and points of interest (POIs): gas stations, motels, hotels, restaurants, hospitals, and cash machines. It can display much more or less, depending on how you program, it, but the logos for the amenities show up just like they do on some road signs with the same information (although the road signs never seem to be there when you need them, or they go by too fast to read). Plus, both the center and driver’s panel displays show in bright vivid blue your route and the turns to make, the lane you should be in, and very accurate distances and times to the next turn, your final destination, and any intermediate points.

    Wonder of wonders, when I turned off the prescribed route (on purpose), I never heard the dreaded “Recalculating…” The system adjusted and gave me new data to my destination based on my waywardness, and a pleasant suggestion to “proceed along the highlighted route.”

    Back on I-25, all of a sudden yellow triangles appeared on both navigation displays, with a visual and audible warning of slow traffic ahead; a few seconds later came an indication that an accident had occurred. The nav system immediately zoomed out to show alternate routes with major thoroughfares that would take me around the slowdown. I took the first turn off the Interstate without making any manual adjustments to the system. It routed me effortlessly around the accident and back to I-25. I never pushed a button or had to ask a question. If I’d wanted to continue on secondary roads, it would have accommodated that automatically.

    On the outskirts of Denver, I programmed the system to find the nearest Starbucks, which was less than a half-mile off the Interstate. There I reprogrammed my return route to go through seven POIs. Having accomplished this feat without once looking at a manual, I was off again.

    I made the trip back on secondary roads mainly so I could cruise with both sun roofs open and listen to the 19 speakers  of the wonderful Bose stereo system (Bang and Olufsen option). I stayed about 5 miles below the speed limit and was passed innumerable times, but I didn’t care because I was having so much fun. This automobile is so comfortable, you find yourself looking for ways to extend your journey: 22-way adjustable leather seats; five-way, five-intensity massage system, automatic seat heating/cooling.

    I made it to all seven POIs, including a couple I had heard of but never visited before, because of the frustration of getting lost trying to find them. Before I was ready, I found myself back at the dealership. The excellent staff encouraged me to keep the car longer, but frankly I was afraid if I did, it would wind up in my garage, and that is just not in the budget right now. That reminds me, I need to ask for a raise.

    Bluetooth connectivity is available; the Apple iPhone can be fully controlled and/or downloaded onto the A8’s terabyte hard drive and accessed from any of the three color touchpad screens in the car.

    You can control the GPS navigation interface to include new destinations, from the full color 10-inch touch screens in the rear passenger compartment, giving new meaning to the phrase “back seat driver.” There is a single DVD-CD drive slot in the center dash console as well as a six-disk changer unit in the optionally refrigerated glove box. That is, if the large cooler that extends into the rear cabin from the trunk space is not enough for you. Understandably, the rear cooler is a bit hard to reach from the front seat while you are barreling along the Autobahn at 130 miles per hour, or down I-25 at 75.

    Information Everywhere

    Bottom line for the Audi A8L: the information you need is displayed almost everywhere you look, and can be called up with the touch of a button, the scroll of a finger, or the sound of your voice. All internal and external data is provided in an atmosphere that is second to none climatologically and ergonomically. It is the only automobile I have driven lately with four full-color touchscreens that, while keeping you situationally aware no matter where you are seated, can simultaneously control all the systems in the automobile. The two 10-inch rear-seat screens can be used to read e-mail, browse the Internet, or watch the latest movies or television programming. Add to this an incredibly performance-minded vehicle, the highest gas mileage rating in its rank, amenities that want to make you slow down and enjoy the journey, and you have my pick for the best GPS-enabled, situationally aware vehicle in its class.

    Thanks to Vince Cimino, general manager at the Phil Long Audi dealership in Colorado Springs, and his staff for unfettered access to the Audi A8L and all their expertise.

    Until next time, happy navigating.


    huhnke_MG-W
    Burkhard Hunhke, executive director of Volkswagen Group’s Experimental Research Laboratory: “We are now able to keep up with and even surpass the technology in mobile devices.”

    Interview with Audi Research Director Burkhard Huhnke

    While testing Audis for this article, I had the opportunity to interview Dr. Burkhard Huhnke, executive director of the VW/Audi Experimental Research Laboratory (ERL) in Palo Alto, California. Palo Alto is also home to Stanford University, and thus to Stanley and Shelley, autonomous vehicles that have driven into the record books. ERL supports all brands within the Volkswagen Group: Audi, Bentley, Bugatti, Lamborghini, Seat, Skoda, and Volkswagen.

    The integration of external and onboard capabilities with GPS and a screamingly fast new Nvidia Tegra 2 chip make the Audi navigation system the first in-car navigation system with 3-D display capabilities.

    Don Jewell (DJ): How is this integrated GPS different from a mobile device adhered to the windshield?

    Burkhard Huhnke (BH): Let’s say the driver is overwhelmed in a very difficult situation, like approaching a traffic jam in bad weather at high speed. The Audi will sense this — we call it pre-sense — alert the driver, begin a series of automatic safety measures, such as tightening the seatbelts and closing windows, and then automatically start to brake the automobile. For us, the systems in the Audi are for more than just displaying information or blinking warning lights. The systems actually take over some of the functions and support the driver, especially in emergency situations. GPS provides a way for us to localize the car in its environment with data such as time of day, weather and traffic conditions, and any other information that both onboard and external sensors, such as the Internet and Google, connected provide.

    DJ: What happens when GPS data is not available?

    BH: We must provide additional sensors and train our systems to learn to bridge the time with GPS outages or interruptions without the driver being aware that GPS is no longer being received, make it seamless. The intelligence, the metadata from other sensors is onboard in the embedded systems, and they are programmed to provide the necessary data when GPS is not available.

    DJ: How does this translate to a better experience for the customer?

    BH: We put a lot of effort into the optimization of the human-machine interface (HMI). We have psychologists working on the HMI along with our designers and programmers. Some car manufacturers provide systems that force you to think like an engineer to operate them. We realized this approach won’t work. To create an intuitive navigation system requires much, much more. It requires input from our customer, what is intuitive to them. For this as I said we use simulators, customer inputs, along with psychologists, clinical studies, and a great deal of effort that goes into understanding what makes a truly intuitive interface and a system that people will like and enjoy using.

    You do not need a handbook to operate our systems. I actually hate handbooks and I believe that if you cannot figure out how to do something, such as program a destination into a GPS in just a few seconds, without a handbook, then the customer will not like it; so we purposely made the system intuitive and very user friendly. The learning curve is very short and our customers find themselves using the system in no time at all.

    We found out one of the key things our customers want is beautiful, high-definition, and fast graphics. So we started working with one of the leading companies (Nvidia) for graphical interfaces. In the end, we created an environment in the Audi A8 that is more like your home living room than a normal automobile.

    In  the A8 we combined the Internet and the onboard Audi network with things like Google Maps so you can continuously download Google Maps as they are needed: beautiful high-definition color graphics and maps with connectivity. The POI search is absolutely as up-to-date as it can be, often including data updated the same day or possibly just a few minutes before from the Internet. In the A8 for a POI you get the same information as if you had searched on your computer at home.

    DJ: How much do you care about accuracy for your GPS/PNT systems in the Audi? Is one meter enough?

    BH: We are extremely interested in a very accurate GPS position down to the centimeter level. Not all manufacturers are. Since you live in Colorado you may have heard about the Audi TT that successfully drove autonomously up Pikes Peak. To do this, we used differential GPS signals to take hairpin turns at race-like speeds.

    But we realized that it is a risk to only depend on external signals such as GPS. GPS information is critical, but we find ourselves depending more and more on our onboard sensors. This gives us a huge advantage, such as with our onboard camera system. It gives us the ability to develop better adaptive cruise-control functions. All these extra sensor inputs combined with GPS gives you the best precision, but when you don’t have GPS, you have to rely on other sensors to take over.

    We launched a navigation system with a processor from Nvidia at the same time it was announced as a capability in a mobile device. In the past, we were always behind the time with technology because we were conservative with what we put in the cars, but with this move we are now able to keep up with and even surpass the technology in mobile devices. We created a very smart motherboard so we can exchange and process data quickly.

    DJ: What do you see as your mission?

    BH: Producing the safest car in the world, and I think we are there. The United States  still has 37,000+ traffic fatalities every year, so we took it as our responsibility to create the safest systems onboard any automobile. Our new navigation system predicts curves and safe speeds for the conditions and sometimes automatically reduces the speed of the automobile. We talk a lot about driverless cars, but actually I think we all enjoy driving, like you do, Don, with your Q7 in the snow in Colorado. But there are also times when we are extremely bored and not paying attention to our driving and just wish we could press an autopilot button and start answering e-mails or something. This could be in a traffic jam or any circumstance where it is no longer fun to drive. So that is something we would like to accomplish.

    Recently we created a new program with Stanford University to work on solutions for mobility challenges. We want to be able to obtain more external information, use onboard information, and create the car of the future with the smart people at Stanford and those of us at ERL. We want a navigation system that is smart and can predict traffic, which helps and supports the driver, and therefore makes driving extremely safe. That is now our mission.


    Don Jewell is contributing editor for defense and government at GPS World. His monthly e-mail newsletter column is free at env-gpsworld-integration.kinsta.cloud/subscribe.

  • On the Edge: Driving Reality Home

    By Tracy Cozzens

    A new navigation system looks to make driving safer by removing the need for drivers to look away from the road at their navigation device. With Wikitude Drive, as a driver moves down the road, the route is “drawn” onto the live video screen of an Android smartphone.

    How is this possible? Augmented reality.

    Augmented reality (AR) is a term for a live direct or indirect view of a physical real-world environment whose elements are augmented by virtual computer-generated imagery. The idea to blend augmented reality with navigation struck Philipp Breuss-Schneeweis, founder of Mobilizy, in 2008 when he was developing the Wikitude World Browser for the first Android Developer Challenge. Considering the awards Wikiude Drive has received so far, including being named Global Champion in the 2010 Navteq Challenge, it could be considered the next big advance in consumer navigation.

    Wikitude Drive, which launched at the end of 2010, works by attaching a mobile phone on top of a dashboard looking at the road. The application then overlays video captured through the camera with driving instructions. This allows users to drive through their phone, watching the road even while they are looking at directions.

    “With Wikitude Drive I don’t find myself looking for directions; the device itself guides me along the way,” said Nicola Radacher, product manager at Mobilizy.

    According to Breuss-Schneeweis, Wikitude Drive distinguishes itself from other navigation systems in two ways: First, due to the overlaying of the route onto the live video stream of the surroundings, the driver can easily recognize and follow the suggested route. Instead of looking at an abstract map, the driver is looking at the real world. The navigation system leads the driver through unfamiliar territory in a natural, real, and easy way.

    Second, Wikitude Drive solves a key problem that all other navigation systems have. These systems require the driver to take his eyes off the road to look at the abstract navigation map. Just by looking at the map screen for one second when driving at 100 km/h (62 mph), the driver is actually “blind” for 28 meters (92 feet).

    “Think about how much can happen in those precious meters. Since Wikitude Drive provides you with driving directions on top of the live video stream, you still see what is happening in front of you when looking at the display of your mobile AR navigation system,” Breuss-Schneeweis said.

    The AR system uses data from a smartphone’s GPS, compass, and movement sensors, retrieves information from its database, then displays the information over the camera feed. The company says millions of points of interest will also be displayed when a future version is integrated with Wikitude World Browser, the company’s AR browser for smartphone users.

    Wikitude Drive still can be used the traditional way. In some driving conditions — for example when driving in the dark — a drawn map is advantageous, and a driver can switch to the 3D map view by tapping the screen. Voice commands are also provided.

  • Elbow Room on the Shoulder: DGPS-Based Lane-Keeping Enlists Laser Scanners for Safety and Efficiency

    Elbow Room on the Shoulder: DGPS-Based Lane-Keeping Enlists Laser Scanners for Safety and Efficiency

    A virtual reference station network covering a metropolitan area supplies position corrections to commuter buses equipped with a driver-assist system to enable safe operation, even under harsh weather conditions, along high-volume roadways.

    By Craig Shankwitz

    Bus-only shoulders on major traffic arteries enable a bus to travel on typically unused road right-of-way, bypassing congestion during peak rush hours. As the shoulder is typically only centimeters wider than the bus itself, lane-keeping becomes a key factor, and is accomplished in a pilot Minnesota project using dual-frequency, carrier-phase differential GPS (DGPS) as its primary positioning technology. DGPS provides position estimates accurate to 5–8 centimeters at a rate of 10 Hz, and is used to determine vehicle position and heading. An on-board map database is used to determine the position, orientation, and trajectory of the vehicle relative to the roadway.

    Use of the shoulder as a busway offers several construction and operational advantages:

    • Ease of Implementation. The shoulder exists; there is no need to acquire and develop additional right of way.
    • Low Costs. The cost to strengthen and modify an existing road shoulder is significantly less than constructing a new busway.
    • Routing. Because bus-only shoulders follow existing routes, no changes to bus routes, bus stops, or transit stations are needed to support bus-only shoulder operations.
    • Customer Satisfaction. Transit customers who travel on buses that use a bus-only shoulder perceive a travel-time saving two to three times greater than actually realized. Keeping the bus moving at all times offers a significant psychological advantage.
    • Increased Ridership. A 1997 study of bus-only shoulders in the Twin Cities analyzed more than nine bus-only shoulder routes for two years and found a 9.2-percent increase in ridership along these routes. At the same time, total ridership had decreased by 6.5 percent.

    However, the use of bus-only shoulders imposes additional stress and strain on a driver. The narrow bus-only shoulder leaves a driver very little margin of error. Operating within this small margin is difficult even during the best traffic and weather conditions, and degrades to nearly impossible during heavy traffic and poor weather conditions, which are frequent during Minnesota’s notoriously hard winters.

    During difficult weather and traffic conditions, the use of the bus-only shoulder offers its greatest transit advantage. If a driver is unable to utilize the bus-only shoulder, this advantage is lost. A properly designed and executed driver-assist system (DAS) enables a driver to use the shoulder under all conditions, thereby increasing schedule adherence and, as a result, rider satisfaction.

    Under the U.S. Department of Transportation’s Urban Partnership Agreement, the University of Minnesota’s Intelligent Vehicles Lab (IV Lab) and HumanFIRST program, the Minnesota Valley Transit Authority (MVTA), and Schmitty and Sons Transportation will soon deploy DAS on 10 Gillig low-floor transit buses. These buses will provide express service between Apple Valley and downtown Minneapolis, a 22-mile, one-way trip.

    Driver-Assist History

    The IV Lab has developed and deployed DGPS-based DAS since 1995. The first deployment on public roads occurred in 2001, as part of the DOT’s Intelligent Vehicle Initiative Generation Zero Field Operational Test. The DGPS-based lane-keeping assistance was integrated with forward-looking radar for collision avoidance, enabling safe vehicle operation in zero-visibility conditions.

    Two separate deployments took place in Alaska. The first occurred in 2003 with a snowplow and a snowblower which clear the Thompson Pass on the Richardson Highway. These vehicles are still in use. Because of this success, the State of Alaska installed the DAS in two more vehicles at Deadhorse Airport.

    During the summer of 2010, the two original Thompson Pass systems will be upgraded with new computational hardware, and three new systems will be installed on three new highway maintenance vehicles. The value of the driver-assist system has been proven, and those who use it have grown to rely on its all-weather capabilities. It has functioned reliably for seven years in extremely harsh conditions.

    ÅDAS-EQUIPPEDSNOWPLOWclearingThompsonPass,Alaska.
    DAS-EQUIPPED SNOWPLOW clearing Thompson Pass, Alaska.

    Driver-Assist for Transit

    The DAS provides two primary capabilities for transit applications: lane-keeping and collision awareness. The system provides assistance only; a driver is always responsible for control of the vehicle. Figure 1 shows the components comprising the DAS.

    Figure 1. Complete driver assist system component schematic, showing both infrastructure-based and vehicle-based components.
    Figure 1. Complete driver assist system component schematic, showing both infrastructure-based and vehicle-based components.

    DGPS-Based Lane-Keeping. The primary positioning sensor used aboard the buses is a dual-frequency, carrier-phase GNSS receiver, providing centimeter-accurate position measurements at 10 Hz. With the exception of the DGPS augmentation system described later, all other DAS system processes are synchronized with the arrival of DGPS position updates.

    Realtime CMR+ DGPS corrections are provided over the 3G cellular network from the IV Lab VRS network. The IV Lab VRS network is based on six receivers located around the perimeter of the Twin Cities Metro area. These six receivers are connected via landlines to a server system located in the IV Lab at the University of Minnesota, running GPSnet and RTKnet applications. To ensure GPS correction reliability, an integrity manager software issues alerts for both short-term and long-term aberrations in the data provided by the six base stations. This ensures accurate corrections are sent to the buses using the narrow shoulders.

    The onboard receiver also plays a crucial role in accurately estimating vehicle body heading. In rural applications where GPS augmentation is unnecessary, GPS velocity heading estimates provided directly from a GPS receiver serve as a sufficiently accurate body-heading estimate. However, in GPS-denied environments where an augmentation system is needed to provide accurate position and heading estimates when GPS is lost, velocity heading from an onboard receiver is an insufficiently accurate estimate of vehicle heading. To support such navigation, the IV Lab developed a technique, described later, by which body heading can be estimated with errors less than 0.1 degree.

    IV Lab mapping rig installed in a pickup truck: three dual-frequency, carrier-phase DGPS receivers; two laser scanners, one measuring retroreflectivity, the other road crown and rutting; and forward and sideview cameras, to help analyze anomalous data.
    IV Lab mapping rig installed in a pickup truck: three dual-frequency, carrier-phase DGPS receivers; two laser scanners, one measuring retroreflectivity, the other road crown and rutting; and forward and sideview cameras, to help analyze anomalous data.

    Map Databases

    Lane-keeping uses DGPS with an onboard map database describing the location and type of lane boundaries and other relevant roadway elements to an accuracy of approximately 10 centimeters. These map databases can be constructed in one of three ways:

    • from sufficiently accurate photogrammetric data,
    • by driving centerlines and using known road-construction standards to d
      etermine the location of lane boundaries and other relevant elements relative to the lane centerline, or
    • by using a combination of laser scanners, DGPS receivers, and cameras to determine the global location of the reflective markings that bound lanes and shoulders.

    Lane-keeping information is continuously provided to the driver; lane-departure alerts and warnings use a comparison of vehicle speed and heading to the map database to determine when alerts and warnings should be issued.

    The alerts and warnings are provided via a multi-modal human-machine interface (HMI), illustrated in Figure 2, through three modes:

    • graphically, through a head-up display (HUD) that gives a virtual view out the windshield when environmental conditions limit visibility;
    • haptically, through a torque-actuated steering wheel giving a restorative torque on the steering wheel in the event of lane drift; and
    • tactically, through a seat equipped with actuators that vibrate on the side of the seat to which the lane is being departed.
    Figure 2. Multi-modal driver interfaces. Left: Graphical, haptic, and tactile feedback modes provided to the driver. Upper right: View through the head-up display. Graphical lane departure alert indicated by left shoulder boundary colored red, collision awareness alert (white rectangles), and collision awareness warning (red rectangle). Lower right: Forward, left, and right side collision awareness information presented on the display on the left “A” pillar.
    Figure 2. Multi-modal driver interfaces. Left: Graphical, haptic, and tactile feedback modes provided to the driver. Upper right: View through the head-up display. Graphical lane departure alert indicated by left shoulder boundary colored red, collision awareness alert (white rectangles), and collision awareness warning (red rectangle). Lower right: Forward, left, and right side collision awareness information presented on the display on the left “A” pillar.

    Lane-departure warnings come in stages. As the vehicle-trajectory estimator determines that the likelihood of a lane departure is sufficiently high, a lane-departure warning is issued to the driver through the HUD: a change in lane boundary color from white or yellow to red. Should the driver contact the lane boundary, a seat-based warning is activated; the side of the seat corresponding to the direction of lane departure vibrates, warning the driver. If the driver fails to respond to these two stimuli and continues past the lane boundary, the steering motor torque is applied. This multi-stage approach captures the drivers’ attention, but if they respond in a timely fashion, their annoyance is limited.

    The torque applied by the steering servo motor is limited, and cannot deliver sufficient control action to autonomously steer the vehicle. This is by design; the driver is responsible for operating the bus. The level of torque applied to the steering wheel is analogous to an automotive front-end misalignment; it is sufficient to capture the drivers’ attention, but not to steer a bus off the road.

    Forward-Collision Awareness. Sensing for forward-collision assistance is provided by a front bumper-mounted multi-plane scanning LIDAR sensor. Forward-collision alert and warning information is provided in two stages to the driver through the HUD. As now configured, if the obstacle detected is in the present shoulder of travel, the obstacle is represented as a red, open rectangle, with red indicating a warning status. If an object is located in an adjacent lane, the obstacle is represented as a white, open rectangle, with white indicating an alert status.

    Obstacle-detection processing is enhanced by the presence of the onboard map database used for lane-keeping. Obstacle target information provided by the LIDAR sensor includes range, range rate, and azimuth angle to the target. The bus position and heading is provided by either DGPS or the DGPS augmentation system. Through a coordinate transformation, LIDAR information in the vehicle coordinate frame is transferred to the global coordinate frame. This allows the LIDAR target to be placed on the map database; if the target is in the vehicle lane of travel, it can be considered a threat, but if the LIDAR target is not in the same lane as the bus, then at that time the target is not a threat to the driver.

    Side-Collision Awareness. Side collision awareness is enhanced by multi-plane LIDAR scanners mounted on on the front bumpers on both the left and right sides of the bus, and connected to a pneumatic actuator.

    Side-collision awareness information is provided to the driver via an LCD panel mounted on the left front A-Pillar (see Figure 2). This display is touch-sensitive, and can be used by the driver to log in (only certified, trained drivers can operate the system) to select feedback modalities (choose any or all of the available feedback modes) and to check system status.

    SIDE-MOUNTED LASER SCANNER used for both side-collision awareness and DGPS augmentation. When extended (left), the LIDAR scans 100 degrees of the horizontal plane. One boundary of the scanned plane points behind and runs alongside the bus; the other boundary points forward of the bus by approximately 10 degrees. When retracted (right), the LIDAR points in the direction of the ground, and can be used for curb-following when DGPS is unavailable.
    SIDE-MOUNTED LASER SCANNER used for both side-collision awareness and DGPS augmentation. When extended, the LIDAR scans 100 degrees of the horizontal plane. One boundary of the scanned plane points behind and runs alongside the bus; the other boundary points forward of the bus by approximately 10 degrees.
    Figure_6B
    SIDE-MOUNTED LASER SCANNER used for both side-collision awareness and DGPS augmentation. When retracted (right), the LIDAR points in the direction of the ground, and can be used for curb-following when DGPS is unavailable.

    Suburban and Urban

    Although the rural implementation of the DAS operates in extremely harsh weather conditions, these implementations are technically less problematic than suburban and urban implementations. In rural applications such as the snowplows, DAS-equipped vehicles typically operate with a single occupant in a small geographic area, travel on relatively low traffic-volume roads, and enjoy a clear view of the sky. Suburban and urban applications carry passengers, operate across a wider geographic area, travel on high-volume roads, and suffer from periods where view of GPS satellites is either partially or completely blocked.

    These operational differences require substantial changes to the DAS subsystems for urban/suburban use.

    DGPS Base Stations. In rural areas, DAS-equipped vehicles typically operate over a relatively small geographic area; a single GPS base station will provide adequate coverage as the maximum baseline between rover and the base station remains less than 25 miles. Suburban applications cover a much wider area, and a network of DGPS correction stations is needed to keep baselines low.

    For the UPA project, the IV Lab operates a six-station virtual reference station (VRS) network. This network covers the greater Twin Cities Metropolitan area, and supplies compact measurement record (CMR) corrections to each DAS-equipped bus. Satellite observables are sent from each base station receiver to both the VRS server at the IV Lab and to a VRS server at the Minnesota Department of Transportation.

    Broadcast of DGPS Corrections. In rural areas, the DAS system has served to keep roads passable in inclement weather conditions. This has been viewed as a safety application, and as such either UHF or VHF channels in the public safety bands have been used to broadcast DGPS corrections. In urban areas, no single UHF or VHF frequency is available to cover an entire metropolitan area. Therefore 3G cellular data communications are used to provide DGPS corrections to DAS-equipped vehicles.

    Use of 3G cellular data communications brings the transit customer an added benefit: free Wi-Fi. The provision of DGPS corrections, using the CMR+ correction format, requires approximately 10 Kbit/second. This bandwidth is assigned high priority by the onboard router. The remaining 700 Kbit/s of 3G bandwidth is made available, at a lower priority, to bus passengers. On an express route service, passengers can e-mail and surf the web on their daily commute, making productive use of
    time that might otherwise be lost.

    The VRS server provides a unique correction to each DAS-equipped bus. Communication between the bus and the VRS server is initiated by the bus when it sends its coarse (uncorrected) position to the server. The server replies with a correction optimized for that coarse location. Corrections are sent at one-second intervals. Every two minutes, the bus sends its current position, and the VRS server responds with corrections optimized for that new location. With this scheme, the baseline between the VRS and the roving bus is never more than two miles. The two-mile limit maintains position accuracy without consuming excessive wireless or computational bandwidth.

    DGPS Redundancy. In rural applications, the view of the sky is generally unobstructed, and FCC licenses provide adequate effective radiated power from the DGPS base stations. This assurance of access to both satellite and corrections signals generally suffices to support uninterrupted vehicle positioning. Both base-station and onboard GPS hardware have proven to be robust and reliable. With these local operating conditions, public agencies have found no need to augment DGPS for rural applications.

    Suburban and urban applications, however, require an augmentation system to support DAS operation when DGPS is unavailable due to outages caused by overpasses, overhead road signs, tree canopies, and so on. Passenger safety and the need to provide reliable schedule adherence require that positioning be provided even when DGPS is unavailable, by a vehicle-based DGPS augmentation system.

    Vehicle-Based Augmentation

    The vehicle-based augmentation system (VBAS) uses direct measurements of ground velocity, a measure of vehicle yaw rate, and an accurate estimate of the vehicle position and heading at the time DGPS is lost to estimate vehicle position and heading for the duration of signal loss.

    A commercial off-the-shelf sensor designed for measuring vehicle and/or tire slip measures vehicle 2D velocity. Yaw rate can be measured either with an inertial rotational rate sensor or a second 2D velocity sensor. Yaw rate measured using a pair of these 2D sensors eliminates the rate bias and rate bias drift associated with inertial sensors. Figure 3 shows both configurations.

    FIGURE 3 Two approaches to VBAS to mitigate DGPS outages. The diagram on left shows implementation with two 2D velocity sensors to determine vehicle yaw rate. Computationally, this is attractive as senor drift need not be considered. The diagram on the right shows an implementation with one yaw rate sensor, and one 2D velocity sensor. This is the configuration operating for the UPA; it requires yaw rate sensor drift compensation to provide accurate measures of vehicle yaw rate.
    FIGURE 3 Two approaches to VBAS to mitigate DGPS outages. The diagram on left shows implementation with two 2D velocity sensors to determine vehicle yaw rate. Computationally, this is attractive as senor drift need not be considered. The diagram on the right shows an implementation with one yaw rate sensor, and one 2D velocity sensor. This is the configuration operating for the UPA; it requires yaw rate sensor drift compensation to provide accurate measures of vehicle yaw rate.

    An accurate measure of vehicle heading at the time GPS positioning is lost is critical to the augmentation process. A performance goal of 20 centimeters tolerable error at the end of a 15-second outage for a vehicle traveling at 25 miles per hour (11.2 meters/second) requires a heading estimation error of no more than 0.07 degrees (that assumes the only source of error is attributable to the heading).

    GPS outages (time from loss of position to reacquisition) attributed to passing under overpasses range from 7 seconds (single bridge) to 9 seconds (double bridge). The IV Lab augmentation system reliably provides sufficiently accurate position and heading estimates to carry through these outages. At the present level of performance, should an outage last more than 15 seconds, the accuracy of the augmentation system cannot be guaranteed. In this event, the driver is alerted, and the DAS is deactivated until a DGPS position fix is reacquired. Fortunately, since new receiver firmware was installed, no instances of an outage exceeding 15 seconds have occurred during two months of test, evaluation, and driver training.

    Figure 4 illustrates the accuracy of the VBAS system. At the time the fix solution is reacquired on the exit ramp, the lateral error between the fix solution and the position estimated by the VBAS is approximately 10 centimeters. This accuracy is sufficient to allow a driver to travel on the entrance ramp even during zero-visibility conditions.

    Figure 4. Example of VBAS as a bus operates on the Cedar Avenue/Old Shakopee Road overpass. Bus trajectory is northbound on Cedar, exiting westbound Old Shakopee Road, then entering southbound Cedar Avenue from Old Shakopee Road. Upper left shows northbound trajectory and loss of satellite lock. Upper right shows reacquisition of DGPS, float, and fix states of the DGPS receiver. Lower right shows accuracy of VBAS system compared to DGPS when DGPS reacquires fix. Lateral error of VBAS at at the time the fix is reacquired is approximately 10 centimeters. Lower left shows satellite view of the interchange.
    Figure 4. Example of VBAS as a bus operates on the Cedar Avenue/Old Shakopee Road overpass. Bus trajectory is northbound on Cedar, exiting westbound Old Shakopee Road, then entering southbound Cedar Avenue from Old Shakopee Road. Upper left shows northbound trajectory and loss of satellite lock. Upper right shows reacquisition of DGPS, float, and fix states of the DGPS receiver. Lower right shows accuracy of VBAS system compared to DGPS when DGPS reacquires fix. Lateral error of VBAS at at the time the fix is reacquired is approximately 10 centimeters. Lower left shows satellite view of the interchange.

    Driver Training

    Bus-only shoulder operation has proven itself safe and, in fact, safer than normal transit operations, according to recent data. The goal of driver training is to prepare drivers to use the DAS system to enable them to safely use the bus-only shoulders in conditions under which they normally would not.

    A rigorous training protocol developed in cooperation with the University of Minnesota HumanFIRST program, Schmitty and Sons Transportation driving instructors, and MVTA involves both simulator-based and on-road training.

    Simulator-Based Training

    Beefore using driver assist systems, bus drivers are continually taught that the driver controls the bus and is responsible for both the passengers and vehicle. Drivers take this responsibility seriously, and as such, develop skills and techniques that guarantee safe passage under all conditions, even when running on narrow, bus-only shoulders.

    To best prepare drivers for using the DAS under difficult conditions, a high-fidelity driving simulator was commissioned. A DAS was installed in the simulator, and an interface to the simulator was created. In this context, a driver has the ability to train in normal and abnormal (low to zero visibility) conditions before beginning on-road DAS training and use.

    In the simulator, the driver learns that the system only provides assistance; responsibility for the safety of the bus and passengers still resides with the driver. Experience with Alaskan snowplow operations, where formal training is limited to a few on-road test drives, has shown that a driver may take a few winter seasons to fully accept the system. This delayed acceptance is in part attributable to the fact that for six months per year a driver has no opportunity to train with the system. Acceptance gained over one winter season is lost during the summer.

    The simulator installed at an MVTA bus garage uses a seat-based motion platform to achieve realistic vehicle dynamics. The DAS installed in the simulator allows a driver to train in all weather and traffic conditions on a geospecific roadway before transitioning to a DAS-equipped bus. Geospecificity is achieved through the creation of virtual worlds based on roadway data collected by the mapping vehicle shown earlier.

    Bus-driving simulator at the MVTA bus garage in Burnsville, Minnesota.
    Bus-driving simulator at the MVTA bus garage in Burnsville, Minnesota.
    Bus-driving simulator at the MVTA bus garage in Burnsville, Minnesota.
    Bus-driving simulator at the MVTA bus garage in Burnsville, Minnesota.
    Bus-driving simulator at the MVTA bus garage in Burnsville, Minnesota.
    Bus-driving simulator at the MVTA bus garage in Burnsville, Minnesota.
    Bus-driving simulator at the MVTA bus garage in Burnsville, Minnesota.
    Bus-driving simulator at the MVTA bus garage in Burnsville, Minnesota.

    On-Road Training

    After a driver both demonstrates an
    d acknowledges comfort and competence with the DAS in the simulator, training transitions to the actual route on which the buses will operate. Each of the 10 buses is equipped with a six-camera data-acquisition system. The six cameras capture not only the driver’s actions (hands, face, feet), but also views of the road (front, left, and right sides.)

    Drivers travel with an instructor. The onboard data acquisition system can be used to reconstruct particular scenarios as a means to offer advice as to how the driver and system can better interact in difficult driving and traffic conditions.

    On-road training benefits system developers as well. Training offers a driver an opportunity to test the system in real-time on an actual road. The perspective a driver brings is generally different than that of the developer, and the insights the end user provides typically produce a better system. As an example, driver experience with the system during the initial training period produced the staged approach to lane-departure alerts previously described.

    Conclusion

    The IV Lab, MVTA, and Schmitty and Sons Transportation will soon release 10 DAS-equipped buses into revenue service to support narrow bus-only shoulder service between downtown Minneapolis and Apple Valley, Minnesota. Although the IV Lab has deployed a number of DAS-equipped vehicles, this UPA deployment represents the first time that the system has been used to transport passengers. This deployment should prove that although DGPS systems are susceptible to periodic outages, a properly designed and executed augmentation system will provide a sufficiently robust system that will be accepted by both drivers and passengers. It will also demonstrate to other transit agencies that even narrow rights of way offer significant transit advantages at low cost, and that potential operational difficulties can be overcome through the use of DAS technologies.

    Manufacturers

    The buses carry Trimble R7 receivers and Ibeo Lux multi-plane scanning LIDAR sensors. The IV Lab VRS network is based on six Trimble NetR5 receivers. The server runs Trimble’s GPSnet and RTKnet applications, with the Trimble Integrity Manager.


    Craig Shankwitz is the director of the Intelligent Vehicles Laboratory at the University of Minnesota.

  • CSR and SiRF Complete Merger

    CSR plc of Cambridge, UK, and SiRF Technology Holdings Inc., of San Jose, California, on June 26 completed the merger between SiRF and a wholly owned subsidiary of CSR. The merger resulted in “creating a provider of connectivity and location platforms and a company with the scale, technology, and strategy to enable its customers to address the exciting and emerging opportunities in mobile markets,” according to a company statement.

    The company said that customers of the enlarged CSR group will be able to deliver new user experiences of connectivity and location technologies in a diverse range of devices such as mobile phones, personal navigation devices, in-car navigation and telematics systems, laptop and netbook PCs, mobile internet devices, digital cameras, gaming machines, cellular accessories, and consumer electronic devices.

    “In bringing together the combined capabilities and broad range of CSR and SiRF technologies and platforms, we have created a new force in the industry and a world-class organization with the commercial, technical and operational scale to build on CSR and SiRF’s existing customer relationships and deliver the next generation of connectivity and location enabled products,” said Joep van Beurden, CEO of CSR. “Our strategic goal is to address the existing and emerging needs of our combined customer base for connectivity and location technologies. The potential applications and benefits to the end user of connectivity plus location are only just starting to open up, and these exciting new opportunities will be driven by our unique combination of leading location technologies and connectivity solutions.”

    “CSR and SiRF have a shared vision of using innovation to bring the benefits of wireless connectivity and location to mainstream consumers and enterprises and to enable new and exciting user experiences”, said Kanwar Chadha, co-founder of SiRF and newly appointed board member and chief marketing officer of CSR. “We believe that through this merger, our customers and consumers will derive benefits from a much stronger player whose focus is on delivering best in class connectivity and location platforms.”

    “Technology innovation represents the foundation for both CSR’s and SiRF’s success in the market place,” said James Collier, co-founder, board member and Chief Technology Officer of CSR.  “We look forward to combining the complementary expertise of our teams to take innovation to the next level in our multifunction radio and system platforms to address emerging customer and market needs.”

    For CSR’s customers, the merger with SiRF means CSR’s Connectivity Centre products are augmented by GPS technologies that are well respected and enjoy widespread adoption, the company said, while SiRF brings to CSR a strong IP portfolio in GPS and assisted GPS (A-GPS), dead reckoning, and location centric platforms. 
The enlarged CSR group will have its global headquarters in Cambridge, UK, with SiRF’s headquarters in San Jose becoming CSR’s U.S. headquarters.