Electronic Design

An Evolving ITS Paves The Way For Intelligent Highways

Future Intelligent Transportation Systems will include telematics, sensors, GPS, RFID, and drive-by-wire capabilities.

The intelligent highway has long been a dream of urban planners everywhere. This is a very efficient highway that permits traffic to flow quickly and effortlessly without congestion. While we have been speaking of this mythical highway for decades, only now are we finally beginning to see real but partial implementations. In the meantime, traffic congestion continues to outpace highway construction.

Recent developments in electronics, especially wireless systems, make it possible to build a practical intelligent highway. However, political issues (federal, state, county, and city) as well as high costs have slowed progress with the exception of small pockets of specialized activity.

Furthermore, just as important is the fact that an intelligent highway isn't fully effective without intelligent cars to use it. So while we don't yet have the intelligent highways visualized for cities of the future, we are gradually seeing more and more intelligent devices that improve our transportation system. Under the auspices of the Intelligent Transportation System (ITS), our roads and our cars are gradually evolving to improve our most widely used mode of transportation (see "The ITS Program," p. 104).

Over the past decade, major progress has taken place in the ITS. Massive traffic problems spurred states and cities to solve the problems with new initiatives in intelligent highways and improved public transportation like light rail. U.S. Department of Transportation (DOT) funds have become available to test concepts and pilot projects.

As with anything that's technology driven, unforeseen problems that have major implications have cropped up. For example, with all of the modern conveniences like in-vehicle entertainment and communications systems now available in new automobiles, driver distraction is becoming a serious problem (see "The Distraction Factor," p. 112). This has given rise to a call for local, state, and government regulations on how and when to use such conveniences while driving safely.

For the ITS to become a reality, it will take not only smart highways and an attendant infrastructure, but also a smart vehicle that can work in conjunction with the system. To make these two work together, the ITS equipment must perform several basic functions, including data acquisition, data transmission, control, and vehicle equipment interaction.

The data-acquisition system for the intelligent highway will use different types of sensors to detect the presence and quantity of traffic and weather conditions. Induction loop detectors are widely used today at intersections to provide control to signal lights. These will remain in use, but other types of sensors will be installed at intersections and along roadways. Radar sensors have successfully been installed on overhead structures to detect traffic on multilane highways. Additionally, video cameras in a closed-circuit television (CCTV) system will be employed.

All of the sensor data and video will then be transmitted by wireless means to a control center for the analysis and compilation for its ultimate use. The ITS also envisions using probe or floating vehicles that are sent out into the traffic to further sense both traffic and road conditions.

Once the data has been collected, analyzed, and formatted, it will again be transmitted by wireless means. Traffic and road-condition data can be transmitted by standard broadcast AM, FM, and TV stations, or by radio data systems (RDSs), the new digital satellite radios.

The ITS control center would be set up to acquire, process, and communicate the collected information. The system would verify the information's accuracy, reconcile conflicting data, and prepare a set of traffic-condition data for transmission. The control center would additionally monitor critical areas of roadways and intersections with CCTVs, as well as display this information. Large traffic maps of the complete area covered would be maintained so operators could continuously observe the status of major roadways. Emergency and rescue operations could be initiated and coordinated.

Control centers would develop wireless messages for transmission to display signs or to supply adaptive control to traffic signals, ramp meters, and other control methods. Ultimately, control centers may even transmit commands to provide remote control of individual vehicles.

Of course, considerable data acquisition will take place inside the vehicle too. A variety of sensors will determine vehicle speed and location. An on-board global positioning satellite (GPS) system will provide the driver with current location information that also can be transmitted to a control or emergency center. Sensors might signal the number of passengers in the car, vehicle orientation (tilted, upside down, and so forth), or engine and chassis data that helps assess and diagnose the physical condition or maintenance status of the vehicle.

Data transmission from the vehicle will occur via cellular telephone. With the data transmission capabilities of the newer and forthcoming 3G cell phones, this seems like the most practical, realistic, and economical method of sending vehicle data.

As for the vehicle equipment, it will consist of sensors, processors, and communications equipment that will interact with the infrastructure systems. Most of this equipment has already been developed and is being deployed in upscale automobiles. Generally known as telematics, this subsystem consists of a built-in cell phone with sensors and control capability.

A key part of the system will be the GPS receiver. It will supply location information that can be transmitted via the cell phone. Additionally, the GPS system will be implemented in conjunction with a processor and digitized maps that will provide on-screen maps for driver navigation. The GPS location information also can be transmitted for the purpose of locating the vehicle in the event of an accident. Furthermore, most new telematic systems automatically dial emergency services when an airbag deploys.

In the future, sensors will monitor all types of vehicle data. In addition to location and speed, things such as engine speed, temperature, transmission gear, fuel and oil levels, and tire pressure can be measured and transmitted or stored. Advanced systems will include sensors for longitudinal or lengthwise distance measurements with radar, laser, or infrared (IR) detectors. This distance information can provide a warning to the driver, or in closed-loop systems it can provide automatic operation of a cruise-control or braking system to increase the gap between vehicles should spacing become too close or the closing rate between vehicles become too great. Ultrasonic sensors or video also can be implemented to detect people, objects, or vehicles in the front or back.

The availability of such data will make it possible to install a "black box" that's similar to those on airplanes. It will record the data necessary to determine a vehicle's status before and after an accident.

Much more progress has been made with smart cars. Recent developments in electronics, including cell phones with their advanced infrastructures, im-proved sensors, fast and inexpensive embedded controllers, practical GPS receivers, and improved power transistors and ICs have made smart cars a reality.

A new term has cropped up in the automotive lexicon. "Telematics" describes the new in-car systems consisting of a data-capable cell phone, a GPS receiver, some sensors, and a central processor.

When coupled with a remote monitoring and control service, a telematics system provides a driver with the ultimate safety and convenience accessory. If telematics users experience an automotive emergency, they simply have to push the access button that automatically dials the service.

The GPS receiver in the system provides accurate location information to the service, which can immediately send assistance in the form of a wrecker, ambulance, or just a can of gas. In the case of a serious accident when an air bag deploys, a sensor triggers the system that automatically dials the service and provides location information so that help can be expedited.

Telematics systems are only beginning to be installed, mostly in upscale vehicles. The first was General Motors' OnStar system available on Cadillacs, Buicks, Saabs, and Lexuses. Some other systems include Mercedes Benz's TeleAid, Jaguar's Assist, Lincoln's RESCU, Ford's Wingcast, and Infinity's (Nissan) Communicator.

Except for OnStar, the back-end services for these systems are supplied by ATX Technologies of Irving, Texas. According to Gary Wallace, marketing director for ATX, live operators provide services to drivers at any time. Other services offered by this company include stolen-car tracking, route assistance, and remote door unlocking service.

Soon, OnStar and ATX will also provide "concierge" services to assist in locating a nearby restaurant, gas station, ATM, or parking area. System users pay an annual fee for these services. This is an attractive business for the auto manufacturers and the service providers like ATX because it provides a long-term revenue stream.

As telematics systems develop, some will tie into on-board navigation systems with the color in-dash LCD screens and CD/DVD maps. Bluetooth wireless links to PDAs will be provided. Obviously, Internet access will be available too. While most buyers purchase telematics for safety and security, the growing number of services and conveniences will make the systems more popular. As costs decline, telematics will eventually become a standard feature on all cars rather than an extra-cost accessory.

The technology to make a telematics system has been available for years. These are, of course, the cell phone and the GPS receiver. Yet amazing advances are happening in both areas. Most telematics systems still employ analog phones because the service is far more widely available across the country and, therefore, more reliable in safety and emergency situations. Forthcoming 3G cell phones will have an even higher-speed data capability.

A typical system like Motorola's mobileGT platform is designed as a starting point for automotive and electronic equipment manufacturers in the development of a telematics system (Fig. 1). The mobileGT platform provides all of the desired basic telematics functions and is easily enhanced to provide custom features.

The heart of the system is an embedded computer featuring Motorola's MPC823e PowerPC RISC chip, along with RAM, ROM, Flash, and a variety of I/O interfaces. This embedded computer will work with one of the I/O buses designed for automotive applications. These include the controller area network (CAN) bus, the new local interconnect network (LIN) bus, and SAE's J-1850 bus for power applications. For multimedia and entertainment devices, the IEEE 1394 (Firewire), the Media Oriented System Transport (MOST) bus, and Automotive Multimedia Interface Collaboration (AMI-C) ITS Data Bus (IDB) could be used. By using a standard bus, the system will quickly and easily accept add-ins of new equipment from the auto manufacturer or an aftermarket supplier.

Additionally, the mobileGT platform utilizes the QNX Neutrino real-time operating system (RTOS) with its Photon microGUI. This provides the overall management of the system, but with a minimum of memory. The other popular RTOS for use in automotive applications is the European OSEK/VDX system, which isn't currently supported by the mobileGT platform.

The mobileGT platform also has the capability to use IBM's J9 Java Virtual Machine from Object Technology International. This permits the addition of Java-enabled software applets as new Internet-related applications come along.

Interfaced to the mobileGT platform is a digital radio, such as one of the forthcoming satellite-based radios being designed for cars, or Motorola's new iRadio. The latter is a unit that combines multiple communications services into a single unit. It receives regular AM/FM broadcasts and digital satellite radio broadcasts, and it has wireless Internet/Web access via a data-enabled cell phone.

Also part of the mobileGT platform is a cell phone and a GPS receiver for location information. Other accessories might include a pager, an imaging device, or a smart card reader. Once the Bluetooth wireless communications standard becomes available, in-car wireless devices like another cell phone, a wireless headset/microphone, or a PDA can also tie into the system. Applications such as voice recognition/speech synthesis, navigation/mapping, and e-mail may be easily added as software modules.

A feature of all 3G cell phones is location notification. The U.S. Federal Communications Commission (FCC) mandates that all cell phones have the capability to announce their location either by an embedded GPS receiver or a proprietary location system developed by the cell-phone carrier. Some carriers use their cell sites and triangulation to pinpoint the position of a cell-phone user actively online. This permits fast and easy location of a person who calls "911" to report accidents or other problems.

The 3G phones also promise much faster Internet access with e-mail and instant messaging. Higher data speeds allow video as well. Obviously the 3G phones will seriously upgrade the telematics systems. But it's expected that individuals with a telematics system will probably have a separate cell phone. Some systems even make the telematics cell phone removable for personal use.

The Importance Of GPS
A primary feature of all telematics systems is automatic vehicle location, accomplished with the GPS. For years, GPS receivers have been available. As usage has increased, costs have dropped. Plus, the U.S Department of Defense (DOD), which manages the GPS system, dropped the Selective Availability (SA) feature which made consumer GPS receivers less accurate than military receivers. Previously, the DOD had dithered the GPS clock, making location accuracy only good to within about 50 to 100 meters. On May 1, the SA was disabled, immediately making GPS receivers accurate to less than 5 meters.

Progress in semiconductor technology has made GPS chip sets smaller and cheaper, too. This makes it possible to incorporate GPS capability into cell phones, laptops, PDA and auto navigation systems, and telematics systems.

Modern chip sets are made up of two chips, one for the receiver and the other for the processor. An example comes from Conexant Systems Inc. The Zodiac 2000 consists of the CS76502 RF MCM and the CX11577-12 baseband processor. The optional CX11239-11 accelerator provides faster acquisition of the satellite signals. So, designing and building a custom GPS receiver is easier and takes less time.

In addition, this chip set includes a backup dead-reckoning feature that allows the receiver to keep track of its location when the satellite view is blocked, as is the case when travelling in a tunnel or in the canyons of big city buildings. When coupled with an on-board gyro and by using the wheel sensors in the ABS system, the receiver employs an algorithm to continue computing location until the satellite signals are reacquired.

Conexant also makes complete GPS receiver modules ready to incorporate into an end product like a telematics system. For years, the company's Jupiter system has been widely employed in timing systems, truck-fleet management and tracking systems, and marine products. The new TU70-D100 GPS Sensor Board is another complete system ready to build into systems. Unlike the older Jupiter unit, the GPS Sensor Board includes a built-in antenna. Other companies producing GPS receiver chips include Infineon, Motorola, and Philips.

A major part of the ITS, its radio-frequency identification (RFID) tag and its related system, permits a vehicle and/or driver to identify itself automatically. RFID systems are employed for automatic data collection. They use low-power, short-range transmitters and receivers to communicate identification numbers. This kind of device permits automatic toll taking and automatic payment for parking, gasoline, fast food, or any other goods or services.

The availability of very small unobtrusive and inexpensive RFID sensors makes it possible to implement a variety of automatic billing and identification functions necessary for a fully intelligent highway and vehicle. Security systems and automatic door locks also are implemented with RFID technology.

In older systems, a fixed basestation transmitter interrogates the vehicle transceiver, which sends its ID in response. Such active systems are bulky and expensive. But today, a new generation of RFID systems has emerged. They use a fully passive receive/transmit unit called a tag or transponder in the vehicle to respond to external interrogation. These RFID tags are small and flat, and they require no battery power. An RFID tag is as easy to attach to the windshield as an inspection sticker.

The tag consists of a resonant circuit tuned to 125 kHz, 134.2 kHz, 13.56 MHz, 915 MHz, or 2.4 GHz. The signal transmitted by the basestation is detected, and the RF output developed in the tuned circuit is rectified into a dc voltage that powers a small transmitter which sends a coded signal back to the basestation. A read range of up to several meters is possible with high enough power and a good antenna. An on-chip Flash memory contains the ID code. Such tags run under $10. Major manufacturers of RFID circuits and equipment are the Amtech Division of TransCore Inc., Microchip Technology Inc., and Texas Instruments.

Amtech invented the concept of RFID back in the 1980s. Since then, the company has refined it into the highly reliable system used worldwide in automatic toll collection and related applications (Fig. 2). The company's newest system uses a 915-MHz base transceiver combined with a paper-thin windshield sticker transponder called an Intellitag. The 915-MHz RFID units have a longer range (up to about 5 meters) than the 125- and 134.2-kHz and 13.56-MHz units.

The system can read data from the tag at highway speeds and write to the tag at lower speeds. Aside from automated toll taking, other applications for the RFID systems include parking and vehicle-access systems, border-crossing approval, and high-occupancy vehicle (HOV) lane monitoring. They're targeting new applications like e-commerce, traffic management, and electronic vehicle registration, as in China.

TransCore makes a variety of other advanced electronic systems for the intelligent highway. One example is the automatic toll violation and red-light violation cameras that photograph the license plates of vehicles that get away. Other TransCore products include Advanced Traveler Information System kiosks, which give road and weather data to drivers at airports, as well as Advanced Traffic Management Systems, which include traffic-light controls and highway-sign radio systems.

Typical short-range RFID products are those made by Microchip Technology. The MCRF355/360 products operate in the FCC's no-license industrial, scientific, and medical (ISM) band at 13.56 MHz. The passive windshield tag/transponder is available in various sizes (Fig. 3). The larger the tag, the greater the read distance. A 2- by 2-in. tag will give a range of over one meter with maximum transmitter power and a large read antenna.

A tag contains a 154-bit reprogrammable memory. The 154 bits of data stored there includes the following fields: a 9-bit header, an 8-bit customer number, 104 bits (13 bytes) of user data, a 16-bit checksum, and 17 zero bits between the various fields and data bytes. This information is transmitted back to the reader at a 70-kbit/s rate using a Manchester-encoded signal that amplitude-modulates the 13.56-MHz carrier.

Such low-cost RFID systems target an enormous range of applications, from airline-baggage identification, to automatic ski-lift ticket validation, to work-in-progress (WIP) management in automobile manufacturing, to the previously mentioned automotive uses (Fig. 4). The RFID products may replace bar coding in some applications.

As we move toward more intelligent vehicles and highways, you will begin to see some truly amazing products. Drive-by-wire (or X-by-wire as it's called in the automotive field), fully automatic guided vehicles, and remote diagnostic systems are only a few examples.

X-by-wire is similar to fly-by-wire systems, which have been available on aircraft for many years. X-by-wire systems effectively replace the mechanical links existing between the driver's controls and the mechanism that actually performs the function. The most common functions being designed are X-by-wire for steering, brakes, and throttle control.

In conventional steering systems, there's a direct link between the steering wheel and the steering components in the front end by way of gears and hydraulic assists. X-by-wire would eliminate that. In such a system, a transducer, like a potentiometer attached to the steering wheel, will send steering-position input signals electrically to a servo system in which electric motors on the steering components provide the power to turn the wheels.

The same scenario applies with brakes. A brake switch or variable transducer activated by the driver's foot will send an electrical signal to the brake system. The mechanical link between the gas pedal and the fuel-injection system will similarly be replaced by a remote control device using a servo actuator.

These types of systems are no longer just experimental. Test systems have been developed using stepper motors, high-power MOSFET switches, and multiple embedded controllers. Such systems also set the stage for fully automatic remote control of the vehicle by wireless signals or guidance sensors embedded in the road. Autopilots have been available for years on boats and planes, so why not on cars?

Additionally, remote diagnostics are being developed. Sensors in the vehicle keep track of vehicle usage, miles traveled and at what speeds, engine-speed extremes, oil-change intervals, tire pressure, condition of shocks, and a variety of other engine and chassis conditions. These conditions are stored and then automatically transmitted to a diagnostic computer at a dealership garage. This analyzes the data and recommends the type of service or repair necessary and maintains a database of the vehicle's service.

As with most large undertakings, the biggest issue is cost in building intelligent highways and cars. Adding telematics and other high-tech goodies only makes it worse. Of course, buyers will always pay more for added value, especially for safety and convenience items. But there's a limit. Most of the costly hardware becomes more affordable once high volume has been attained. So an evolutionary approach to introducing intelligent components is still the best way to go.

Another issue is complexity. As the vehicle subsystems grow more sophisticated, dealing with them requires greater driver knowledge and skill. A key design goal is to make the intelligent systems as transparent to the driver as possible. Excessive complexity puts drivers off. We don't need a dashboard that looks like it came out of a new 777 aircraft. Just operating a multidisk CD player in a car is a challenge to many. The more buttons, dials, knobs, levers, switches, and displays, the greater the driver confusion.

Are we facing a future that must include driver training and check rides in our new cars? As usual, the working term here is "keep it simple." Make any intelligent systems fully automatic or very easy to apply. Furthermore, make them as nondistracting as possible.

Last but not the least of these issues is customer acceptance. Will drivers actually want all of the stuff engineers are capable of designing and building? Many of the intelligent systems take away driver duties and responsibility, and a lot of drivers don't want that. For example, many drivers still like shifting gears by themselves. Plus, remote-control X-by-wire may never happen. Do you want it in your car? Perhaps we will evolve into it. But without question, most of us will support any device or service that provides safety and convenience while also improving the traffic situation. (For more information, see "Useful Web Sites," at left)

Useful Web Sites
Automotive Multimedia Interface Collaboration (AMI-C): www.ami-c.com
Collection of electronics and communications information: www.howstuffworks.com
Federal Highway Administration: www.fhwa.dot.gov
GPS tutorial: www.colorado.edu/geography/gcraft/notes/gps/gpsf.html
The Institute for Electrical and Electronic Engineers: www.ieee.org
Intelligent Transportation Systems (ITS) America: www.itsa.org
OnStar comprehensive discussion: www.onstar.com
The Society of Automotive Engineers (SAE): www.sae.org
U.S. Department of Transportation and its ITS initiative: www.dot.gov or www.its.dot.gov
The Vehicular Technology Society of the IEEE: www.vtsociety.org

Companies And Organizations Mentioned In This Report
Conexant Systems Inc.
(949) 483-4600
Fax (949) 483-4078

Microchip Technology Inc.
Eric Sells, (480) 786-7478
Fax (480) 917-4150

Infineon Technologies Corp.
(408) 501-6382
Fax (408) 501-2424

Motorola Inc.Transportation Systems Group,
Semiconductor Products Sector

Bill Pfaff or James Farrell,
(512) 895-2035
Fax (512) 891-0318

Sensoria Corp.
Brian Davis, (858) 673-4460
Fax (858) 673-5112

TransCore Inc.
(800) 923-4824
Barb Catlin, (972) 733-6056
Fax (972) 733-6486
www.transcore.com or www.amtech.com

TAGS: Intel
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