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CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is related to co-pending applications Ser. No.
(94-1220) entitled "VEHICULAR EMERGENCY MESSAGE SYSTEM" and Ser. No.
(94-1223) entitled "VEHICULAR EMERGENCY MESSAGE SYSTEM WITH AUTOMATIC
PERIODIC CALL-IN", filed concurrently herewith.
BACKGROUND OF THE INVENTION
The present invention relates in general to a communication system that
provides an automated and simplified interface between a vehicle and an
emergency response center, and more specifically to controlling the
message system to place a second call to the response center using only
voice contact and bypassing data transmission via modem in the event that
a first data call is unsuccessful.
The use of transportation vehicles such as automobiles on roads and
highways inevitably involves some number of breakdowns or collisions, or
situations involving health difficulties of a driver or a passenger in
which roadside vehicle service, such as a tow truck, or emergency
assistance, such as police, ambulance, or fire, are needed. A means of
summoning help is desirable in such situations and the availability of
radio communications has been very beneficial in that regard. Cellular
telephones are often installed or carried in vehicles by their owners for
this reason.
The response time to a request for help should be minimized to meet any
potential need for critical services. Accurate information must be
provided to the emergency service provider to permit effective and timely
response. However, many cellular phone callers to emergency services are
unable to provide their location accurately in a timely manner. In
addition to position information, a service provider benefits from having
information on vehicle identification, cellular phone number of the
telephone in the vehicle, the cellular system identification from which a
call originated, and speed and heading of a vehicle.
Automatic position locating systems such as a global positioning system
(GPS) receiver have been utilized in conjunction with a cellular telephone
unit to provide position information over a cellular link (see U.S. Pat.
No. 5,043,736, for example). However, prior systems have failed to
adequately automate operation of a communication system to sufficiently
reduce the burden on the vehicle operator to follow a rigid operating
procedure or provide certain information to the service provider. Such
complexity has limited the effectiveness of such systems, especially when
the user is in a stressful emergency situation or unable to respond.
SUMMARY OF THE INVENTION
The present invention provides a positioning and communication system
having the advantage that a user need activate only a single button to
secure roadside or emergency assistance. The invention automatically
reverts to a voice mode from a data transmitting mode if a data call is
not completed on the first try, thereby allowing more reliable connection
over a cellular telephone network and the capability of providing the
needed assistance.
Specifically, the present invention provides a vehicular emergency message
system in a mobile vehicle for communicating with a response center. A
position locator receives reference broadcast signals and determines a
position of the vehicle. A cellular transceiver, such as a cellular phone,
has an audio input, an audio output, and a control input. A controller is
coupled to the position locator and the cellular transceiver for causing
the cellular transceiver to communicate with the response center in a
predetermined manner, wherein the controller operates in a wait mode, an
activation mode, and a communication mode. The controller includes a tone
detector for detecting a tone signals from said response center. The
system includes an activation unit coupled to the controller which is
responsive to a manual activation to send an activating signal to the
controller to place the controller in the activation mode.
The activation mode is comprised of 1) obtaining control of the cellular
transceiver through the control input in order to establish a
communication channel between the cellular transceiver and the response
center, 2) initiating a first call to the response center including the
initial transmission of audio signals responsive to a data output of the
controller for specifying a unique identifier code of the vehicle while
the audio output is muted, 3) detecting a failure of the first call in
response to tone signals received or not received during the first call,
and 4) initiating a second call to the response center if the first call
fails, the second call being comprised of an initial transmission and
reception of voice responsive to the audio input and the audio output
without muting.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing vehicle hardware and infrastructure
elements of a vehicle emergency message system.
FIGS. 2-4 show a flowchart describing operation of a vehicle apparatus in
the present invention.
FIG. 5 is a schematic block diagram showing the controller of FIG. 1 in
greater detail.
FIG. 6 illustrates a data string utilized in the present invention.
FIG. 7 is a table showing construction of the account block of FIG. 6.
FIG. 8 is a table showing construction of the event block of FIG. 6.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIG. 1, a vehicle emergency message system includes vehicle
hardware 10 and system infrastructure 11. Infrastructure 11 includes GPS
satellites 12 in earth orbit, a network of cellular towers 13 connected to
a land-line phone system 14. A response center 15 is connected to
telephone system 14 and provides a 24 hour monitoring service responsive
to messages and requests for assistance from registered users.
Vehicle hardware 10 includes a system controller 20 connected to a GPS
receiver 21 and a cellular transceiver 22. GPS receiver 21 is connected to
a GPS antenna 23 typically in the form of a radome, while cellular
transceiver 22 is connected to a cellular antenna 24. A cellular handset
25 is connected to cellular receiver 22 through system controller 20
thereby allowing system controller 20 to control cellular transceiver 22
and access the audio signal transmissions of transceiver 22.
System controller 20 interacts with a user (i.e., the driver or a passenger
of the vehicle) through a switch assembly 26 and a display message center
27. Switch assembly 26 preferably includes two push buttons for activating
the vehicle emergency message system according to the type of assistance
that is needed, thereby allowing the response center to prioritize
incoming requests. Preferably, the two push buttons identify either a
request for roadside assistance (i.e., vehicle mechanical trouble) or
emergency assistance (i.e., a medical condition or a crime in progress).
Switch assembly 26 may preferably be mounted to an overhead console in a
vehicle, for example. Display message center 27 is preferably mounted to
an instrument panel of the vehicle and provides an alphanumeric display
(e.g., an LED matrix or a vacuum fluorescent display) to show system
status and to display system information as will be described below.
Transceiver 22 operates in either a handset or a hands-free mode. A
hands-free microphone 28 is mounted in the vehicle and connected to
transceiver 22. A hands-free speaker 29 can be connected directly to
transceiver 22 or may be connected through the vehicle audio system 30
(i.e., the amplifier and speakers of the vehicle audio/radio system can be
employed as the hands-free speaker for the cellular phone).
Operation of vehicle hardware 10 will be described with reference to the
flowchart of FIGS. 2-4. In general, hardware operation is characterized
herein by four operating modes; a power-up mode, a wait mode, an
activation mode, and a communication mode. The power-up mode includes the
performance of system diagnostics to determine if component failures
exist. The wait mode includes the updating of vehicle position information
while waiting for a manual activation by the user. The activation mode
includes the assembly of data for transmission to the response center,
dialing of the cellular phone to establish communication with the response
center, and detection of a successful connection. In the communication
mode, digital data may be sent to the response center and voice contact
between the user and the response center is established.
Referring to FIG. 2, the power-up mode begins when the vehicle ignition
switch is turned on in step 35. A self-diagnostic check of the vehicle
emergency message system (VEMS) components is run in step 36 and
preferably includes GPS diagnostics, cellular phone diagnostics, and
activation switch diagnostics. If any fault condition is detected that
prevents proper operation of the system, then a message such as "SYSTEM
FAILURE" is displayed in the message center in step 37. An indicator light
may be provided, e.g., mounted on switch assembly 26, that is illuminated
during power-up diagnostics at the beginning of step 36 and is
extinguished in the event that all diagnostic tests are passed at the end
of step 36. Step 37 bypasses the turning off of the indicator light so
that it remains lit as a reminder that a fault has been detected.
Following the diagnostic tests, an automatic call-in procedure may be
optionally utilized during the power-up mode. In step 38, a check is made
whether a predetermined duration of time (e.g., preferably at least six
months) have passed since the last time that VEMS 10 was connected to the
response center. If at least six months have passed, then an automatic
call-in is performed in step 39. The automatic call-in to the response
center helps assure that the system is functioning properly and that a
user's cellular account is active. If the response center has not received
an automatic call-in from a particular vehicle within a predetermined time
after the six month period, then the response center can send a reminder
to the vehicle owner to have their system checked.
After the power-up mode, system 10 enters the wait mode and waits for a
manual activation of the switch assembly in step 40. While in the wait
mode, system 10 obtains periodic position updates from the GPS receiver in
step 41. Position may be updated at one second intervals, for example. In
addition to position, each update includes an updated time (i.e.,
time-of-day and date) and vehicle direction and speed (as determined by
doppler effects on the received GPS satellite signals provided the vehicle
is moving at at least about 15 MPH). The most recently obtained valid
position in longitude and latitude, together with the time it was
collected and the last obtained vehicle heading and speed information, are
stored in a memory in system 10. Thus, system 10 is able to provide the
response center with the most recently collected valid position of the
vehicle and the direction it is or was most recently heading. The GPS
receiver may be momentarily unable to determine position in the event that
obstructions are preventing reception of GPS signals at the time the call
for assistance is made. If system 10 is unable to collect GPS readings for
greater than a predetermined period of time, it may be desirable to
indicate a failure to the user via the message center or an indicator
light, and to store an indication of the failure in memory as a diagnostic
code.
In step 40, the controller polls the manual activation buttons in the
switch assembly to detect a manual activation. The switch assembly
preferably provides a roadside assistance (RA) button labeled with a
tow-truck and an emergency assistance (EA) button labeled with an
ambulance, for example. When the user presses either button, an RA signal
or an EA signal is generated which places system 10 in the activation mode
and causes a message, such as "ROADSIDE REQUEST" or "EMERGENCY REQUEST",
to be displayed.
In step 42 of the activation mode, the controller formats a data string to
be transmitted to the response center using a modem signal via the
cellular transceiver. The data string includes customer identification,
position, and other information as will be described below. In step 43,
the controller wakes-up (i.e., activates, if necessary) and establishes
control of the cellular transceiver. If the controller is not successful
in obtaining control of the cellular phone, then a message is displayed,
such as "SYSTEM FAILURE", and the attempt to make a call aborted with a
return to point A. If the cellular phone is active and in use, step 43 may
include terminating an existing call so that the response center can be
contacted. In step 45, the VEMS controller verifies whether cellular
service is available in the area where the vehicle is located (i.e,
whether the cellular transceiver can establish communication with a
cellular tower). If cellular service is not available after attempting to
establish a connection for a certain time (e.g., up to two minutes), then
a message such as "NO CELLULAR SIGNAL" is displayed in step 46 and a
return is made to the wait mode via point A.
In the event that cellular service is available, the controller causes the
cellular transceiver to dial a first number to the response center while
the hands-free audio of the phone is muted in step 47. Two separate
numbers to the response center are preferably utilized wherein the first
number connects to an automated data receiver for receiving digitally
transmitted information via modem prior to connecting the user with a
human operator. A second number bypassing the automated data reception and
connecting directly to the human operator is used in some circumstances as
will be described below. In the first call, however, the automated
transmission of data is attempted and the audio outputs of the phone are
muted in the vehicle so that modem signals are not heard by the user.
Preferably, the system controller maintains full, uninterruptible control
over the cellular transceiver during this first call to ensure a reliable
connection with the response center in the majority of instances.
Upon connection with the automated data receiver at the response center, a
handshake signal is sent from the response center using a tone at a
predetermined frequency. System 10 attempts to detect a handshake tone and
if one is received in step 48 then a jump is made to the communications
mode at point C (as will be described below with reference to FIG. 4). If
a handshake signal is not received in step 48, then the activation mode
continues at point B in FIG. 3.
After point B, a command to end any pending call is sent to the cellular
transceiver in step 49. In response to the failure to receive a handshake
signal, a call attempt counter is incremented in step 50 (this counter
should equal 1 after a failure during the first call).
In step 51, the failure counter is checked to determine whether greater
than a predetermined number of attempted calls have occurred, e.g., 4. If
yes, then a message is displayed in step 52 such as "UNABLE TO PLACE CALL"
and a return is made to the wait mode at point A. If less than the maximum
number of attempted calls have occurred, then a recheck for availability
of cellular service is performed in step 53. If cellular service is not
obtained within two minutes, then a message is displayed in step 54 such
as "NO CELLULAR SIGNAL" and a return is made to the wait mode at point A.
Otherwise, the controller causes the cellular receiver to dial a second
number to the response center in step 55. In the call to the second
number, which is a voice number that bypasses the data receiver at the
response center, the cellular phone is placed in hands-free mode and is
unmuted to allow conversation between the user and the operator at the
response center. Unlike during the first call, the user has full control
over the cellular phone via the handset during the second call to provide
maximum flexibility in unusual circumstances.
In an alternative embodiment, only one attempted call is made to the second
number. In that case, it is not necessary to maintain a call attempt
counter. A return to the wait mode is made if the second call fails to
reach the response center on its first try.
An important reason to conduct the second call to a second number and
having the hands-free phone audio unmuted during the second call, is that
if the user is outside his home cellular phone area (i.e., is "roaming")
an operator for the cellular system to which the user connects may come
on-line to request credit card or other information before completing a
cellular call. By unmuting the phone, not automatically transmitting the
data during a second call, and relinquishing control of the cellular phone
to the user, the user can interact with the cellular operator to obtain a
phone connection to the response center. The response center can still
then obtain the digital data using a retransmit tone as described below.
If the cellular phone detects a failure to establish a cellular connection
after dialing the second number, then the failure is detected by the
controller in step 56 and a return is made via point B to step 50 for a
possible redial to the second number. If dialing the second number is
successful as detected in step 56, then the system is placed in the
communication mode via point D.
Operation of system 10 in the communication mode is shown in FIG. 4. After
successful connection to the first phone number at point C, the data
string that was previously formatted is sent to the response center via
modem in step 60. Upon successful reception of the data at the response
center, the response center produces an acknowledgement tone at a
predetermined frequency. System 10 checks for receipt of the
acknowledgement tone in step 61. If no acknowledgement tone is received,
then a check is performed in step 62 to determine whether to try to resend
the data string. For example, a maximum of four attempts to send the data
string may be performed. If less than the maximum number of tries have
been attempted, then a return is made to step 60, otherwise a return is
made to the activation mode at point B for attempting to connect to the
second phone number without data transmission. If an acknowledgement tone
is received to the data string, then the cellular phone is unmuted in step
63 to provide two-way audio and voice contact is made with the response
center after the call is transferred to a live operator. In addition, at
least some of the information from the data string is displayed on the
message center in step 64. During the first call, this information may be
used to confirm the data already sent to the response center.
If the communication mode is entered at point D following a call to the
second (non-data) phone number, then the information from the data string
displayed on the message center in step 64 preferably includes an
identification of the user (e.g., a customer ID) and the last obtained
position from the GPS receiver displayed in latitude and longitude. As
this information is displayed in step 64, the response center can obtain
the displayed information by having the user read it over the cellular
communication channel.
During voice contact with the response center, the system controller in the
vehicle monitors the communication channel for tone signals transmitted by
the response center. In step 65, the communication channel is monitored
for a retransmit tone indicating a request by the response center for the
vehicle to resend the data string. A new, updated data string is formed
and then transmitted in step 66. Thus, the response center may obtain the
data in the data string even though the first data call may have been
unsuccessful. Also, the response center can obtain updates to the
information as a call is in progress, such as where the vehicle continues
to move during the emergency.
The controller likewise monitors the communication channel for a
termination tone in step 67. The response center will send a termination
tone when a successful resolution has been reached in the call for
assistance (e.g., a service provider has been dispatched to the scene).
Upon detection of the termination tone, the controller sends an end-call
command to the cellular phone and stores the current time in memory to
replace the time of last successful connection with the response center in
step 68. Then a return to the wait mode is made at point A.
In step 69, if the cellular transceiver detects that a call has ended;
either intentionally or because of loss of the cellular carrier signal, it
sends a signal to the controller indicating an end of call, otherwise the
communication channel continues to be monitored for retransmit or other
tones.
In response to premature ending of the call in step 69, the controller may
preferably return to point B in the activation mode for a possible attempt
to reconnect the user with the response center. In an alternative
embodiment as shown in FIG. 4, an attempt to automatically reconnect is
made only if it was the first call that ended prematurely. Thus, step 70
checks whether the call was the first call. If it was the first call, then
a return is made to point B for a second call. If it was not the first
call, then a return is made to the wait mode at point A.
FIG. 5 shows system controller 20 in greater detail. A control block 75
such as a microprocessor is connected to a modem 76 and a memory 77.
Control block 75 is connected to GPS receiver 21, handset 25, and switch
assembly 26. Control block 75 is further connected to cellular transceiver
22 via a control bus 80. Control signals that are exchanged between
control block 75 and cellular transceiver 22 via bus 80 include a mute
control signal, a phone in-use signal, and control signals to place the
cellular transceiver into a desired configuration and to command certain
actions such as dialing of supplied phone numbers. Furthermore, control
signals from handset 25 may be passed through control block 75 to
transceiver 22 during normal phone operation.
A handset audio input of transceiver 22 is connected to an output of modem
76 and to an output of handset 25 allowing a modem audio output to be
input to the cellular transceiver. The handset microphone may be
inactivated during modem output using the control line between control
block 75 and handset 25. The handset audio output of transceiver 22 is
connected to an input of modem 6 and to an input of handset 25. Modem 76
includes tone detector circuits comprising narrow bandpass filters and
level detectors responsive to the predetermined tones that may be
transmitted by the response center. For example, a termination tone of
2,025 Hz and a retransmit tone of 2,225 Hz and each having a duration of
about 1 to 1.4 seconds are employed in a preferred embodiment. Of course,
any frequency within the audio range of the cellular transceiver can be
employed. Upon detection of a particular tone, a signal is provided to
control block 75 such as a retransmit signal, an acknowledgement (ACK)
signal, a negative acknowledgement (NACK) signal, or a termination signal.
Memory 77 stores data such as the first and second phone numbers to the
response center, the last GPS position longitude and latitude, time-of-day
and date of GPS position, time-of-day and date of last connection with the
response center, a customer identification code, any diagnostic codes
detected during system diagnostics, and other information. Control block
75 utilizes data from memory 77 in formatting a data string for
transmission. In addition, information such as the cellular telephone
number of the cellular phone and any identification of the cellular
carrier to which the cellular phone is currently connected are obtained
from transceiver 22 for inclusion in the data string.
Switch assembly 26 includes a roadside assistance pushbutton 81 and an
emergency assistance pushbutton 82 for providing signals RA and EA,
respectively, to control block 75.
Message center 27 is connected to control block 75 over a bus 83. Message
center 27 is shown as a matrix display capable of displaying alphanumeric
characters in a 3.times.8 matrix.
Data communications between controller 20 and the response center will be
described in greater detail with reference to FIGS. 6-8. Data
communications are preferably in conformance with Section 3 of the Digital
Communications Standard by SIA, February, 1993.
FIG. 6 illustrates the contents of the data string assembled for
transmission. The data string includes an account block 85, an event block
86, one or more ASCII blocks 87 and 88, and a zero block 89. Each block is
transmitted separately by the modem.
Account block 85 is the first block to be sent and is used to pass the
customer identification number (CID) stored in memory that may be assigned
based on the identity of the vehicle. Thus, the response center
automatically retrieves information on the identity of the vehicle and the
owner involved in the request. The account number may preferably have an
assigned unique identifier code based on the vehicle identification (VIN)
number given to a vehicle at the time of manufacture. Some subset of the
full VIN number may be used if the CID has less characters than the VIN.
Event block 86 is the second block to be sent and is used to pass
information concerning the type of request (i.e., either roadside
assistance or emergency assistance) and time-of-day and date information.
ASCII blocks 87 and 88 are transmitted after event block 86 and include
additional information such as latitude and longitude position, vehicle
heading, vehicle speed, dilution of precision (DOP), cellular phone
number, cellular system identification, and any diagnostic codes logged
into the memory.
The last block to be transmitted is the zero block which marks the end of
the data and which requests acknowledgement from the response center to
receipt of the data.
Each block is constructed with a header byte, a function byte, data bytes,
and a column parity byte. FIG. 7 shows an example of the construction of
an account block. The header byte includes a reverse channel enable (RCE)
bit, and acknowledge request (AR) bit, and block length (BLen) bits. As
defined in the SIA document referred to above, the RCE bit serves to
identify the beginning of a block. The AR bit tells the receiver at the
response center whether to acknowledge receipt of a particular block. In a
preferred embodiment of the present invention, only the account block and
the zero block request acknowledgement. The value of the BLen bits
specifies the number of data bytes being transmitted in the block. A shown
in FIG. 7, the binary value of RCE is always zero. The binary value of AR
is one since the account block requests acknowledgement. The binary value
of BLen of "1010" corresponds to the length of the CID data field equal to
10 in decimal. The hexadecimal and ASCII values of the block are also
shown in FIG. 7, with the exception of column parity (CPar) values which
are not shown but are within the skill of the art to derive. A function
code of "#" in ASCII is shown identifying that the block is the account
block.
FIG. 8 shows an example of a construction of an event block. The function
code for the event block identifies the position information in a request
as new ("N") GPS data or old ("O") GPS data. The data in the event block
specifies the date and time-of-day of the last valid GPS position and also
identifies the type of event causing the data to be transmitted. Thus, an
event code is specified for an emergency assistance request, a roadside
assistance request, a follow-up or retransmission of data in response to a
retransmit tone, and an automatic (6 month) call-in. In a preferred
embodiment, an event code "QA" identifies emergency assistances "QS"
identifies roadside assistance, "YY" identifies a follow-up transmission,
and "RP" identifies an automatic call-in.
As shown in FIG. 8, data fields in the blocks may include alphanumeric
characters to identify data within a block, such as "da" prior to the date
and "ti" prior to the time-of-day in the data field of FIG. 8. These
identifiers are provided in the event that the operator at the response
center needs to view the transmitted data directly because of an equipment
failure at the response center.
The ASCII blocks contain the remaining information to be transmitted as
described above (e.g., latitude, longitude, heading, speed, DOP, cellular
phone number, and cellular system ID). In addition, the ASCII blocks may
transmit information on the revision or version of the vehicle hardware
and software installed in the vehicle or diagnostic failure codes.
Although global position system (GPS) and cellular technologies have been
described in the preferred embodiment, other positioning and communication
technologies could be used in the present invention. For example, position
information could be obtained from the Loran-C system or other navigation
systems. A communication system such as the personal communication service
(PCS) could also be used. In addition to activating the vehicle emergency
message system from any manual switch assembly, service requests could
also be initiated automatically, such as in response to deployment of an
airbag.
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