Patent Publication Number: US-8996309-B2

Title: Apparatus and method to indicate instrument saturation

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation in part of U.S. application Ser. No. 12/176,838, filed Jul. 21, 2008, now U.S. Pat. No. 8,224,566, which claims priority pursuant to 35 U.S.C. §119(e) to then U.S. Provisional Patent Application Ser. No. 60/951,206, filed Jul. 21, 2007, both titled APPARATUS AND METHOD TO INDICATE COURSE DEVIATION INSTRUMENT SATURATION, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present general inventive concept relates to displaying information on data display instruments and, more particularly, to an apparatus and a method of displaying a given condition and a degree of deviation therefrom on electronic data display instruments even when the degree of deviation exceeds the limits of the display instruments so that the instruments become saturated. 
     2. Description of the Related Art 
     A navigational system on an aircraft presents guidance cues to a pilot in terms of “steering commands.” These guidance cues are used to convey to the pilot whether the aircraft is on course or off course and are applied during multiple phases of flight. Specific examples of use include long-range en-route navigation and precision zero-visibility runway landings. 
     Guidance cues are generated when the aircraft is off course or “deviated” from a desired navigational course to an intended destination that has been programmed into the navigation system. Upon detecting a deviation, guidance cues are presented to the pilot in the form of steering commands such as “fly up” or “fly down” when vertical guidance is available, and/or “turn right” or “turn left” when lateral guidance is available. 
     Traditional implementations of these guidance cues have been presented via physical needles including a first needle that may move back and forth, or “deflect” to a left or a right of a center position, and a second needle that may deflect up or down of a center position. If both needles are in the center position, the aircraft is on the desired navigational course. If either needle is not in the center position, the needle is considered to be deflected and a steering command is generated to instruct the pilot as to the direction in which the aircraft should be maneuvered so that the deflected needle returns to the center position, thus returning the aircraft to the desired navigational course. 
     The degree of deflection of the first and/or second needle corresponds to the degree the aircraft has deviated from the desired navigational course. Small deviations are shown with small needle deflections while larger course deviations are likewise indicated via larger needle deflections. Thus, the amount that the pilot steers left/right or up/down, corresponds generally to the amount of needle deflection present to correct the navigational error. 
     The physical needle is limited by a range in that there is a maximum right deflection and a maximum left deflection. Since the degree of deflection relates to the degree in which the aircraft is off course, if the aircraft is significantly off course, the navigational error may be greater than what the physical needle can present, thus resulting in the needle being fully deflected or in a “pegged” position. When this condition occurs, the needle provides a misleading presentation. 
     For example, if a lateral position error is 5 nautical miles and the needle can only show a deviation of 3 nautical miles, the needle will be deviated to a maximum physical extent in either a left or right direction and in the pegged position. From the pilot&#39;s point of view, there is no difference between a condition where the actual navigational error is 3 nautical miles and a conditional where the actual navigational error is greater than 3 nautical miles. 
     In this situation, the pilot may attempt to correct the heading by altering course in reliance of the pegged needle so that the needle returns to the center position. However, depending on the extent the aircraft is off course and the corresponding extent of pegging, the needle may remain in the pegged position for a period of time and possibly after significant course correction, which may cause the pilot to speculate as to the cause of why the needle is not moving. The pilot may assume that the needle is not moving because it is pegged, or the pilot may assume that the needle and/or another device is defective. 
     Even if the pilot speculates that the needle is pegged and is correct, the extent of pegging or heading deviation is unknown, which results in further speculation. Naturally, any pilot uncertainty is very dangerous even if the timeframe of uncertainty is merely a momentary window. 
     Some advantages of the present inventive concept become apparent by examining the process a pilot uses to intercept and track a desired course from an off-course condition. When intercepting a new desired course a pilot flies a steady heading until intercepting the desired course, and then turns the aircraft to track that new course. During the intercept phase the course deviation indication may be off scale, or “pegged”. If the indicator is pegged, the pilot must continuously monitor this course deviation indication and detect the instant when the instrument transitions from the off-scale, “pegged” condition, to the on-scale condition. Depending on the speed of the aircraft and the angle of intercept, a very short period of time may elapse between the point when the needle transitions from being pegged off-scale until the needle is at the centered position. 
     This transition is important because it provides a visual cue that the pilot uses to determine when to alter the aircraft heading to capture a new desired course. Because the pilot must take action to intercept the desired course, the transition from the off-scale to on-scale condition must be timely detected in order to properly intercept and capture the desired course. When flying an instrument approach there may be very little time to recognize this transition and make the required course changes. With traditional instruments that represent the current state of the art, this transition is detectable only by the motion of the needle, and can be easily missed if the pilot is not extremely attentive to this gauge. However to properly control the aircraft, the pilot must be extremely attentive of all aircraft gauges, including this gauge, which can contribute to pilot difficulty in detecting the transition from off-scale to on-scale, and subsequently result in the pilot being late to initiate the aircraft heading change to capture the desired course. With the present inventive concept, the transition from off-scale to on-scale is more clearly indicated, and includes attention-getting features such as shape and color changes, enabling the pilot to more easily detect and take the appropriate action at the appropriate time. 
     Although the examples provided herein relate to flight and navigation, one skilled in the art will appreciate that the present inventive concept is equally advantageous in applications unrelated to flight and/or navigation. 
     SUMMARY OF THE INVENTION 
     The present general inventive concept provides an apparatus and method to maintain traditional information presentation in a manner that is consistent with existing training and safety methodology, but eliminates confusion generated when an indicator is placed in a fully “pegged” position by positively indicating that the indicator is off-scale and not representing an actual accurate deviation. 
     Additional aspects and advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present general inventive concept. 
     The foregoing and/or other aspects and advantages of the present general inventive concept may be achieved by providing an electronics display instrument configured to display information, the instrument including an output to convey information by displaying a conditional symbol on a scale, wherein the conditional symbol has a first form and a second form to indicate whether the symbol is accurate. 
     The conditional symbol may correspond to a conventional readout having a limited measurement scale. 
     The conditional symbol may be moveable from a first extreme to a second extreme with a central position therebetween. 
     If the conditional symbol is between the first extreme and the second extreme, then the conditional symbol may be in the first form. 
     If the conditional symbol is not between the first extreme and the second extreme, then the conditional symbol may be in the second form. 
     The first form may indicate that the conditional symbol is accurate and the second form may indicate that the conditional symbol is not accurate. 
     The conditional symbol may be a bar and the first form may be the bar in a solid form and the second form may be the bar in an outlined form. 
     The position information may be displayed in real time. 
     The foregoing and/or other aspects and advantages of the present general inventive concept may be achieved by providing a method of conveying a condition using an electronics display instrument, the method including displaying the condition with a symbol on a scale, the scale having a limited range, and varying a symbol appearance depending on whether the condition is measurable by the scale having the limited range. 
     The foregoing and/or other aspects and advantages of the present general inventive concept may also be achieved by displaying the symbol appearance in one of a first form if the condition is measurable by the scale and a second form if the condition is not measurable by the scale. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  illustrates a block diagram illustrating the present general inventive concept according to an exemplary embodiment. 
         FIG. 2  illustrates a front elevation view of a display having needle symbol in a normal non-pegged state according to an exemplary embodiment of the present general inventive concept. 
         FIG. 3  illustrates a front elevation view of a display having a needle symbol in a pegged state according to an exemplary embodiment of the present general inventive concept. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept while referring to the figures. 
     The present general inventive concept, as illustrated in  FIG. 1 , provides a navigational apparatus  1  having a readout  10  to display guidance cues to a pilot to indicate a plurality of factors related to whether an aircraft is on course or off course with respect to a desired navigational course. The navigational apparatus  1  has a plurality of inputs  20  and  30  to receive information such as, but not limited to, navigation and position information. A controller  40  performs a plurality of processes including comparing the navigation information and position information to yield a signal to a user and/or other apparatus, e.g., readout  10 . 
     These guidance cues may be visual and/or audible commands and the plurality of factors may be states of the aircraft and/or the aircraft instruments, including generally, but not limited to, whether the aircraft is on course or off course, the degree the aircraft is on course of off course, and/or whether the navigational apparatus is providing an accurate reading. Moreover, if the aircraft is off course, the guidance cues may provide visual and/or audible steps to the pilot, i.e., “steering commands,” so that the pilot may take action to return the aircraft to on course. 
     These guidance cues, presented to the pilot as steering commands, may be applied during multiple phases of flight. Specific examples of use may include long-range en-route navigation and precision zero-visibility runway landings. 
     Steering commands may be generated when the aircraft is off course or “deviated” from a desired navigational course to an intended destination that has been programmed into the navigation system. Upon detecting a deviation, steering commands may be presented to the pilot visually and/or audibly in the form of instructions such as “fly up” or “fly down” when vertical guidance is available, and/or “turn right” or “turn left” when lateral guidance is available. 
     Visual indicators may include displaying traditional aircraft instruments via electronic representations via the readout  10 . Such electronic representations provide increased flexibility relative to mechanical needles and utilize display symbology, such as a needle symbol, to convey information to the pilot. The introduction of completely new and unique display symbology would raise a plurality of training and safety issues, particularly for pilots familiar with needle symbology. Therefore, consistency with conventional flight and navigational symbology is desired. 
     The readout  10  of the present general inventive concept provides display symbology (see  FIGS. 2 and 3  generally) on an electronic flight display similar to that of older mechanical instruments to preserve familiarity and thereby increase the likelihood that a pilot, who is familiar with older mechanical instruments, will recognize the new display symbology on the electronic flight display. 
     Likewise, the steering commands may be presented in electronic format in a manner similar to that of older mechanical instruments, consisting of a vertical deviation bar to replace the vertical deviation needle and a lateral deviation bar to replace the lateral deviation needle. 
     Because of the importance of maintaining consistency between new electronic formats of the present general inventive concept and older mechanical instruments, which may include shapes and/or colors, the display symbology may have a number of limitations dictated by the manner in which the mechanical instruments display information. One such limitation of the needle symbol includes a maximum deviation. 
     Like the older mechanical needle, a needle symbol  50   a ,  50   b , and  50   c  of the electronic flight display may be designed to be limited by a range having a maximum first deflection  52   a ,  52   b , and  52   c , and a maximum second deflection  53   a ,  53   b , and  53   c  with respect to a center position  54   a ,  54   b ,  54   c , as illustrated in  FIGS. 2 and 3 . Since the degree of deflection relates to the degree in which the aircraft is off course, if the aircraft is significantly off course, the navigational error may be greater than what the needle symbol  50   a ,  50   b , and  50   c  can present, thus resulting in a fully deflected or in a “pegged” needle symbol  55   a ,  55   b , and  55   c , as illustrated in  FIG. 3 . This condition results in display ambiguity and pilot uncertainty. 
     Unlike a traditional mechanical needle, the needle symbol  50   a ,  50   b , and  50   c  of the electronic flight display of the present general inventive concept provides positive indication if the needle symbol  50   a ,  50   b , and  50   c  is an off-scale or pegged needle symbol  55   a ,  55   b , and  55   c . In one embodiment, the off-scale needle symbol  55   a ,  55   b , and  55   c  is represented by altering the appearance of the off-scale needle symbol from the normal, on-scale needle symbol  55   a ,  55   b , and  55   c . Such changes of form are accomplished by “ghosting” whereby the normal needle symbol  50   a ,  50   b , and  50   c  changes color and/or shape to become the pegged needle symbol  55   a ,  55   b , and  55   c , as illustrated in  FIG. 3 . Nevertheless, it will be appreciated that various other forms of changes between the normal needle symbol  50   a ,  50   b , and  50   c  and the pegged needle symbol  55   a ,  55   b , and  55   c  may be utilized without departing from the spirit and scope of the present general inventive concept. 
     In another embodiment, if the normal needle symbol  50   a ,  50   b , and  50   c  becomes the pegged needle symbol  55   a ,  55   b , and  55   c , a color of the normal needle symbol  50   a ,  50   b , and  50   c  or a color of a portion of the normal needle symbol  50   a ,  50   b , and  50   c  changes from a first display color to a second, more subtle color to indicate the pegged needle  55   a ,  55   b , and  55   c . For example, the normal needle symbol  50   a ,  50   b , and  50   c  may have a base primary color, such as bright green, which to indicate the pegged needle symbol  55   a ,  55   b , and  55   c , changes to a darker version of the same primary color, such as dark green. 
     Other changes of form include changing the pegged needle symbol  55   a ,  55   b , and  55   c  to an outlined form of the on-scale needle symbol  50   a ,  50   b , and  50   c , thus equating the displayed position to a place-holder for the on-scale needle symbol. 
     Thus, given the increased versatility of the electronic display  1  of the present general inventive concept, it is possible to eliminate the misleading condition that is created when the deviation needle is fully deflected and “off-scale” by altering the symbology. 
     In use, a pilot inputs a desired navigational course into a navigation system. During flight, the pilot may occasionally reference an instrument having two needle symbols to indicate whether the aircraft is on or off course with respect to the desired navigational course. The needle symbols may be on one or more instruments and may include any number of needle symbols or other like symbology. If the pilot drifts off course, one or more of the needle symbols may deviate from a center position to indicate the aircraft is left or right and/or higher or lower than the desired navigational course. An audible alarm may sound and/or steering commands may sound to alert the pilot that the aircraft is off course. If the needle symbol, for example, is limited to displaying a maximum deviation of 3 nautical miles and if an actual lateral position error of the aircraft begins to exceed 3 nautical miles, the needle symbol will be deviated or pegged to a maximum physical extent in either a left or right direction. When the needle symbol reaches its maximum deviation of 3 nautical miles, the needle symbol will change appearance to positively indicate to the pilot that the needle is pegged and that the aircraft is off course an excess of 3 nautical miles. Thus, the pilot will begin to correct the course of the aircraft while the needle symbol remains pegged. Since the needle symbol is positively indicating its pegged state, any pilot uncertainty as to why the needle symbol is not moving is eliminated. 
     An additional instrument and/or display may be included to cooperate with the needle symbol and instrumentation thereof to display the extent the needle symbol is pegged and/or the extent the aircraft is off course. 
     The present general inventive concept may be embodied in a retrofit device. In this scenario, the retrofit device may encompass not only the present general inventive concept, but may also include a back-up battery, a back-up GPS, and/or a data converter to enable the present general inventive concept to utilize wiring from the older mechanical needle and instrumentation thereof. 
     While the exemplary embodiment of the present general inventive concept is in an aircraft, the present general inventive concept may be employed in other types of vehicles such as water, land, and space vehicles. 
     Embodiments of the present general inventive concept, including but not limited to symbology, changing of symbology to represent states including off-scale and on-scale conditions, processing of data utilized to control symbology, and/or data including sensory data that the symbology represents, can be written as computer programs, stored on computer-readable recording media, and read and executed by computers. Examples of such computer-readable recording media include magnetic storage media, e.g., ROM, floppy disks, and hard disks, optical recording media, e.g., CD-ROMs, and DVDs, and storage media such as carrier waves, e.g., transmission over the Internet. The computer-readable recording media can also be distributed over a network of coupled computer systems so that the computer-readable code is stored and executed in a decentralized fashion. 
     As described above, the present general inventive concept provides an apparatus and method to maintain the traditional information presentation in a manner that is consistent with existing training and safety methodology, but eliminates the confusion generated when a needle is placed in the fully pegged position by positively indicating that the needle is off-scale and not representing actual accurate information. 
     Although a few exemplary embodiments of the present general inventive concept have been illustrated and described, it will be appreciated by those skilled in the art that changes may be made in these exemplary embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.