JP2003526222A - Remote vehicle data interface tag system - Google Patents

Abstract

(57) [Summary] This is a vehicle information system including a tag system (120B) installed in a vehicle (100). This tag system (120B) transmits the vehicle-related data acquired from the vehicle (100) to the interrogator (300B). This vehicle information system utilizes a tag system (120B) and a bus (110) in a vehicle (100) with low cost RF communication in an interrogator (300B) to enable vehicle-related information when the vehicle enters and exits a designated area. Access data remotely. The interrogator (300B) sends the vehicle-related information obtained from the tag system (120B) to the host computer (320). The vehicle information system can use an encoding system that includes an encoder. The encoder performs Manchester encoding of the data value to generate an encoded data value, and generates a first invalid Manchester encoded sequence as the beginning of the frame. Also, the second invalid Manchester code is generated as the end of the frame. The transmission packet is generated so as to sequentially include the head of the frame, the encoded data value, and the end of the frame. The beginning of the frame is a sequence “110110”, and the end of the frame is a sequence “001000”.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a system for processing vehicle information. The invention also relates to a system for transmitting data, in particular a system for encoding and decoding data which can be used in a system for processing vehicle information.

[0002]

[Prior art]

Well-known in the art of data transmission, Simon Haykin, "Communications (Comm
unication Systems) "(2nd edition, 1983), pages 414-415, but both clock data and clock data are encoded using Manchester encoding. It is possible to generate a signal containing This coding scheme is particularly useful when the transmitter and receiver are not controlled by the same clock. In this case, the receiver may need clock data associated with the data to be transmitted in order to recover the transmitted data. The Manchester encoded signal contains both the data to be decoded and the associated clock data in a single transmission so that the receiver can decode the Manchester encoded signal. Manchester coding effectively doubles the bandwidth of the signal to be transmitted.

[0003]

[Problems to be Solved by the Invention]

In addition to the clock data, the receiver needs to identify the beginning and end of the transmission from the receiver. Systems have been developed that identify the start of encoded data by transmitting an illegal Manchester code. An example of the illegal Manchester code is shown in FIG. Manchester encoded data typically contains only two consecutive high data bits (eg "11"). The illegal code includes four consecutive high data bits (eg, "1111"). As a result, a wide bandwidth transmitter is required to transmit the illegal Manchester code. Furthermore, the Illegal Manchester code is 3
RAW data bits (eg, “000”). As a result, the receiver may have difficulty synchronizing to its internal clock. In addition, the energy of the transmitted signal over time is reduced. As a result, the receiver can increase its gain due to the low energy and thus reduce its signal to noise ratio.

Although the end of transmission cannot be identified, it can be determined by monitoring the number of received bits. As a result, if two data packets are transmitted at the same time, it may be difficult to determine if a collision has occurred between these transmissions.

In the past, there have been several proposals using the available technology for automated trading on vehicles. For example, US Pat. No. 5,580,044 to Stewart et al.
The '044 patent presents a system including a vehicle-mounted processing system that collects data regarding vehicle operation history and transfers the data to a stationary processing system. The system provides mechanics with the necessary repair information and automates commercial transactions such as billing vehicle rentals and billing repair work on owned / leased vehicles. The onboard system includes a processor that collects data from sensors associated with the vehicle's selected operating system (eg, lights, drive train, tires, fluid level). The processor may continually update its status in the storage area (eg mileage or gas level) depending on the system being monitored, or simply store the information when service is required. Good (lights and drive trains). When the vehicle enters the service area, the onboard system is queried for its stored information. This inquiry is executed by the annunciator system. The annunciator system first detects the physical presence of the vehicle and then sends an RF interrogation signal to the receiver. This receiver is installed in the vehicle,
Connected to the onboard processor. When the inquiry signal is recognized by the onboard processor, the vehicle identification code is converted into an RF signal together with the stored information and transmitted from the vehicle. The '044 patent is incorporated herein by reference.

[0006]

[Means for Solving the Problems]

The present invention provides an encoding scheme and encoder that Manchester encodes a data value to produce a coded data value and produces a first valid Manchester code encoded in an illegal Manchester sequence as the beginning of a frame code. .
A second effective Manchester code encoded in the illegal Manchester sequence is also generated as the end of the frame sequence. The transmission packet is
It is generated so as to sequentially include the beginning of the frame sequence, the encoded data value, and the end of the frame sequence. The beginning of the frame sequence is “110110
, And the end of the frame sequence is the sequence “001000”.

The present invention also provides a decoder for receiving a Manchester encoded signal that sequentially includes the beginning of a frame sequence, an encoded data value, and the end of the frame sequence. The decoder also includes a detector that detects the beginning of the frame sequence and determines the beginning of the encoded data value in the Manchester encoded frame. The detector also detects the end of the frame sequence to determine the end of the encoded data value in the Manchester encoded frame.

With the preferred system, a wide bandwidth transmitter is not needed to transmit the illegal Manchester sequence. Furthermore, due to the continuous transition between high and low data values in the received signal, the RF receiver 30
5 can be synchronized with the received signal. Moreover, the energy of the transmitted signal increases over time. As a result, the RF receiver 305 can reduce its gain and improve the signal to noise ratio. Further, since the number of bits at the beginning of the frame sequence and the number of bits at the end of the frame sequence are reduced, the size of the message packet 400 can be reduced as compared with the related art.

The invention further provides a decoder including an integrator. The integrator receives a first signal that includes a first data value and a second data value that is different from the first data value. The integrator increases a first count value when the first signal contains a first data value and decreases a first count value when the first signal contains a second data value.
Contains a counter. The integrator produces a third data value when the first count value is greater than or equal to a first threshold value and a fourth data value when the first count value is less than or equal to a second threshold value. . The integrator further produces a second signal including a third data value and a fourth data value. The decoder also includes a discriminator having a second counter. The second counter increments the second count value when the second signal includes the third data value and sets the second count value to a predetermined value when the second signal includes the fourth data value. Reset to value. The discriminator also generates a clock synchronization signal when the second count value is equal to or greater than the third threshold value. The decoder also generates a third signal that includes a fifth data value when the count value is greater than or equal to a first threshold value and a sixth data value when the count value is reset. The first signal is decoded according to the third signal and the clock synchronization signal.

The present invention further provides a vehicle information system including a tag system installed in a vehicle. This tag system transmits vehicle-related data obtained from a vehicle to an interrogator. The vehicle information system utilizes a bus in the vehicle with low cost RF communication in a tag system and interrogator to remotely access vehicle related data as the vehicle enters and leaves designated areas. The interrogator sends the vehicle-related data acquired from the tag system to the host computer.

While both the foregoing general description and the following detailed description are exemplary of the present invention, they are not intended to limit the present invention.

[0012]

DETAILED DESCRIPTION OF THE INVENTION

The invention may best be understood by reading the following detailed description with reference to the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. Conversely, the dimensions of the various features are arbitrarily expanded or reduced for clarity.

Overview In the following, reference is made to the drawings: Here, like reference numbers refer to like elements throughout. FIG. 1 shows a vehicle information system 10 including a tag system 120B installed in a vehicle 100. This tag system 120B is for the vehicle 10
The vehicle-related data acquired from 0 is transmitted to the interrogator 300B. The vehicle information system 10 utilizes the bus 110 (shown in FIG. 2) in the vehicle 100 with low-cost communication in the tag system 120B and the interrogator 300B to provide vehicle-related data when the vehicle 100 enters and leaves the designated area 20. Access remotely. Interrogator 300B
Displays the vehicle-related information acquired from the tag system 120B in the host computer 32.
Send to 0.

This vehicle-related data includes, for example, temperature, fluid level, oil pressure,
It includes an odometer and other data related to vehicle 100. The tag system 120B indicates the status of the exhaust gas related parameter and the safety related parameter,
It can also be used for reading without having to connect the equipment directly to the vehicle.

The tag system 120B includes an RF transmitter 210 (FIG. 3) for transmitting vehicle-related data.
(Shown in A) only. The interrogator 300B receives the vehicle-related data R
Only the F receiver 305 (shown in FIG. 6) is included. As a result, the tag system 12
The cost and complexity of the tag system 120B and the interrogator 300B can be reduced because each of the OB and the interrogator 300B does not include a circuit and software for both transmitting and receiving data. In another embodiment, the tag system 1
20B and interrogator 300B may each include a transceiver for transmitting and receiving data.

The tag system 120B only monitors the data transmitted on the bus 110, so that there is no need to modify the control and operation of the bus 110 to tune the tag system 120B. In this method, the tag system 120B can be integrated into the vehicle 100 with minimal modification to the vehicle 100. For this reason, the vehicle information system 10 is more easily accepted by the vehicle manufacturer and is easily incorporated into the vehicle 100. In other embodiments, tag system 120B may send data on bus 110.

The vehicle information system 10 can be used in various environments to remotely monitor a vehicle. For example, the vehicle information system 10 can be used to determine the speed of the vehicle. In this case, the tag system 120B repeatedly transmits the speed of the vehicle 100 and the vehicle identification data while the vehicle 100 travels along the road. The interrogator 300B arranged near the road receives this transmission data for subsequent processing.

Alternatively, the vehicle information system can be used to monitor the truck as it arrives at and departs from the central terminal. In this case, the interrogator 300B can be located at the entry point to the central terminal to obtain the data transmitted from the tag system 120B connected to the truck. The host computer 320 uses the data obtained from the interrogator 300B to determine which truck has entered or exited the central terminal.

In yet another aspect, the vehicle information system 10 can be used in a vehicle rental system. The operation of the vehicle information system 10 is described in detail below in connection with the vehicle rental system.

Description of the Preferred Embodiments FIG. 1 shows a vehicle information system 10 that includes a tag system 120B mounted on a vehicle 100. This tag can be mounted in a place that can only be seen by looking carefully. The mounting location can be anywhere that is not completely enclosed by the metal surface. Suitable locations include, for example, the back of the dashboard in the passenger compartment, the back of the bumper, the back of the non-metal body parts, the underside of the vehicle. Vehicle 100 may be, for example, a rental vehicle deployed at an airport. Vehicle 100
The person renting the car (hereinafter "borrower") is provided with the driver tag system 120A when the borrower arrives at the airport. This driver tag system 120A
Contains stored data identifying the borrower and the rented vehicle. The driver tag system 120A includes a circuit for transmitting this stored data.

As shown in FIG. 1A, after receiving the driver tag system 120A, the borrower gets on the shuttle flight 40 and moves to the rental place where the vehicle 100 is located. The shuttle flight 40 includes an interrogator 300A that acquires the data transmitted from the driver tag system 120A. This acquired data is transmitted to the host computer 320. The host computer 320 notifies the driver of the shuttle flight 40 where the vehicle 100 is located in the rental area. Host computer 320 maintains a database of rental data that identifies borrowers, rented vehicles 100, and other data related to vehicles 100. For example, the other data may include the position of the vehicle 100 in the rental site, the remaining fuel amount of the vehicle 100, and the odometer reading.

Returning to FIG. 1, the borrower is unloaded from vehicle 100, enters vehicle 100, and drives toward the exit of the rental lot. The tag system 12 arranged in the vehicle 100
0B transmits the message data packet 400 (FIG. 4) intermittently. The interrogator 300B displays the message packet 400 when the vehicle 100 is in the designated area 20.
To receive. The size of the designated area 20 can be adjusted by increasing the strength of the signal transmitted from the tag system 120B or by increasing the sensitivity of the RF receiver 305 (FIG. 6) in the interrogator 300B. The interrogator 300B has an antenna (not shown) oriented to receive one or more message packets 400 transmitted from the tag system 120B while the vehicle 100 passes through the designated area 20. is doing. The interrogator 300B may be a portable device or may be permanently attached. At each facility, such as an airport, an interrogator 300
There is a wireless or hardwired link from B to the host computer 320.

As shown in FIG. 4, the tag system 120 B uses the message packet 400
Send various kinds of data in. The message packet 400 is for the vehicle 100.
Vehicle identification data (VID) 41 such as a vehicle identification number (VID) that uniquely identifies
Includes 5. The message packet 400 may include vehicle-related data such as fuel data 420 indicating a fuel tank level and odometer data 425 indicating an odometer reading.

As shown in FIG. 2, the vehicle 100 includes a tag system 120B.
Vehicle 100 includes a fuel tank system 130, an instrument panel 140, other modules 150, and a bus 110 used to transfer data between vehicle computers 160. Module 150 may include other components (eg,
It is an interface with an engine (not shown) in the vehicle 100. The vehicle computer 160 may be, for example, a vehicle body computer or an engine computer in the vehicle 100.

Data is provided to and retrieved from bus 110 in accordance with vehicle bus standards such as the Society of Automotive Engineers (SAE) J1850 standard and Controller Area Network (CAN) standard. SAEJ1850 standard is bus 1
00 and components connected to bus 100 (eg, fuel tank system 130, instrument panel 140, module 150, vehicle computer 160) define electrical data protocols. The bus 100 is, for example, a single wire loop. Fuel tank 130, instrument panel 140, module 150, and vehicle computer 160 provide data to bus 110, or bus 11
Receives data from 0.

The inventor understands that it may not be desirable to provide additional components for transmitting data on the bus 110. Vehicle manufacturers have designed the bus 110 and components connected to the data bus 110 to ensure reliable data transmission. Adding components that send data on the data bus 110 may require coordinating the operation of other components to ensure reliable data transmission.

The tag system 120B avoids these problems because it simply monitors the data transmitted on the data bus 110. The tag system 120B is, for example, the bus 1
The connector is crimped onto the wiring forming the tag 10 and the connector is attached to the tag system 120
By connecting to B, it is possible to connect to the bus 110. As a result, there is no need to modify the operation of bus 110. In this way, the tag system 120B can be incorporated with minimal modification of the vehicle 100. Further, the vehicle manufacturer may be more motivated to incorporate the tag system 120B into the vehicle 100, since the vehicle manufacturer does not have to modify the bus 110 or the components connected to the bus 110. Furthermore, the installation cost of the tag system 120B can be minimized because the installation of the tag system 120B requires only minor modifications. In another embodiment, tag system 120B may send data on bus 110.

The tag system 120B determines the status of various components connected to the bus 110 by monitoring the data transmitted from these components on the bus 110. For example, the fuel tank system 130 includes a circuit for determining the amount of fuel remaining in the fuel tank, as is well known, and this data is read by the instrument panel 140.
Transmit on bus 110 for later display with an inside level gauge (not shown).
The data system 120B receives the transmission data from the bus 110 and transmits the remaining fuel amount to the interrogator 300B. As a result, the tag system 120B uses a special circuit for monitoring the remaining fuel amount, or is used as a circuit for measuring the remaining fuel amount.
It is possible to provide the remaining fuel amount without directly connecting.

Tag system 120B may be connected to various components in vehicle 100. As described in more detail below, the tag system 120B may include circuitry to determine an odometer reading of the vehicle, for example, by monitoring data provided by wheel sensors.

The tag system 120B is described in detail below with reference to FIG. 3A. The tag system 120B complies with the SAE J1850 standard, and the tag system 1
It includes an interface 200 that provides an interface between the 20B and the bus 110. Interface 200 is connected to bus 110 and simply retrieves data from bus 110. Alternatively, the interface 200 sends the data to the bus 110.
May be provided to Bus 110 depending on the components connected to bus 110
The data transmitted above includes identification data that identifies which component transmitted the data on bus 110. For example, the fuel tank system 130 (
2) transmits a data packet on the bus 110 indicating the data transmitted from the fuel tank 130. Further, the data packet may include data indicating the amount of fuel in the fuel tank. Still further, this data packet is transmitted by the bus 110.
May include data indicating which of the other components connected to the server should receive the transmitted data packet. For example, the data packet may include data indicating that instrument panel 140 should search for a transmitted data packet from fuel tank system 130.

The data obtained from the bus 110 is sent to the processor 205 (eg, microcontroller). The interface 200 and the processor 205 can be combined as a single component. One such suitable combination of interface 200 and processor 205 is part number MC68HC05V7, commercially available from Motorola. This particular part is a Gen that complies with the SAE J1850 standard.
Compatible with eral Motors cars. The operation of processor 205 is illustrated in FIG. 3B.
Will be described in detail below with reference to.

As shown in FIG. 3B, in step S100, the data packet is transferred to the bus 11
It is retrieved from 0 and sent to the processor 205. In step S110, the processor 205 determines whether the retrieved data packet is further processed.
If no further processing is performed, step S100 is repeated. Processor 20
5 determines whether the bus data packet is further processed by examining the identification data of the data packet. For example, if the data packet is from the fuel tank system 130, the processor 205 selects this data packet for further processing. Processor 205 does not further process the data packet if the data packet is from, for example, vehicle computer 160. Which data packet is processed can be determined using a look-up table (LUT) (not shown) provided to the processor 205. This LUT may contain data indicating the data packets to be selected for further processing. For example, the LUT may be a fuel tank system 130.
And may include data indicating that the data packet from instrument panel 140 should be selected for further processing.

Processor 205 may receive data from analog-to-digital (A / D) converter 215 (FIG. 3A) directly connected to components within vehicle 100. For example, A / D converter 215 may measure fuel level as described in the '044 patent and connect directly to sensor 155, which is not connected to bus 110. In this case, A / D converter 215 converts the analog signal from sensor 155 into a digital signal for further processing by processor 205. The processor 205 determines the remaining fuel amount based on the fuel sensor reading. Alternatively, processor 205 may recover data from other components in vehicle 100 that do not require conversion by A / D converter 215. In other words, this component can provide digital data directly to the tag system. In this case, these components may be directly connected to the processor 205.

Returning to FIG. 3B, in step S120, vehicle-related data is retrieved from the data packet. In step S130, the processor 205 generates the message packet 400 (FIG. 4). At step S140, the processor 205 modulates the RF transmitter 210 and transmits the message packet 400. RF transmitter 21
0 is, for example, an AM surface acoustic wave (SAW) transmitter. The modulated signal is generated by processor 205 which turns transmitter 210 on and off.

The RF link between the tag system 120B and the interrogator 300B is implemented using active or “semi-active” transmission technology. In an active transmission system, tag system 1208 uses battery 170 (FIG. 2) to power the entire tag system 120B. In a semi-active transmission system, the tag system 120B is the transmitter 21
Battery power is used for the tag system 120B except zero. The message packet 400 is transmitted via the passive backscatter to the tag system 120B and the interrogator 3.
Can be transmitted between 00B. As is known, in this passive backscatter, a constant wave is transmitted from the interrogator 300B and passively modulated to the tag system 120B.
Is reflected from and returned to the interrogator 300B.

The RF link can provide either one-way communication (from tag system 120B to interrogator 300B) or two-way communication. The one-way link provides a monitoring function by which the tag system 120B reports the current status of all monitored parameters of the vehicle 100, as described above. The bidirectional link allows the interrogator 300B to send a message to the tag system 120B, instructing the tag system 120B to monitor a particular parameter, or to pass the parameter to a system within the vehicle 100. In the latter case, this link may provide a means to remotely perform functions such as locking / unlocking the door and monitoring / adjusting emission control sensors and systems.

As shown in FIG. 5, the RF transmitter 210 is modulated using Manchester coding. It is well known in the field of data transmission and uses Manchester encoding for clock data and data to be transmitted, as described in "Communications Systems" by Simon Haykin (2nd edition, 1983), pages 414-415. By encoding the signal, a signal including both the message packet 400 and the clock data can be generated. The width 2t of the encoded data pulse is twice the width t of the Manchester encoded data. As a result, Manchester encoding is
Efficiently doubles the bandwidth of the transmitted signal. The interrogator 300B recovers both the clock data and the data from the Manchester encoded signal, as described in more detail below.

As shown in FIG. 4, the processor 205 can send one or more message packets 400 containing data regarding various components in the vehicle 100 (FIG. 1). The message packet 400 has packet type data 405.
Is included. The packet type data 405 indicates whether the message packet 400 is a single message packet or one of related message packets in one sequence. The packet sequence data 410 is
The position of the message packet 400 in the sequence of related message packets is shown. The associated message packet 400 is provided to reduce the size of the message packet. The size of message packet 400 is reduced in preparation for transmission from many different tag systems 120B.

To reduce the complexity and cost of the tag system, limit the number of frequencies for transmission,
For example, it may be one frequency. Therefore, the vehicle 10 including the tag system 120B
In an environment with many 0's, the packet size is reduced to minimize the time to transmit the message packet 400. In this way, the packet 400
More is less likely to be transmitted at one time. By dividing a large data transmission into a plurality of packets 400, interference can be suppressed.

By using a sequence of message packets 400, it is possible to provide data relating to vehicle 100 that contains more bits than is provided in a single message packet. The packet type data 405 and the packet sequence data 410 are each 1 byte, for example. The message packet 400 may include vehicle identification data (VID). This VID can be a unique sequence of numbers, letters, or symbols used to identify a particular vehicle 100. For example, VID 415 is a vehicle identification number (VIN)
May be The VID 415 is 13 bytes, for example. A compression algorithm can be used to reduce the number of bits in the VID 415.

Data relating to vehicle 100 is also provided in message packet 400. For example, this message packet may include fuel data 420 and odometer data 42.
Includes 5. Fuel data 420 indicates the amount of fuel remaining in the fuel tank of vehicle 100. The odometer data indicates the current distance traveled by the vehicle 100. The fuel data 420 and the odometer data 425 are, for example, 2 bytes each. Additional data 430 may be included in message packet 400 to provide additional data regarding vehicle 100. The additional data 430 can include, for example, data indicating the state of the engine and data indicating whether or not the vehicle 100 has caused a collision. If the vehicle 100 has a collision, the tag system 120B receives data from one or more sensors (eg, accelerometers (not shown)) in the vehicle 100 that detect an impact on the vehicle 100. The additional data 430 can also include information about vehicle rentals. The message packet 400 also includes a 2-byte error correction code 435, for example. The message packet 400 may send only the VID 415. In this case, the tag system may not be connected to the bus 110.

The message packet 400 is transmitted from the tag system 120B in the range of 0 to X seconds. Here, X is, for example, 1/2. Furthermore, the message packet 40
Zeros are sent 1-2% of this time. Also, message packet 4
00 is transmitted during one of the Y time slots. For example, three separate tag systems 120C, 120D and 12 that are the same as tag system 120B.
Consider FIG. 7, which shows a message packet 400 sent from OE.

As mentioned above, collisions between message packets 400 result in message packet 4
It is minimized by reducing the size of 00. However, at time T
As shown at 1, two message packets 400 may be sent from two separate tag systems 120C and 120D at the same time. in this case,
Interrogator 300B receives the segments of the two message packets and consequently determines that the received transmission is invalid. The operation of interrogator 300B when receiving message packet 400 is described in more detail below. If message packet 400 is sent from each tag system 120C and 120D at regular time intervals, then message packet 400 from each tag system 120C and 120D will be sent continuously and simultaneously.

To avoid this problem, the preferred processor 205 (FIG. 3A) can send a message packet in one of the 16 random time slots S1 to S16 shown in FIG. The time slots S1 to S16 are selected according to the random number generated by the processor 205. As a result, the time intervals ΔT1, ΔT2 and Δ
T3 can vary between each message packet 400 sent from the tag system 120C. Therefore, although the message packet 400 transmitted from the tag systems 120C and 120D may collide at time T1, the subsequent message packet 4 transmitted from the tag systems 120C and 120D
00 is unlikely to be sent at the same time. Therefore, many tag systems 120B transmitting at the same frequency can be used in close proximity to each other. As a result,
Since it is not necessary to prepare various tag systems 120C to 120E that transmit at different frequencies, the cost of the tag systems 120C to 120E can be reduced. Further, because the interrogator 300B can be designed to receive transmissions at one frequency instead of multiple frequencies, the cost of the interrogator 300B can also be reduced. Alternatively, the tag systems 120C-120E may transmit on different frequencies. In this case, the interrogator 300B would include circuitry that receives transmissions at different frequencies.

In another embodiment, tag system 120B can monitor the voltage level of battery 170 (FIG. 1) to determine how often message packet 400 is transmitted. Normally, the battery 170 is used when the vehicle 100 is in motion.
Is charged. In contrast, when vehicle 100 is idling or the engine is off, battery 170 has little or no charge. Therefore, the tag system 120B can determine whether or not the vehicle is moving by monitoring the difference in voltage level. Tag system 120B
Monitors the voltage level using data retrieved from bus 110 or by a direct connection to a sensor (not shown) connected to battery 170.

The tag system 120 can increase the transmission rate of the message packet 400 when the vehicle 100 is moving. In this way, a large number of message packets 400 can be transmitted while the vehicle 100 passes through the designated area 20. Therefore, the interrogator 300B is more likely to receive the message packet 400. Tag system 120B may reduce the transmission rate of message packet 400 when the vehicle is not moving. In this way, a large number of message packets 400 can be transmitted within the designated area 20 while reducing the total number of message packets 400 transmitted within a specific time. Therefore, the possibility of collision between the message packets 400 is reduced.

Returning to FIG. 1, when the vehicle 100 enters the designated area 20, the interrogator 300 B
Tag system 120B including fuel data 420 and odometer data 425
Receives data sent from. VID 415, odometer data 420, and fuel data 425 are sent to host computer 320 for storage and processing. Further, the interrogator 320 receives the data transmitted from the driver tag system 120A.

The host computer 320 determines whether or not the vehicle 100 and the borrower “match” based on the data transmitted from the tag system 120B and the driver tag system 120A. When the stored data indicates that the borrower borrowed the vehicle 100 that is about to leave the rental site, the borrower and the vehicle 100 match. If there is a match, the host computer signals the entry / exit system 30 to allow the vehicle 100 to exit the rental area. If there is no match, the borrower is instructed to return to the rental site for help.

In other embodiments, the user interface 165 may be connected to the bus 110,
It can be directly connected to the tag system 120B. User interface 16
5 can be used by the borrower to enter an access code, credit card number, or other information obtained directly by tag system 120B or obtained from bus 110. The user interface 165 can be, for example, a keypad, a card reader, or other known device that supplies data to the system from an external source. In operation, for example, the user interface 16
5 can be used to obtain the borrower's credit card number. The tag system 120B transmits the credit card number to the interrogator 300B. This credit card number is used to confirm that the borrower and vehicle 100 match. If there is a match, the vehicle is allowed to leave the rental area. If they do not match, the vehicle is not allowed to leave the rental area.

After returning from the rental place and returning to the rental place or the drop-off point, the interrogator 300B receives the message packet 400 transmitted from the tag system 120B.
Host computer 320 compares the fuel data 420 and odometer data 425 from tag system 120B with the data stored in the database. The host computer 320 uses the difference between the fuel data 420 sent from the tag system 120B as the vehicle exits the rental location and the fuel data 425 sent from the tag system 120B when the vehicle 100 is returned to the rental location. , Determine if the borrower should refuel with gasoline. Similarly, odometer data 425 is used to determine whether to charge the borrower for the distance traveled by the vehicle. A receipt is issued and given to the borrower. After this, the borrower parks the vehicle. Alternatively, the borrower may receive a receipt after parking the vehicle.

As shown in FIG. 6, the transmitted message packet 400 (FIG. 4) is received by the interrogator 300B. The interrogator 300B sends the transmitted message packet 4
An RF receiver 305 for receiving 00 is included. Received message packet 40
The 0 is sent to the demodulator 310 which demodulates the received message packet 400. The processor 315 processes the received message packet and
The data formed in 00 is converted into a format suitable for use by the host computer 320.

FIG. 9 is a block diagram of the processor 315. Processor 315 includes an integrator 505 that integrates the data over a period of time. It has a maximum threshold MAX1 (eg 208 counts) and a minimum threshold MIN1 (eg 0 counts). In addition, it has a built-in hysteresis and a low-high threshold TRH (about 187 counts) and a high-low threshold TRL (e.g., 21 counts). The example values above are for a 9600 baud rate communication. Whenever one of these thresholds is reached, a "start" pulse is generated for synchronization of subsequent circuits. The demodulated signal DATA_IN is sent to the integrator 505 that executes the integration operation, and the influence of high frequency noise on the demodulated signal DATA_IN is reduced. In other words, the integrator 505 performs a low pass filter operation. The integrator 505 includes a counter 507 that counts up when the demodulated signal DATA_IN is high and counts down when the demodulated signal DATA_IN is low.

The operation of the integrator 505 will be described below with reference to FIG. At time T1,
The counter 507 counts up because the data signal DATA_IN is high. The counter counts up to the maximum value MAX1. Data DATA_IN
At time T4 when is low, the counter 507 counts down. The counter never counts less than the minimum count value MIN1.

The integrator 505 utilizes the counter 507 to generate the data signal INT_OUT. The data signal INT_OUT transitions from the low state to the high state when the count exceeds the threshold value TRH. The threshold value TRH is, for example, TRH = 0.9 × MAX1. Therefore, the time T2 when the count COUNT1 is equal to or greater than the threshold value TRH.
Then, the data signal INT_OUT becomes high. The data signal INT_OUT is
When the count equals the threshold TRL, the high state is transitioned to the low state. The threshold value TRL is, for example, TRL = 0.1 × MAX1. Therefore, the time T when the count value COUNT1 is equal to or less than the threshold value TRL.
At 5, the data signal INT_OUT goes low. In this way, the high frequency components in the data signal DATA_IN are minimized. As a result, the data signal D
High frequency noise in ATA_IN is suppressed.

The integrator 505 shifts the data signal INT_OUT with respect to the demodulated signal in time. The integrator 505 has a demodulated signal DATA_IN and a data signal INT_OUT.
The pulse duration is not changed significantly between and.

Returning to FIG. 9, the processor 315 includes a discriminator 510. Discriminator 510
Distinguishes 0s and 1s in a Manchester encoded data stream. The discriminator includes a retriggerable counter (eg, a modulo 416 counter with input value sampling at count 208). The discriminator 510 discriminates 0 and 1 in the Manchester encoded data in the data signal INT_OUT. Further, the discriminator 510 synchronizes the internal clock with the clock data in the Manchester encoded data. The operation of the discriminator 510 will be described below with reference to FIG. At time T1, since the data signal INT_OUT is high, the counter 512 arranged in the discriminator 510 counts up. Counter 51
2 counts up to the maximum value MAX2, but never exceeds the maximum value MAX2. The maximum value MAX2 is, for example, substantially equal to one half of the expected amplitude of the pulse in the data signal INT_OUT.

At time T2 when the count value COUNT1 is greater than or equal to the maximum value MAX2, the signal FR
ESH goes from a low state to a high state. The transition from the low state to the high state is used to synchronize the clock with the Manchester encoded data. Counter 5
The signal generated by 12 is sent to the decoder 515 as the data signal SAMPLE. The data signal SAMPLE is either high or low. Therefore, at time T1, the data signal SAMPLE is low. At time T2, the data signal SAMPLE is high. The rising edge of the data signal FRESH indicates that a valid data sample was provided in the data signal SAMPLE.
The counter 512 is set to, for example, 0 when the data signal INT_OUT shifts from the high state to the low state.

In response to the data signal FRESH and the data signal SAMPLE, the decoder
Decode Manchester encoded data and retrieve message data packet 400 (FIG. 4). Decoder 515 extracts the data from message packet 400 and sends the data to host computer 320. Alternatively, the decoder sends the message packet 400 to the host computer 320 and the host computer 3
20 may extract data from the message data packet 400.

Decoder 515 receives Manchester encoded data and converts it into message packets 400. Decoder 51 for converting Manchester encoded data
5 identifies the beginning and the end of the Manchester encoded data corresponding to the message packet. The beginning of the frame sequence is added to the Manchester encoded data by the processor 205 during communication. The beginning of the frame sequence is
It is shown in FIG. The beginning of the frame sequence is a series of pulses representing 1s and 0s added to the beginning of the Manchester encoded message packet 400 (FIG. 4). The beginning of the frame sequence is a combination of 0s and 1s that are not generated when message packet 400 is Manchester encoded.

When the beginning of the frame sequence is detected, the decoder 515 determines the beginning of the Manchester encoded message packet 400 and decodes it. The end of the Manchester encoded message packet 400 can be determined by two methods. If the number of bits of the Manchester encoded message packet 400 is known, the decoder 515 can count the number of bits after receiving the beginning of the frame sequence. When the number of counted bits equals the number of bits in the Manchester encoded message packet, decoder 515 ignores the remaining bits. Alternatively, the tag system 120 may add the end of the frame sequence after the Manchester encoded data.

The end of the frame sequence is shown in FIG. The end of the frame sequence is a series of pulses representing 1s and 0s added by processor 205 to the end of Manchester encoded message packet 400 (FIG. 4) during communication.
The end of the frame sequence is a combination of 0s and 1s that are not generated when message packet 400 is Manchester encoded. By using the beginning and end of the frame sequence, the decoder 515 can determine the boundaries of the message packet 400. Furthermore, if a collision occurs between message packets, one of the message packets can be detected and recovered by detecting the beginning of the frame sequence. Furthermore, the detection of the beginning of the second frame sequence is invalid for the Manchester encoded data currently being decoded,
Indicates that it should be ignored. In contrast, prior art systems utilize the illegal Manchester code to indicate the beginning of encoded data. As a result, if a collision occurs between the transmitted message packets 400 in the prior art system,
It may be impossible to recover either message packet 400.

By using the exemplary system, a wide bandwidth transmitter is not required to transmit the illegal Manchester sequence. Moreover, the continuous transition between the high and low data values in the received signal allows the RF receiver 305 to synchronize to the received signal. Moreover, the energy of the transmitted signal increases over time. As a result, the RF receiver 305 can reduce its gain and improve the signal-to-noise ratio. Further, since the number of bits at the beginning of the frame sequence and the number of bits at the end of the frame sequence are reduced, the size of the message packet 400 can be reduced as compared with the related art.

When the decoder 515 retrieves the message packet 400, it sends this message packet to the host computer 320. Alternatively, the processor 315 (see FIG.
) May include additional circuitry and / or software to perform various operations performed by host computer 320.

The tag system 120B is protected from modification such as removal from the vehicle 100. The tag system 120B, once removed from the vehicle 100, can be used to indicate that the vehicle has been returned to the rental location. Tag system 12
OB is protected from modification by storing data such as vehicle identification data in volatile memory 730 in tag system 120B. In this case, the tag system 120B is connected to the battery 170 (FIG. 2). Tag system 12
When OB is removed, tag system 120B is disconnected from battery 170. The data stored in the volatile memory 730 in the tag system 120B is lost. For example, vehicle identification data may be stored in volatile memory 730. When battery power is reapplied, volatile memory 730 is initialized to indicate that tag system 120B was previously disconnected.

A car rental system using the vehicle information system 10 simplifies and automates the process of lending, returning, and paying for rental cars, especially in large facilities such as airports. Further, the number of personnel used in the rental place can be minimized. For example, it is possible to eliminate the number of personnel arranged at the exit of the rental area and reduce the number of personnel arranged at the lending and return reception.

In another embodiment, the vehicle 100 may be placed in a short parking lot dedicated to reservations, such as at an airport. The interrogator 300A is arranged in the sidewalk to the reserved parking place. When the borrower passes through the interrogator 300A, the interrogator is the driver tag system 1
It receives the data from 20A and determines which vehicle 100 to provide to the borrower. In order to determine which vehicle 100 was rented to the borrower, the interrogator 3
00A includes a display and / or speaker system that notifies the borrower of the location of vehicle 100.

Another interrogator 300 B next to the vehicle 100 is the driver tag system 120.
It receives a data packet from A and issues a key for vehicle 100. Also, the interrogator 3
00B allows the vehicle 1 to be started by using the key.
00 ignition device is activated. Reservation locations can be located around short and long parking areas and near rail, taxi and bus connections.

When the vehicle is returned to the reserved parking place, the interrogator 300B displays the VI as described above.
D data, mileage data and fuel level data are received from the tag system 120B and relayed to the central computer. The borrower leaves the vehicle 100 and approaches the interrogator 300B, where the tag of the borrower is read. The key box is opened and the interrogator 300B disables the vehicle ignition. After this, the key is placed in the box, the box is closed and the receipt is printed. The host computer 320 also notifies the person to collect the vehicle 100. This embodiment eliminates the need to board a shuttle flight when getting on and off the vehicle 100.

While the present invention has been illustrated and described herein with reference to particular embodiments,
The invention is not limited to the details shown here. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims without departing from the spirit of the invention.

[Brief description of drawings]

[Figure 1]   1 is a block diagram of a vehicle information system 10 according to an embodiment of the present invention.

FIG. 1A   FIG. 8 is a diagram of a shuttle flight including an interrogator 300A according to an embodiment of the present invention.

FIG. 2 is a block diagram of a vehicle 100 including a tag system 120B according to an embodiment of the present invention.

FIG. 3A   FIG. 6 is a block diagram of a tag system 120B according to an embodiment of the present invention.

FIG. 3B   6 is a flow chart useful in showing the operation of processor 205.

FIG. 4 is a diagram showing the contents of a message packet 400 transmitted from the tag system 120B according to the embodiment of the present invention.

[Figure 5]   FIG. 6 is a timing diagram showing Manchester encoding.

[Figure 6]   FIG. 6 is a block diagram of an interrogator 300B according to an embodiment of the present invention.

FIG. 7 is a timing diagram illustrating transmission of message packet 400 from various tag systems 120C-120E according to an embodiment of the invention.

FIG. 8 is a data diagram showing time intervals in which a message packet 400 is transmitted from the tag system 120B.

[Figure 9]   FIG. 9 is a block diagram of a processor 510 according to an embodiment of the present invention.

[Figure 10]   It is a timing diagram which shows operation | movement of the interrogator 505.

FIG. 11   6 is a timing chart showing the operation of the discriminator 510. FIG.

[Fig. 12]   It is a figure which shows the head of a frame sequence.

[Fig. 13]   It is a figure which shows the end of a frame sequence.

FIG. 14 is a diagram showing a format of an illegal Manchester code according to the prior art.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), AU, BR, C A, CN, JP, KR, MX (72) Inventor Shepps, Jonathan, Lloyd             New Jersey, United States             State, Princeton Junction,             Marblehead Drive 10 (72) Inventor Karokitis, David             New Jersey, United States             State, Robbinsville, Stephanie             Lane 4 F-term (reference) 5K004 AA01 BA02 BB01                 5K029 DD02 FF10 GG03 HH21 HH26                 5K030 HA08 HB28 HB29 JA05 JA10                       JL01 KA21 LA07 LA15 MC07                       MC09 [Continued summary] The end of the frame is the sequence "001000" Is.

Claims (23)

[Claims] 1. A means for Manchester coding a data value to generate a coded data value, a means for generating a first invalid Manchester coded sequence as a head of a frame signal, a head of the frame code and the coded data. A coding system comprising: a means for generating a transmission packet that sequentially includes values. 2. The method further comprising: means for generating a second invalid Manchester encoded sequence as the end of the frame code, and means for inserting the end of the frame code in the transmission packet after the encoded data value. 1. The encoding system according to 1. 3. A means for Manchester encoding a data value to generate an encoded data value, a means for generating a first invalid Manchester encoded sequence at the beginning of a frame code, and a second valid Manchester code at the end of a frame code. A coding system, comprising: a means for generating a coded sequence; and a means for generating a transmission packet that sequentially includes a head of the frame code, the coded data value, and an end of the frame code. 4. Receiving means for receiving a first Manchester coded signal sequentially including a first frame code head and a first coded data value, wherein the first frame code head is a valid Manchester code. And a means for detecting the head of the first frame code and determining the head of the first encoded data value in the first Manchester encoded signal. 5. The Manchester encoded signal includes a first frame code end following the first encoded data value, the first frame code end being a valid Manchester code, and the first frame code being the effective Manchester code. The decoding system according to claim 4, further comprising means for detecting an end to determine the end of the first encoded data value in the first Manchester encoded signal. 6. Receiving means for receiving a first signal including a first data value and a second data value different from the first data value, and counting when the first signal includes the first data value. Increase the value,
Counter means for decrementing the count value when the first signal includes the second data value, and generating a third data value when the count value is greater than or equal to a first threshold value, the count value Is a second threshold value or less, a data means for generating a fourth data value, and a signal generating means for generating a second signal including the third data value and the fourth data value. 7. Receiving means for receiving a first signal including a first data value and a second data value different from the first data value, and counting when the first signal includes the first data value. Increase the value,
Counter means for resetting a count value to a predetermined value when the first signal includes the second data value; and a clock for generating a clock synchronization signal when the count value is equal to or greater than a first threshold value. A discriminator comprising: a synchronization unit. 8. The data means for generating a third data value when the count value is equal to or greater than the first threshold value, and a fourth data value when the count value is reset. The discriminator according to 7. 9. A decoder comprising an integrator and a discriminator, the integrator comprising: (a) a first data value and a second data value different from the first data value;
Receiving means for receiving a signal; (b) incrementing a first count value when the first signal includes the first data value, and the first signal including the second data value First counter means for decrementing the first count value, and (c) generating a third data value when the first count value is greater than or equal to a first threshold value, and the count value is a second threshold value. The discriminator comprising: a data means for generating a fourth data value when: (d) a signal generating means for generating a second signal including the third data value and the fourth data value; (A) increases the second count value when the second signal includes the third data value, and increases the second count value when the second signal includes the fourth data value. Second counter means for resetting to a predetermined value; (b) the second Decoder count value contains a clock synchronization means for generating a clock synchronization signal when it is more than the third threshold value, the. 10. A vehicle information system for a vehicle, comprising:   A tag system that retrieves data from the vehicle and transmits the retrieved data,   An interrogator that simply receives the search data, Vehicle information system including. 11. The vehicle includes a battery having a voltage level, the tag system: (a) means for transmitting a message packet containing the search data at a speed; and (b) the voltage level. 11. The vehicle information system according to claim 10, further comprising: means for monitoring, and (c) means for changing the speed according to the monitored voltage level. 12. The search data is transmitted at a fixed average packet transmission rate,
The vehicle information system according to claim 10, wherein a time difference between transmissions of individual packets fluctuates randomly. 13. A vehicle information system for a vehicle, comprising: a data bus in the vehicle; a component for transmitting data on the data bus; simply searching for data from the data bus and transmitting the search data. A vehicle information system comprising: a tag system for controlling the interrogator and an interrogator for receiving the transmitted search data. 14. The search data is transmitted at a fixed average packet transmission rate,
14. The vehicle information system according to claim 13, wherein a time difference between transmissions of individual packets randomly changes. 15. A tag system for a vehicle having a component for generating vehicle-related data, comprising: means for retrieving the vehicle-related data; and means for transmitting the vehicle-related data. 16. The tag system according to claim 15, wherein the vehicle includes a data bus, and the tag system further comprises means for simply retrieving the vehicle-related data from the data bus. 17. A means for simply receiving vehicle-related data,   Means for processing said vehicle-related data, Interrogator equipped with. 18. A rental system for monitoring a rental vehicle, which is a tag system connected to the rental vehicle, searches a vehicle-related data, and transmits the vehicle-related data, and a transmission system for transmitting the vehicle-related data. A rental system that includes an interrogator that simply receives vehicle-related data. 19. The interrogator further comprises entry / exit means for generating a control signal in accordance with the transmitted vehicle-related data and controlling entry / exit to / from a rental site in accordance with the control signal. 18. The rental system described in 18. 20. A rental system for monitoring a rental vehicle, comprising: a data bus in the rental vehicle; a component for collecting data on the rental vehicle and transmitting the collected data; and a data bus for simply collecting the data from the data bus. A rental system comprising: a tag system for searching and transmitting the search data; and an interrogator for receiving the search data. 21. The interrogator further comprises entry / exit means for generating a control signal in accordance with the transmitted vehicle-related data and controlling entry / exit to / from a rental site in accordance with the control signal. Item 20. The rental system according to Item 20. 22. A data packet used in a vehicle information system, comprising:   (A) packet type data,   (B) packet sequence data,   (C) Vehicle information data,   (D) vehicle-related data, A data packet comprising. 23. (e) Additional data,   (F) error correction data, 23. The data packet of claim 22, further comprising: