Vehicle location system

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VEHICLE LOCATION SYSTEM

This is a continuation of application Ser. No. 194,479, filed May 16, 1988, now U.S. Pat. No. 4,891,650, issued 5 01/02/90.

BACKGROUND OF THE INVENTION

The invention relates to a practical system for locating a selected vehicle from which an alarm signal is 10 generated. More particularly, this invention concerns a system for automatically locating an automobile which is broken into and automatically tracking its position if it is driven away and for expeditiously dispatching police cars to it or intercepting it respectively. 15

The statistics on passenger vehicle or car theft in the United States are mind boggling and exceed one million cars a year. Insurance rates are climbing at an alarming rate and there are few if any feasible solutions in sight. The current car protection equipment available to indi- 20 vidual car owners include a range of features and capabilities.

Specifically, the current available equipment can be categorized as localized alarm system protection, car location systems and fleet management systems. The 25 localized alarm protection systems activate a warning device such as a siren when the car is broken into. Generally speaking this type of system is effective only if the car owner or the police are in the vicinity. Other people tend not to get involved in this situation and in many 30 cases car alarm sounds are not being acted on by the police. The pros are that they are inexpensive and in some cases the warning device deters theft. The cons are that if the owner is not around there is a high likelihood that no action will be taken to apprehend the 35 intruder. Also if the owner is around and is able to get to the vehicle he may be risking personal injury or worse, by the intruder. Car location systems will identify the location of the car after the fact, that is sometime after the intrusion is detected and the car is driven 40 away from its parking spot. A good example of such a system is disclosed by U.S. Pat. No. 4,177,466 to Reagan. While there is a relatively high likelihood that the car will be eventually located, this type of system suffers from some distinct practical shortcomings, some of 45 which are technical and some of which are political. The pros are that there is a relatively high livelihood that the stolen car will be located and returned to the rightful owner. The cons are that the car owner must notify the police that his car is missing before the police 50 can take any search action. The problem is that if the owner is not around it may take sometime before he becomes aware that the car is missing and by then the car may be extensively vandalized. Furthermore such a system does not prevent nor deter stealing. Also be- 55 cause the system such as disclosed by the Reagan patent is based on esoteric infrastructure requiring very specialized antenna sites and equipment, it is quite expensive. Furthermore the state police are very reluctant to finance such a system. As such the system is available 60 only in Massachusetts and even there the inventor had to donate the required equipment to the police before they were willing to use it. Furthermore, the car location system as disclosed in the Reagan patent utilizes location stations having location indicators, the latter 65 comprising proximity detectors and/or radio direction finders. These location stations may be placed at fixed locations or carried by driver-operated finder vehicles.

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Another car location system of a different type, such as disclosed in U.S. Pat. No. 3,922,678 to Frenkel, utilizes a plurality of wireless signal detecting and relaying means which must be equidistantly spaced from one another in a fixed array, all of which respond to an alarm signal from a wireless signal generating means carried by a mobile source located within a zone in their detection region, and each of which respond and transmit at frequencies differing from one another. A plurality of receivers are also required at a central control station such as police headquarters. Each of these receivers are tuned to receive signals of different frequencies corresponding in frequency to the signals transmitted by the relaying means to thereby determine the zone within which said mobile source is located and track its movement. Each zone corresponds to a particular area of a map within which the relays are arrayed and each zone is identified by one of a plurality of lamps disposed on the map, each lamp of which is responsive to those wireless detecting means which detect a mobile source located within a zone in their detection region. This type of system is also impractical in that it requires the construction of a fixed array of specialized antenna sites each of which are equidistantly spaced from one another, an expensive proposition and impractical in most densely populated urban areas. Fleet management systems are geared toward specialized application in truck fleet management. It is somewhat outside the scope of this discussion in that it is geared toward very large truck fleet owners who keep tabs on their vehicles. An example of the type of system utilize for fleet management are those which include LORAN -C transmitters. The elements of automatic car location and "alarm" detection are available on these systems, but the link to a monitoring central alarm station is beyond the realm of financial feasibility to an individual who would use such a system to protect against theft of his own car. The bulkiness and expense of such equipment effectively rules it out as a viable alternative in the individual car alarm and location detection market.

SUMMARY OF THE INVENTION

It is, therefore, an object of this invention to provide an automatic vehicle location system which can utilize the presently existing nationwide cellular radio network including its antenna sites and equipment located there and its controlling mobile telecommunications switching office ("MTSO") with only minor modifications to its software.

Another object of the present invention is to provide an automatic vehicle location system which can utilize both the aforedescribed, existing nationwide cellular radio system and the presently existing monitoring central alarm station's facilities and infrastructive. Both cellular networks and monitoring central stations can currently be found everywhere.

A further object of the present invention is to provide an automatic vehicle location system which is truly practical and inexpensive and which is almost totally based on presently existing and relatively inexpensive hardware none of which must be specifically designed to implement the system.

A still further object of this invention is to provide an automatic detection capability by a central alarm station in case of a car intrusion and/or theft.

Still another object of the invention is to provide a central alarm station with the location of the said vehi20

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cle at its parked location and thereafter its location if the car is stolen and while it is driven away.

Another object of the invention is to provide a system which automatically determines a vehicle's location both when there is an intrusion and while it is being 5 driven away, the later resulting in on-going vehicle tracking, and to immediately have the police notified as to these acts to thereby have them either dispatched to the scene of the intrusion and/or dispatched to pursue the stolen vehicle. Multiple police cars may be dis- 10 patched and guided by the central alarm station's dispatcher.

A further object of the invention is to provide a system which automatically determines a vehicle's location without the necessity of the owner or anyone at the 15 scene notifying the police.

A still further object of the invention is to provide a system which automatically determines a vehicle's location when there is an intrusion and/or theft thereby protecting its owner against a possible confrontation with the intruder.

Still another object of the invention is to provide a system which determines tho car's location while the break-in is occurring and not sometime later thereby obviating any possible vandalization.

Another object of the invention is to automatically disable the car when a break-in occurs thereby requiring the intruder to initially spend additional time in trying to enable the car during which time the police 3Q are alerted to the break-in and are already dispatched to the site of the intrusion.

A further object of the invention is to offer to a car owner a choice of deterrents including a mode wherein the intruder will not be aware that the car is under ^ continuous surveillance by virtue of its position being automatically made known through an operation in the central alarm station.

A still further object of another embodiment of the present invention is to provide an automatic vehicle ^ parking location system which can utilize the presently existing nationwide cellular network without any modifications at the presently existing central alarm station's facilities and infrastructure with only very minor modifications to its software. 45

The foregoing and related objects are obtained in accordance with the invention which, in its broadest aspects, provides a system for determining a location of a selected vehicle from which an alarm signal is generated. The system comprises a fixed array of a plurality 50 of individual wireless signal detecting means for receiving an input alarm signal having a strength which is a function of the distance between the position of the vehicle generating the alarm and the position of each of the wireless signal detecting means. Each of these wire- 55 less includes a wireless signal generating means for transmitting an output signal which is a function of the strength of the input alarm signal. The system further includes a main wireless signal detecting means for receiving an output signal from each of the wireless 60 signal generating means and a control monitoring means coupled to the main wireless signal detecting means. This control monitoring means receives output signals from the main wireless signal detecting means, which output signals are a function of the received input 65 alarm signal. The control monitoring means also functions to determine the approximate location of the selected vehicle.

BRIEF DESCRIPTION OF THE INVENTION

The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which:

FIG. 1 is a simplified functional block diagram of the vehicle location system constructed in accordance with the principals of the invention;

FIG. 2 is a functional block diagram of the vehicle's wireless generating apparatus of the vehicle location system of FIG. 1;

FIG. 3 is another simplified functional block diagram of the vehicle locational system of FIG. 1 with a portion of its fixed array of cell sites and its central alarm station shown in more detail;

FIG. 4A shows the geographic layout of cell sites for use in the system of FIG. 1 and the four shortest "radii", shown with arrows, as determined by an algorithm used in the computer of said system of FIG. 1;

FIG. 4B shows the cell site within which the vehicle's wireless generating apparatus of FIG. 2 is located and graphically illustrates the process of "arculation" in accordance with said algorithm;

FIG. 5 is a functional block diagram of the central alarm station of the system of FIG. 1;

FIG. 6 shows a portion of the flow chart of the processor of the computer, and the computer monitor of the central alarm station of FIG. 5; and

FIG. 7 is a functional block diagram of a portion of the vehicle's wireless generating apparatus of another embodiment of the vehicle location system of FIG. 1.

DETAILED DESCRIPTION OF THE
INVENTION

Referring to FIG. 1, which is a simplified functional block diagram of the preferred embodiment of the invention, a system for determining the location of a selected vehicle from which an alarm signal is generated or vehicle location system, is generally indicated by reference numeral 10. This system 10 comprises a vehicle wireless generating means carried by a selected vehicle or mobile unit, generally indicated by reference numeral 12, a fixed array of cellular or cell sites (only one of which is shown therein), generally indicated by reference numeral 14, each of which includes a wireless signal detecting and generating means, a controlling mobile telecommunication switching office ("MTSO") or main wireless detecting means, generally indicated by reference numeral 16 coupled to a central telephone office, generally indicated by reference numeral 18, and a central alarm station or control monitoring means, generally indicated by reference numeral 20, coupled to the central telephone office 18.

In operation, when an unauthorized entry into the vehicle carrying the wireless generating means 12 is detected, an alarm signal is generated thereby which is transmitted over-the-air to a nearby fixed cellular or cell sites 14. The alarm signal contains information concerning the vehicle's identity and when this signal is received by the closest cell sites 14, each of their wireless signal detecting and generating means transmits a signal strength report message which is indicative of the signal strength of the received alarm signal from mobile unit 12, the signal strength of which is a function of and proportional to the distance between the position of the selected vehicle's wireless generating means 12 and the position of the receiving cell sites 14. These transmitted messages also include information concerning theaden