Personal security system

A fully automatic personal security system which combines the advantages of worldwide LORAN-C or GPS navigation with the substantially worldwide communication capabilities of a cellular telephone or communication satellite. The security system comprises a mobile unit which communicates emergency data including position coordinates, and a central dispatch station which receives the emergency data and accurately displays all necessary emergency information superposed on a digitized map at a position corresponding to the location of the mobile unit.

BACKGROUND OF THE INVENTION 
1. Field of the invention 
The present invention relates generally to a security system for protecting 
vehicles and, more importantly, the people travelling therein. In 
particular, the present invention is a device for expediting a response by 
the appropriate authorities whenever and wherever the personal security of 
a mobile person is compromised. The device includes a mobile communication 
unit and a central station. The mobile communication unit is transported 
with the mobile person and is triggered by the occurrence of a variety of 
personal security conditions to establish cellular telephone contact with 
the central station. The mobile communication unit then communicates 
longitude and latitude coordinate acta, emergency, ana personal 
information to the central station. All pertinent information is 
conveniently displayed to an operator at the central station in a manner 
which permits the most efficient dispatching possible of the proper 
responding agents to administer the proper security measures. 
2. Description of the Background 
Considering this nation's widespread uprise in violent crimes, a person 
compromises his or her personal security each and every time he or she 
undertakes travel. The threat to personal security is most appreciable 
when the travel is by motor vehicle. Our public highways are becoming more 
congested and the frequency of roadside emergency situations is likewise 
increasing. 
Emergency situations may arise as the result of an accident or vehicle 
breakdown. The emergency may be compounded by inclement weather, a lack of 
communication ability, a disabling injury, etc. For the duration, the 
motorist is completely prone to theft or violent attack. It follows that a 
prompt emergency response from police, paramedics, the fire department, or 
other service organization is essential for maintaining personal security. 
Generally, a vehicle operator must find the nearest accessible telephone, 
dial an emergency number, and attempt to provide landmark or navigational 
data for the benefit of the authorities. These tasks are difficult when 
performed under the stress of an emergency, and they can be impossible 
where a disability or injury exists. 
Cellular telephones provide a partial solution in the form of a convenient 
communication link to authorities in times of emergencies. For this 
reason, cellular car phones are now widely considered to be a prerequisite 
for personal security. 
Unfortunately, a cellular telephone only provides the communication link. 
It will not of itself perform the task of communicating. This task is left 
to the vehicle operator. Consequently, the operator must perform the 
following tasks: 
1. remember the telephone number of the proper authorities or service 
providers; 
2. dial the number; and 
3. convey landmark or navigational data to direct the respondents to the 
site. 
The time it takes to complete the above-described tasks needlessly 
jeopardizes the personal security of the operator. This is especially true 
when the operator has no idea of his or her location and cannot provide 
the requisite navigational data and/or emergency situation information to 
the authorities. More often, the instructions and information provided are 
inaccurate, misleading, or misunderstood. 
A number of prior art devices have been proposed for automating the 
dispatch of the proper authorities to a vehicle in an emergency situation. 
For example, U.S. Pat. No. 3,568,161 issued to Knickel discloses a vehicle 
locator system comprising a network of sensors tied to a central command 
station. A vehicle travelling amidst the sensors emits a code to the 
sensors which is indicative of the identity of the vehicle. The code is 
received at the nearest sensor station, which in turn signals the central 
command station that it has received the code. The location of the vehicle 
is then displayed at the central station. The central command station 
includes a display panel with a number of lights placed on a map at 
locations corresponding to each sensor. 
U.S. Pat. No. 4,596,988 issued to Wanka likewise discloses a remote-control 
tracking transmitter and tracking support network of remote stations. As a 
vehicle passes through the network, the vehicle communicates with a remote 
station. The remote station in turn transmits location data to a base 
station which plots the location on a map plotter. 
U.S. Pat. No. 4,904,983 issued to Mitchell discloses a theft alarm system 
for vehicles including an alarm sensor, an auto-dialing mechanism, and a 
cellular telephone. The alarm sensor activates the auto-dialing mechanism 
to seize the cellular telephone and dial a central station. A recorder 
then broadcasts a two-part message over the cellular telephone. The 
message includes fixed information relating to the identity of the 
automobile and variable information relating to the location of the 
automobile. The variable information may be input by the operator through 
a microphone when the vehicle is to be left unattended. 
U.S. Pat. No. Re. 32,856 issued to Millsap et al. discloses an alarm system 
in which an alarm condition causes a cellular transceiver to automatically 
transmit a telephone call to a central station. The invention incorporates 
a cellular telephone link in a fixed alarm system. The use of a cellular 
telephone eliminates the need for telephone lines. Hence, cutting of the 
telephone lines will not result in negation of the alarm signal. A circuit 
is also shown for determining a particular zone in which the alarm 
condition exists and for transmitting alarm information to the central 
station via the cellular telephone. 
In addition to the above-described alarm systems, a number of improvements 
have been developed for particular components of the alarm systems. 
For instance, U.S. Pat. No. 3,683,114 issued to Egan et al. discloses an 
automatic dialing and reporting system which is responsive to an alarm 
condition. The Egan et al. device seizes a telephone line and initiates 
automatic transmission over the telephone line. 
U.S. Pat. No. 4,428,057 issued to Setliff et al. discloses an electronic 
system for use in a marine environment. The system includes a plurality of 
digitized maps which are stored in a database for display on a video 
terminal. "The purpose of this invention is to provide a more efficient 
use of the operator's time by automatically correlating and monitoring the 
data" (Column 1 lines 55-57). The displayed map may be compressed or 
expanded to meet the demands of the operator. In addition, a LORAN-C or 
other positioning device may be coupled to the system and the LORAN-C 
coordinate data may be correlated and displayed at the proper location of 
the map. 
Despite the above-described improvements in the field of tracking and 
navigation, it is important to note that the prior art generally teaches 
the protection of chattels as opposed to people. For example, the prior 
art devices will prevent theft, tampering, and other encroachments on 
property interests, and they will provide information on a vehicle. 
However, the prior art does not adequately protect the personal security 
interests of the passenger(s). 
More specifically, too much effort is required of the passenger in an 
emergency situation and too little information is provided to the 
authorities to insure a prompt and efficient response. Personal security 
demands a fully automated yet economical system for summoning an emergency 
response in accordance with the specific personal needs of the individual. 
SUMMARY OF THE INVENTION 
It is, therefore, an object of the present invention to provide a personal 
security system which quickly and accurately provides a central dispatch 
operator with emergency information displayed on digitized map in a format 
which allows efficient dispatching of emergency assistance to a mobile 
person(s). 
It is another object of the present invention to provide the central 
dispatch operator with personal information as well as vehicle-specific 
information for all potential operators of the vehicle. 
It is another object of the present invention to provide a fully automatic 
personal security system and communication protocol which is operative 
under the most severe circumstances to automatically summon an emergency 
response in accordance with the specific personal needs of the mobile 
person. 
It is still another object of the present invention to provide a personal 
security system as described above which may be operated under less severe 
circumstances to allow the mobile person to manually summon road service 
or other assistance. 
It is another object of the present invention to provide a personal 
security system as described above which allows the central dispatch 
operator to selectively establish two-way voice contact with the mobile 
person and which gives the central dispatch operator remote control over 
various functions of the vehicle. 
It is yet another object of the invention to combine the advantages of 
long-range navigation systems such as LORAN-C or Global Position Satellite 
(GPS) with the extensive communication capabilities of a cellular 
telephone or communications satellite to yield a practical personal 
security system with the above-described emergency assistance 
capabilities. 
According to the present invention, the above-described and other objects 
are accomplished by providing a method for dispatching help to a mobile 
entity. The method comprises the steps of storing an identifier in a 
mobile unit, outfitting a mobile entity with the mobile unit, storing 
identification information relating to the mobile entity at a central 
station, activating the mobile unit upon occurrence of an alarm condition 
to determine a position of the mobile entity and to generate a code 
indicative of the alarm condition, the identifier, and the position of the 
mobile entity, transmitting the code to a central station, and processing 
the code at the central station to display the position of the mobile 
entity on a digitized map. The alarm condition and identity of the mobile 
entity are superposed on the map at a point corresponding to the location 
of the mobile entity. 
In addition, an apparatus for monitoring a mobile entity in accordance with 
the above-described method is disclosed. The apparatus comprises the 
mobile unit, which further includes a programmable memory containing 
identification information characteristic of the mobile entity, a keypad 
for allowing manual entry of various help requests, a LORAN-C receiver for 
providing position information, and a processor connected to the 
programmable memory, to the push buttons, and to the LORAN-C receiver. The 
processor is activated upon occurrence of an alarm condition to input 
position coordinates from the LORAN-C receiver, and to compose a digital 
code corresponding to the alarm condition, to the identification 
information, and to the position coordinates. The mobile unit also 
includes a cellular telephone or other communication device (such as a 
communication satellite) connected to the processor through a first 
communication circuit which communicates the digital code to a central 
dispatch station via the cellular phone. A central dispatch station is 
also disclosed. The central dispatch station comprises a second 
communication circuit for receiving the digital code from the mobile unit, 
a programmable memory containing identification information relating to 
the mobile entity, a processor connected to the second communication 
circuit and memory for decoding the digital code, and for correlating the 
position of the mobile entity to a point on a digitized map, and a video 
display connected to the processor for displaying the digitized map with 
the alarm condition and identification information superposed at the 
appropriate point. 
It should be noted that the invention is not limited to the security of a 
motorist. Rather, the invention can be employed with any type of vehicle, 
including boats and planes. Further, the invention is capable of 
protecting the security of pedestrians, animals, and inanimate objects. 
The invention can pin-point the location of anything capable of carrying a 
mobile unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1, a personal security system according to the 
present invention generally includes a mobile security assembly 30 which 
is transported along with a mobile person. Mobile security assembly 30 is 
shown in FIG. 1 to be incorporated in an automobile 20. Alternatively, 
mobile security assembly 30 may be incorporated in any other type of 
vehicle, or may be hand-carried by a pedestrian. 
The personal security system also includes a central dispatch station 40 
which is manned by a central dispatch operator. 
In general operation, the mobile security assembly 30 is automatically 
triggered by the occurrence of a variety of personal security conditions 
or is manually operated to initiate contact with the central dispatch 
station 40. Once a communication link is established, the mobile security 
assembly 30 communicates a hierarchy of longitude and latitude coordinate 
data, as well as emergency and personal information to the central 
dispatch station 40. The information is conveniently displayed to the 
dispatch operator. 
It is the combination of the coordinate data hierarchy and the automatic 
communication protocol, as well as the specific content of the information 
and the unique format in which it is displayed at central station 40 which 
allows the operator to dispatch the proper responding agents. The response 
is more efficient, more accurate, and it is based on foreknowledge of the 
proper security measures to be taken. 
As shown in FIG. 2, the mobile security assembly 30 further includes a 
mobile unit 32 which may be mounted in the dashboard of the automobile in 
much the same manner as a conventional AM/FM radio. The anterior of mobile 
unit 32 includes a plurality of push buttons 33, indicator lights 35, 
alphanumeric display 34 and contrast adjustment knob 31, and a data 
keyslot 38 which receives a personal identification key 36. 
The push buttons 33 are used to manually initiate and confirm specific help 
requests or a self-test. 
Data keyslot 38 and personal identification key 36 provide information 
regarding the identity and characteristics of the mobile person. Personal 
information such as name and personal account number is digitally stored 
in a memory which is resident on the key 36. This personal information is 
read by the keyslot 38 when key 36 is inserted therein. A wealth of 
supplemental personal information may also be stored directly on key 36 or 
may be stored in a central dispatch station 40 database. The supplemental 
personal information may include social security number, names of 
relatives to contact in an emergency, special medical needs, and/or 
medical records, etc. 
In addition to the personal information stored on key 36, system-specific 
information such as the serial number of the mobile unit 32 is stored in a 
memory which is resident in mobile unit 32. Supplemental vehicle-specific 
information such as the vehicle identification number, make, model, color, 
etc., may likewise be stored in mobile unit 32 or in a central dispatch 
station 40 database. 
It is essential to the invention that personal, system and/or 
vehicle-specific data are made available to the central dispatch operator 
regardless of the many potential operators of the vehicle. The personal 
identification key 36 is an innovative solution. The quality of the 
combined information and the manner in which it is displayed at central 
dispatch station 40 allows the dispatch operator to coordinate a prompt 
and comprehensive response to any personal security situation which may 
befall the mobile person. The response capability is far superior to any 
existing security system. 
FIG. 3 is a block diagram of the mobile security assembly 30 of FIG. 1. In 
addition to mobile unit 32, the assembly includes a cellular telephone 60 
and a plurality of remote sensors 41 each connected to the mobile unit 32. 
Cellular telephone 60 may be any conventional cellular telephone. It should 
be appreciated by one skilled in the art that other types of communication 
devices such as satellite transceivers may perform the function of the 
cellular telephone 60 and may easily be substituted therefor. Hence, the 
present invention should not be construed as limited to a cellular 
telephone. 
Remote sensors 41 automatically initiate specific help requests upon 
detecting various alarm conditions. For instance, remote sensors 41 may 
include smoke or heat detectors for detecting a fire within the vehicle, a 
tamper switch or motion detector for detecting a possible theft of the 
vehicle, an impact detector for detecting a collision, a sensor for 
detecting activation of a vehicle air-bag, and any of numerous other 
sensor types for automatically detecting a wide variety of personal 
security situations. The above-described and many other sensors are 
well-known in the art and commercially available. 
In the preferred embodiment of mobile unit 32, there are six push buttons 
33 which are mounted on the face of mobile unit 32. These allow the mobile 
person to manually enter and confirm that a personal security situation 
has arisen. Push buttons 33 are conventional momentary switches 
(preferably touch-sensitive). Four of the push buttons 33 are dedicated to 
each of four common types of emergency assistance, i.e., fire, paramedics, 
police, and roadside service and are clearly labeled with the specific 
type of assistance. In addition, one of the push buttons 33 is marked 
"ENTER" and is provided to confirm the use of the emergency push buttons. 
This dual-entry convention insures that the emergency push buttons are not 
inadvertently depressed. Alternatively, if a single-entry convention is 
desired, the "ENTER" push button can be configured to cancel the use of an 
emergency push button within a predetermined amount of time. Finally, the 
sixth push button is marked "TEST" and is provided to initiate a self-test 
of the mobile security assembly 30. 
Mobile unit 32 includes a display 34, which is preferably a liquid crystal 
display (LCD) for displaying messages to the mobile person. A contrast 
adjustment knob 31 is mounted proximate to the display 34. 
A panel of indicator lights 35 is provided under push buttons 33 to 
indicate which of the push buttons have been depressed. In addition, an 
optional piezoelectric element or other audible signal may be incorporated 
to sound when a push button has been depressed. 
Keyslot 38 is also mounted on the face of mobile unit 32 for convenient 
insertion of personal identification key 36. As explained, both are 
commercially available data entry components. For instance, 
Keyceptical.RTM. KC4210PCB and Serial Data Key.RTM. DK4000 by Datakey.RTM. 
may be used. Up to 512 bytes of personal information may be stored 
directly on the personal information key 36. At a minimum, the name and 
personal account number are stored to identify the mobile person. 
The general method of operation of the personal security system is 
described as follows. 
Mobile unit 32 remains in a stand-by mode at all times before the personal 
identification key 36 has been inserted in keyslot 38. While in stand-by 
mode, mobile unit 32 remains partially operational and continuously polls 
remote sensors 41 to detect vehicular security conditions. Position 
locator 70 also remains on during stand-by mode and communications through 
cellular telephone 60 to central dispatch station 40 may be established. 
Hence, the location of the vehicle can be monitored at all times at 
central dispatch station 40. However, the push buttons 33 are disabled in 
stand-by mode. 
A person entering the vehicle must first insert a personal identification 
key 36 in order to fully activate the mobile security assembly 30. When 
key 36 has been inserted, digitally encoded personal information is 
automatically read from the key 36 and is stored within mobile unit 32 for 
subsequent communication to the central dispatch station 40. The manual 
push buttons 33 become operational and mobile unit 32 enters full security 
mode. 
When in full security mode, a help request may be entered manually at push 
buttons 33 or may be automatically detected at a remote sensor 41. In 
either case, the mobile unit 32 dials the telephone number of central 
station 40. When a cellular communication link is established, the mobile 
unit 32 transmits an array of digitally encoded data. The transmitted data 
is received by central dispatch station 40. The central dispatch station 
40 processes the data and displays all pertinent information to a dispatch 
operator. The information is displayed in the form of a quickly 
recognizable symbol such as a shield (for police), a fire (for the fire 
department), a cross (for medical assistance), or a tow-truck (for 
roadside service). The symbol appears superposed on a digitized map at a 
position which corresponds to the location of the mobile entity. Both the 
vehicle-specific and personal information is displayed adjacent to the 
symbol. Central dispatch station 40 provides a zoom function to allow the 
operator to reduce or enlarge the specific area of the digitized map in 
which the emergency symbol appears. For instance, the dispatch operator 
may begin with a general map of the United States and the emergency symbol 
would indicate a state in which an emergency has occurred. The dispatch 
operator may then zoom in on a particular city, then area, and finally, 
the street on which the mobile entity 20 is proceeding. It has been found 
that these display capabilities greatly assist the dispatch operator in 
directing the proper authorities to the exact location of the vehicle for 
emergency assistance. 
An important feature of the personal security system is a voice mode which 
allows the operator of the central dispatch station 40 to switch from 
digital (serial) communication to voice communications at any time. In 
voice mode, the operator can provide essential instructions to the mobile 
person prior to the arrival of the responding agents, or the operator can 
query the mobile person to acquire any additional information which may be 
useful. Voice mode is a useful feature when the mobile person signals a 
need for service. The central dispatch operator can further determine the 
appropriate type of service. 
Another important feature is tone recognition which can be utilized while 
in voice mode to give the central dispatch operator direct control over 
selected vehicle functions. By depressing touch-tone telephone 48 keys 
while in voice mode, the central dispatch operator can sound various 
tones. The mobile unit 32 is provided with the capability of recognizing 
these tones and controlling various vehicle functions in accordance 
therewith. This feature is extremely useful in an emergency when, for 
instance, the vehicle 20 is obscured. Electromagnetic, visual or audible 
signals can be emitted to help the responding authorities locate the 
vehicle and mobile person. Also, if tampering with the vehicle is detected 
by one of the remote sensors 41, the microcontroller 310 or operator of 
the central dispatch station 40 can activate one of the relays in actuator 
bank 50 to sound the vehicle horn, illuminate the headlights, etc. If an 
actual theft is detected, the dispatch operator can immediately cut power 
to the engine. 
FIG. 4 shows a detailed block diagram of the mobile security assembly 30 
which illustrates the internal circuitry of the mobile unit 32. The 
internal circuitry includes a microcontroller 310 which receives external 
inputs from push buttons 33 and remote sensors 41. Microcontroller 310 may 
be any conventional microcontroller which incorporates an on-board 
universal asynchronous receiver-transmitter (UART), clock/timer and 
internal memory. For example, an Intel.RTM. 87C51FB may be used. 
The internal circuitry also includes a number of peripheral devices 
connected to microcontroller 310 via the following bidirectional busses: a 
CONTROL bus which allows microcontroller 310 to selectively enable the 
device; a DATA bus which allows microcontroller 310 to transfer data 
to/from a selected device; and an ADDRESS bus which allows microcontroller 
310 to specify a memory address in a selected device. The peripheral 
device includes a RAM 340 which is connected by the CONTROL, DATA, and 
ADDRESS busses to microcontroller 310 to serve as working memory, a 
position locator 70, actuator bank 50, and the following devices which 
facilitate serial communication and control via cellular telephone 60: a 
serial steering module 330 which is connected by the CONTROL, DATA, and 
ADDRESS busses to microcontroller 310 to manage the transfer of serial 
data between the microcontroller 310 and other serial devices; an adapter 
module 360 connected between cellular phone 60 and serial steering module 
330 which adapts the system for use with a specific brand and model of 
cellular phone 60; a modem 370 which is connected between the adapter 
module 360 and microcontroller 310 (via the CONTROL, DATA, and ADDRESS 
busses) for asynchronous serial communication; and a Dual Tone 
Multifrequency (DTMF) decoder 350 for sensing tones communicated to 
cellular phone 60 and generating control bit patterns in response thereto 
for operating actuator bank 50. 
Serial steering module 330 is comprised of one or more conventional 
programmable logic arrays (s) such as, for example, 16L8 s. The 
serial steering module 330 directs serially-encoded input received from 
the UART internal to microcontroller 310 to the adapter module 360, 
personal identification keyslot 38, or signal conditioning module 380 in 
accordance with control data provided by the microcontroller 310. 
RAM 340 is a conventional 8 K by 8 static random access memory. 
The Dual Tone Multifrequency (DTMF) decoder 350 is a conventional 
tone-sensing device for generating control bit patterns in response to 
selected tones. DTMF decoder 350 is enabled by microcontroller 310 when a 
voice mode request is sent by the central dispatch operator. Once in voice 
mode, tones of various frequencies are emitted when the operator of 
central dispatch station 40 depresses the telephone keys. DTMF 350 
differentiates the tone and transmits a unique data word in response to 
each tone. The data may be interpreted by microcontroller 310 or it may be 
used to directly access and control any of the peripheral devices, 
including the display device 34 and actuator bank 50. 
Modem 370 is preferably a conventional single-chip modem such as a 73K222U 
from Silicon Systems, Inc..RTM.. 
The display 34 comprises a conventional octal bus transceiver connected via 
the CONTROL, DATA, and ADDRESS busses to microcontroller 310 and a 20 by 2 
character LCD connected to the octal bus transceiver for displaying 
messages to the mobile person. A potentiometer (not shown) is preferably 
connected to display 34 to allow contrast adjustment. 
Status bank 390 comprises a conventional eight-bit register coupled to the 
DATA bus and address decoder 320 through an octal line driver. An 
eight-bit data word is stored in status bank 390 to indicate the status of 
mobile security assembly 30. Hence, status bank 390 may be accessed from 
the microcontroller 310 in mobile unit 32. Central dispatch station 40 may 
then obtain the contents of status bank 390 from microcontroller 310. 
The panel of indicator lights 35 comprises six conventional LEDs driven by 
an octal D-type latch which is in turn coupled to the DATA bus and address 
decoder 320. The indicator lights 35 indicate which of push button 
switches 33 has been depressed. 
Actuator bank 50 comprises a conventional bank of relays each coupled to 
the DATA bus through a conventional latch for digital activation. Actuator 
bank 50 is also coupled to the address decoder 320. The relay coils in 
actuator bank 50 may be individually activated by microcontroller 310 or 
directly by the central dispatch station 40. This configuration provides 
the dispatch operator with direct control over actuator bank 50. The 
individual relay contacts are series-connected throughout the vehicle 
electrical system to allow control of selected vehicle functions. For 
instance, if a medical emergency is communicated to the central dispatch 
station 40, the dispatch operator can activate one or more relays in 
actuator bank 50 to trigger an electromagnetic or visual beacon (such as 
flashing headlights) and/or an audible signal (such as the vehicle horn) 
to help the responding authorities locate the mobile person when the 
vehicle is otherwise obscured. Time is often of the essence in such 
situations, and the time saved by this feature may save a life. Also, if 
tampering with the vehicle is detected by one of the remote sensors 41, 
the microcontroller 310 or operator of the central dispatch station 40 can 
activate one of the relays in actuator bank 50 to sound the vehicle horn, 
illuminate the headlights, etc. If an actual theft is detected, the 
dispatch operator can immediately cut power to the engine. 
Status bank 390, indicator lights 35, and actuator bank 50 are configured 
as memory-mapped input/output devices. For this purpose, these devices are 
coupled to the CONTROL and ADDRESS busses of microcontroller 310 through 
an address decoder 320. Address decoder 320 enables a selected one of 
these devices in accordance with an address generated by microcontroller 
310. In addition, status bank 390, indicator lights 35, and actuator bank 
50 are connected by the DATA bus to microcontroller 310 and, when enabled, 
may be controlled thereby. 
The position locator 70 may be a conventional global positioning system 
receiver (GPS) such as a Rockwell.RTM., or alternatively, a LORAN-C system 
such as a J.E.T.RTM.. In both cases, many suitable models are commercially 
available. Position locator 70 is used to determine and supply accurate 
location coordinate data to the mobile unit 32. 
The signal conditioning module 380 comprises a conventional logic level 
converter such as a Maxim.RTM. TTL-to-RS232 converter for interfacing the 
position locator 70. Signal conditioning module 380 is connected between 
the position locator 70 and the serial steering module 330 for formatting 
the latitude and longitude coordinate data from position locator 70 for 
standard RS-232C serial data transmission. 
The adapter module 360 is enabled by the serial steering module 330 to 
transmit serially-encoded data supplied by modem 370. In addition to 
straight-through data transmission, the adapter module must adapt the 
mobile security assembly to the specific brand and model of cellular 
telephone 60 which is employed. This is because handsets of conventional 
cellular telephones emit control codes for controlling the operation of 
the cellular transmitter/receiver. Different cellular telephones employ 
different control codes and different communication protocols between the 
cellular handset and transmitter/receiver. 
FIG. 5 illustrates a block diagram of an exemplary adapter module. The 
cellular telephone handset 61 is unplugged from the cellular transceiver 
62 and is instead plugged into a mobile unit 32 connector, which in turn 
connects to adapter module 360. Likewise, the mobile unit 32 is provided 
with a connecting cord which is also connected to adapter module 360. The 
connecting cord is plugged into the cellular transceiver 62. The adapter 
module 360 acts as an intermediary. Depending on the particular make and 
model of cellular telephone 60, certain lines are routed straight through 
and others are routed to a bank of relays 363 such as an OMRON G6A274-P. 
The single-pole, single-throw relays are controlled by the microcontroller 
310. This way, microcontroller 310 may tap into any of the lines from 
handset 61 in order to accomplish the purposes of the mobile unit 32. A 
conventional line driver 365 is also provided as necessary for lines 
requiring additional source current. 
The detailed operation of the preferred embodiment of the personal security 
system will now be described with reference to the flow-chart of FIG. 6. 
In step 500, the system is initialized when a mobile person inserts his or 
her personal identification key 36 in keyslot 38. Microcontroller 310 
enters full security mode and enables keyslot 38 to read all personal 
information from data key 36. The personal data is transferred to 
microcontroller 310 where it is stored in an on-board RAM along with 
vehicle-specific data. 
In step 510, the microcontroller 310 polls position locator 70 for new 
latitude and longitude coordinate data and a reliability rating. Along 
with each set of coordinate data, conventional LORAN-C and GPS position 
locators generally provide an indication of the reliability of the 
coordinates. For example, a JET.RTM. LORAN-C position locator emits a 
reliability rating ranging from 11 to 88 which represents a progressively 
deteriorating reliability. It is an essential feature of the present 
invention that these reliability ratings are put to best use. In the 
preferred embodiment of the present invention, the raw reliability rating 
obtained from the position locator 70 is reassigned an error code 
comprising one of letters A-D. Each time microcontroller 310 polls 
position locator 70 for new coordinate data and reliability rating, the 
coordinate data and error code are displayed at display 34 and are 
transferred to microcontroller 310 where they are stored in the on-board 
RAM. 
In step 512, the microcontroller 310 sets an internal timer to an elapsed 
time after which the microcontroller 310 will again poll the position 
locator 70. 
The microcontroller 310 repeatedly polls the position locator 70 at an 
approximate rate of every two seconds in accordance with the internal 
timer. If desired, the speed and heading of the vehicle may be computed 
from the accumulated data at each poll. 
As shown in step 514, each time the microcontroller 310 obtains new 
coordinate data and error code from position locator 70, the personal 
security system message is assembled for transmission to the central 
dispatch station 40. In the preferred embodiment, the message comprises 
128 bytes of data, including the following components: 
current latitude 
current longitude 
current heading 
current speed 
best latitude 
best longitude 
best heading 
best speed 
quality count 
personal identification/account number from personal identification key 36 
system identification/serial number of mobile unit 32 
personal/vehicular security condition code. 
The current latitude, current longitude, current heading, and current speed 
are derived from the most recent polling of position locator 70. The best 
latitude, best longitude, best heading, and best speed are computed as the 
most recent values which were obtained along with an "A" error code. 
Initially, the best values are empty. However, as soon as the current 
polling is rated an "A" then the current values become the best values. 
Likewise, at each poll thereafter where the current polling is rated an 
"A" then the existing best latitude, best longitude, best heading, and 
best speed are updated to the current latitude, current longitude, current 
heading, and current speed. Conversely, if the error code of the current 
polling is less than an "A" rating, then the best latitude, best 
longitude, best heading, and best speed are not updated. This way, there 
is always a set of fall-back best values in case the position locator 70 
"blinks". In addition, each time that the error code of the current 
polling is less than an "A" rating, then microcontroller 310 begins a 
second timer. This elapsed time (beginning when the last best values were 
obtained) is a "quality count". The quality count is also included in the 
formatted message to give the central dispatch operator an idea of the 
trustworthiness of the best coordinate data. 
In step 516, the current coordinate data is displayed at display 34. 
In step 518, the remote sensors 41 and the push button switches 33 are 
sequentially polled to determine whether a personal security situation 
exists or whether system test has been initiated. If neither, and the 
elapsed time counted at the internal timer has not expired, then the 
program repeats step 518. 
As shown in step 520, if the elapsed time counted at the internal timer has 
expired, then the program returns to step 510 and the position locator 70 
is polled for new coordinate data. 
On the other hand, if a personal security situation is detected at step 
518A by one of remote sensors 41 or push button switches 33, then the 
program continues to step 521 where microcontroller 310 attempts to 
transmit the personal security system message. 
At step 522, the microcontroller 310 begins to time a redial interval. 
At step 524, the microcontroller 310 causes adapter module 360 to seize 
control of the cellular telephone 60. This is done even if the cellular 
phone was already in use. 
At step 526, the microcontroller 310 dials the central dispatch station 40. 
As shown in step 527, if the central dispatch station 40 fails to answer, 
the redial counter expires and the program returns to step 522. Otherwise, 
if the central dispatch station 40 answers, then at step 528 the 
microcontroller 310 again polls position locator 70 for new latitude and 
longitude coordinate data and the personal security system message is 
formatted for transmission to the central dispatch station 40. 
At step 529, the personal security system message is transmitted. 
As shown in step 530, to provide assurance to the vehicle operator, the 
central dispatch station 40 must acknowledge receipt of the personal 
security system message or the program returns to step 522. The call-back 
confirmation is indicated on the alphanumeric display device 34. 
Once the personal security system message has been transmitted, the central 
dispatch station 40 decodes the personal security system message and 
prepares a properly scaled map display with the appropriate emergency 
symbol superpositioned according to the best coordinate data. An 
information window is displayed near the emergency symbol to convey all 
personal information and vehicle-specific information to the dispatch 
operator. 
As shown in step 531, the central dispatch operator may initiate voice mode 
at any time or, as shown in step 532, may reinitiate data mode. 
If system test is initiated at step 518B, then the program jumps to step 
534 and the self-test routine illustrated in steps 534-564 is conducted. 
FIG. 7 is a block diagram of the presently preferred embodiment of the 
central dispatch station 40. The central dispatch station 40 generally 
comprises a conventional touch-tone telephone 48 connected to a 
communications console 42, which is in turn connected to one or more 
display consoles 49. All of the communications console 42 and display 
consoles 49 may be any commercially available brand of microcomputer which 
includes a video monitor. Incoming cellular calls from mobile unit 30 are 
received and logged by communications console 42 via touch-tone telephone 
48 and modem 46. The personal security message is decoded and transmitted 
to display console 49. Numerous display consoles 49 may be networked to a 
single communications console 42 and incoming personal security messages 
may be allocated to the appropriate display consoles 49 to accommodate a 
high frequency of incoming calls. The display console(s) 49 continuously 
run a conventional digital map program. Preferably, the map program 
includes the following features: 
capable of displaying detailed geographical area maps complete with street 
names and addresses; 
capable of real-time plotting of coordinate data at the appropriate 
position on the map; 
user-controlled zoom function; and 
programmable display windows, symbols, and legend. 
A number of suitable map programs incorporating these features are 
commercially available. 
Although the preferred embodiment requires a separate communications 
console 42 and display console(s) 49, the respective functions of the two 
consoles may easily be accomplished in a single microcomputer by 
multi-tasking. 
FIG. 8 is a detailed illustration of the display which appears at display 
console 49. The alarm symbol corresponding to the type of emergency 
assistance required is superimposed on the map at the position of the 
mobile entity. For instance, a mobile person signalling difficulty at the 
corner of Wiley Road and Kent Road would be represented by the appropriate 
emergency symbol shown at the corresponding position on the map. In 
addition, the vehicle subscriber account number, the vehicle make and 
model, the license number, and any relevant personal or vehicle-specific 
supplemental information is superposed next to the emergency symbol. The 
central dispatch station operator immediately contacts the proper 
authorities as indicated by the emergency symbol, and/or enters voice 
mode. 
By scanning adjacent maps and zooming in on the vehicle position from 
broader maps of the surrounding areas, the central dispatch station 
operator is able to direct the authorities to the exact position of the 
mobile entity 20 by the shortest possible route. In addition, the central 
dispatch station operator can identify the make, model, and license number 
of the vehicle to the authorities and can actuate blinking headlights 
and/or sound the horn via the DTMF 350 and actuator bank 50 in mobile unit 
30. The dispatch operator can also provide supplementary information such 
as special health conditions of the vehicle operator (for instance, 
diabetes, heart problems, etc.). 
Having now fully set forth the preferred embodiments and certain 
modifications of the concept underlying the present invention, various 
other embodiments as well as certain variations and modifications of the 
embodiments herein described will obviously occur to those skilled in the 
art upon becoming familiar with said underlying concept. It is to be 
understood, therefore, that within the scope of the appended claims, the 
invention may be practiced other than as specifically set forth in the 
disclosure.