Patent Publication Number: US-6661347-B2

Title: Systems within a position locator device for evaluating movement of a body and methods of operating the same

Description:
RELATED APPLICATIONS 
     This patent application is a continuation in part of U.S. patent application Ser. No. 09/396,991 filed Sep. 15, 1999 now U.S. Pat. No. 6,307,481. The present invention is related to that disclosed in U.S. patent application Ser. No. 09/727,974 filed Nov. 30, 2000 now U.S. Pat. No. 6,501,386. Both of the related patent applications are commonly assigned to the assignee of the present invention. The disclosures of both of the related patent applications are hereby incorporated by reference in the present application as if fully set forth herein. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to means for detecting body movement, and, more particularly, relates to systems, and methods of operation thereof, within a position locator device for evaluating movement of a body relative to an environment. The invention can provide a care giver information concerning the location and the orientation of the body of a person in the care giver&#39;s care. The present invention is especially useful in indicating that a person who is mentally or physically disabled has wandered away from bed and may fall. 
     BACKGROUND OF THE INVENTION 
     Methods for determining specific movements of a body that use a variety of devices, apparatus and systems are, generally speaking, known. The term “body” is defined broadly hereafter and includes both organic and inorganic objects. 
     In point of fact, many methods are known for sensing body movement, or non-movement (i.e., sensed dynamic accelerations, including cessation of movement), as well as, for sensing body movement over time, which is commonly used to determine comparative levels of activity of a monitored body (See, U.S. Pat. Nos. 4,110,741, 4,292,630, 5,045,839, and 5,523,742). These methodologies, however, merely report various levels of body activity, and, simply stated, fail to recognize possible causes for any increased or decreased level of body activity. 
     In contrast, other methodologies have developed over time for the detection of falls (See also, U.S. Pat. Nos. 4,829,285, 5,477,211, 5,554,975, and 5,751,214). These methodologies are largely based upon the utilization of one or more mechanical switches (e.g., mercury switches) that determine when a body has attained a horizontal position. These methods however fail to discern “normal,” or acceptable, changes in levels of body activity. Stated another way, the foregoing fall detection methodologies provide no position change analysis and, therefore, cannot determine whether a change in position, once attained, is acceptable or unacceptable. 
     Various training methods have been conceived for sensing relative tilt of a body (See, U.S. Pat. Nos. 5,300,921 and 5,430,435), and some such methodologies have employed two-axis accelerometers. The output of these devices, however, have reported only static acceleration of the body (i.e., the position of a body relative to earth within broad limits). It should be appreciated that static acceleration, or gravity, is not the same as a lack of dynamic acceleration (i.e., vibration, body movement, and the like), but is instead a gauge of position. While accelerometers that measure both static and dynamic acceleration are known, their primary use has heretofore been substantially confined to applications directed to measuring one or the other, but not both. 
     Thus, it may be seen that the various conventional detectors fall into one of two varieties, those that gauge movement of the body and those that gauge a body&#39;s position by various means, with neither type capable of evaluating body movement to determine whether the same is normal or abnormal; and if abnormal, whether such movement is so abnormal to be beyond tolerance, for instance, to be damaging, destructive, crippling, harmful, injurious, or otherwise alarming or, possibly, distressing to the body. None of the methodologies heretofore known have provided a suitable means to evaluate body movement over time and to determine whether such movement is tolerable. Further improvement could thus be utilized. 
     One very important area involving the evaluation of body movement involves monitoring the attempted movements of persons who are physically disabled or who suffer from cognitive decline. It is estimated that as many as five million (5,000,000) persons in the United States suffer from cognitive decline. Alzheimer&#39;s disease and senile dementia are the major causes of cognitive decline. Alzheimer&#39;s disease is estimated to afflict between three million (3,000,000) and four million (4,000,000) persons. Senile dementia afflicts the majority of the remainder of those persons who suffer from cognitive decline. Some persons may suffer a temporary cognitive decline due to illness and recover their cognitive faculties when they recover from the illness. 
     Alzheimer&#39;s disease is caused by the formation of amyloid plaques of protein that disrupt normal neural activity. Many persons who get Alzheimer&#39;s disease begin to experience the onset when they are in their sixties. 
     Senile dementia is caused by a number of different factors that are related to brain aging and geriatric diseases. Many persons who get senile dementia begin to experience the onset when they are in their seventies and eighties. 
     An estimated fifteen percent (15%) of people who suffer from cognitive decline are in institutions such as hospitals, nursing homes or similar institutions. The procedures that are used in such institutions are specifically designed to closely monitor persons who are suffering from cognitive decline. 
     However, most of the people who suffer from cognitive decline are not institutionalized but are cared for at home. It is estimated that as many as ten percent (10%) to twenty percent (20%) of these cases are in the advanced stages of cognitive decline. 
     Persons who are in the advanced stages of cognitive decline are very likely to be unable to prevent themselves from falling when they attempt to rise from a bed or a chair. The same is true for persons who are suffering from either temporary or permanent physical decline. For example, a person who has suffered a stroke or who has broken a leg may have a similar risk of falling when they attempt to rise from a bed or a chair. 
     In order to prevent such persons from falling, it would be advantageous to have a position locator device that could alert a care giver whenever a person who suffers from cognitive or physical decline leaves his or her bed (or chair) and wanders away. It would also be advantageous to have a position locator device that is capable of evaluating movement of the body of a monitored person relative to an environment. For example, when the position locator device detects a body movement that signifies the occurrence of a potentially dangerous event (e.g., a fall), the position locator device can immediately send an alarm to call for assistance. 
     SUMMARY OF THE INVENTION 
     To address the above-introduced deficiencies of the prior art, the present invention introduces systems, as well as methods of operating such systems, within a position locator device for evaluating movement of a body relative to an environment. For the purposes hereof, the term “body” is defined broadly, meaning any organic or inorganic object whose movement or position may suitably be evaluated relative its environment in accordance with the principles hereof; and where the term “environment” is defined broadly as the conditions and the influences that determine the behavior of the physical system in which the body is located. The term “position locator device” is defined broadly to include, without limitation, devices that are capable of sending an electronic transmission as a locator signal, Global Positioning System (GPS) devices, and other similar types of devices that are capable of detecting the location of a person who is being monitored. 
     An advantageous embodiment of a system that evaluates movement of a body relative to an environment in accordance herewith includes both a sensor and a processor. In operation, the sensor is associated with the body and operates to repeatedly sense accelerative phenomena of the body. The processor, which is associated with the sensor, processes the sensed accelerative phenomena as a function of at least one accelerative event characteristic to determine whether the evaluated body movement is within environmental tolerance. The processor also preferably generates state indicia while processing the sensed accelerative phenomena, which represents the state of the body within the environment over time. 
     For the purposes hereof, the term “sensor” is defined broadly, meaning a device that senses one or more absolute values, changes in value, or some combination of the same, of at least the sensed accelerative phenomena. According to a preferred embodiment, described in detail hereafter, the sensor may be a plural-axis sensor that senses accelerative phenomena and generates an output signal to the processor indicative of measurements of both dynamic and static acceleration of the body in plural axes. 
     According to this embodiment, the processor receives and processes the output signal. The processor is preferably programmed to distinguish between normal and abnormal accelerative events, and, when an abnormal event is identified, to indicate whether the abnormal event is tolerable, or within tolerance. In further embodiments, the processor may be programmed to distinguish other physical characteristics, including temperature, pressure, force, sound, light, relative position, and the like. 
     It should be noted that the relevant environment may be statically or dynamically represented. The sophistication of any such representation may be as complex or as uncomplicated as needed by a given application (e.g., disability, injury, infirmity, relative position, or other organic assistance monitoring; cargo or other transport monitoring; military, paramilitary, or other tactical maneuver monitoring; etc.). It should further be noted that any representation may initially be set to, or reset to, a default, including, for instance, a physically empty space, or vacuum. 
     Regardless, the principles of the preferred exemplary embodiment discussed heretofore require at least one accelerative event characteristic to be represented to enable the processor to determine whether the evaluated body movement is within environmental tolerance, which is again advantageously based upon both dynamic and static acceleration measurements. 
     According to a related embodiment, the processor is further operable, in response to processing the sensed accelerative phenomena, to generate state indicia, which includes tolerance indicia, generated in response to determining whether the evaluated body movement is within environmental tolerance. Preferably, such tolerance indicia is compared with at least one threshold, likely associated with the accelerative event characteristic. In response to such comparison, the processor controls a suitable indicating means to initiate an alarm event; to communicate such tolerance indicia to a monitoring controller; to generate statistics; or the like. 
     According to a related preferred embodiment, the system may be associated with other components or sensing systems. For instance, in an assistance monitoring application, the sensor may repeatedly sense dynamic and static acceleration of the body in the plural axes and generate output signals indicative of the measurements. The processor continuously processes the output signals to distinguish between selected accelerative and non-selected accelerative events (described in detail hereafter) based upon both the dynamic and the static acceleration of the body, and generates state indicia, including tolerance indicia, that is communicated to a remote monitoring controller. The tolerance indicia is communicated to the monitoring controller for record keeping/statistical purposes, as well as to provide “live” monitoring of the individual subscriber. 
     Communication between the processor and the controller may be by a wireless network, a wired network, or some suitable combination of the same, and may include the Internet. Preferably, the system generates an alert whenever the monitored subscriber is in “jeopardy,” as determined by the system, such as in response to a debilitating fall by the subscriber. In a further embodiment, the processor is operable to repeatedly generate “heartbeat” indicia that indicates that the system is in an operable state, whereby absence of the same informs the monitoring controller that some other part of the system is malfunctioning. 
     In an alternate embodiment of the present invention, the sensor and the processor are located within a position location device. The position location device may communicate information to a care giver by a wireless network, a wired network, or some suitable combination of the same, and may include the Internet. The information sent by the position location device may comprise (1) information concerning the body orientation of a person and (2) information concerning the location of a person. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the DETAILED DESCRIPTION OF THE INVENTION that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and specific embodiments disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form. 
     Before undertaking the DETAILED DESCRIPTION OF THE INVENTION, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, and the term “associable” may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the terms “controller” and “processor” mean any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some suitable combination of at least two of the same. It should be noted that the functionality associated with any particular controller/processor may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, wherein like numbers designate like objects, and in which: 
     FIG. 1 illustrates an isometric view of an exemplary embodiment of a system that evaluates body movement in accordance with the principles of the present invention; 
     FIG. 2 illustrates a block diagram of the exemplary system set forth with respect to FIG. 1; 
     FIGS. 3 a  to  3   d  illustrate exemplary strip chart records of output of the sensor introduced in FIGS. 1 and 2 taken during illustrative situations; 
     FIG. 4 illustrates an operational flow diagram of an exemplary method of programming a processor in accordance with a fall detection application of the principles of the present invention; 
     FIG. 5 illustrates a functional block diagram of an alternate sensing system that may suitably be associated with the processor of the present invention; 
     FIG. 6 illustrates a perspective view of an exemplary remote receiver unit of the system of this invention; 
     FIG. 7 illustrates a functional block diagram of the exemplary receiver unit of FIG. 6; 
     FIG. 8 illustrates an exemplary wireless network that is associated via a wired network, such as the Internet, to a remote monitoring controller according to one embodiment of the present invention; and 
     FIG. 9 illustrates an exemplary position location device that contains an exemplary embodiment of the system of the present invention for evaluating body movement. 
    
    
     DESCRIPTION OF THE INVENTION 
     Turning initially to FIG. 1, there is illustrated an isometric view of an exemplary embodiment of a system (generally designated  11 ) that evaluates body movement in accordance with the principles of the present invention, and more particularly that measures and distinguishes selected accelerative events of a body (not shown). As used in this disclosure, the phrases “accelerative events” or “accelerative phenomena” are defined as occurrences of change in velocity of the body (or acceleration), whether in magnitude, direction or both. 
     System  11  includes circuit boards  13  and  15  (connected boards at right angles to one another) that are associated with a housing (generally designated  17 ) utilizing known mounting techniques. Exemplary housing  17  (and system  11 , for that matter), when assembled, is approximately one centimeter thick and is approximately five centimeters across in any direction. 
     Housing  17  may comprise, for example, exemplary housing halves  19  and  21  that encase boards  13  and  15 , although those skilled in the art will understand that any configuration suitable for a particular implementation of the invention may be arranged. 
     Exemplary rear half  21 , is provided with a clip  23  for associating system  11  with the body (e.g., people, animals, objects of various sorts, etc.). Exemplary clip  23  is shown as a mechanical spring-type clip, but could be any known attachment device or system, including either mechanical or chemical attachment systems, or any other suitable means for associating system  11  with the body. 
     System  11  includes a processor (shown in FIG. 2) and a sensor  25 . Exemplary sensor  25  operates to sense accelerative phenomena of the body, and is mounted on circuit board  13  with x and y axes  27  and  29 , respectively, oriented thereat (though other orientations could be utilized). 
     Sensor  25  is illustratively shown as a plural-axis (dual shown) acceleration measuring device suitably mounted on a single monolithic integrated circuit (one conventional sensor is an accelerometer available from ANALOG DEVICES, INC., located at One Technology Way, Norwood, Mass., United States of America, namely, Model No. ADXL202). Sensor  25  includes polysilicon surface-micromachined sensor layer  31  built on top of silicon wafer  33 . Polysilicon springs  35  resiliently suspend sensor layer  31  over the surface of wafer  33  providing resistance against acceleration forces. Deflection of the sensor layer is measured using a differential capacitor formed by independent fixed and central plates, the fixed plates driven by 180° out of phase square waves having amplitude proportional to acceleration. Signal outputs from each axis of sensor  25  are conditioned (i.e., phase sensitive demodulation and low pass filtering) and presented at analog output nodes. While not utilized in the primary advantageous embodiment of this invention, the ANALOG DEVICES&#39; accelerometer is operable to convert the analog signals to duty cycle modulated (“DCM”) signals at a DCM stage providing digital output signals capable of being directly counted at a processor. 
     While techniques for reconstructing analog signals from the digital output signals may suitably be utilized (e.g., passing the duty cycle signals though an RC filter), thereby allowing use of the digital signal output of a sensor of system  11  hereof, use of the analog signal outputs has been found advantageous due to the increased bandwidth availability (0.01 Hz to 5 kHz, adjustable at capacitors at the output nodes to bandlimit the nodes implementing low-pass filtering for antialiasing and noise reduction), and the measuring sensitivity that may be attained. A typical noise floor of five hundred micro “g” per Hertz (500×10 −6  “g”/Hz) is achieved, thereby allowing signals below five milli “g” (5×10 −3  “g”) to be resolved for bandwidths below 60 Hz. The value “g” is the acceleration of gravity at the surface of the earth (32 feet/sec 2  or 9.8 m/sec 2 ). 
     According to the illustrated embodiment, sensor  25  generates analog output voltage signals corresponding to measurements in the x and y axes, which include both an ac voltage component proportional to G forces (i.e., dynamic acceleration component related to vibrations of sensor layer  31 ) and a dc voltage component proportional to an angle relative to earth (i.e., static acceleration component related to gravity). This open loop acceleration measurement architecture, capable of measuring both static and dynamic acceleration, can thus be utilized to determine position of a body by measuring both the x and y output voltages simultaneously, as well as measure forces of impact experienced by a body. This information comprises state indicia, and utilizing both signal components from both outputs, the sensed accelerative phenomena of the body may subsequently be processed to distinguish a variety of accelerative phenomena and, ultimately, to selectively act based on the distinctions, as is described in detail hereafter to determine whether the evaluated body movement is normal or abnormal, and, if abnormal, whether the same is within tolerance. 
     It is noted that the foregoing embodiment has been introduced for illustrative purposes only. In alternate embodiments, any sensor that is capable of sensing accelerative phenomena relative to a body may be used in lieu of, or even in conjunction with, sensor  25 . Further, alternate orientations of sensor  25  may be used for different applications. 
     Turning next to FIG. 2, there is illustrated a block diagram of the exemplary system of FIG. 1, which includes processing circuitry  39 , indicating means  41 , power supply  67 , and a switch  68 , along with sensor  25 . 
     Exemplary processing circuitry  39  illustratively includes a processor  47  and buffer amplifiers  43  and  45  that buffer the analog x and y outputs from sensor  25 . Exemplary processor  47 , which is associated with sensor  25 , is capable of processing the sensed accelerative phenomena as a function of at least one accelerative event characteristic to thereby determine whether an evaluated body movement is within environmental tolerance. Processor  47  also preferably generates state indicia while processing the sensed accelerative phenomena, which may represent the state of the body within the environment over time. Processor  47  is associated with a crystal oscillator/clock  49 , switch (DIP) inputs  51 , an analog-digital conversion circuitry  53  and a DSP filter  55  (one conventional processor is available from TEXAS INSTRUMENTS, INC., located in Dallas, Tex., United States of America, namely, Model No. MSP430P325). 
     Exemplary indicating means  41 , in response to direction from processor  47 , is operable to accomplish at least one of the following: initiate an alarm event; communicate such state, or tolerance, indicia to a monitoring controller; generate statistics; etc. Indicating means  41  may take any number of forms, however, for use in system  11  of the present embodiment, stage  41  is an RF transmitter including RF modulator  61  enabled by processor  47 . Exemplary data is presented and modulated at modulator  61 , amplified at amplifier  63  and transmitted at antenna  65  (to a remote receiver unit as discussed hereinafter). 
     According to the present embodiment, power for the various components of system  11  is provided by power supply  67 , which illustratively is a 3.6 volt lithium ion battery. Low power management may suitably be under the control of processor  47  utilizing exemplary switched/power supply voltage FET switch  68  at sensor  25 , which provides power only during sampling cycles, and operates to shut components down during non-use cycles. For instance, processor  47  may be taken off-line when processing is complete, reducing current drain. 
     It should be noted that the various circuitry discussed heretofore has been introduced herein for illustrative purposes only. System  11  may be implemented using any suitably arranged computer or other processing system including micro, personal, mini, mainframe or super computers, as well as network combinations of two or more of the same. In point of fact, in one advantageous embodiment, sensor  25  and processor  47  are not co-located, but rather associated wirelessly. To that end, the principles of the present invention may be implemented in any appropriately arranged device having processing circuitry. Processing circuitry may include one or more conventional processors, programmable logic devices, such as programmable array logic (“PALs”) and programmable logic arrays (“PLAs”), digital signal processors (“DSPs”), field programmable gate arrays (“FPGAs”), application specific integrated circuits (“ASICs”), large scale integrated circuits (“LSIs”), very large scale integrated circuits (“VLSIs”) or the like, to form the various types of circuitry, processors, controllers or systems described and claimed herein. 
     Conventional computer system architecture is more fully discussed in THE INDISPENSABLE PC HARDWARE BOOK, by Hans-Peter Messmer, Addison Wesley (2nd ed. 1995) and COMPUTER ORGANIZATION AND ARCHITECTURE, by William Stallings, MacMillan Publishing Co. (3rd ed. 1993); conventional computer, or communications, network design is more fully discussed in DATA NETWORK DESIGN, by Darren L. Spohn, McGraw-Hill, Inc. (1993); conventional data communications is more fully discussed in VOICE AND DATA COMMUNICATIONS HANDBOOK, by Bud Bates and Donald Gregory, McGraw-Hill, Inc. (1996), DATA COMMUNICATIONS PRINCIPLES, by R. D. Gitlin, J. F. Hayes and S. B. Weinstein, Plenum Press (1992) and THE IRWIN HANDBOOK OF TELECOMMUNICATIONS, by James Harry Green, Irwin Professional Publishing (2nd ed. 1992); and conventional circuit design is more fully discussed in THE ART OF ELECTRONICS, by Paul Horowitz and Winfield, Cambridge University Press (2nd ed. 1991). Each of the foregoing publications is incorporated herein by reference for all purposes. 
     Turning next to FIGS. 3 a  to  3   d , illustrated are exemplary strip chart records of output of exemplary sensor  25  of FIGS. 1 and 2 taken during illustrative situations. More particularly, FIGS. 3 a  and  3   b  illustrate the analog signal at the x and y outputs of sensor  25  during a fall by a body to the left, and whereas FIGS. 3 c  and  3   d  illustrate the analog signal at the x and y outputs of sensor  25  during a fall by a body to the right (the dark blocks indicating an alarm condition). As can be seen from the exemplary traces, a fall to the left and to the right are both distinguishable by the disruption of a stable position, or normal body movement, by a concussive force followed by a distinctly different ending stable position. According to the illustrative embodiment introduced herein, the direction of fall is clear from the position of the ending trace at the y outputs. If the fall had been more forward or backward, the x output traces would likewise clearly indicate the same (this assumes x and y sensor axes orientation as set forth in FIG.  1 ). Of course, the same x and y outputs of the sensor  25  may be suitably processed to simply determine position of the body, for instance, such as when a person is lying down, when a box has tipped over, etc. 
     Turning next to FIG. 4, illustrated is operational flow diagram of an exemplary method (generally designated  400 ) of programming of processor  47  in accordance with a fall detection application of the principles of the present invention. For the purposes of illustration, concurrent reference is made to system  11  of FIGS. 1 and 2. It should be noted that this illustration introduces an exemplary operational method for programming processor  47  for its use as a fall detector, and that suitable alternate embodiments of system  11  for evaluating movement of a body relative to different environments may likewise be implemented in accordance with the principles hereof, such as for relative position, other assistance monitoring, transparent monitoring, tactical maneuver monitoring etc. 
     Exemplary method  400  begins and a request for sampling measurements is generated, likely by processor  47  (Step  405 ), either in response to an executing operations program or upon initiation by a user, possibly remotely from a monitoring controller (discussed with reference to FIG.  8 ). Sensor  25  sense x and y acceleration values generating measurement signals at the outputs at sensor  25 . 
     In the present implementation, the measurement signals are converted from analog to digital format and filtered by filter  55  (Step  410 ; thereby reducing probability that an out-of-tolerance abnormal movement will be determined incorrectly in response to a single sharp impact, such as a collision between mount  17  and a hard surface when sensor  25  is off the body causing a sharp signal spike). 
     Processor  47  uses dc voltage components of the outputs from sensor  25  to determine a last stable position of the body on which sensor  25  is mounted (Step  415 ). More particularly, processor  47  repeatedly compares successive input values with immediately preceding input values and, if within tolerance, are added thereto and stored in an accumulator. This is repeated until Z samples have been accumulated and added over some defined period of time (e.g., one second) or until a received input is out of tolerance, in which case the sampling cycle is reinitiated. When Z samples are accumulated and added, the accumulated value is divided by Z to determine a “last stable” static acceleration average value, which is saved and is indicative of the last stable position of the body. Sampling and/or sampling cycle rates may be varied, but, while preferably not continuous due to power consumption concerns, should be substantially continual. It is important to note, therefore, that such characteristics maybe statically maintained or dynamically generated. 
     Processor  47  uses ac voltage components of each output from sensor  25  to check against a G force threshold value set at DIP switch  51  to see if it exceeds the threshold (Step  420 ; thus qualifying as a potential fall impact, in the current example, possibly an intensity in excess of about 2 to 4 G depending upon desired sensitivity). According to the present implementation, if three of these dynamic acceleration measurements are received in excess of the threshold without five intervening measurements that are less than the threshold, the impact detect flag may be set. 
     Processor  47  determines a fall by testing a post-impact stream of samples against a tolerance (Step  425 ; for instance, a selected value of the ac voltage components, for example a value less than about 2 G). Each new sample is tested against the previous sample to see if the position of the body has stabilized. When the position has stabilized to less than the tolerance, W samples are averaged to get the new stable static acceleration average value corresponding to the new stable position. 
     Processor  47 , in response to the value corresponding to the new stable position is shifted indicating a change of body position of 45° or more from the last stable position, classifies the event as a debilitating fall and alert stage  41  is activated (Step  430 ). A greater stabilization or post-stabilization sample period may be selected to allow more time for an uninjured user to rise without issuance of an alert. 
     Processor  47 , after setting the last stable position, adds the absolute values of the x and y last stable positions together, and, then determines whether the body associated with sensor  25  is lying down if the added value exceeds a value corresponding to 90° plus or minus 25% (Step  435 ). In such case, after a selected time (for example, four seconds) with repeated like values, the laying down detect flag is set. While this flag is set, any impact that exceeds the G force threshold is treated as a debilitating fall (Step  440 ). The flag is set only as long as the added value continues to indicate that the wearer is laying down. 
     It should be noted that the foregoing embodiment was introduced for illustrative purposes only and that the present invention broadly introduces systems, as well as methods of operating such systems, that evaluate movement of a body relative to an environment, which in the above-given example is an assistance monitoring environment. An important aspect of the present invention is that processor  47  is operable to process sensed accelerative phenomena as a function of at least one accelerative event characteristic, and that such characteristics will largely be defined by the specific application. Therefore, system  11 , and, more particularly, processor  47 , generates state indicia relative the environment of interest, and determines whether the evaluated body movement is within tolerance in the context of that environment. For instance, “tolerance” would likely be very different for a monitored body of an elderly person with a heart condition, a toddler, a box in a freight car, a container of combustible gas, etc. 
     Turning next to FIG. 5, illustrated is a functional block diagram of an alternate sensing system (generally designated  71 ) that may suitably be associated with processor  47  of FIGS. 1,  2 , and  4  in accordance with the principles of the present invention. In this embodiment, components utilizable with system  11  are configured again as a human fall monitor/detector, and any or all of these additional monitoring functions may be employed with system  11 . For purposes of illustration, concurrent reference is made to processor  47  of FIGS. 2 and 4. 
     Exemplary sensor  71  includes a respiration module  73 , which includes a body contact breath sensor  75  (for example a volumetric sensor, or a near body breath sensor), low pass filter  77  and amplifier  79  providing output signals indicative of respiration rate and vitality to processor  47 . The outputs are processed and, when a dangerous respiratory condition is suggested (generates state indicia relative the environment, and determines whether the evaluated body movement (broadly defined herein to include organic physiologic phenomena) is within environmental tolerance), an identifiable (for example, by signal coding) alarm sent indicating means  41 . 
     Sensor  71  further includes an ECG module  81 , which includes input electrodes  83  and  85  providing heart rate signals to filters  87  and  89 . The filtered signals are amplified at amplifier  91  and band pass filtered at filter  93 . The output is amplified at  95  for input to processor  47  and processed so that dangerous heart rhythms and events can be detected (generates state indicia relative the environment, and determines whether the evaluated body movement is within environmental tolerance) and an identifiable alarm sent at alert stage  41 . 
     Sensor  71  further includes a panic button module  97  that is operable using a standard user activated switch  99  positioned at housing  17  allowing a user to initiate a call for help. The switch output is input to processor  47  to initiate an identifiable alarm at alert stage  41 . 
     Turning momentarily to FIGS. 6 and 7, illustrated are a perspective view of an exemplary remote receiver unit of the system of this invention and a functional block diagram of the same. In a distributed system in accord with one embodiment of this invention, a remote receiver unit  103  (for example a wall mountable unit) as shown in FIGS. 6 and 7 is provided for receipt of transmissions from sensor  25  and/or system  71 . Unit  103  includes a receiver antenna  105 , indicator LED&#39;s  107  (including indicators for as many detector functions as are employed in the specific embodiment of the apparatus being monitored, as well as an indicator for unit on/off status), and a user interface input keypad  111  for unit setup, reset and alarm deactivation. Power access  113  is provided at the bottom of the unit. 
     RF receiver  115  is tuned to receive alarm transmissions from sensor  11 / 71  and presents the signal received for processing at processor  117  for alarm identification and appropriate output. Processor  117  also receives inputs from keypad  111  and power switch  119 . Non-volatile memory  121  is provided for input of identification of the user and/or of the apparatus being monitored. Audible alarm  123 , LED bank  107  and retransmission unit  125  (an autodialer, imbedded digital cellular technology, RF transmitter, an Internet appliance, or the like) are connected to receive outputs from processor  117 . 
     When a transmission is received, or when battery power at the body mounted apparatus is low, an audible alarm is sounded and the appropriate LED (indicative of the condition causing the alarm, for example a debilitating fall by a user of apparatus  11 ) is activated. If not disabled by the user at key pad  111  within a short period, processor  117  activates retransmission unit  125  initiating a call for help or other remote notification. 
     Operational setup of unit  103  is also accomplished under programming at processor  117  and by sequential operation by a user or technician of keypad  111  and/or power switch  119  as is known (including user ID set, learn mode operations, reset or reprogramming operations, and urgency code operations). 
     Turning next to FIG. 8, illustrated is an exemplary hybrid wireless/wired network (generally designated  800 ) that is associated with a remote monitoring controller  805  according to one embodiment of the present invention. The wireless network  810  is introduced for illustrative purposes only, and comprises a plurality of cell sites  821  to  823 , each containing one of the base stations, BS  801 , BS  802 , or BS  803 . Base stations  801  to  803  are operable to communicate with a plurality of mobile stations (MS) including MS  103  (remote receiver unit  103 ), and MS  811 , MS  812  and MS  814 . Mobile stations MS  103 , and MS  811 , MS  812  and MS  814 , may be any suitable cellular devices, including conventional cellular telephones, PCS handset devices, portable computers, metering devices, transceivers, and the like (including, for instance, remote receiver unit  103 ). 
     Dotted lines show the approximate boundaries of the cell sites  821  to  823  in which base stations  801  to  803  are located. The cell sites are shown approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the cell sites also may have irregular shapes, depending on the cell configuration selected and natural and man-made obstructions. 
     In one embodiment of the present invention, BS  801 , BS  802 , and BS  803  may comprise a base station controller (BSC) and a base transceiver station (BTS). Base station controllers and base transceiver stations are well known to those skilled in the art. A base station controller is a device that manages wireless communications resources, including the base transceiver station, for specified cells within a wireless communications network. A base transceiver station comprises the RF transceivers, antennas, and other electrical equipment located in each cell site. This equipment may include air conditioning units, heating units, electrical supplies, telephone line interfaces, and RF transmitters and RF receivers, as well as call processing circuitry. For the purpose of simplicity and clarity in explaining the operation of the present invention, the base transceiver station in each of cells  821 ,  822 , and  823  and the base station controller associated with each base transceiver station are collectively represented by BS  801 , BS  802  and BS  803 , respectively. 
     BS  801 , BS  802  and BS  803  transfer voice and data signals between each other and the public telephone system (not shown) via communications line  831  and mobile switching center (MSC)  840 . Mobile switching center  840  is well known to those skilled in the art. Mobile switching center  840  is a switching device that provides services and coordination between the subscribers in a wireless network and external networks  850 , such as the Internet, public telephone system, etc. Communications line  831  may be any suitable connection means, including a T1 line, a T3 line, a fiber optic link, a network backbone connection, and the like. In some embodiments of the present invention, communications line  831  may be several different data links, where each data link couples one of BS  801 , BS  802 , or BS  803  to MSC  840 . 
     In the exemplary wireless network  800 , MS  811  is located in cell site  821  and is in communication with BS  801 , MS  103  is located in cell site  822  and is in communication with BS  802 , and MS  814  is located in cell site  823  and is in communication with BS  803 . MS  812  is also located in cell site  821 , close to the edge of cell site  823 . The direction arrow proximate MS  812  indicates the movement of MS  812  towards cell site  823 . 
     For the purposes of illustration, it is assumed that system  11  is associated with an elderly person whose residence is wirelessly monitored. It is further assumed that sensor  25  is associated with the elderly person and that processor  47  is coupled in MS/remote receiver unit  103 , such that sensor  25  and processor  47  are wirelessly associated. 
     System  11  repeatedly senses various physiological phenomena of the elderly person, including accelerative phenomena of his body. Remote processor  47  processes the repeatedly sensed phenomena, and, particularly, the accelerative phenomena of the body, as a function of at least one accelerative event characteristic to thereby determine whether the evaluated body movement is within environmental tolerance. Processor  47  advantageously generates state indicia while processing the sensed accelerative phenomena, representing the state of the body within the environment over time. 
     Exemplary processor  47  is programmed to distinguish between normal and abnormal accelerative events (e.g., walking, sitting, lying down, etc. versus tripping, falling down, etc.), and, when an abnormal event is identified, indicates whether the abnormal event is tolerable, or within tolerance. Processor  47  may also suitably be programmed to distinguish other physical characteristics, including temperature, pressure, force, sound, light, relative position (including lying down), and the like. 
     As processor  47  generates state indicia, which includes tolerance indicia, it uses the same to determine whether the evaluated body movement is within environmental tolerance. Preferably, such tolerance indicia is compared with at least one threshold, likely associated with the accelerative event characteristic. In response to such comparison, processor  47  controls a suitable indicating means to initiate an alarm event (locally and via network  810  to monitoring controller  805 ), to communicate such tolerance indicia to a monitoring controller  805 , to generate statistics (locally and via network  810  to monitoring controller  805 ), or the like. 
     According to a related preferred embodiment, such state indicia, and other information is communicated from time to time to monitoring controller  805 , from which such information may suitably be perceived. For instance, a technician, medical professional, or relative might wish to review the activities and status of the elderly person. This may easily be facilitated via a centralized data repository accessible via the Internet, or via any other suitably arranged network. While viewing such information, the technician, medical professional, or relative (subscriber  2 , generally designated  855 ) might initiate a diagnostic equipment check, a physiological test, a simple status check, or the like. Similarly, monitoring controller  805 , via the network  800 , may monitor a “heartbeat” signal generated periodically by MS/remote receiver unit  103 , the heartbeat indicating that unit  103  is functional. 
     FIG. 9 is a block diagram illustrating how the circuitry of the present invention may utilized within an exemplary position location device. The exemplary position location device may comprise wireless mobile station/remote receiver unit  103 . The MS designation has been dropped for convenience. Position location device  103  (i.e., remote receiver unit  103 ) is worn by the person whose location is being monitored. 
     Position location device  103  comprises radio frequency (RF) transceiver  910  coupled to antenna  905  for receiving a forward channel signal from wireless network base station BS  802  and for sending a reverse channel signal to wireless network base station BS  802  in accordance with well known principles. As will be more fully described, position location device  103  is also capable of receiving a radio frequency (RF) signal from a transmitter (not shown) located on or near the bed or chair of the person whose location is being monitored. 
     RF transceiver  910  is coupled to receiving processing circuitry  925  which, in turn, is coupled to speaker  930  and main controller  940 . Main controller  940  is coupled to transmission processing circuitry  915  which, in turn, is coupled to microphone  920  and RF transceiver  910 . Main controller  940  controls the reception of forward channel signals and the transmission of reverse channel signals in accordance with well known principles. Main controller  940  is also coupled to I/O interface  935 , keypad  950  and display unit  955 . Main controller  940  controls the transmission of signals to and from these elements with methods well known in the art. 
     Sensor  25  is coupled to main controller  940 . Processing circuitry  39  comprising processor  47  (not shown in FIG. 9) is also coupled to main controller  940 . The x output signal of sensor  25  and the y output signal of sensor  25  are coupled to processing circuitry  39  as previously described. In this embodiment of the present invention, the structure of indicating means  41  (not shown in FIG. 9) comprises transmit processing circuitry  915 , RF transceiver  950  and antenna  905 . 
     When sensor  25  detects a body movement that signifies the occurrence of a potentially dangerous event (e.g., a fall), processing circuitry  39  immediately causes main controller  940  to send an alarm via transmit processing circuitry  915 , RF transceiver  950  and antenna  905 . The alarm signal may also include detailed information concerning the values of the measured x and y signals. 
     As previously mentioned, a radio frequency (RF) transmitter (not shown) is located on or near the bed or chair of the person whose location is being monitored. This transmitter will be referred to as the “range transmitter.” Either continually or periodically, the range transmitter sends a low intensity RF signal to position location device  103 . The low intensity RF signal from the range transmitter is received via antenna  905  in RF transceiver  910  of position location device  103 . The range transmitter signal is then sent to main controller  940  via receiving processing circuitry  925 . 
     Main controller  940  continually monitors the signal strength of the range transmitter signal. If the signal strength of the range transmitter signal is above a threshold level, then position location device  103  is located near the range transmitter. This means that the person whose location is being monitored is near the range transmitter and therefore near the person&#39;s bed or chair. 
     When main controller  940  determines that the signal strength of the range transmitter signal is below the threshold level, then position location device  103  is no longer near the range transmitter. This means that the person whose location is being monitored has wandered away from the range transmitter and is therefore no longer near the person&#39;s bed or chair. When this happens, main controller  940  sends an alarm signal to the person&#39;s care giver via wireless network  800 . 
     This description of the operation of position location device  103  is by way of example only. That is, many different types of position location devices exist, and it is clear that the present invention is not limited to use with only one type of position location device. 
     The present invention has been described with reference to an advantageous embodiment for obtaining (1) information concerning the body orientation of a person and (2) information concerning the location of a person. However, it is clear that the present invention is not limited to use with persons. The present invention may also be generally used to obtain information concerning animate and inanimate objects. 
     In an alternate embodiment of the present invention, processing circuitry  39  comprising processor  47  (not shown in FIG. 9) is capable of recording the values of the measured x and y signals and recording the times of the measurements using time signals from clock  49  (not shown in FIG.  9 ). In some cases it will be more practical to record the values of the x and y signals for later downloading that to immediately transmit an alarm signal and the values of the x and y signals. For example, when a shipping container is allowed to tip over or is otherwise mishandled during shipment, it may not be practical to immediately respond to the mishandling event. At the conclusion of the shipment, however, the time that the mishandling event occurred may be recovered from processing circuitry  39 . The time of the mishandling event may then be compared to the shipping schedule to determine the identity of the individual carrier responsible for the mishandling event. 
     In an alternate embodiment of the present invention, sensor  25  may comprise tilt switch sensors of the type described in U.S. patent application Ser. No. 09/542,197 filed Apr. 4, 2000 by Halleck et al. entitled “Apparatus and Method for Detecting An Inclination of A Body.” 
     Although the present invention has been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form.