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Wireless technology for automobile theft prevention.


Automobile theft is a major crime problem throughout the world. In the US, a vehicle is stolen every 19 seconds, costing consumers an estimated $8 B each year. In fact, auto theft costs Americans more than the combined expense of robbery, larceny and burglary. The automobile theft prevention authority of Michigan reports that if automobile theft were run by a single company as a business, it would rank as the 56th largest company in the US behind Coca Cola, Union Carbide and Bristol Myers.

This high theft rate has a dramatic effect on insurance rates. In some states as much as 88 percent of an automobile owner's comprehensive insurance premium is attributable to theft claims.

In a defensive effort, Americans will spend an estimated $800 M on anti-theft devices in 1994, up from $355 M spent in 1989, according to the National Insurance Crime Bureau (NICB). Although some car companies have offered options, such as perimeter security, most of the money spent on anti-theft devices is for retrofit alarms or locking devices that attempt to prevent theft once the car has been entered. While most theft prevention devices will dissuade the average joyrider, they barely cause the professional thief to pause. External items designed to lock the steering wheel in place can be easily removed using several simple techniques. Car alarms that produce little concern on busy city streets can be quickly disabled with a few snips of a wire cutter, and devices that help police track the location of stolen vehicles aid the recovery, but fail to prevent the theft itself. A simple, transparent and user friendly system is needed that will immobilize the car and prevent it from being started even if the key barrel is removed or if an attempt is made to hot-wire it. PATS

The Ford Motor Co. has introduced a new wireless security system called the passive anti-theft security system (PATS). Figure 1 shows a block diagram of the system and Figure 2 shows how the system operates. Currently, it is being tested on Ford Escorts being delivered in the UK and continental Europe. It is scheduled for introduction in the US on some 1995 models. The system is based on a Texas Instruments technology, Texas Instruments' registration and identification system (TIRIS) |TM~, which is a wireless electronic link between the starter key and the car's computer system. The heart of the PATS system is a tiny transponder imbedded in the head of the ignition key. The transponder contains a factory-programmed, 64-bit identification code that can not be altered and is uniquely identified using FM transmission methods. The capsule is battery-free and hermetically-sealed in glass. The capsule contains a small antenna, the bits of code on an IC and a capacitor that is charged from a burst sent from the radio frequency reader.

Figure 3 shows a drawing of the TIRIS transponder. The steering column contains a reader consisting of a transceiver radio frequency module and a small customized antenna that integrates with the steering lock and ignition switch barrel. The transceiver module is electronically connected with the PATS control module. The PATS control module is situated behind the instrument panel and controls the engine management, ignition and fuel pump circuits for immobilizing the engine unless an authorized transponder identification number is received. When a key with the correct identification number is inserted into the ignition switch, it can be turned from the off position through run to start in the usual manner. As the accessory/ignition switch is closed, the PATS control module sends out a charging pulse at 134 kHz to the transponder in the head of the key. The transponder receives this pulse then charges a capacitor, enabling the transponder to retransmit its unique code back to the reader. The communication takes place between the two antennas, one connected to the RF

module, the other an integral part of the transponder. The bit stream of information received back from the transponder is then sent out by hard wire to the PATS control module. The module decodes the information and compares it with the number stored in its memory during manufacture. If the identifications match, the module enables the engine management ECU, the ignition and the fuel pump to operate. 1.8 x |10.sup.19~ individual codes are available within the system, which makes the likelihood of cracking the code small. The transponder has a range of |is less than~ 1 m, so interception of the transponder signal by another receiver is also unlikely.

Since every transponder supplied to Ford has a unique code that can not be altered, it was necessary to develop a method whereby replacement or duplicate keys could be generated. The answer to this problem lies in the use of a master key. This key is supplied to the purchaser of the vehicle and contains a read/write transponder. The master key is inserted into and then removed from the ignition. A blank key is then inserted. The master key permits the code from the slave key to be read by the PATS control module and entered into its memory. From then on the slave key will start the car. Naturally, once this has been achieved, the master key should be removed and stored well away from the car. The major advantage of the system includes its higher level of security over other systems because of the transponder's unique and unchangeable code. The integrating signal contains no information that can be intercepted as in the case of some of the popular infrared systems. These can be easily overridden by thieves who intercept and emulate the infrared signal using low cost equipment that can be bought in most popular electronic stores. Because the transponders are battery-free and passive, the system is extremely rugged and should last the lifetime of the car. The small size of the TIRIS transponders make them virtually transparent to a driver who is expected to do no more than insert the proper key into the ignition.

Other Applications

The flexibility of radio frequency technology allows automotive manufacturers to adapt it to a variety of future uses. Through RF identification the vehicle could be tailored to individual needs, such as seat and mirror adjustments, and preset radio stations. The vehicle's top speed could also be preset, and special mechanics or parking attendant keys, which limit access to the trunk or glove compartment are also feasible.

The concept of RF identification technology lends itself to many other applications both inside and outside the transportation industry. Changing the RF frequency would allow the whole system of codes to be reused in another application and would permit transmission over greater ranges and in more directional applications. TIRIS technology is already being used in a number of additional applications other than the described automobile security system. These applications include automatic vehicle identification (AVI) and electronic toll and traffic management (ETTM). These systems offer technologies that will lead to the first generation of intelligent vehicle highway systems. The TIRIS organization is working with MFS Network Technologies to provide AVI technology for California's SR-91, America's first private all AVI highway. Also, the organization is working on fleet maintenance applications, including fuel dispensing, tire tracking systems and security, as well as security and access control for perimeter and building security systems, and vehicle and parking lot applications.

Automatic Billing

Combining the TIRIS technology with automatic, or semi-automatic truck lifts used in trash collection allows for pay-by-volume billing of customers. With truck base scales, pay-by-weight approaches can also be implemented.

The use of RF identification technology in the freight and distribution industries is growing rapidly as companies look for ways to track, manage and transport cargo more accurately. The TIRIS system is used to guide cargo vehicles and track containers and is incorporated into automatic truck and transport systems.


The unique application of wireless technology for auto-theft prevention is exciting enough in its own right. Additional applications of the same basic technology should challenge anyone's imagination.


The TIRIS organization, established by Texas Instruments in 1991 as an internal entrepreneurial unit, includes more than 250 employees in engineering, marketing and manufacturing. It also encompasses operating groups in more than nine locations in six countries. Worldwide headquarters are located in Bedford, UK, and North American operations are centered in Attleboro, MA. Additional information can be obtained by contacting Texas Instruments, TIRIS North American operations at (508) 699-3450.
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Title Annotation:Texas Instruments Inc.'s registration and identification system
Author:Howe, Harlan, Jr.; Blanchard, Christine
Publication:Microwave Journal
Date:Jan 1, 1994
Previous Article:Adaptive Radar Detection and Estimation.
Next Article:Wireless technology: how test fits in.

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