Abstract:
A taxi meter system mounted on a taxicab for accurately computing a fare for a taxicab trip as function of time and distance is disclosed. The system provides discrimination means that eliminate the contribution to the fare that may otherwise be created by illegal means that degrade the performance of the taxi meter system.

Description:
BACKGROUND OF THE INVENTION 
     1.0 Field of the Invention 
     The invention relates to a taxi meter system that computes the fare for a trip in a taxicab as a function of distance and time and, more particularly, to a taxicab system having means for detecting erroneous inputs that would otherwise cause for erroneous calculations of the fare. 
     2.0 Description of the Related Art 
     Taxicab businesses are highly interactive with the general public, and as such, are regulated to provide penalties so as to prevent the public from being mistreated. One such mistreatment is the incorrect calculation of the fare for the taxicab ride. 
     Taxicab businesses have recently employed digital devices having a computer therein serving as a computational means so as to automatically provide accurate fee calculations without any intervention from the taxicab driver. However, some taxicab drivers employ a so called “zapper” or deceiving system that disrupts the taxicab meter system so as to illegally increase the fare paid by the rider of the taxicab. It is desired that a taxicab meter system be provided that has means to detect erroneous inputs from the deceiving systems that would otherwise cause higher and inaccurate fare calculations. 
     OBJECTS OF THE INVENTION 
     It is the primary object of the present invention to provide for discriminating means for use in a taxi meter system that detects erroneous inputs resulting from the undesired contributions from external devices that would otherwise contribute to higher and inaccurate fare calculations. 
     It is another object of the present invention to provide for a taxi meter system that also provides for alarm conditions upon the detection of erroneous and illegal inputs to the taxi meter system. 
     It is another object of the present invention to provide for discriminating means for use in a taxi meter system that eliminates the undesired contributions from external devices. 
     It is another object of the present invention to provide for a taxi meter system that not only calculates accurate fares, but also provides for alarm conditions upon the detection of erroneous and illegal inputs to the taxi meter system. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a system mounted on a taxicab for accurately computing the fare for a taxicab trip as a function of distance and time. The system comprises means for generating true pulses each representative of the actual distance and time traveled by the taxicab. Means for receiving the true pulses as well as receiving false pulses erroneously representing the distance and time traveled by the taxicab. The system further comprises means for dividing the number of true and false pulses by a predetermined amount and providing an output therefrom representative of the number of true and number of false pulses received. The system further comprises discriminating means for receiving the output of the means for dividing and detecting the presence of false pulses from the output thereof. The system further comprises visual or audio alarm means for indicating the detection of said false pulses. The system further comprises processing means for registering the detection of said false pulses. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention may be realized when considered in view of the following detailed description, taken in conjunction with the accompanying drawings. 
     FIG. 1 is a block diagram of the system of the present invention for calculating the fare for a taxicab. 
     FIG. 2 illustrates the possible outputs from a device that would otherwise, without the benefits of the present invention, detrimentally effect the computations performed by the computing system of the taxi meter system. 
     FIG. 3 illustrates the receipt and response of the divider of the present system without any contributions from erroneous sources. 
     FIG. 4 illustrates the receipt and response by the divider of the present system receiving true and false pulses with the false pulses, which without the benefits of the present invention, would detrimentally effecting the calculated taxicab fare. 
     FIG. 5 is a flow chart showing the overall operation of the discriminating means of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, wherein the same reference numbers indicate the same elements throughout, there is shown in FIG. 1 a block diagram of the system  10  that is capable of being mounted on a taxicab for computing the fare for a taxicab trip as a function of distance and time. The system  10  comprises a divider  12  having an output  12 A and a processor  14  having an application program  16  that is of particular importance of the present invention, and preferably an alarm and display subsystem  18  that supplies inputs into the processor  14  and is responsive to the output of the processor  14 . 
     The system  10  receives its representative time and distance inputs from a gear mechanism  20 . The gear mechanism  20  has mechanical features that control the speedometer  22  of a taxicab by way of path  24 , but with regard to the present invention, when the taxicab is traveling the gear mechanism  20  produces pulses and transmits the pulses  26 A (to be further described with reference to FIGS. 3 and 4) to the taxi meter system  10  by way of signal path  26 . As will be explained, the processor  14  uses the number of received pulses  26 A for calculating the fare of the taxicab. The number of pulses generated by the gear mechanism  20  and received by the processor  14 , in particular the divider  12 , typically range from about 1200 to about 6000 pulses per mile of taxicab travel. This number is not constant but rather is a reflection of the taxi model and maker. 
     The gear mechanism  20  serves as means for generating true pulses  26 A each representative of the actual distance and time traveled by the taxicab. The accuracy of the system  10 , that is, the taxi meter system  10 , to process such true pulses is interfered with by the illegal device sometimes referred to as a “zapper” or deceiving system  28 . 
     The zapper  28  generates erroneous pulses  28 A (to be further described with reference to FIG. 4) representative to the time traveled by the taxicab causing the system  10 , without the benefits of the present invention, to incorporate a higher number of pulses into the fare calculation. As a result the passenger would otherwise be charged an incorrect fare that is higher than the amount that should be paid. 
     The system  10  of the present invention has dividing means  12  that divides the number of true and false pulses by a predetermined amount, such as  4 , and provides an output therefrom representative of the number of true and the number of false pulses received by the divider  12  and which is applied on signal path  12 A and accepted by the processor  14 . The processor  14  has an application program  16  running therein that serves as the discriminating means of the present invention for receiving the output  12 A of the divider  12  and detecting the contribution of the false pulses generated by the zapper  28 . The application program  16  provides for an output that is used by the processor  14  for signaling the existence of false pulses. 
     The application program  16  of the present invention may be loaded and executed by the processor  14  which may be a conventional computer system. Upon such loading, the processor  14  becomes a primary apparatus for the practice of the present invention. The present invention can also be embodied in the form of a computer program code, for example, whether stored on a storage medium, loaded into and/or executed by a computer or transmitted over some transmission medium such as over electrical wires or cables, through fiber optics, or via electromagnetic radiation, wherein the application program  16  is loaded into and executed by a computer or processor  14 . 
     The zapper  28  commonly produces a sequence of pulses  28 A with the pulses  28 A being triggered by a clock and with a constant frequency. The zapper  28  may include pulse rates in a low range from one (1) pulse per second up to four (4) pulses per second, and in a high range in excess of hundreds of pulses per second. The zapper  28  may also include an adjustment knob or modulator which enables the users, such as the taxicab driver, to modulate the rate of pulses during the trip. The zapper  28  may be operated in automatic and manual modes, wherein the automatic operation allows the zapper  28  to be operative without an operator&#39;s, such as a taxicab driver, intervention, and conversely, the manual operation allows the zapper  28  to be turned on and off by the taxicab driver or left on continuously by the taxicab driver. The zapper  28  may produce different pulse outputs which may be further described with reference to FIG.  2 . 
     FIG. 2 illustrates the various types of typical pulse patterns that may appear at output of the zapper  28  as pulses  28 A and which may comprise three different types shown as  32 ,  34  and  36  each showing the pattern of different pulses initiated at the start of trip (indicated as event  38 ) and terminated at the end of trip (indicated as event  40 ). Pulse pattern  32  represents a constant rate of pulses generated by zapper  28  commonly turned on automatically when the conventional taxi meter is activated. Pulse pattern  34  represents the modulated output of zapper  28  commonly employed automatically with the activation of the conventional taxi meter. Pulse pattern  36  represents the output of zapper  28  commonly caused by the manual operation thereof allowing for the transmitting of pulses at a constant rate. 
     The response of the divider  12  to the true pulses  26 A is illustrated in FIG. 3, while the response of the divider  12  to the false pulses generated by the zapper  28  is illustrated in FIG.  4 . 
     FIG. 3 illustrates that signal path  26  as only carrying the true pulses  26 A generated by the gear mechanism  20 . FIG. 3 further illustrates that the divider  12  divides the number of true pulses received by a constant, e.g. three (3) so that the divider  12  provides one pulse at its output  12 A for every three pulses  12 A that it receives. FIG. 3 indicates that the time interval between adjacent pulses that are transmitted by the divider  12  is constant. 
     FIG. 4 illustrates the response of the divider  12  to both the true pulse  26 A and the false pulses  28 A, that is, the pulses  28 A generated by the zapper  28 . Again the divider  12  generates one pulse  12 A for every three (including the pulses  28 A) received; however, as seen in FIG. 4, when compared to the constant time interval for the pulses  12 A of FIG. 3, the time interval between the output pulse  12 A of FIG. 4 is disturbed because of the occurrence of the false pulses  28 A. This disturbed non-constant interval, without the benefits of the present inventor, would cause incorrect taxicab fare calculations. 
     In general, the divider  12  transmits a pulse on signal path  12 A to the processor  14  when the number of received pulses reaches its constant, that is, it generated one (1) pulses for every three (true and false) pulses that it receives. Each zapper pulse  28 A will increase the number of pulses received by the divider  12  and will therefore shorten the time interval between the pulses  12 A. 
     The time interval between adjacent gear pulses  26 A on signal path  26  is constant and changes only slightly when the taxicab accelerates or decelerates. Therefore, the time intervals between the divider pulses  12 A shown be constant except for the variations thereof caused by zapper pulses  28 A which are not synchronized to the gear pulses  26 A. The pulses  28 A randomly fall between the pulses  26 A generated by the gear mechanism  20  and cause random changes in the time interval between divider pulses  12 A. The present invention provides for discriminating means that detect the contribution of the zapper pulses  28 A to those pulses  12 A acted upon by the processor  14 . The discriminating means comprises the application program  16  which is represented by a flow chart  42  that indicates the overall operation of the application  16  and is shown in FIG. 5 which indicates program segments that are given in Table 1. 
     
       
         
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Program 
                   
               
               
                 Segment 
                 Nomenclature 
               
               
                   
               
             
             
               
                 44 
                 Detection of pulses 
               
               
                 46 
                 Detection of more than 4 accelerations during one minute, 
               
               
                   
                 which are higher that 3 m/sec 2   
               
               
                 48 
                 Detection of velocity increases by more that 10 MPH 
               
               
                   
                 (miles per hour) within one second 
               
               
                   
                 (acceleration of ˜4.5 m/sec 2 ) 
               
               
                 50 
                 Detection of pulse rates which are normally expected 
               
               
                   
                 at very high speeds (e.g. more than 100 MPH). 
               
               
                 52 
                 Detection of pulse rates which are constant for a 
               
               
                   
                 relatively long period (e.g. 1 minute) 
               
               
                 54 
                 Alarm response 
               
               
                   
               
             
          
         
       
     
     In general, upon the detection of pulses (includes both true  26 A and false  28 A) indicated by the event  44  of FIG. 5, the application program  16  activates signal path  56 , which in turn activates program segments  46 ,  48 ,  50  and  52 , and if either of these program segments  46 ,  48 ,  50  or  52  detects its predetermined alarms condition, the alarm notification thereof is placed on signal path  58  which, in turn, causes the alarm response  54  to be activated. The alarm response  54  is by way of the display and alarm subsystem  18  of FIG. 1 which may be a conventional device that generates appropriate visual or audio alarms or registers the alarm response  54  in a processing unit (not shown). 
     The program segment  46  provides means for detecting pulses representative of more than four taxicab acceleration occurrences during a one minute period which are higher that an acceleration of the taxicab of 3 m/sec 2 . To better appreciate that 3 m/sec 2  acceleration, referenced is made to Table 2 giving the velocity and distance traveled for a taxicab accelerating at a rate of 2 m/sec 2 , reaching a velocity of 72 Km per hour (45MPH), and then traveling at a constant rate of speed. 
     
       
         
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 time 
                 velocity 
                 velocity 
                 distance 
               
               
                   
                 (sec) 
                 (m/sec) 
                 (km per hour) 
                 (m) 
               
               
                   
                   
               
             
             
               
                   
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 1 
                 2 
                   7.2 
                 1 
               
               
                   
                 2 
                 4 
                  14.4 
                 4 
               
               
                   
                 3 
                 6 
                  21.6 
                 9 
               
               
                   
                 4 
                 8 
                  28.8 
                 16  
               
               
                   
                 5 
                 10  
                 36  
                 25  
               
               
                   
                 6 
                 12  
                  43.2 
                 36  
               
               
                   
                 7 
                 14  
                  50.4 
                 49  
               
               
                   
                 8 
                 16  
                  57.6 
                 64  
               
               
                   
                 9 
                 18  
                  64.8 
                 81  
               
               
                   
                 10  
                 20  
                 72  
                 100  
               
               
                   
                 11  
                 20  
                 72  
                 120  
               
               
                   
                 12  
                 20  
                 72  
                 140  
               
               
                   
                 . 
                 . 
                 . 
                 . 
               
               
                   
                 . 
                 . 
                 . 
                 . 
               
               
                   
                 . 
                 . 
                 . 
                 . 
               
               
                   
                 60  
                 20  
                 72  
                 1100   
               
               
                   
                   
               
             
          
         
       
     
     Under normal conditions experienced by moving taxicabs, the time intervals between legal adjacent divider pulses  12 A caused by true pulses  26 A will at most, differ by only 0-1 milliseconds between each other. Accordingly, under these radical accelerations of 3 m/sec 2 , zapper pulses  28 A will cause adjacent intervals between pulses  12 A to vary by 4-5 milliseconds. If all accelerations of taxicab between consecutive pulses are computed without the benefit of the present invention, zapper pulses  28 A will causes multiple detections of accelerations of 20-40 m/sec 2  each minute. Such accelerations are not physically feasible because accelerations during a taxi trip will not exceed 2-3 m/sec 2 , and even their number is not expected to be greater than 1-2 per minute. 
     The measuring resolution in the taxis meter system  10  of the present invention is typically in the order of 1 millisecond. The intervals between pulses  28 A in a high rate zapper (500 pulses and more) are less than 2 milliseconds. Therefore, for a high rate zapper, it becomes increasingly more difficult to confidently resolve differences in intervals and the related accelerations. Thus, the criterion of program segment  46  of FIG. 5 is particularly suited for lesser rate or normal zappers  28 , whereas the high rate zappers  28  are handled more advantageously by program segment  48  to be described. 
     Under normal conditions (no zapper pulses  28 A) the pulses  26 A being received by divider  12  and divided and transmitted on signal path  12 A, is about 1000 pulses per Km (1600 pulses per mile) and creates time intervals of 50-100 millisecond when velocities are greater that 45 Km per hour (approximately 30 miles per hour). Under normal conditions that intervals between adjacent pulses  12 A is at most different from each other by 0-1 milliseconds. 
     The program segment  48  detects pulses representative of velocity increases by the taxicab of more than ten miles per hour within one second. When the zapper  28  is activated, the rate of pulses increase immediately to a higher rate (which is the sum of the legal pulses  26 A from the gear mechanism  20  and the illegal pulses  28 A from the zapper  28 ). These increases can be detected by comparing the number of pulses between short consecutive time steps such as those shown in Table 2. The number of possible increases that the processor  14  could receive by the unwanted contribution of the pulses  28 A from the zapper  28  in the order of ten seconds, is shown in Table 3. 
     
       
         
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                 increase in number of 
                   
               
               
                   
                 pulses 28A sensed by the 
                 related increase 
               
               
                 zapper&#39;s 28 frequency 
                 processor 14 
                 in velocity 
               
               
                 (pulses per second) 
                 (pulses per second) 
                 (Km/hr) 
               
               
                   
               
             
             
               
                 100 
                 10 
                  36 
               
               
                 300 
                 30 
                 108 
               
               
                 500 
                 50 
                 180 
               
               
                 1,000   
                 100  
                 360 
               
               
                   
               
             
          
         
       
     
     From Table 3 it may be determined that the zapper  28  may cause a difference in the number of pulses, between two consecutive one second time intervals, that is equivalent to an increase of 18-36 Km/hr (11-22 miles per hour) in velocity within one (1) second. Such an increase is equivalent to an acceleration of 5-10 m/sec 2 , which is not physically possible to be experienced by a taxicab. A higher zapper rate handled by program segment  48  (detection of velocity increases by more than 10 MPH within 1 second) results in higher and more exceptional differences in velocity between consecutive time steps. 
     Program segment  50 , in addition to the safeguards of the program segments  46  and  48 , provides for the identification of exceptional velocities that are caused when the zapper  28  is activated. A rapidly operated zapper  28  (with hundred of pulses and more per second) will force a very high rate of pulses into the processor  14  and cause increases in the number of zapper pulses  28 A, in a manner as shown in Table 4. 
     
       
         
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                 adjacent intervals 
                 related velocities 
                 related velocities 
                 maximum 
               
               
                 (milliseconds) 
                 (m/sec) 
                 (km/hr) 
                 acceleration 
               
               
                   
               
             
             
               
                 50-45-50-50    
                 20-22-20-20 
                 72-80-72-72 
                 40 m/sec 2   
               
               
                 50-47.5-47.5-50 
                 20-21-21-20 
                 72-76-76-72 
                 20 m/sec 2   
               
               
                   
               
             
          
         
       
     
     From Table 4 it may be determined that the increase in velocity when such a zapper  28  is activated is very high. Comparing the number of pulses in consecutive time steps of 1 second will show a difference in velocity by at least 18 Km/hr between two consecutive time steps for such a zapper  28  activation. 
     As illustrated in Table 4, 50 pulses per seconds into the processor  14  are equivalent to a velocity of 112 miles per hour. Higher rates are equivalent to higher velocities. Such velocities are not expected during a taxicab trip. Therefore, the program segment  50  detection of such high pulses rates is used as a criterion for the presence of the zapper  28  and for the generation, by way of signal path  58  (which is also activated by program segments  46 ,  48 , and  50 ) of the response (audible or visual) by alarm response  54 . 
     Program segment  52 , in addition to the safeguards provided by program segments  46 ,  48  and  50 , provides for the detection of pulses having pulse rates which are abnormally constant. More particularly, pulses rates that are constant for a relatively long period (e.g. 1 minute) are considered to be abnormal. The pulses  28 A of the zapper  28  are typically triggered by a clock and the intervals between the pulses  28 A are substantially identical (can be measured in microseconds). During a normal taxicab drive, even at a constant speed, slight variations are normally expected between adjacent and legal pulses  26 A intervals however; when the taxicab is not moving and the zapper  28  is operating, the processor  14 , in particular program segment  52 , receives only the zapper pulse, i.e. pulses  28 A with very constant and identical intervals (measured in microseconds) therebetween. Such an occurrence is not expected during a normal trip and the detection of many consecutive identical intervals with relatively long periods of time (e.g. one minute) is used by program segment  52  as an indication of the presence of zapper  28 . Upon such a detection, the alarm response  54  is activated by program segment  52  by way of signal path  58 . 
     It should now be appreciated that the practice of the present invention provides for a system  10  that detects the presence of false pulses  28 A, generated by zapper  28 . 
     Although certain features of the invention have been illustrated and described therein, better modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modification and changes that fall within the spirit of the invention.