PATENT ABSTRACT
Entering an identifier to select a navigational waypoint requires “head-down” time, resulting in less time for operating a vehicle. Accordingly, a technique for selecting a navigational waypoint for use is provided. The present invention includes receiving a partially entered identifier identifying, in part, a navigational waypoint for use, searching for the navigational waypoint for use from amongst a plurality of identifiers using the partially entered identifier and a search criterion other than a criterion based on a pre-existing ordering of the plurality of identifiers, and completing the partially entered waypoint identifier based on results from the searching. The completed waypoint identifier forms a user-selectable navigational waypoint for use. The present invention uses as a search criterion a geographical relationship between a location of each identifier of the plurality and a reference location/area to reduce the number of user-entered characters needed to select a navigational waypoint, thereby reducing “head-down” time.

PATENT DESCRIPTION
RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/792,289, filed Apr. 14, 2006. The entire teachings of the above application are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Navigation is the science of moving a vehicle or person from one place to another place. More specifically, the science of navigation deals with methods for determining position, course, distance traveled, and of planning steering commands that will result in motion along an intended path from one place to another place. Position is generally determined with regards to a fixed coordinate system, for example, the familiar system of latitude and longitude for terrestrial or nautical navigation. Position fixing methods often make use of navigational aids, whose positions with respect to the navigational coordinate system are known or can be calculated as the basis for determining the location of the vehicle. For example, celestial bodies, e.g., stars, sun, and moon have been used since antiquity to aid sailors in navigating the seas, while a constellation of Global Positioning System (GPS) satellites serves much the same need in a modern, automated fashion. Waypoints, whose positions with respect to the navigational coordinate system are fixed and known, are used to define locations with significance to the navigational problem at hand. For ease of reference, waypoints are generally assigned a waypoint identifier. 
       SUMMARY OF THE INVENTION 
       [0003]    Using a computerized navigation device to navigate a path (or a track) from a first point (e.g., an origin) to a second point (e.g., a destination), a navigator enters descriptions (or indications) of the first point and the second point into the navigation device. In response the navigation device then displays the path to be navigated. In the case of a flight plan, a flight crew member (e.g., a pilot) enters a first waypoint identifier and a second waypoint identifier into a Flight Management System (FMS) or other similar area navigation device using a keypad or other data entry device. The FMS then renders a display of the flight plan on a display monitor, such as a Multifunction Display (MFD). 
         [0004]    One method for entering a waypoint identifier into the FMS requires entering the complete text of the waypoint identifier. The pilot, via the keyboard, enters (or keys in) each and every character of the waypoint identifier into the FMS. This requires the pilot to spend “head-down” time. That is, rather than flying the aircraft, the pilot is busy keying in waypoint identifiers character by character. The problem of requiring “head-down” time is further aggravated by short duration and/or high speed flights where the pilot has little time to spare keying in each and every character of a waypoint identifier (candidate). 
         [0005]    Another problem relating to having to key in or otherwise enter each and every character of a waypoint identifier is unrestricted entry. Because this method requires entering the complete text, the pilot may enter characters for a waypoint identifier not contained in a navigation database, i.e., an invalid entry. Consequently, the problem of unrestricted entry requires an ability to annunciate or otherwise indicate invalid entries to the user or pilot. 
         [0006]    To remedy these problems “smart” or automatic text entry systems have been developed to automatically complete a text entry field. These text entry systems allow the pilot to enter one or more characters of a desired waypoint identifier into the subject field, and the system then automatically displays the complete text of a most likely waypoint identifier. 
         [0007]    These systems are based on an alphanumerical entry. A search string is used to determine which waypoint identifiers include the one or more piloted-entered characters. Thus, the more similar waypoint identifiers are to one another, the more pilot-entered characters are required to identify the desired waypoint identifier. For example, a collection of waypoint identifiers contains waypoint identifiers, “A,” “AA,” and “AAA.” Using a search string “A,” all the waypoint identifiers are equally likely to be identified as the desired waypoint identifier (candidate). The waypoint identifier “A” can be completed from the search string of “A,” as can the waypoint identifiers “AA” and “AAA.” Adding an additional “A” to the search string (i.e., the search string is now “AA”) reduces the likely (candidate) waypoint identifiers to either “AA” or “AAA”. Further adding an “A” to the search string (i.e., the search string is now “AAA”) further reduces the likely (candidate) waypoint identifier to only “AAA.” In this example, for each additional character entered, the number of likely (candidate) waypoint identifiers is reduced by one. In the worst case, identifying the desired waypoint identifier requires entering the complete text of the desired waypoint identifier. 
         [0008]    The efficiency with which a pilot or navigator can enter waypoints, and thus the amount of attention he or she must apply to operating the navigation system as opposed to other activities on the airplane, is dependent on the number of characters he or she must enter in order for the system to correctly identify the desired waypoint. 
         [0009]    Accordingly, what is a needed is a method or a corresponding apparatus for filling in an entry field requiring the least number of characters entered. 
         [0010]    It is easily appreciated that the likelihood of a given waypoint being the desired waypoint may be influenced by factors other than alphanumerical order. In particular, the geographical position of a given waypoint may exert a considerable influence on its likelihood of being the desired waypoint. 
         [0011]    Most navigational problems involve piecing or otherwise assembling a flight plan from a series of segments or legs, each of which describes an intended path from one waypoint to another. As the description of such a flight plan is initiated, waypoints near the point of origin are typically more likely to be the desired next waypoint than are waypoints more distant from the point of origin. As the description of the flight plan progresses, each subsequent waypoint is more likely to be found near the most recently entered waypoint than far from it. Thus, a waypoint identifier completion technique which permits the use of a geographical reference point in evaluating candidate completions can result in greater overall efficiency. 
         [0012]    A computer implemented method and corresponding computer system for selecting a navigational waypoint for use includes: i) receiving a partially entered waypoint identifier identifying, in part, a navigational waypoint for use, ii) searching for the navigational waypoint for use from amongst a plurality of waypoint identifiers using the partially entered waypoint identifier and a search criterion other than a criterion based on a pre-existing ordering of the plurality of waypoint identifiers, and iii) completing the partially entered waypoint identifier based on results from the searching, the completed waypoint identifier forming a user-selectable navigational waypoint for use. 
         [0013]    In an alternative embodiment, a computer implemented method and corresponding apparatus for filling in an entry field with a desired waypoint identifier includes: i) generating an initial vicinity list of waypoint identifiers from a database of waypoint identifiers using a reference position and a vicinity term, ii) generating a final vicinity list of waypoint identifiers from the initial vicinity list of waypoint identifiers using a search string followed by a character from a set of characters, iii) generating an autofill list of waypoint identifiers from the database of waypoint identifiers using the search string followed by a character from the set of characters, and iv) generating a GeoFill list of waypoint identifiers from a combination of the final vicinity list of waypoint identifiers and the autofill list of waypoint identifiers using the search string followed by a character from the set of characters, the GeoFill list of waypoint identifiers being used to fill in the entry field. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The foregoing and other objects, features and advantages of the present invention will be apparent from the following more particular description of preferred embodiments of the present invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
           [0015]      FIG. 1  is a block diagram illustrating an example flight management system supporting example embodiments of the present invention; 
           [0016]      FIGS. 2A and 2B  are block diagrams illustrating a comparison between filling an entry field with a desired waypoint identifier using an autofill technique and a GeoFill technique in accordance with example embodiments of the present invention; 
           [0017]      FIGS. 3A-E  are block diagrams illustrating example apparatuses to generate an initial vicinity list, a final vicinity list, an autofill list, and a GeoFill list of waypoint identifiers in accordance with example embodiments of the present invention; 
           [0018]      FIG. 4  is a flow chart of an example process for filling in an entry field in accordance with an example embodiment of the present invention; 
           [0019]      FIG. 5  is a flow chart of example process for generating an initial vicinity list of waypoint identifiers in accordance with an example embodiment of the present invention; 
           [0020]      FIG. 6  is a flow chart of an example process for generating a final vicinity list of waypoint identifiers in accordance with an example embodiment of the present invention; 
           [0021]      FIG. 7  is a flow chart of an example process for generating an autofill list of waypoint identifiers in accordance with an example embodiment of the present invention; and 
           [0022]      FIG. 8  is a flow chart of an example process for generating a GeoFill list of waypoint identifiers in accordance with an example embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    A description of example embodiments of the present invention follows. 
         [0024]      FIG. 1  is a block diagram illustrating a flight management system (FMS)  10  supporting example embodiments of the present invention. The FMS  10  includes a digital processor  15 , a memory  20 , a data entry device  25 , and a display unit  30 , such as a Multifunction Display (MFD) or monitor. 
         [0025]    In operation, a user  11  (e.g., a pilot or navigator) enters a character(s) of a desired waypoint identifier into the FMS  10  via the data entry device  25 . In response to the entered character(s), the FMS  10  searches a database of waypoint identifiers stored in the memory  20 . The search is based in part on the character(s) entered by the user  11  and a geographical relationship between a geographical location of each waypoint identifier stored in the memory  20  and a location of a reference location or area (described in greater detail below). The result of the search is displayed back to the user  11  on the display  30 . 
         [0026]      FIG. 1  is merely an example illustration of a configuration supporting example embodiments of the present invention, and as such, one of ordinary skill in the art will readily recognize that other configurations are also contemplated. For example, the digital processor  15  and the memory  20  may be integrated onto a single integrated circuit. In another example, the data entry device  25  may be a keyboard, a keypad, a trackball, microphone, voice activated unit, or other input device known in the art. In yet another example, the display  30  may be a Primary Flight Display (PFD). 
         [0027]      FIG. 2A  illustrates a comparison between filling in or otherwise completing a first entry field  205  with a desired waypoint identifier “ACALA” using a technique according to embodiments of the present invention, hereinafter referred to as GeoFill, and filling in a second entry field  206  with the same desired waypoint identifier “ACALA” using an automatic complete text entry or autofill technique. 
         [0028]    For this comparison, assume a database of waypoint identifiers includes (amongst others) waypoint identifiers “ACABE” and “ACALA.” Also assume for this comparison the waypoint identifier “ACALA” is closer to a reference position then the waypoint identifier “ACABE.” As will be described later, whether a waypoint identifier is “close” or “geographically close” to a reference position or not, may be determined by whether the distance between the waypoint identifier and the reference position is within a vicinity term. Continuing with this example, a search string “AC”  207   a  is used to search the database of waypoint identifiers for the desired waypoint identifier “ACALA.” 
         [0029]    Using an example autofill technique, the database is searched for waypoint identifiers beginning with the search string “AC”  207   a . However, not every occurrence of the search string “AC”  207   a  found is returned using the autofill technique. Rather, for each character in a set of characters (e.g., A-Z), autofill returns a first occurrence of the search string followed by a character from the set of characters. As such, an autofill list  211   a  is populated, with a first waypoint identifier beginning with “AC” followed by “A,” a first waypoint identifier beginning with “AC” followed by “B,” and so on. 
         [0030]    Because the autofill list  211   a  is populated only with the first occurrence of the search string “AC”  207   a  followed by a character from a set of characters and “ACABE” is the first occurrence of the search string “AC”  207   a  followed by “A,” the second entry field  206  is filled in with “ACABE,” rather than the desired waypoint identifier “ACALA.” To fill in the second entry field  206  with the desired waypoint identifier “ACALA,” an additional character must be added to the search string “AC”  207   a . In other words, the autofill technique requires entering in an additional character. 
         [0031]    The database of waypoint identifiers is now searched with a “longer” search string “ACA”  207   b . As before, a resulting autofill list  211   b  is populated with a first waypoint identifier beginning with “ACA” followed by “A,” a first waypoint identifier beginning with “ACA” followed by “B,” and so on. Because the autofill list  211   b  is populated with the first occurrence of the search string “ACA”  207   b  followed by a character from a set of characters and “ACALA” is a first single occurrence of the search string “ACA”  207   b  followed by “L,” the second entry field  206  can now be filled in with the desired waypoint identifier. 
         [0032]    Another example autofill technique selects the most likely text identifier by comparing entered characters typed against those corresponding sequential text identifiers previously stored within a database. That is, after entering a first character and locating a first waypoint identifier with the first entered character, a second waypoint identifier with a second entered character is located by comparing the entered second character with the next waypoint identifier in sequence. In this way, this autofill technique uses a search criterion which is based on a pre-existing ordering, namely, the sequential ordering of waypoint identifiers in the database. Pre-existing orderings are typically alphabetical or alphanumerical or other sequential ordering. 
         [0033]    The distinction between the two autofill techniques described above is illustrated by considering the following example. A database of waypoint identifiers includes the following waypoint identifiers in the following order: “HBSR 1 ,” “HBSR 2 ,” and “HBSR 3 .” Using a search string “HBSR” and a character from a set of characters (e.g., the numeral “2”) the first autofill technique returns “HBSR 2 ,” which is the second waypoint identifier, as ordered in the database of waypoint identifiers. Using the same search string “HBSR,” the second autofill technique compares in sequence the entered characters “HBSR” with the waypoint identifiers stored within the database. Because “HBSR 1 ” is before “HBSR 2 ” and “HBSR 3 ” in sequence, the second autofill technique returns the “HBSR 1 ,” not “HBSR 2 ” or “HBSR 3 .” 
         [0034]    The second autofill technique is further distinguished from the first autofill technique. Unlike the first described autofill technique, which uses a search string followed by a character from a set of characters (i.e., a concatenated search string) to search, the second autofill technique relies solely on a search string. Consequently, the second autofill technique requires at least one character to be entered. 
         [0035]    In contrast to either autofill techniques described above, the GeoFill technique uses a search criterion not based on a pre-existing ordering, such as alphanumerical ordering or sequential ordering of waypoint identifiers previously stored within a database. Rather, GeoFill uses, as a search criterion, a geographical relationship between a location of a waypoint identifier and a reference position or area. In this way, GeoFill returns for each character in a set of characters, a closest single occurrence of a search string followed by a character from the set of characters (described in greater detail below). 
         [0036]    An assumption is made that the desired waypoint identifier is in a vicinity of a reference position. However, a priori knowledge of the reference position (e.g., designating a reference position in a flight plan) is not required. For example, a reference position may be continuously updated. In this way, it may be further assumed that the desired waypoint identifier is in a vicinity of a current (sensed or calculated) reference position. Furthermore, the reference position need not lie in a general direction of a destination. For example, a change in events may necessitate a deviation and require travel not in a general direction of a destination. In this way, GeoFill is not the same as identifying a most likely waypoint identifier that is geographically closest to, for example, a previous flight plane waypoint identifier or a waypoint identifier which lies in a general direction of a destination. 
         [0037]    Continuing with  FIG. 2A , because a GeoFill list  210  is populated with a closest waypoint identifier beginning with the search string “AC”  207   a  followed by a character from a set of characters and “ACALA” is the closest occurrence of the search string “AC”  207   a  followed by “A,” the first entry field  205  is filled in with the desired waypoint identifier. 
         [0038]    As  FIG. 2A  illustrates, filling in an entry field with a desired waypoint identifier using the autofill technique may require entering a “longer” search string than using GeoFill. As such, filling in an entry field with a desired waypoint identifier using the autofill technique may require more time (or user steps) than using GeoFill. 
         [0039]      FIG. 2B  illustrates using GeoFill to fill in an entry field  255  with a desired waypoint identifier based on an entry of no characters, i.e., a NULL search string  257 . As an illustration, given a set of characters “A-Z,” a GeoFill list  260  is populated with a geographically closest occurrence of a waypoint identifier with “A,” a geographically closest occurrence of a waypoint identifier with “B,” and so on. In this way, GeoFill is not the same as presenting likely text identifiers based on entry of a character of a text identifier for comparison and auto completion of the identifier. 
         [0040]    Continuing with the example illustrated in  FIG. 2B , using the NULL search string  257 , GeoFill returns for each character in a set of characters, a geographically closest occurrence of a waypoint identifier formed of the NULL search string  257  followed by a character from the set of characters. Because a GeoFill list  260  is populated with a geographically closest waypoint identifier beginning with the NULL search string  257  followed by a character from a set of characters and “ACALA” is the geographically closest occurrence of a waypoint identifier having the NULL search string  257  followed by “A,” the entry field  255  is filled in with the desired waypoint identifier. 
         [0041]      FIGS. 2A and 2B  illustrate the listing of waypoint identifiers (e.g.,  210 ,  211   a - b , and  260 ) as a display element capable of presenting multiple lines simultaneously. One skilled in the art, however, will readily recognize there may be alternative ways to display a listing of candidate waypoint identifiers. For example, a single-lined display element with scroll feature may be used. Additionally, a cursor (e.g.,  215 ) indicates a character in the subject search string to be changed. In another example embodiment, a highlight (or highlighting) may be used to indicate a character to be changed. Moreover, the MFD  30  (of  FIG. 1 ) may affect a manner in which an entry field and a listing of waypoint identifiers are displayed. These alternatives are within the contemplation of example embodiments of the invention. 
         [0042]    For purposes of illustrating and describing principles and concepts of the present invention, example embodiments are illustrated and described as processing and producing “lists.” This is merely a convenient way for illustrating and describing the principles of the present invention and is not intended to limit embodiments of the present invention to list. 
         [0043]      FIG. 3A  illustrates an example apparatus  300  to fill in an entry field (e.g.,  205  of  FIG. 2A ) with a desired waypoint identifier. In brief overview, the example apparatus  300 , from database waypoint identifiers  305 , generates a GeoFill list of candidate waypoint identifiers  355 . The GeoFill list of candidate waypoint identifiers  355  is used to fill in the entry field with the desired waypoint identifier. 
         [0044]    In further detail, from the database of waypoint identifiers  305 , an initial vicinity list generator  306  generates an initial vicinity list of waypoint identifiers  320 . From the generated initial vicinity list of waypoint identifiers  320 , a final vicinity list generator  321  (being coupled to or otherwise responsive to the initial vicinity list generator  306 ) generates a final vicinity list of waypoint identifiers  335 . 
         [0045]    Also from the database of waypoint identifiers  305 , an autofill list generator  308  generates an autofill list of waypoint identifiers  345 . From the generated final vicinity list of waypoint identifiers  335  and the generated autofill list of waypoint identifiers  345 , a GeoFill list generator  323  (being coupled to or otherwise responsive to both the final vicinity list generator  321  and the autofill list generator  308 ) generates the GeoFill list of waypoint identifiers  355 . 
         [0046]    Having provided an overview, further details of the initial vicinity list generator  306 , the autofill list generator  308 , the final vicinity list generator  321 , and the GeoFill list generator  323  are provided below in reference to  FIGS. 3B-3E . 
         [0047]      FIGS. 3B-3E  illustrate in greater detail filling in an entry field (e.g.,  205  of  FIG. 2A ) with a desired waypoint identifier using a reference position “ACALA”  310  and a search string “AC”  325 . More particularly, the database of waypoint identifiers  305  is searched for waypoint identifiers which are “geographically close” to the reference position “ACALA”  310  and begin with the search string “AC”  325 . 
         [0048]    In  FIG. 3B , from the database of waypoint identifiers  305 , the initial vicinity list generator  306  generates the initial vicinity list  320 . The initial vicinity list generator  306  includes a logic unit  307  to include a waypoint identifier from the database of waypoint identifiers  305  in an event the distance between the waypoint identifier and the reference position “ACALA”  310  is within or is otherwise less than or equal to a vicinity term  315 . As such, the generated initial vicinity list  320  is populated with waypoint identifiers from the database of waypoint identifiers  305  whose distance from the reference position “ACALA”  310  are within the vicinity term  315 . In contrast, waypoint identifiers from the database of waypoint identifiers  305  whose distance from the reference position “ACALA”  310  are not within or otherwise greater than the vicinity term  315  are not included in the generated initial vicinity list  320 . In this way, a “geographically close” or “geographically closest” waypoint identifier to a reference position is determined by whether the distance between the waypoint identifier and the reference position is within a vicinity term. 
         [0049]    In  FIG. 3C , from the initial vicinity list  320 , the final vicinity list generator  321  generates the final vicinity list  335 . The final vicinity list generator  321  includes a logic unit  322  to include waypoint identifiers from the initial vicinity list  320  as described below. 
         [0050]    A search string is concatenated with a character from a set of characters to form a concatenated search string. For example a NULL search string (i.e., a search string with zero characters) is concatenated with a character from a set of characters “A” through “Z,” to form concatenated search strings “A,” “B,” “C,” and so on. In another example, a search string “ 1 ” is concatenated with a character from a set of characters “A” through “Z,” to form concatenated search strings “ 1 A,” “ 1 B.” “ 1 C,” and so on. 
         [0051]    Continuing with  FIG. 3C , the search string “AC”  325  is concatenated with characters from the set of characters “A-Z”  330  to form concatenated search strings “ACA,” “ACB,” “ACC,” and so on. The logic unit  322  includes waypoints identifiers beginning with these concatenated search strings. However, the logic unit  322  does not include every waypoint identifier beginning with the concatenated search strings. That is, not every occurrence of the concatenated search strings is included. While there may be more than one occurrence of any given concatenated search string, the logic unit  322  includes from the initial vicinity list  320 , one or otherwise a single occurrence of each concatenated search string. 
         [0052]    Because the initial vicinity list  320  itself includes waypoint identifiers whose distances to the reference position  310  are within the vicinity term  315 , the logic unit  322  may be said to include a waypoint identifier which is the closest single occurrence of a concatenated search string. In this way, the generated final vicinity list  335  is populated with waypoint identifiers whose distance from the reference position “ACALA”  310  are within the vicinity term  315 , and are single occurrences of the search string “AC”  325  concatenated with characters from the set of characters “A-Z”  330 . The following example illustrates the above in greater detail. 
         [0053]    In a first iteration  340   a , the initial vicinity list of waypoint identifiers  320  is searched for a geographically closest single occurrence of a concatenated search string “ACA” (formed from concatenating the search string “AC”  325  with a character “A” from the set of characters “A-Z”  330 ). In the initial vicinity list of waypoint identifiers  320 , there are multiple occurrences of the concatenated search string “ACA,” namely, a waypoint identifier “ACALA”  341  and a waypoint identifier “ACABE”  342 . The subject or working reference position “ACALA”  310 , however, is geographically closer to the waypoint identifier “ACALA”  341 , than to the waypoint identifier “ACABE”  342 . Accordingly, the closest single occurrence of the concatenated search string “ACA” is the waypoint identifier “ACALA”  341 . After the first iteration  340   a , a final vicinity list of waypoint identifiers  335   a  includes the waypoint identifier “ACALA”  341 , but not the waypoint identifier “ACABE”  342 . 
         [0054]    In another example embodiment, a final vicinity list of waypoint identifiers  335  includes a preferred single occurrence of a concatenated search string. In contrast, to a geographically closest single occurrence of a concatenated search string described above, if a waypoint identifier is preferred or is otherwise a preferred navaid, it is included in the final vicinity list of waypoint identifiers  335 , while a waypoint identifier which is closest to a reference position is not. For example, if the waypoint identifier “ACABE”  342  is a preferred navaid, it is included in the final vicinity list of waypoint identifiers  335  despite the waypoint identifier “ACALA”  341  being geographically closest to the reference position “ACALA”  310 . 
         [0055]    In a second iteration  340   b , the initial vicinity list of waypoint identifiers  320  is searched for a geographically closest single occurrence of a concatenated search string “ACB” (formed from concatenating the search string “AC”  325  with a character “B” from the set of characters “A-Z”  330 ). There are no occurrences of the concatenated search string “ACB” in the initial vicinity list of waypoint identifiers  320 . Consequently, after the second iteration  340   b , a final vicinity list of waypoint identifiers  335   b  includes the waypoint identifier “ACALA”  341  (from the first iteration  340   a ). 
         [0056]    Subsequent iterations are likewise performed. After an nth iteration  340   n , a final vicinity list of waypoint identifiers  335   n  includes a geographically closest single occurrence for each concatenated search string. 
         [0057]    In  FIG. 3D , from the database of waypoint identifiers  305 , the autofill list generator  308  generates the autofill list  345 . The autofill list generator  308  includes a logic unit  309  to include a waypoint identifier from the database of waypoint identifiers  305  as described below. 
         [0058]    Similar to generating the final vicinity list of waypoint identifiers  335 , described above, the search string “AC”  325  is concatenated with characters from the set of characters “A-Z”  330  to form concatenated search strings. The concatenated search strings are used to search the database of waypoint identifiers  305 . Again, not every occurrence of each concatenated search string is included in the generated autofill list of waypoint identifiers  345 . While there may be more than one occurrence of any given concatenated search string, the logic unit  309  includes a first single occurrence of each concatenated search string. The first single occurrence of each concatenated search string may be first in terms of, for example, alphanumerical ordering, an ordering in the database of waypoint identifiers  305 , or other ordering. In this way, the generated autofill list of waypoint identifiers  345  is populated with the first single occurrence of the search string “AC”  325  followed by a character from the set of characters “A-Z”  330 . The following example illustrates the above in greater detail. 
         [0059]    In a first iteration  350   a , the database of waypoint identifiers  305  is searched for a first single occurrence of a concatenated search string “ACA” (formed from concatenating the search string “AC”  325  with a character “A” from the set of characters “A-Z”  330 ). In the database of waypoint identifiers  305  there are multiple occurrences of the concatenated search string “ACA,” namely, the waypoint identifier “ACALA”  341  and the waypoint identifier “ACABE”  342 . In the database of waypoint identifiers  305 , the waypoint identifier “ACALA”  341  is preceded by the waypoint identifier “ACABE”  342 . As such, the first single occurrence of the concatenated search string “ACA” is the waypoint identifier “ACABE”  342 . After the first iteration  350   a , an autofill list of waypoint identifiers  345   a  includes the waypoint identifier “ACABE”  342 , but not the waypoint identifier “ACALA”  341 . 
         [0060]    In the above example embodiment, the autofill list of waypoint identifiers  345  includes a first single occurrence of each concatenated search string. Alternatively, an included single occurrence may not be first, but may be, for example, last or preferred. One skilled in the art will readily recognize these and other alternatives are all within the contemplation of the invention. 
         [0061]    Continuing with  FIG. 3D , in a second iteration  350   b , the database of waypoint identifiers  305  is searched for a first single occurrence of a concatenated search string “ACB” (formed from concatenating the search string “AC”  325  with a character “B” from the set of characters “A-Z”  330 ). There are no occurrences of the concatenated search string “ACB” in the database of waypoint identifiers  305 . Consequently, after the second iteration  350   b , an autofill list of waypoint identifiers  345   b  includes the waypoint identifier “ACABE”  342  (from the first iteration  350   a ). 
         [0062]    Subsequent iterations are likewise performed. After an nth iteration  350   n , an autofill list of waypoint identifiers  345   n  includes a first single occurrence for each concatenated search string. 
         [0063]    In  FIG. 3E , from the final vicinity list  335  and the autofill list  345 , the GeoFill list generator  323  generates the GeoFill list  355 . The GeoFill list generator  323  includes a logic unit  324  to include a waypoint identifier either from the final vicinity list  335  and the autofill list  345  as described below. 
         [0064]    Similar to generating the autofill list of waypoint identifiers  335 , described above, the search string “AC”  325  is concatenated with characters from the set of characters “A-Z”  330  to form concatenated search strings. The concatenated search strings are used to search the final vicinity list  335 . If a concatenated search string occurs in the final vicinity list  335 , the logic unit  324  includes the occurrence (i.e., a waypoint identifier beginning with the concatenated search string) from the final vicinity list  335 . In this instance, the GeoFill list of waypoint identifiers  355  is populated with a geographically closest single occurrence of the concatenated search string. Recall, a “geographically close” or “geographically closest” waypoint identifier to a reference position is determined by whether the distance between the waypoint identifier and the reference position is within a vicinity term. 
         [0065]    If, however, the concatenated search string does not occur in the final vicinity list of waypoint identifiers  335 , but does occur in the autofill list of waypoint identifiers  345 , the logic unit  324  includes the occurrence from the autofill list of waypoint identifiers  345 . In this instance, the GeoFill list of waypoint identifiers  355  is populated with a first single occurrence of a concatenated search string. In this way, the GeoFill list of waypoint identifiers  355  may be populated with both the geographically closest and the first single occurrences of the search string “AC”  325  followed by a character from the set of characters “A-Z”  330 . 
         [0066]    If such an occurrence is neither found in the final vicinity list of waypoint identifiers  335  nor in the autofill list of waypoint identifiers  345 , then no waypoint identifier is included in the GeoFill of waypoint identifiers  355 . 
         [0067]    In one embodiment, if an occurrence of a concatenated search string is found in both the final vicinity list  335  and the autofill list of waypoint identifiers  345 , the logic unit  324  includes the occurrence from the final vicinity list  335  rather then from the autofill list  345 . In this way, the logic unit  324  may be said to prefer a waypoint identifier from the final vicinity list  335  over a waypoint identifier from the autofill list  345 . However, as described above, in an event the concatenated search string does not occur in the final vicinity list of waypoint identifiers  335 , but does occur in the autofill list of waypoint identifiers  345 , the logic unit  324  includes the occurrence from the autofill list of waypoint identifiers  345 . As such, the GeoFill list of waypoint identifiers  355  may be preferably populated with the closest single occurrences of the search string “AC”  325  followed by a character from the set of characters “A-Z”  330 . The following example illustrates the above in greater detail. 
         [0068]    In a first iteration  360   a , the final vicinity list of waypoint identifiers  335  is searched for an occurrence of a concatenated search string “ACA” (formed from concatenating the search string “AC”  325  with a character “A” from the set of characters “A-Z”  330 ). The occurrence of the concatenated search string “ACA” is found, namely, the waypoint identifier “ACALA”  341 . Accordingly, after the first iteration  360   a , the waypoint identifier “ACALA”  341  (a geographically closest single occurrence of the concatenated search string “ACA”) populates a GeoFill list of waypoint identifiers  355   a.    
         [0069]    Note there is another occurrence of the concatenated search string “ACA,” namely the waypoint identifier “ACABE”  342  from the autofill list of waypoint identifiers  345 . This waypoint identifier is not included in the GeoFill list of waypoint identifiers  355  because the occurrence of the concatenated search string “ACA” is already found in the final vicinity list of waypoint identifiers  335 . As such, it may be said there is a bias or preference for including waypoint identifiers which are geographically closest single occurrences of concatenated search strings. 
         [0070]    In a second iteration  360   b , the final vicinity list of waypoint identifiers  335  is searched for an occurrence of a concatenated search string “ACB” (formed from concatenating the search string “AC”  325  with a character “B” from the set of characters “A-Z”  330 ). There is no occurrence of the concatenated search string “ACB” in the final vicinity list of waypoint identifiers  335 . Subsequently, the autofill list of waypoint identifiers  345  is also searched for an occurrence of the concatenated search string “ACB.” Likewise, there is no occurrence of the concatenated search string “ACB” in the autofill list of waypoint identifiers  345 . Consequently, after the second iteration  360   b , a GeoFill list of waypoint identifiers  355   b  includes the waypoint identifier “ACALA”  341  (from the first iteration  360   a ). 
         [0071]    Subsequent iterations are likewise performed. After an nth iteration  350   n , GeoFill list of waypoint identifiers  355   n  includes an occurrence for each concatenated search string. Each occurrence of a given concatenated search string maybe a geographically closest single occurrence or a first single occurrence, as described above in iterations  360   a  and  360   b.    
         [0072]    Waypoint identifiers from the generated GeoFill list of waypoint identifiers  355  are subsequently used to fill in an entry field (e.g., the entry field  205  of  FIG. 2A ). Accordingly, the entry field is filled in with waypoint identifiers which begin with a search string followed by a character from a set of characters, and which are either closest to a reference position or if not closest geographically, then a first occurrence in a database of waypoint identifiers. 
         [0073]    While  FIGS. 3A-3F  illustrate and corresponding text describes example embodiments of the present invention in reference to lists, one skilled in the art will readily recognize that such references are merely for convenience. Furthermore, principles of the present invention are not intended to be limited to lists, but are applicable to other forms of collections of data, such as sets (ordered and unordered). 
         [0074]      FIG. 4  is a flow diagram illustrating an example invention process  400  for filling in an entry field (e.g.,  205  of  FIG. 2A ) with a desired waypoint identifier. An initial vicinity list of waypoint identifiers (e.g.,  320  of  FIGS. 3A and 3B ) is generated ( 405 ) from a database of waypoint identifiers (e.g.,  305  of  FIG. 3A ) using a reference position (e.g.,  310  of  FIG. 3B ) and a vicinity term (e.g.,  315  of  FIG. 3B ). 
         [0075]    A final vicinity list of waypoint identifiers (e.g.,  335  of  FIG. 3C ) is generated ( 410 ) from the initial vicinity list of waypoint identifiers (generated at  405 ) using a search string (e.g.,  325  of  FIG. 3C ) and a character from a set of characters (e.g.,  330  of  FIG. 3C ). 
         [0076]    An autofill list of waypoint identifiers (e.g.,  345  of  FIG. 3D ) is generated ( 415 ) from the database of waypoint identifiers using the search string and a character from the set of characters. 
         [0077]    A GeoFill list of waypoint identifiers (e.g.,  355  of  FIG. 3D ) is generated ( 420 ) from a combination of both the final vicinity list of waypoint identifiers (generated at  410 ) and the autofill list of waypoint identifiers (generated at  415 ) using the search string and a character from the set of characters. 
         [0078]    Waypoint identifiers from the resulting GeoFill list are used to fill in the entry field with the desired waypoint identifier. 
         [0079]      FIG. 5  is a flow diagram illustrating an example process  500  for generating an initial vicinity list of waypoint identifiers (e.g.,  320  of  FIG. 3B ) from a database of waypoint identifiers (e.g.,  305  of  FIG. 3B ) using a reference position (e.g.,  310  of  FIG. 3B ) and a vicinity term (e.g.,  315  of  FIG. 3B ). A distance between a waypoint identifier from the database of waypoint identifiers  305  and the reference position  310  is computed ( 505 ). If at  510  the computed distance is within (e.g., less than or equal to) the vicinity term  315 , the waypoint identifier is included ( 515 ) in the initial vicinity list of waypoint identifiers  320 . If, however, at  510  the computed distance is not within (e.g., greater than) the vicinity term  315 , the waypoint identifier is excluded ( 520 ) from the initial vicinity list of waypoint identifiers  320 . 
         [0080]    If there are more waypoint identifiers ( 525   a  and  525   b ) in the database of waypoint identifiers  305 , the process  500  returns to compute ( 505 ) a distance between a next waypoint identifier and the reference position  310 . Consequently, the generated initial vicinity list of waypoint identifier  320  includes waypoint identifiers within (or otherwise less than or equal to) the vicinity term  315 , and does not include waypoint identifiers not within (or otherwise greater than) the vicinity term  315 . 
         [0081]    In an example embodiment, the vicinity term  315  used to include and exclude waypoint identifiers from the initial vicinity list of waypoint identifiers  320  is defined by a user, such as a pilot of an aircraft. The user may define the vicinity term  315  to be small, and thereby limit the included waypoint identifiers to waypoint identifiers which are geographically closer to the reference position  310 . Alternatively, the user may define the vicinity term  315  to be relatively large, and thereby expand the included waypoint identifiers to waypoint identifiers which are geographically further from the reference position  310 . In this way, the user may determine which waypoint identifiers are included and which are excluded from the initial vicinity list of waypoint identifiers  320  generated by the process  500 . 
         [0082]    In another example embodiment, the vicinity term  315  used to include and exclude waypoint identifiers from the initial vicinity list of waypoint identifiers  320  is defined in response to the size of the generated initial vicinity list of waypoint identifiers  320 . That is, the vicinity term  315  is increased, causing the process  500  to include more waypoint identifiers if the initial vicinity list of waypoint identifiers  320  would otherwise be small in number. Conversely, the vicinity term  315  is decreased if the initial vicinity list of waypoint identifiers  320  would otherwise be large in number. In yet another example embodiment, the vicinity term  315  is defined by an application, such as Federal Aviation Administration (FAA) regulations, particular flight procedures or particular flight conditions. 
         [0083]      FIG. 6  is a flow diagram illustrating an example process  600  for generating a final vicinity list of waypoint identifiers (e.g.,  335  of  FIG. 3C ) from an initial vicinity list of waypoint identifiers (e.g.,  320  of  FIG. 3C ) using a search string (e.g.,  325  of  FIG. 3C ) and a character from a set of characters (e.g.,  330  of  FIG. 3C ). The search string  325  is concatenated ( 605 ) with a character from the set of characters  330  to form a concatenated search string. 
         [0084]    The initial vicinity list of waypoint identifiers  320  is searched ( 610 ) for an occurrence of the concatenated search string. If a closest single occurrence of the concatenated search string is found ( 615 ) (i.e., a waypoint identifier beginning with the concatenated search string and is geographically closest to the reference position  310 ) the waypoint identifier is included ( 620 ) in the final vicinity list of waypoint identifiers  335 . If, however, a closest single occurrence is not found, the waypoint identifier is excluded ( 625 ) from the final vicinity list of waypoint identifiers  335 . 
         [0085]    After including the waypoint identifier ( 620 ) or excluding the waypoint identifier ( 625 ) from the final vicinity list of waypoint identifiers  335 , if there are more waypoint identifiers ( 630   a  and  630   b ) in the initial vicinity list of waypoint identifiers  320 , the process  600  returns to concatenate ( 605 ) the search string  325  with a next character from the set of characters  330 . Consequently, the final vicinity list of waypoint identifiers  335  includes a geographically closest single occurrence for each concatenated search string. 
         [0086]      FIG. 7  is a flow diagram illustrating an example process  700  for generating an autofill list of waypoint identifiers (e.g.,  345  of  FIG. 3D ) from a database of waypoint identifiers (e.g.,  305  of  FIG. 3D ) using a search string (e.g.,  325  of  FIG. 3D ) and a character from a set of characters (e.g.,  330  of  FIG. 3D ). The search string  325  is concatenated ( 705 ) with a character from the set of characters  330  to form a concatenated search string. 
         [0087]    The database of waypoint identifiers  305  is searched ( 710 ) for an occurrence of the concatenated search string. If a first single occurrence of the concatenated search string is found ( 715 ) (i.e., a waypoint identifier beginning with the concatenated search string and proceeding other occurrences of the concatenated search string, for example, alphanumerically or by some other ordering) the waypoint identifier is included ( 720 ) in the autofill list of waypoint identifiers  345 . If, however, a first single occurrence is not found, the waypoint identifier is excluded ( 725 ) from the autofill list of waypoint identifiers  345 . 
         [0088]    After including the waypoint identifier ( 720 ) or excluding the waypoint identifier ( 725 ) from the autofill list of waypoint identifiers  345 , if there are more waypoint identifiers ( 730   a  and  730   b ) in the database of waypoint identifiers  305 , the process  700  returns to concatenate ( 705 ) the search string  325  with a next character from the set of characters  330 . Consequently, the autofill list of waypoint identifiers  345  includes a first single occurrence for each concatenated search string. 
         [0089]      FIG. 8  is a flow diagram illustrating an example process  800  for generating a GeoFill list of waypoint identifiers (e.g.,  355  of  FIG. 3E ) from a combination of a final vicinity list of waypoint identifiers (e.g.,  335  of  FIG. 3E ) and an autofill list of waypoint identifiers (e.g.,  345  of  FIG. 3E ) using a search string (e.g.,  325  of  FIG. 3E ) and a character from a set of characters (e.g.,  330  of  FIG. 3E ). Recall from  FIG. 6  above, the final vicinity list  335  of waypoint identifiers includes a respective geographically closest single occurrence of each concatenated search string. Also recall from  FIG. 7  above, the autofill list  345  of waypoint identifiers includes a first single occurrence of each concatenated search string. 
         [0090]    The search string  325  is concatenated ( 805 ) with a character from the set of characters  330  to form a concatenated search string. The final vicinity list  335  of waypoint identifiers and the autofill list  345  of waypoint identifiers are searched ( 810 ) for an occurrence of the concatenated search string. If a geographically closest single occurrence of the concatenated search string is found ( 815 ) (i.e., a waypoint identifier from the final vicinity list  335  of waypoint identifiers), the found waypoint identifier is included ( 820 ) in the GeoFill list  355  of waypoint identifiers. If, however, a geographically closest single occurrence is not found, but a first single occurrence of the concatenated search string is found ( 825 ) (i.e., a waypoint identifier from the autofill list  345  of waypoint identifiers) the found waypoint identifier is included ( 820 ) in the GeoFill list  355  of waypoint identifiers. If neither a geographically closest single occurrence nor a first single occurrence is found, no waypoint identifier is added ( 830 ) to the GeoFill list  355  of waypoint identifiers at this time. 
         [0091]    After including the waypoint identifier ( 820 ) or excluding the waypoint identifier ( 830 ) from the GeoFill list  355  of waypoint identifiers, if there are more waypoint identifiers ( 835   a  and  835   b ) in the final vicinity list  335  of waypoint identifiers or the autofill list  345  of waypoint identifiers, the process  800  returns to concatenate ( 805 ) the search string  325  with a next character from the set of characters  330 . Consequently, the GeoFill list  355  of waypoint identifiers includes a geographically closest single occurrence or a first single occurrence for each concatenated search string. 
         [0092]    While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. 
         [0093]    For example, the above described apparatuses and processes may not be limited to waypoint identifiers, but may include other types of identifiers, such as procedure identifiers or approach identifiers. In an example embodiment, a database of identifiers may be searched by indicating an identifier type along with providing a search string, a reference position and a vicinity term. Accordingly, the above described apparatuses and processes would be applied to those identifiers having a same type as the indicated identifier type. 
         [0094]    Moreover, while some example embodiments are illustrated within the context of aviation, one skilled in the art will readily recognize embodiments of the present invention are applicable to other navigational applications, such as aeronautical, terrestrial, and nautical and the like. For example, embodiments of the GeoFill technique may be used to select navigational waypoints for navigating a car or a ship. 
         [0095]    The term “list” is used throughout this disclosure, for example, the GeoFill list of waypoint identifiers  355  of  FIG. 3E . It should be noted, however, such use is not intended to limit the present invention to only lists. Generally, example embodiments of the present invention relate to processing a first collection of data or “data collection” and producing a second data collection or “resultant.” In processing the first data collection and producing the second data collection, there may be one or more intermediate data collections or “working data collections.” 
         [0096]    For example, consider  FIG. 3C  again. The final vicinity list generator  321  processes the initial vicinity list  320  (a first data collection) and produces the final vicinity list  335  (a second data collection). At each iteration in processing the initial vicinity list  320  and producing the final vicinity list  335 , there is an intermediate final vicinity list  335   a  . . .  335   n  (a working data collection). 
         [0097]    It should be readily recognized by those skilled in the art that the first data collection, the second data collection, and the working data collection may be implemented as various data computer structures, such as an array or double-linked list. Additionally, such data collections may be presented to a user in a variety of forms and formats, such as a table listing every entry from a data collection or as a single entry listing one entry from a data collection. 
         [0098]    It should be understood that the block diagrams (e.g.,  FIGS. 2A-3E ) and flow diagrams (e.g.,  FIGS. 5-8 ) may include more or fewer elements, be arranged differently, or be represented differently. It should be understood that implementation may dictate the block and flow diagrams and the number of block and flow diagrams illustrating the execution of embodiments of the invention. 
         [0099]    For example, a GeoFill list of waypoint identifiers may be alternatively generated by replacing entities in an autofill list of waypoint identifiers with waypoint identifiers from a vicinity list of waypoint identifiers that match a search string and that are closest to a reference position. 
         [0100]    In this alternative implementation, a database of waypoint identifiers is searched for database entities in the vicinity of a reference position. The results of this first search are placed into a “vicinity list” (or an initial vicinity list). The “vicinity” (or vicinity term) is typically defined as an area within a specified radius of the reference position, but may be tuned based on the application. The vicinity list is then filtered such that a “resulting vicinity list” (or final vicinity list) contains the geographically closest entity with a unique identifier (or geographically closest single occurrence of the search string followed by a character from a set of characters). 
         [0101]    In removing or otherwise filtering duplicates from the resulting vicinity list, additional criteria may be applied to determine which entity should remain. For example, one may prefer a navaid named “ABC” over a waypoint identifier named “ABCDE” when a search string is “AB”, even though the waypoint identifier “ABCDE” may be geographically closer to the reference position. 
         [0102]    Once the vicinity list is completely filtered, the database of waypoint identifiers is searched with the search string for all entities starting with the specified search string. The list of waypoint identifier (or autofill list) resulting from this initial search is filtered such that only one entry exists for each possible character following the search string (or a single occurrence of the search string followed by a character from a set of characters). 
         [0103]    Each entity in the autofill list that has a matching waypoint identifier in the vicinity list (according to the search string) is replaced with the entity from the vicinity list. The resulting list is considered a GeoFill list. Entities from the GeoFill list are used to fill in an entry field. 
         [0104]    The reference position  310  may be defined or otherwise established by current location, location on a flight plan or other appropriate location. 
         [0105]    It should be further understood that elements of the block diagrams (e.g.,  FIGS. 2A-3E ) and flow diagrams (e.g.,  FIGS. 5-8 ) described above may be implemented in software, hardware, or firmware. In addition, the elements of the block diagrams and flow diagrams described above may be combined or divided in any manner in software, hardware, or firmware. If implemented in software, the software may be written in any language that can support the embodiments disclosed herein. The software may be stored on any form of computer-readable medium, such as random access memory (RAM), read only memory (ROM), compact disk read only memory (CD-ROM), and so forth. In operation, a general purpose or application specific processor loads and executes the software in a manner well understood in the art.