![Intelligent key](https://upload.wikimedia.org/wikipedia/commons/d/da/Intelligent_key.JPG)
A smart key is an
electronic
Electronic may refer to:
*Electronics, the science of how to control electric energy in semiconductor
* ''Electronics'' (magazine), a defunct American trade journal
*Electronic storage, the storage of data using an electronic device
*Electronic co ...
access and authorization system that is available either as standard equipment, or as an option in several car designs. It was first developed by
Siemens
Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad.
The principal divisions of the corporation are ''Industry'', '' ...
in 1995 and introduced by
Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...
under the name "Keyless-Go" in 1998 on the W220
S-Class, after the design patent was filed by Daimler-Benz on May 17, 1997.
How it works
The smart key allows the driver to keep the
key fob
A keychain (also key fob or keyring) is a small ring or chain of metal to which several keys can be attached. The length of a keychain allows an item to be used more easily than if connected directly to a keyring. Some keychains allow one or bo ...
pocketed when unlocking, locking and starting the vehicle. The key is identified via one of several
antennas
In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies a ...
in the car's bodywork and a radio pulse generator in the key housing. Depending on the system, the vehicle is automatically unlocked when a button or sensor on the door handle or trunk release is pressed. Vehicles with a smart-key system have a mechanical backup, usually in the form of a spare key blade supplied with the vehicle. Some manufacturers hide the backup lock behind a cover for styling.
Vehicles with a smart-key system can disengage the
immobilizer
An immobiliser or immobilizer is an electronic security device fitted to a motor vehicle that prevents the engine from being started unless the correct key (''transponder'' or '' smart key'') is present. This prevents the vehicle from being " ...
and activate the
ignition
Ignition may refer to:
Science and technology
* Firelighting, the human act of creating a fire for warmth, cooking and other uses
* Combustion, an exothermic chemical reaction between a fuel and an oxidant
* Fusion ignition, the point at which a ...
without inserting a key in the ignition, provided the driver has the key inside the car. On most vehicles, this is done by pressing a starter button or twisting an ignition switch.
When leaving a vehicle that is equipped with a smart-key system, the vehicle is locked by either pressing a button on a door handle, touching a capacitive area on a door handle, or simply walking away from the vehicle. The method of locking varies across models.
Some vehicles automatically adjust settings based on the smart key used to unlock the car. User preferences such as seat positions, steering wheel position, exterior mirror settings, climate control (e.g. temperature) settings, and stereo presets are popular adjustments. Some models, such as the
Ford Escape
The Ford Escape is a compact crossover SUV sold by Ford since 2000 over four generations. The first generation was jointly developed with Mazda which also created the Mazda Tribute and Mercury Mariner as the twin model. Second generations of th ...
, even have settings to prevent the vehicle from exceeding a maximum speed if it has been started with a certain key.
Nomenclature
![Keyless start in Honda Odyssey](https://upload.wikimedia.org/wikipedia/commons/9/9c/Keyless_start_in_Honda_Odyssey.jpg)
Manufacturers use keyless authorization systems under different names:
*
Acura
Acura is the luxury vehicle, luxury and performance division of Japanese automaker Honda, based primarily in North America. The brand was launched in the United States and Canada on March 27, 1986, marketing luxury and performance automobiles. It ...
: Keyless Access System
*
Alfa Romeo
Alfa Romeo Automobiles S.p.A. () is an Italian luxury car manufacturer and a subsidiary of Stellantis. The company was founded on 24 June 1910, in Milan, Italy. "Alfa" is an acronym of its founding name, "Anonima Lombarda Fabbrica Automobili." ...
: Passive Entry
*
Audi
Audi AG () is a German automotive manufacturer of luxury vehicles headquartered in Ingolstadt, Bavaria, Germany. As a subsidiary of its parent company, the Volkswagen Group, Audi produces vehicles in nine production facilities worldwide.
Th ...
: Advanced Key
*
Aston Martin
Aston Martin Lagonda Global Holdings PLC is an English manufacturer of luxury sports cars and grand tourers. Its predecessor was founded in 1913 by Lionel Martin and Robert Bamford. Steered from 1947 by David Brown, it became associated with ...
: Keyless Entry and Push Button Start
*
BMW: Comfort Access or Display Key
*
Bugatti
Automobiles Ettore Bugatti was a German then French manufacturer of high-performance automobiles. The company was founded in 1909 in the then-German city of Molsheim, Alsace, by the Italian-born industrial designer Ettore Bugatti. The cars w ...
: Keyless Entry Remote
*
Cadillac
The Cadillac Motor Car Division () is a division of the American automobile manufacturer General Motors (GM) that designs and builds luxury vehicles. Its major markets are the United States, Canada, and China. Cadillac models are distributed i ...
: Adaptive Remote Start & Keyless Access
*
Citroën
Citroën () is a French automobile brand. The "Automobiles Citroën" manufacturing company was founded in March 1919 by André Citroën. Citroën is owned by Stellantis since 2021 and previously was part of the PSA Group after Peugeot acquired ...
: Keyless Entry and Start System
*
FIAT-Chrysler
Fiat Chrysler Automobiles N.V. (FCA) was an Italian-American multinational corporation primarily known as a manufacturer of automobiles, commercial vehicles, auto parts and production systems. The Italian holding company Exor was the largest sh ...
: Keyless Enter-N-Go
*
Ford
Ford commonly refers to:
* Ford Motor Company, an automobile manufacturer founded by Henry Ford
* Ford (crossing), a shallow crossing on a river
Ford may also refer to:
Ford Motor Company
* Henry Ford, founder of the Ford Motor Company
* Ford F ...
: Intelligent Access with push-button start
*
General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
: Passive Entry Passive Start (PEPS)
*
Honda
is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan.
Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
: Smart Entry System
*
Hyundai Hyundai is a South Korean industrial conglomerate ("chaebol"), which was restructured into the following groups:
* Hyundai Group, parts of the former conglomerate which have not been divested
** Hyundai Mobis, Korean car parts company
** Hyundai ...
: Proximity Key and smart entry key
*
Infiniti
is the luxury vehicle division of the Japanese automaker Nissan. Infiniti officially started selling vehicles on November 8, 1989, in North America. The marketing network for Infiniti-branded vehicles included dealers in over 50 countries in ...
: Infiniti Intelligent Key with Push-button Ignition
*
Isuzu: Genius Entry
*
Jaguar Cars
Jaguar (, ) is the luxury vehicle brand of Jaguar Land Rover, a British multinational car manufacturer with its headquarters in Whitley, Coventry, England. Jaguar Cars was the company that was responsible for the production of Jaguar cars ...
: Smart Key System
*
Jeep
Jeep is an American automobile marque, now owned by multi-national corporation Stellantis. Jeep has been part of Chrysler since 1987, when Chrysler acquired the Jeep brand, along with remaining assets, from its previous owner American Moto ...
: Keyless Enter-N-Go
*
Kia Motors
Kia Corporation, commonly known as Kia (, ; formerly known as Kyungsung Precision Industry and Kia Motors Corporation), is a South Korean multinational automobile manufacturer headquartered in Seoul, South Korea. It is South Korea's second lar ...
: Smart Key System
*
Land Rover
Land Rover is a British brand of predominantly four-wheel drive, off-road capable vehicles, owned by multinational car manufacturer Jaguar Land Rover (JLR), since 2008 a subsidiary of India's Tata Motors. JLR currently builds Land Rovers ...
: Keyless Entry
*
Lexus
is the luxury vehicle division of the Japanese automaker Toyota. The Lexus brand is marketed in more than 90 countries and territories worldwide and is Japan's largest-selling make of premium cars. It has ranked among the 10 largest Japanese ...
: Smart Access System
*
Lincoln
Lincoln most commonly refers to:
* Abraham Lincoln (1809–1865), the sixteenth president of the United States
* Lincoln, England, cathedral city and county town of Lincolnshire, England
* Lincoln, Nebraska, the capital of Nebraska, U.S.
* Lincol ...
: Intelligent Access System
*
Maserati
Maserati S.p.A. () is an Italian luxury vehicle manufacturer. Established on 1 December 1914, in Bologna, Italy, the company's headquarters are now in Modena, and its emblem is a trident. The company has been owned by Stellantis since 2021. Ma ...
: Passive Entry System
*
Mazda
, commonly referred to as simply Mazda, is a Japanese multinational automotive manufacturer headquartered in Fuchū, Hiroshima, Japan.
In 2015, Mazda produced 1.5 million vehicles for global sales, the majority of which (nearly one m ...
: Advanced Keyless Entry & Start System
*
Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...
: Keyless Go integrated into SmartKeys
*
Mini
The Mini is a small, two-door, four-seat car, developed as ADO15, and produced by the British Motor Corporation (BMC) and its successors, from 1959 through 2000. Minus a brief hiatus, original Minis were built for four decades and sold during ...
: Comfort Access
*
Mitsubishi Motors
is a Japanese multinational automobile manufacturer headquartered in Minato, Tokyo, Japan.[Nissan
, trade name, trading as Nissan Motor Corporation and often shortened to Nissan, is a Japanese multinational corporation, multinational Automotive industry, automobile manufacturer headquartered in Nishi-ku, Yokohama, Japan. The company sells ...](_blank)
: Nissan Intelligent Key
*
Peugeot
Peugeot (, , ) is a French brand of automobiles owned by Stellantis.
The family business that preceded the current Peugeot companies was founded in 1810, with a steel foundry that soon started making hand tools and kitchen equipment, and the ...
: PEUGEOT Open & Go
*
Porsche
Dr. Ing. h.c. F. Porsche AG, usually shortened to Porsche (; see #Pronunciation, below), is a German automobile manufacturer specializing in high-performance sports cars, SUVs and sedans, headquartered in Stuttgart, Baden-Württemberg, Germany ...
: Porsche Entry & Drive System
*
Proton
A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...
: Passive Keyless Entry
*
Renault
Groupe Renault ( , , , also known as the Renault Group in English; legally Renault S.A.) is a French multinational automobile manufacturer established in 1899. The company produces a range of cars and vans, and in the past has manufactured ...
: Renault Hands Free Keycard
*
Saab
Saab or SAAB may refer to:
Brands and enterprises
* Saab Group, a Swedish aerospace and defence company, formerly known as SAAB, and later as Saab AB
** Datasaab, a former computer company, started as spin off from Saab AB
* Saab Automobile, a fo ...
: Keyless Passive Entry
*
SsangYong Motor
The SsangYong Motor Company ( ko, 쌍용자동차 주식회사) is a South Korea–based automobile manufacturer. It traces its origins back to a manufacturer established in 1954. The name SsangYong appeared in 1988, after its acquisition by the ...
: Smart Key System
*
Subaru
( or ; ) is the automaker, automobile manufacturing division of Japanese transportation conglomerate (company), conglomerate Subaru Corporation (formerly known as Fuji Heavy Industries), the Automotive industry#By manufacturer, twenty-first ...
: Keyless Smart Entry With Push-Button Start or Keyless Access with Push-Button Start
*
Suzuki
is a Japan, Japanese multinational corporation headquartered in Minami-ku, Hamamatsu, Japan. Suzuki manufactures automobiles, motorcycles, All-terrain vehicle, all-terrain vehicles (ATVs), outboard motor, outboard marine engines, wheelchairs ...
: SmartPass Keyless entry & starting system
*
Toyota
is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
: Smart Key System
*
Vauxhall
Vauxhall ( ) is a district in South West London, part of the London Borough of Lambeth, England. Vauxhall was part of Surrey until 1889 when the County of London was created. Named after a medieval manor, "Fox Hall", it became well known for ...
/
Opel
Opel Automobile GmbH (), usually shortened to Opel, is a German automobile manufacturer which has been a subsidiary of Stellantis since 16 January 2021. It was owned by the American automaker General Motors from 1929 until 2017 and the PSA Grou ...
: Keyless Open & Start
*
Volkswagen
Volkswagen (),English: , . abbreviated as VW (), is a German Automotive industry, motor vehicle manufacturer headquartered in Wolfsburg, Lower Saxony, Germany. Founded in 1937 by the German Labour Front under the Nazi Party and revived into a ...
: Keyless Entry & Keyless Start or KESSY
*
Volvo
The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...
: Personal Car Communicator "PCC" and Keyless Drive or Keyless Drive
*
Mahindra & Mahindra
Mahindra & Mahindra Limited (M&M) is an Indian multinational automotive manufacturing corporation headquartered in Mumbai. It was established in 1945 as Mahindra & Mohammed and later renamed as Mahindra & Mahindra. Part of the Mahindra Group, ...
: Smart Key Module
Insurance standard
In 2005, the
UK motor insurance research expert Thatcham introduced a standard for keyless entry, requiring the device to be inoperable at a distance of more than 10 cm from the vehicle. In an independent test, the
Nissan Micra
The Nissan Micra, also known as the , is a supermini car ( B-segment) that has been produced by the Japanese automobile manufacturer Nissan since 1982.
The Nissan Micra replaced the Japanese-market Nissan Cherry. It was exclusive to Nissan J ...
's system was found to be the most secure, while certain BMW and Mercedes keys failed, being theoretically capable of allowing cars to be driven away while their owners were refueling. Despite these security vulnerabilities, auto theft rates have decreased 7 percent between 2009 and 2010, and the National Insurance Crime Bureau credits smart keys for this decrease.
SmartKeys
SmartKeys were developed by Siemens in the mid-1990s and introduced by
Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...
in 1997 to replace the infrared security system introduced in 1989. Daimler-Benz filed the first patents for SmartKey on February 28, 1997, in German patent offices, with multifunction switchblade key variants following on May 17, 1997. The device entailed a plastic key to be used in place of the traditional metal key. Electronics that control locking systems and the ignitions made it possible to replace the traditional key with a sophisticated computerized "Key". It is considered a step up from
remote keyless entry
A remote keyless system (RKS), also known as keyless entry or remote central locking, is an electronic lock that controls access to a building or vehicle by using an electronic remote control (activated by a handheld device or automatically by ...
. The SmartKey adopts the remote control buttons from keyless entry, and incorporates them into the SmartKey fob.
Once inside a Mercedes-Benz vehicle, the SmartKey fob, unlike keyless entry fobs, is placed in the ignition slot where a starter computer verifies the rolling code. Verified in milliseconds, it can then be turned as a traditional key to start the engine. The device was designed with the cooperation of
Siemens
Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad.
The principal divisions of the corporation are ''Industry'', '' ...
Automotive and Huf exclusively for Mercedes-Benz, but many luxury manufacturers have implemented similar technology based on the same idea. In addition to the SmartKey, Mercedes-Benz now integrates as an option
Keyless Go
A smart key is an electronics, electronic access and authorization system that is available either as standard equipment, or as an option in several car designs. It was first developed by Siemens in 1995 and introduced by Mercedes-Benz under the n ...
; this feature allows the driver to keep the SmartKey in their pocket, yet giving them the ability to open the doors, trunk as well as starting the car without ever removing it from their pocket.
The SmartKey's electronics are embedded in a hollow, triangular piece of plastic, wide at the top, narrow at the bottom, squared-off at the tip with a half-inch-long insert piece. The side of the SmartKey also hides a traditional Mercedes-Benz key that can be pulled out from a release at the top. The metal key is used for valet purposes such as locking the
glove compartment
A glove compartment or glove box is a compartment built into the dashboard of an automobile, located over the front-seat passenger's footwell, and often used for miscellaneous storage. The name derives from the original purpose of the compart ...
and/or trunk before the SmartKey is turned over to a parking attendant. Once locked manually, the trunk cannot be opened with the SmartKey or interior buttons. The key fob utilizes a radio-frequency transponder to communicate with the door locks, but it uses infrared to communicate with the engine immobilizer system. The original SmartKeys had a limited frequency and could have only been used in line-of-sight for safety purposes. The driver can also point the smart key at the front driver side door while pushing and holding the unlock button on the SmartKey and the windows and the sunroof will open in order to ventilate the cabin. Similarly, if the same procedure is completed while holding the lock button, the windows and sunroof will close. In cars equipped with the Active Ventilated Seats, the summer opening feature will activate seat ventilation in addition to opening the windows and sunroof.
Display Key
Display Key is a type of smart key developed by BMW that includes a small LCD color touchscreen on it. It performs the standard functions that a key fob would normally do such as locking, unlocking & keyless start, but because of the screen the user can also perform a number of the features from BMW's app. One of which includes commanding the car to self park from the key if your car has self parking capability. The key is currently available for the
3 Series
The BMW 3 Series is a line of compact executive cars manufactured by the German automaker BMW since May 1975. It is the successor to the 02 Series and has been produced in seven generations.
The first generation of the 3 Series was only avail ...
,
4 Series,
5 Series
The BMW 5 Series is an executive car manufactured and marketed by BMW since 1972, succeeding the New Class Sedans, and currently in its seventh generation.
The 5 Series was initially available as a sedan, with a wagon/estate body style (market ...
,
6 Series,
7 Ser ies,
8 Series,
X3,
X4,
X5,
X6, and
X7. The key is rechargeable and will last about 3 weeks. It can be charged via a micro USB port on the side or wirelessly on the center console.
Keyless Go
Keyless Go (also: Keyless Entry / Go; Passive Entry / Go) is Mercedes' term for an automotive technology which allows a driver to lock and unlock a vehicle without using the corresponding SmartKey buttons. Once a driver enters a vehicle with an equipped Keyless Go SmartKey or Keyless Go wallet-size card, they have the ability to start and stop the engine, without inserting the SmartKey. A
transponder
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend word, blend of ''transmitter'' and ''responder''.
In air navigation or radio frequency identification, a T ...
built within the SmartKey allows the vehicle to identify a driver. An additional safety feature is integrated into the vehicle, making it impossible to lock a SmartKey with Keyless Go inside a vehicle.
![KeylessEntryGoCircuitUnits](https://upload.wikimedia.org/wikipedia/commons/e/ed/KeylessEntryGoCircuitUnits.jpg)
The system works by having a series of LF (
low frequency
Low frequency (LF) is the ITU designation for radio frequencies (RF) in the range of 30–300 kHz. Since its wavelengths range from 10–1 km, respectively, it is also known as the kilometre band or kilometre wave.
LF radio waves exh ...
125 kHz) transmitting antennas both inside and outside the vehicle. The external antennas are located in the door handles. When the vehicle is triggered, either by pulling the handle or touching the handle, an LF signal is transmitted from the antennas to the key. The key becomes activated if it is sufficiently close and it transmits its ID back to the vehicle via RF (
Radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upp ...
>300 MHz) to a receiver located in the vehicle. If the key has the correct ID, the PASE module unlocks the vehicle.
The hardware blocks of a Keyless Entry / Go
Electronic control unit
An electronic control unit (ECU), also known as an electronic control module (ECM), is an embedded system in automotive electronics that controls one or more of the electrical systems or subsystems in a car or other motor vehicle.
Modern vehic ...
ECU are based on its functionality:
* transmitting low-frequency LF signals via the 125 kHz
power amplifier
An audio power amplifier (or power amp) is an electronic amplifier that amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspea ...
block
* receiving radio frequency RF signals (> 300 MHz) from the built-in
ISM receiver block
* encrypting and decrypting all relevant data signals (security)
* communicating relevant interface signals with other
electronic control units
*
microcontroller
A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable i ...
Inside Outside detection
The smart key determines if it is inside or outside the vehicle by measuring the strength of the LF fields. In order to start the vehicle, the smart key must be inside the vehicle.
Security requirements
It is important that the vehicle can't be started when the user and therefore the smart key is outside the vehicle. This is especially important at fueling stations where the user is very close to the vehicle. The internal LF field is allowed to overshoot by a maximum of 10 cm to help minimise this risk. Maximum overshoot is usually found on the side windows where there is very little attenuation of the signal.
![RelayStationAttack](https://upload.wikimedia.org/wikipedia/commons/2/2b/RelayStationAttack.jpg)
A second scenario exists under the name "relay station attack" (RSA). The RSA is based on the idea of reducing the long physical distance between the car and the regular car owner's SmartKey. Two relay stations will be needed for this: The first relay station is located nearby the car and the second is close to the SmartKey. So on first view, the Keyless Entry / Go ECU and the SmartKey could communicate together. A third person at the car could pull the door handle and the door would open. However, in every Keyless Entry / Go system provisions exist to avoid a successful two-way communication via RSA. Some of the most known are:
* measuring
group delay
In signal processing, group delay and phase delay are delay times experienced by a signal's various frequency components when the signal passes through a system that is linear time-invariant (LTI), such as a microphone, coaxial cable, amplifier, l ...
time to detect illegal high values
* measuring
third-order intercept point
In telecommunications, a third-order intercept point (IP3 or TOI) is a specific figure of merit associated with the more general third-order intermodulation distortion (IMD3), which is a measure for weakly nonlinear systems and devices, for exampl ...
to detect illegal
intermodulation
Intermodulation (IM) or intermodulation distortion (IMD) is the amplitude modulation of signals containing two or more different frequencies, caused by nonlinearities or time variance in a system. The intermodulation between frequency compo ...
products
* measuring
field strength In physics, field strength means the ''magnitude'' of a vector-valued field (e.g., in volts per meter, V/m, for an electric field ''E'').
For example, an electromagnetic field results in both electric field strength and magnetic field strength.
As ...
of the
electric field
An electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field fo ...
* measuring the response time of 125 kHz
LC circuit
An LC circuit, also called a resonant circuit, tank circuit, or tuned circuit, is an electric circuit consisting of an inductor, represented by the letter L, and a capacitor, represented by the letter C, connected together. The circuit can ac ...
* using a more complex
modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
(i.e.
quadrature amplitude modulation
Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message signal ...
) which can't be demodulated and modulated by a simple relay station
Furthermore, Keyless Entry / Go communicates with other ''Control Units'' within the same vehicle. Depending on the electric car architecture, the following are some ''Control Systems'' that can be enabled or disabled:
* ESCL Electric Steering Column Lock
* EIS Electronic Ignition Switch
* Central door locking system
*
Immobiliser
An immobiliser or immobilizer is an electronic security device fitted to a motor vehicle that prevents the engine from being started unless the correct key (''transponder'' or ''smart key'') is present. This prevents the vehicle from being " ...
*
Engine Control Unit
An engine control unit (ECU), also commonly called an engine control module (ECM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by re ...
(Motor management system)
* BCU Body control unit
Another possibility is using a motion sensor within the key fob.
Internal LF field dead spots
Dead spots are a result of the maximum overshoot requirement from above. The power delivered to the internal LF antennas has to be tuned to provide the best performance i.e. minimum dead spots and maximum average overshoot. Dead spots are usually near the extremities of the vehicle e.g. the rear parcel shelf.
Battery Backup
If the battery in the smart key becomes depleted, it is necessary for there to be a backup method of opening and starting the vehicle. Opening is achieved by an emergency (fully mechanical) key blade usually hidden in the smart key. On many cars emergency starting is achieved by use of an
inductive coupling
In electrical engineering, two conductors are said to be inductively coupled or magnetically coupled when they are configured in a way such that change in current through one wire induces a voltage across the ends of the other wire through el ...
. The user either has to put the key in a slot or hold it near a special area on the cockpit, where there is an inductive coil hidden behind which transfers energy to a matching coil in the dead key fob using
inductive charging
Inductive charging (also known as wireless charging or cordless charging) is a type of wireless power transfer. It uses electromagnetic induction to provide electricity to portable devices. Inductive charging is also used in vehicles, power tool ...
.
Slots have proven to be problematic, as they can go wrong and the key becomes locked in and cannot be removed. Another problem with the slot is it can't compensate for a fob battery below certain operating threshold. Most smart key batteries are temperature sensitive causing the fob to become intermittent, fully functional, or inoperative all in the same day.
Special Cases
A Keyless Entry / Go system should be able to detect and handle most of the following cases:
* SmartKey Transponder was forgotten in the rear trunk
* More than one SmartKey is present inside the car
* SmartKey getting lost during the drive
* Smartkey battery low
(Limp-Home)
History
![KeylessGoSiemensVDO](https://upload.wikimedia.org/wikipedia/commons/c/c7/KeylessGoSiemensVDO.jpg)
The system is based on a technology invented by Siemens VDO called PASE: Passive Start and Entry System. It operates in the
ISM band
The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific and medical (ISM) purposes, excluding applications in telecommunications.
Examples of applications for the use of radio frequency (RF) ener ...
of radio frequencies. Keyless Entry / Go was introduced first by
Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...
in the S-Class car series in 1998.
Outlook
Today a Keyless Entry / Go system is a state-of-the art technology and still has a lot of potential to optimise. Here are some general trends of the advance (AD) and series development (SD):
* SD: reduction of used LF antennas in low-cost compact cars (results in a loss of detection quality)
* AD: using electric field antennas instead of magnetic field antennas (cost reduction)
* AD: using microwave frequencies (radar) instead of an LF and RF combination (more comfort)
* AD:
Biometric
Biometrics are body measurements and calculations related to human characteristics. Biometric authentication (or realistic authentication) is used in computer science as a form of identification and access control. It is also used to identify in ...
authentication
Authentication (from ''authentikos'', "real, genuine", from αὐθέντης ''authentes'', "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicati ...
would identify the user and not the SmartKey transponder
Effectiveness
A test by
ADAC
ADAC, officially the Allgemeiner Deutscher Automobil-Club (), is Europe's largest motoring association. ADAC is the largest club (Verein) in Germany with around 21 million members. It would be more aptly described today as an individual mobi ...
revealed that 20 car models with Keyless Go could be entered and driven away without the key. In 2014, 6,000 cars (about 17 per day) were stolen using keyless entry in
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
.
See also
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Remote keyless system
A remote keyless system (RKS), also known as keyless entry or remote central locking, is an electronic lock that controls access to a building or vehicle by using an electronic remote control (activated by a handheld device or automatically by ...
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Transponder car key
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''.
In air navigation or radio frequency identification, a flight trans ...
References
External links
Relay Attacks on Passive Keyless Entry and Start Systems in Modern CarsSecurity_Flaws_of_Remote_
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Automotive_technology_tradenames.html" ;"title="Smart devices">Security Flaws of Remote
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Smart devices
Automotive technology tradenames">Smart devices">Security Flaws of Remote
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Smart devices
Automotive technology tradenames
Radio electronics
Vehicle security systems