Emergency locator device transmitting location data by wireless telephone communications

Field of the Invention

The present invention relates to emergency locator devices, specifically emergency locator beacons that transmit a distress signal for detection and location by rescue teams.

Description of Related Art

Emergency locator beacons are built into aircraft or other vehicles to broadcast a distress signal during emergency conditions. The distress signal is used by rescue teams to become aware of an emergency and to locate the emergency site by performing triangulation on the detected signal. Specifically, beacon detectors are positioned at two or more locations to identify the relative direction of the emergency locator beacon. The relative directions detected by the respective detectors are correlated to identify the specific location of the emergency locator beacon transmitting the distress signal.

Conventional emergency locator beacons have the problem of requiring substantially continuous transmission of distress signals to ensure reliable detection thereof. For example, rescue teams need to detect the distress signal for a sufficient period of time to verify the emergency condition, dispatch rescue personnel, install directional receivers at two or more locations for triangulation, and then triangulate the detected distress signals to fix the approximate location of the emergency locator beacon. In addition, successive measurements by rescue teams may be necessary in order to determine more precise locations of the beacon. Hence, if an emergency locator beacon ceases to transmit because its battery runs down over an extended period of time, the search team may be unable to locate the emergency locator beacon.

In addition, such emergency locator beacons typically transmit distress signals at VHF frequencies which propagate as line of sight transmissions from the beacons. If a crash site is in a canyon, the canyon walls may limit the propagation of the distress signals. Hence, detection of the transmitted distress signal may be difficult for terrestrial-based receivers or receivers aboard low-flying aircraft (i.e., below 50,000 feet) if an emergency locator beacon from an aircraft ends up in canyon areas unless rescue aircraft are directly overhead. Similar problems may exist for sea-based emergency beacons that transmit a distress signal from beyond a horizon.

The prior art includes at least one product which combines the use of a conventional RF voice radio with a global positioning system (GPS) receiver. However, the product still suffers from the disadvantage that rescue receivers may be unable to detect the radio signal either due to limited range, interference, or obstructions preventing reception of a line of sight transmission.

SUMMARY OF THE INVENTION

In view of the foregoing, there is a need for an emergency locator device that enables a distress signal to be received from any location, regardless of geography or topography of a crash site.

There is also a need for a portable emergency locator device that is compact and portable by survivors of a crash.

There is also a need for an emergency locator device that provides updated location information for rescue teams to locate survivors moving away from a crash site.

There is also a need for an emergency locator device that provides location information indicating the current location of the emergency locator device, and information related to the condition of a vehicle that suffered a crash.

These and other needs are attained by the present invention, where according to one aspect of the present invention an emergency locator device includes a wireless receiver interface receiving digital location data indicating a current location, and a wireless telephone transceiver sending the digital location data to a called station via a wireless telephone communications system in response to an emergency trigger. Use of existing commercial wireless telephone communication system enables the emergency locator device of the present invention to be applied in a variety of applications, including highway vehicle locator devices, aircraft rescue devices, sea rescue devices, etc. Moreover, the digital location data may be provided from a commercially available wireless location data receiver that receives wireless location data from a wireless location detection system. Hence, the emergency locator device of the present invention can be implemented as a low cost device that provides accurate location data to rescuers using existing wireless telephone technology.

In another aspect of the present invention, a method includes the steps of determining a current location from wireless location data received from a wireless location detection system, initiating a first telephone call using a wireless telephone in communication with a wireless telephone communication system and accessing a called station in response to an emergency trigger, and supplying digital data identifying the determined current location to the called station during the first telephone call. Use of a wireless telephone to transmit the digital data identifying the determined current location to the called station enables existing wireless telephone systems, including cellular, PCS, and satellite telephone systems, to serve as communication carriers for emergency locator devices with minimal complexity.

Still another aspect of the present invention provides a system having a portable device and an emergency receiver. The portable device includes a wireless receiver interface receiving first digital location data indicating a current location of the portable device, and a wireless telephone transceiver initiating a telephone call via a wireless telephone communication system and sending the first digital location data in response to an emergency trigger. The emergency receiver includes a telephone interface receiving the telephone call from the portable device, and a decoder identifying the current location in response to the received digital location data. Hence, the system of the present invention enables a portable device, for example, a wireless telephone having a location detection device, to initiate a telephone call to ground-based and airborne rescue teams using the available wireless telephone communication systems. In addition, the emergency receivers enable rescue to maintain contact with survivors, while receiving updated position information of the portable devices.

Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

Reference is made to the attached drawings, wherein elements having the same reference numeral designations represent like elements throughout and wherein: <ul id="ul0001" list-style="none" compact="compact"><li><b>Figure 1</b> is a block diagram of an emergency locator system according to an embodiment of the present invention.</li><li><b>Figures 2A</b> and <b>2B</b> are flow diagrams summarizing the operations of the control processor in the portable device and the emergency receiver system of Figure 1, respectively.</li><li><b>Figures 3A, 3B</b> and <b>3C</b> summarize an alternative embodiment of an emergency receiver system receiving wireless telephone calls from the emergency locator device of <b>Figure 1</b>.</li></ul>

NOTATIONS AND NOMENCLATURE

The detailed descriptions which follow may be presented in terms of program procedures executed on a computer or network of computers. These procedural descriptions and representations are the means used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art.

A procedure is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result. These steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It proves convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. It should be noted, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities.

Further, the manipulations performed are often referred to in terms, such as adding or comparing, which are commonly associated with mental operations performed by a human operator. No such capability of a human operator is necessary, or desirable in most cases, in any of the operations described herein which form part of the present invention; the operations are machine operations. Useful machines for performing the operation of the present invention include general purpose digital computers or similar devices.

The present invention also relates to apparatus for performing these operations. This apparatus may be specially constructed for the required purpose or it may comprise a general purpose computer as selectively activated or reconfigured by a computer program stored in the computer. The procedures presented herein are not inherently related to a particular computer or other apparatus. Various general purpose machines may be used with programs written in accordance with the teachings herein, or it may prove more convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these machines will appear from the description given.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a portable emergency locator device that combines the availability of wireless location detection systems, for example, the global positioning system (GPS) network, and commercially-available wireless telephone communications systems to provide an economic emergency locator device. As described below, the emergency locator device includes a GPS receiver interface, a crash sensor or manual triggering device, and a wireless telephone transceiver in communication with a wireless telephone communication system, for example, a cellular, PCS, or satellite-based telephone communications system. The emergency locator device may be implemented as a portable unit suitable for hand-held use for survivors of a crash, or as an integrated system that receives vehicle condition data, for example, aircraft flight status data. Similarly, the system can be adapted for sea rescue by providing the emergency locator device as part of a rescue package stored aboard a life boat. The system may also be incorporated as part of a mobile telephone system in a highway or off-road motor vehicle, where available cellular telephone systems may be used instead of satellite telephone systems. Finally, the system may be implemented as a conventional wireless telephone having a distress key enabling a user to automatically notify law enforcement authorities of the user's location.

<b>Figure 1</b> is a block diagram of the emergency location system according an embodiment of the present invention. The emergency system includes an emergency locator device <b>10</b> and an emergency receiver system <b>12</b>. The emergency locator device <b>10</b>, preferably a portable device, includes a wireless receiver interface, such as a GPS interface <b>14</b>, that receives digital location data indicating a current location of the emergency locator device <b>10</b> from a wireless location data receiver <b>16</b>. The receiver <b>16</b>, preferably a GPS receiver, receives wireless location data from a wireless location detection system such as the global position system (GPS), and calculates and outputs the digital location data to the GPS interface <b>14</b>. Depending of the application, the GPS receiver <b>16</b> may be integrated as part of the emergency locator device, where the emergency locator device <b>10</b> operates as an integrated wireless telephone having the GPS receiver <b>16</b>. Alternately, the emergency locator device may be implemented as a low cost wireless telephone having the GPS interface <b>14</b> that receives the digital location data from an external GPS receiver <b>16</b> that can be disconnected from the telephone portion.

The GPS receiver <b>16</b> is preferably implemented as a miniaturized GPS receiver integrated with the telephone portion of the emergency locator device <b>10</b>. The receiver <b>16</b> measures the time a radio signal takes to travel from a GPS satellite in the GPS network (not shown) until it arrives at the antenna <b>16a</b>. The GPS receiver <b>16</b> will listen to signals from either 3 or 4 satellites at a time and triangulate a position fix using the interval between the transmission and reception of the satellite signal from the GPS satellite system. The GPS receiver <b>16</b> may track up to 8 satellites at a time, such that if one satellite becomes unavailable, the GPS receiver <b>16</b> knows where to find a best possible replacement. As known in the art, three satellites are used for two dimensional positioning, although 4 satellites may be used for three dimensional positioning, i.e., position and elevation.

The GPS receiver <b>16</b> thus determines a current location of the emergency locator device <b>10</b> within an accuracy of +/- 100 meters and supplies the current location information to the GPS interface <b>14</b> for storage in memory, described below. If desired, accuracy may be reduced to an error of less than <b>24</b> meters by eliminating errors introduced by selective availability, currently implemented by the U.S. Air Force, or by performing differential GPS by placing a second GPS receiver at a fixed point, for example at the emergency receiver system <b>12</b>. Error reduction techniques using differential GPS are well known in the art.

The emergency locator device <b>10</b> and the emergency receiver system <b>12</b> each include a wireless telephone portion including a wireless telephone transceiver <b>18</b> that communicates with a wireless telephone network <b>20</b> via respective antennas <b>22.</b> The telephone portion also includes a control processor <b>24,</b> for example, a microprocessor, that controls the operations of the telephone transceiver, described below. The telephone portion further includes a keypad <b>26</b> that accepts user-input digits corresponding to a telephone number of a destination station. The control processor <b>24</b> controls the transceiver <b>18</b> to initiate a wireless telephone call to the corresponding destination station in accordance with the user-input digits and in response to the user depressing the send key <b>28</b>. The telephone portion also includes a handset <b>32,</b> and a speakerphone <b>36</b> that converts received audio signals into digital signal samples for transmission by the transceiver <b>18</b>, and converts received digital signal samples from the transceiver <b>18</b> into signals audible by a user. The speakerphone is activated in response to a user input, for example, pressing a speakerphone key (not shown). Thus, a user of the portable emergency locator device <b>10</b> would activate the speakerphone <b>36a</b> by pressing an appropriate button on the keypad <b>26a</b>.

Finally, the telephone portion of the emergency locator device <b>10</b> and the emergency each include a non-volatile memory <b>38</b> that stores a predetermined number corresponding to a rescue station. For example, a user may trigger the emergency locator device manually by pressing a help/distress key <b>30a</b> on the keypad <b>26a</b>, causing the control processor <b>24a</b> to access the predetermined number corresponding to the rescue station. Depending on the application, the predetermined number may be a centralized dispatch center, a specific rescue service, a vehicle assistance service, or local law enforcement authorities. If no predetermined emergency telephone number is stored in the memory <b>38</b>, pressing the help key <b>30</b> will cause the control processor <b>24</b> to initiate a call to the default value of 911 for emergency services.

The emergency locator device <b>10</b> may also initiate the emergency telephone call in response to an emergency trigger generated by a crash sensor <b>50</b> in response to a detected crash event. For example, the crash sensor <b>50</b> may be part of a vehicle crash detection system which outputs the signal to a vehicle status monitoring system <b>52</b>. The vehicle status monitoring system <b>52</b> may be part of a centralized control in a vehicle, for example, an aircraft control system, that periodically outputs vehicle status data to the emergency locator device <b>10.</b> For example, the monitoring system <b>52</b> includes non-volatile memory registers <b>52a, 52b, 52c</b> and <b>52d</b> storing vehicle identification, vehicle condition, vehicle orientation (for example, pitch, roll, attitude), and vehicle crash data, respectively. The vehicle status data is supplied to a status interface <b>54</b> in the emergency locator device <b>12,</b> which passes the received vehicle status data to the control processor <b>24a</b> for storage in the memory <b>38a.</b>

Hence, the control processor <b>24a</b> receives environmental data including digital location data indicating the current location of the device <b>10,</b> vehicle status information, etc. and stores the information in the memory <b>38a.</b> If the emergency locator device <b>10</b> becomes separated from the rest of the vehicle during a crash, the control processor <b>24a</b> can still provide location and vehicle status information to rescue teams by accessing the memory <b>38a.</b> A rescue team using the receiver <b>12</b> is thus able to quickly obtain the status of the events at the emergency locator device. If desired, the called station <b>12</b> can issue a command during the 2-way telephone call to initiate the external microphone <b>34</b> in order to listen to surrounding events.

As shown in <b>Figure 1</b>, the emergency receiver system <b>12</b> includes a GPS decoder <b>60</b> and status decoders <b>62</b> to decode the received digital data from the emergency locator device into the GPS location data and the vehicle status information, respectively. If desired, the control processor <b>24b</b> outputs the decoded data onto a display <b>64</b>, for example, as a digitized map identifying the current location of the emergency locator device as represented by the received digital location data. In addition, the decoded vehicle condition data may be used by rescue crews to determine the status of the emergency and the condition of the vehicle, for example, whether an aircraft landed intact, and whether the aircraft is oriented in an upright position.

According to the disclosed embodiment, the emergency locator device <b>10</b> and the emergency receiver <b>12</b> are each implemented -as wireless telephone transceivers, for example, cellular or satellite telephone transceivers, where digitally-encoded data received from the data interfaces <b>14</b> and <b>54</b> can be transmitted during 2-way voice conversations. Hence, the control processor <b>24</b> is adapted to perform all telephone control functions associated with communication via the wireless telephone network, and to manage the reception of status data. For example, the control processor <b>24a</b> stores the data received from the GPS interface <b>14</b> and the status interface <b>54</b> and stores the received data in memory <b>38a.</b> Upon detecting an emergency trigger, the control processor <b>24a</b> activates the wireless telephone transceiver <b>18a</b> to initiate a 2-way telephone call to the called station <b>12</b> via the wireless telephone communication system <b>20</b>. During the 2-way voice conversation, the control processor <b>24a</b> transmits the status data stored in memory <b>38a</b>. The control processor <b>24b</b>, upon receiving the digital data during the 2-way voice conversation, outputs the digital data to the decoders <b>60</b> and <b>62.</b> The decoded data is output from the decoders <b>60</b> and <b>62</b> and stored by the contrql processor <b>24b</b> and the memory <b>38b</b>.

If desired, the emergency receiver <b>12</b> may activate the microphone <b>34</b> on the emergency locator device by pressing the microphone key <b>29</b> on the keypad <b>26b,</b> causing the control processor <b>24b</b> to send a digital command via the wireless telephone network to the control processor <b>24a</b>. Upon receiving the microphone activation command, the control processor <b>24a</b> activates the external microphone <b>34</b> and transmits the received digital signal samples of received audio inputs from the microphone <b>34</b> to the called station <b>12</b>.

The wireless telephone network <b>20</b> is preferably a commercially-available network, for example, a terrestrial cellular or personal communication system (PCS) telephone network. Alternatively, the wireless telephone network <b>20</b> may be a satellite-based telephone communication network, where the wireless telephone transceiver <b>18a</b> is a low-power satellite transceiver that links with one of the satellites of the satellite network. As recognized in the art, one available satellite system is a low-earth-orbit phone system, such as the Iridium system. Other satellite systems will be recognized by those skilled in the art. Satellite-based telephone networks <b>20</b> have the advantage of worldwide access, regardless of location or topography of the location (for example, a canyon), since a direct line of site transmission is generally available between one of the satellites of a network and the emergency locator device <b>10</b>. Hence, satellite-based emergency locator devices <b>10</b> are preferable for ships, airplanes, or users that may be in remote locations, for example, during wilderness exploration, etc. In contrast, cellular or PCS-based emergency locator devices are preferable in applications involving highway, vehicles or users located in regions having established cellular and PCS telephone networks.

A particularly economic implementation is a telephone portion of the emergency locator device physical separable from the GPS receiver <b>16</b> and the vehicle status registers <b>52</b>. In such a case, the user may detach the emergency locator device <b>10</b> from the vehicle status sensor <b>52</b> and the GPS receiver <b>16</b> in order to operate the portable device as a wireless telephone. Hence, the emergency locator device may be implemented as an intrinsic part of the wireless telephone, enabling a user under non-emergency conditions to place regular cellular, PCS or satellite telephone calls.

<b>Figure 2</b> is a flow diagram of the operations of the control processor <b>24a</b> according to the disclosed embodiment. The method shown in <b>Figure 2A</b> may be implemented as software executable by the control processor <b>24a</b>, which is stored in the memory <b>38a</b> or some other tangible medium. The control processor <b>24a</b> begins after initialization by entering a event detection state in step <b>100</b>. Control and signaling operations may also be performed periodically between the control processor <b>24a</b>, the telephone transceiver <b>18a</b>, and with the wireless telephone network <b>20</b>, for example during roaming.

Upon detecting an event other than background telephone operations, the control processor <b>24a</b> determines in step <b>102</b> whether the detected event is the reception of status data from the GPS interface 14 or the status interface <b>54</b>. If the detected event is received data, the control processor <b>24a</b> determines in step <b>103</b> if the received data is GPS data. If the received data is GPS data, the control processor <b>24a</b> accesses the previously-stored GPS data from the memory <b>38a</b> in step <b>104,</b> and compares the received GPS data with the stored GPS data in step <b>106</b>. If the variations between GPS data indicate that the device <b>10</b> has moved at least a predetermined distance, for example, a distance L=100 meters, the control processor <b>24a</b> updates the memory <b>38a</b> in step <b>108.</b> The control processor <b>24a</b> then checks its internal registers to determine whether an emergency condition has been set in step <b>110.</b> If no emergency condition has been set, the control processor <b>24a</b> returns to the event detection state <b>100</b>. However, if an emergency condition is detected in step <b>110,</b> the control processor <b>24a</b> checks in step <b>112</b> whether a telephone call is in progress. If the telephone call is in progress, the stored GPS data is transmitted in step <b>122</b>. If in step <b>112</b> a call is not in progress, the control processor initiates a telephone call, described below.

If the control processor <b>24a</b> determines in step <b>102</b> that the detected event is not the reception of interface data, the control processor <b>24a</b> determines in step <b>114</b> whether the detected event is an emergency trigger. For example, an emergency trigger may be generated by the crash sensor <b>50</b>, or by the user pressing the help/distress key <b>30a</b> on the keypad <b>26a.</b> If the control processor <b>24a</b> detects the emergency trigger, an internal flag is set indicating the emergency condition, and the stored GPS data and vehicle data is accessed from the memory <b>38a</b> in step <b>116</b>. The control processor <b>24a</b> also accesses a predetermined telephone number of a rescue station to be called from the memory <b>38a</b> in step <b>118.</b> The telephone number may correspond to a headquarters of an organization, a personal friend, or local or federal law enforcement or regulatory agencies.

After accessing the predetermined rescue telephone number, the control processor <b>24a</b> activates the telephone transceiver <b>18a</b> in step <b>120</b>, and initiates a telephone call with the wireless telephone network <b>20</b>. After the wireless network <b>20</b> has established a communication link between the emergency device <b>10</b> and the called station <b>12</b>, the control processor <b>24a</b> transmits the accessed GPS data and the vehicle data from the memory <b>38a</b> in step <b>122</b>, and enables 2-way voice conversations between the emergency device <b>10</b> and the called station <b>12</b> on the communication link in step <b>124.</b>

Once the telephone call has been established, the control processor <b>24a</b> returns to the event detection state. Additional events may occur during the telephone call that require action by the control processor <b>24a</b>. For example, if the control processor <b>24a</b> detects in step <b>102</b> the reception of interface data, and the control processor <b>24a</b> determines in step <b>103</b> that the received data is vehicle data from the status interface <b>54</b>, the memory <b>38a</b> is updated in step <b>108</b>, and the updated data is transmitted during the emergency call in step <b>122.</b> Similarly, if the control processor <b>24a</b> detects reception of a microphone activation command from the emergency receiver system <b>12</b> in step <b>126,</b> the control processor <b>24a</b> engages the external microphone <b>34</b> in step <b>128</b>.

The telephone call continues until the control processor <b>24a</b> detects an on-hook indication from either the wireless telephone network <b>20</b> or the user keypad <b>26a</b> in step <b>152</b>, at which point the wireless telephone transceiver <b>18a</b> goes through conventional tear-down procedures in step <b>154.</b>

The control processor <b>24a</b> also detects events related to normal telephone operations. For example, if the emergency locator device <b>10</b> is idle in step <b>100</b> and the control processor <b>24a</b> determines in step <b>130</b> that a detected event is an incoming call, the control processor <b>24a</b> checks in step <b>132</b> whether the internal registers are set indicating an emergency condition in step <b>132</b>. If the internal registers are not set, the control processor <b>24a</b> performs a convention ringing function in step <b>134</b>, indicating to the user an incoming call. If the user answers the call, then standard wireless telephone procedures are performed.

If the control processor <b>24a</b> detects the emergency condition in step <b>132</b>, the control processor <b>24a</b> automatically answers the call in step <b>136,</b> enabling rescuers to access the telephone regardless of whether a user is able to answer the telephone. After answering the telephone call, the control processor <b>24a</b> determines whether a microphone activation command (e.g., "auto-mike") has been received in step <b>138.</b> If the microphone activation command has been received, the control processor <b>24a</b> engages the microphone <b>34</b> in step <b>140</b>. If a download command has been received in step <b>142</b>, the control processor <b>24a</b> accesses the stored GPS data and vehicle status data from the memory <b>38a</b> and transmits the data in step <b>144.</b> Finally, the control processor <b>24a</b> enables 2-way conversations in step <b>146</b>. Thus, the rescuers using the receiver system <b>12</b> receive updated information from the portable emergency locator device before beginning conversations with users of the emergency locator device.

As described above, the portable device <b>10</b> may also be used as a convention wireless telephone during normal operations. Hence, if the control processor <b>24a</b> determines that a detected event is a user input in step <b>148,</b> for example, user input of dialed digits for a conventional call to station, the control processor <b>24a</b> initiates the wireless telephone transceiver <b>18a</b> to place the phone call in step <b>150</b> according to the protocol of the wireless telephone network <b>20.</b> Finally, if the detected event is an onhook indication in step <b>152</b>, the control processor <b>24a</b> performs standard tear-down procedures in step <b>154</b>.

<b>Figure 2B</b> is a flow diagram illustrating the operations of the control processor <b>24b</b> in the emergency receiver system. The receiver system <b>12</b> may be implemented as a portable handheld telephone device having an LCD display <b>64</b> for use by rescue personnel. Alternately, the receiver system <b>12</b> may be implemented as a computer based system at a headquarters or a rescue operations center, such as shown in Figures <b>3A</b> and <b>3B.</b> Although characterized as a receiver system, the receiver system <b>12</b> includes a wireless telephone transceiver <b>18b</b> to send and receive telephone calls. In addition, the wireless telephone transceiver <b>18b</b> may be replaced with conventional land line access for centralized rescue operations. Hence, a plurality of rescue systems <b>12</b> may be used to enable a plurality of rescuers to place calls between each other in order to coordinate rescue efforts.

As recognized in the art, the system <b>12</b> may use advanced calling operations of the telephone network <b>12,</b> for example, conferencing capabilities to enable simultaneous conversations between the rescuers and the users of the emergency locator device <b>10.</b>

As shown in <b>Figure 2B</b>, the control processor <b>24b</b> begins by detecting an incoming call in step <b>160</b>. The control processor <b>24b</b> determines in step <b>162</b> if the incoming call is an emergency call, typically by a digitally-encoded message included in the telephone call, or by telephone screening by an operator monitoring incoming calls. If the incoming call is not an emergency call, then normal telephone operations are performed in step <b>164.</b> However, if the incoming call is an emergency call, then emergency operations procedures are initiated in step <b>166,</b> including activation of the decoders <b>60</b> and <b>62</b>, and display of relevant information on the display <b>64</b>. As recognized in the art, the control processor <b>24b</b> may also access digital map databases to provide a geographical and/or topographical display of a region of a crash site on the display <b>64</b> based upon the received GPS data.

The control processor <b>24b</b> then checks in step <b>168</b> whether encoded data such as GPS data or vehicle status data has been received in step <b>168.</b> If encoded data has been received, the control processor <b>24b</b> supplies the encoded data to the respective decoders <b>60</b> and <b>62</b> for decoding of the data in step <b>170</b>. The decoded data is then stored in the memory <b>38b</b> in step <b>172</b> and displayed on the display <b>64</b> in step <b>174</b>. The control processor <b>24b</b> then returns to the emergency operations event detection stage in step <b>166</b>.

If the detected event is not the receipt of encoded data in step <b>168</b>, the control processor <b>24b</b> checks in step <b>176</b> whether rescue personnel have pressed the microphone key <b>29</b> on the keypad <b>26b</b>. If the microphone key <b>29</b> has been pressed, the control processor <b>24b</b> sends a microphone activation command in step <b>178</b> to the emergency locator device <b>10</b>. If the emergency event detected by the control processor <b>24b</b> is an onhook indication from the wireless telephone network <b>20</b> in step <b>180,</b> the control processor <b>24b</b> activates the wireless telephone transceiver <b>18b</b> to initiate a call back procedure in step <b>182.</b> Such a call back procedure is desirable, for example, if a user of the emergency locator device <b>10</b> becomes incapacitated or inadvertently hangs up the wireless telephone transceiver <b>18a</b>.

Finally, if the control processor <b>24b</b> detects in step <b>184</b> a command from rescue personnel to terminate the emergency status, the control processor <b>24b</b> terminates the emergency operations and returns to normal status.

<b>Figures 3A, 3B</b> and <b>3C</b> disclose one arrangement for the control processor <b>24b</b> of <b>Figure 1</b>. As recognized in the art, the control processor may be implemented as a computer <b>300</b> that accepts a tangible medium storing executable code that performs the above-described functions, such as a diskette as shown in <b>Figure 3C</b>. The tangible medium is inserted into a disk drive <b>310A</b> or <b>310B</b> and loaded into the computer <b>300</b> in response to user inputs via the keyboard <b>330</b> or the mouse <b>340.</b> Output from execution of the software is displayed on the display screen <b>320</b>. As recognized in the art, the computer <b>300</b> may also be used to download executable software to the control processor <b>24a</b> via a communications port <b>385.</b> Hence, the tangible medium in <b>Figure 3C</b> may store software that includes executable code for performing the functions of <b>Figure 2A</b> and <b>Figure 2B</b>. Alternatively, the control processor <b>24a</b> may store the executable code corresponding to wireless telephone operations and the emergency locator device functions of <b>2A</b> in a read only memory, such as a plug-in EPROM.

<b>Figure 3B</b> is a block diagram illustrating the hardware structure of the computer <b>300.</b> The computer <b>300</b> includes a central processing unit <b>355</b> that executes the software stored on the tangible medium. The tangible medium may be inserted into a floppy drive <b>373</b>, or a CD ROM drive <b>371</b> under the control of a disk controller <b>370.</b> In addition, the software may be stored on the tangible medium of a hard disk, under the control of a hard drive <b>372</b>. Hence, the software may be stored on the tangible medium of a CD ROM, a floppy drive, or a hard drive which is read by the CD ROM drive <b>371</b>, the floppy drive <b>373,</b> and the hard drive <b>372</b>, respectively. The software stored on the tangible medium is accessed by the disk controller <b>370</b> and temporarily stored in the random access memory <b>365</b> for execution.

The computer <b>300</b> also includes a read only memory (ROM) <b>360</b> that controls the low-level operations of the computer <b>300,</b> for example BIOS operations. The CPU <b>355</b> responds to user inputs from the keyboard <b>330</b> or the mouse <b>340</b> via a user interface <b>345</b>, which sends control signals to the CPU representing the user inputs. Execution of the software is also displayed on the display <b>320</b> which is driven by the display interface <b>375.</b> Communications between the computer <b>300</b> and the wireless telephone network occurs via the communications port <b>385</b>, which may be coupled either to a wireless telephone transceiver, such as a cellular or satellite phone, or may be coupled by land line to a public switched telephone network.

Although not shown in <b>Figure 3B</b>, the computer <b>300</b> may also include a speakerphone <b>36b</b> or a handset <b>32b</b> that interfaces with a computer <b>300</b> to establish the 2-way voice conversations.

According to the present invention, an emergency locator device is implemented as a wireless telephone having interfaces for receiving digital location data from a GPS receiver and a vehicle status data from a vehicle status management system. Under normal operations, the emergency locator device operates as a convention wireless telephone, and stores any received location data or vehicle data in an internal memory. Upon the detection of an emergency trigger, the emergency locator device automatically places a wireless telephone call to a predetermined emergency number, and supplies the stored location data and vehicle condition data. Hence, the present invention provides an economic and portable emergency locator device having sufficient flexibility to meet a variety of applications.

Although the disclosed embodiment discloses the use of a GPS receiver, it will be appreciated that other wireless location detection systems may be used. Moreover, the complementary rescue system 12 may be implemented either as portable devices or ground-based devices, as needed. In addition, the emergency locator device may be implemented as a modular system complementary to a vehicle control, navigation and communication systems, as desired.

While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.