Abstract:
A method and apparatus is disclosed for displaying a dynamic parameter of an aircraft, the apparatus comprises a display unit receiving a display signal and displaying a scale that changes dynamically and non-linearly in accordance with a selected display algorithm, the display unit further displaying a pointer pointing to said scale in accordance with a reading of said dynamic parameter, thereby emphasizing a range of said reading of said dynamic parameter.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This patent application claims priority of U.S. provisional patent application No. 60/415,807, entitled “Electronic non-linear aircraft altitude and vertical speed display”, which was filed on Oct. 4, 2002, the specification of which is herewith enclosed by reference. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates to the field of aircraft instruments. More precisely, this invention relates to aircraft dynamic parameter displays.  
         BACKGROUND OF THE INVENTION  
         [0003]    Measurement and displaying of dynamic parameters of an aircraft is a key issue for properly controlling, managing and validating aircraft position and velocity.  
           [0004]    It is known that measurement of aircraft altitude and vertical speed, by barometric and other means, is a mature technology which is founded on principles which have remained relatively unchanged since the first deployment of altimeters and vertical speed indicators (VSI).  
           [0005]    In contrast, the “modern” altimeter display has evolved through four distinct iterations.  
           [0006]    An earliest modern variant, the “three-pointer” consists of a circular analog display housing three concentric pointers read against a common scale. A pointer is dedicated for displaying each of the 100&#39;s, 1,000s and 10,000s feet as shown in FIG. 1 a . This format is difficult to interpret, particularly during dynamic situations. Use of this technology resulted in several aircraft accidents because the small 10,000 ft pointer is easily obscured by larger pointers, leading to interpretation errors of multiples of 10,000 ft. This tendency became unacceptable with the advent of jet aircraft, whose high rates of climb and descent rendered the three-pointer altimeter virtually useless. It will be appreciated by someone skilled in the art that the three-pointer altimeter is still in widespread use in low-performance general aviation aircraft.  
           [0007]    A second generation of mechanical altimeters, the “counter-pointer” altimeter, is a refinement of the “three-pointer” altimeter which comprises a single 100 ft pointer, sweeping over a circular scale, with an additional digital display of altitude presented on a drum or counter on the face of the instrument as shown in FIG. 1 b.    
           [0008]    Although the details of the digital display, such as its smallest digital altitude increment, vary between different embodiments, the principle remains unaltered. The main benefits of the “counter-pointer” altimeter include its ease of interpretation and elimination of the 10,000 ft interpretation error potential.  
           [0009]    A third generation of altimeters comprises a moving vertical altitude tape read against a central stationary pointer, as shown in FIG. 2. The instrument typically includes a digital readout of the aircraft altitude adjacent to the tape display. Refinements to this system include provision of a vertical speed display adjacent to the altitude scale, and which allows the pilot to monitor altitude and vertical speed simultaneously, with a minimum of eye movement.  
           [0010]    A current generation of altimeters reflects a transition from mechanical instruments to Electronic Flight Instrument Systems (EFIS) and Head-up Displays (HUD) . Such systems have allowed the altitude display indications to be decoupled from any “physical” altimeter instrument, thereby allowing incorporation of new display formats.  
           [0011]    Modern altimeter formats described above have several important disadvantages.  
           [0012]    Except at very low altitudes, there is no analog representation of the aircraft&#39;s altitude above the altitude reference datum which is typically mean sea-level (MSL). This is because at high altitudes, neither the counter pointer nor the tape altimeter can show the zero-altitude datum, because of the scaling compromise between adequate resolution and adequate range. In other words, the analog part of these altimeters can only display a relatively narrow altitude band around the aircraft&#39;s current altitude, which typically does not include the zero point. This is an important drawback, because it has been contemplated that humans are much better at evaluating rates of change of analog data (e.g. pointers) than digital data, and the simultaneous display of the zero datum and the reference datum is critical, particularly in very dynamic situations. Traditional implementations have been unable to display the altitude information in the preferred analog fashion, while simultaneously displaying both the zero datum and current altitude.  
           [0013]    Furthermore, the resolution of the mechanical altimeters is generally fixed at all altitudes, even though flight operations may require differing resolutions for different circumstances (e.g. higher resolution is desirable at low altitudes, where terrain clearance is most critical).  
           [0014]    With respect to aircraft airspeed, it is known that measurement of the aircraft airspeed, by pitot-static means, is also known as a very mature technology which is founded on principles which have remained largely unchanged since the deployment of the first airspeed indicators (ASI). Modern airspeed indicators takes one of two forms: a dial/pointer display, occasionally supplemented with a digital counter and the fixed pointer/moving tape display typically incorporated in Electronic Flight Instrument Systems (EFIS) and Head-Up Display (HUD), as shown in FIG. 3. Both of these formats share an important disadvantage, they use a fixed scale which requires a tradeoff between resolution and scale range. In other words, a large scale is more legible, but has a relatively small display range, whereas a smaller scale achieves good range while compromising legibility.  
           [0015]    There is therefore a need for a method and apparatus that will overcome the above-identified drawbacks.  
         SUMMARY OF THE INVENTION  
         [0016]    It is an object of the invention to provide an apparatus for displaying an aircraft dynamic parameter in using a flexible dynamic parameter scale.  
           [0017]    It is another object of the invention to provide a method for displaying an aircraft dynamic parameter using a flexible dynamic parameter scale.  
           [0018]    Yet another object of the invention is to provide an apparatus for displaying a measured altitude signal of an aircraft together with a flexible altitude scale.  
           [0019]    Yet another object of the invention is to provide an apparatus for displaying a measured airspeed signal of an aircraft together with a flexible speed scale.  
           [0020]    Yet another object of the invention is to provide an apparatus for displaying a vertical airspeed value of an aircraft.  
           [0021]    According to a first aspect of the invention there is provided an apparatus for displaying a dynamic parameter of an aircraft, the apparatus comprising a processing unit receiving a selected display algorithm signal and a reading of the dynamic parameter, the processing unit determining a display signal and a display unit receiving the display signal and displaying a scale that changes dynamically and non-linearly in accordance with the selected display algorithm, the display unit further displaying a pointer pointing to the scale in accordance with the reading of the dynamic parameter, thereby emphasizing a range of the reading of the dynamic parameter.  
           [0022]    According to another aspect of the invention there is provided a method for displaying a dynamic parameter of an aircraft, the method comprising providing a reading of the dynamic parameter, generating a scale that changes dynamically and non-linearly using the provided reading of the dynamic parameter, and a selected display algorithm signal and a pointer pointing to the scale in accordance with the reading of the dynamic parameter of the aircraft and displaying the scale with the pointer thereby emphasizing a range of the reading of the dynamic parameter.  
           [0023]    According to another aspect of the invention, there is provided an apparatus for displaying a dynamic parameter of an aircraft, the apparatus comprising a display unit receiving a display signal and displaying a scale that changes dynamically and non-linearly in accordance with a selected display algorithm, the display unit further displaying a pointer pointing to the scale in accordance with a reading of the dynamic parameter, thereby emphasizing a range of the reading of the dynamic parameter. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:  
         [0025]    [0025]FIG. 1 a  is a front view of a “three-pointer” prior art altimeter; it will be appreciated that efforts are required to synthesize the readings of the three pointers into a coherent altitude; furthermore it will be appreciated that the small 10,000 ft pointer may be occluded by a larger one;  
         [0026]    [0026]FIG. 1 b  is a front view of a “counter pointer” prior art altimeter;  
         [0027]    [0027]FIG. 2 is a front view of a prior art embodiment of a tape altimeter; someone skilled in the art will appreciate the absence of a zero, mean sea level or ground plane reference datum due to the small portion of the hypothetical “tape” which is visible due to scale constraints;  
         [0028]    [0028]FIG. 3 is a front view of a fixed pointer/moving tape prior art display typically incorporated in Electronic Flight Instrument Systems (EFIS) and Head-Up Display (HUD);  
         [0029]    [0029]FIG. 4 is a block diagram of an electronic non-linear aircraft dynamic parameter display comprising a processing unit and a display unit in accordance with a preferred embodiment of the invention;  
         [0030]    [0030]FIG. 5 is a flowchart which shows how the electronic non-linear aircraft dynamic parameter display operates in the preferred embodiment of the invention;  
         [0031]    [0031]FIG. 6 is a diagram which shows a first example of a dynamic parameter tape provided on an electronic non-linear aircraft dynamic parameter display;  
         [0032]    [0032]FIG. 7 is a diagram which shows a second example of the dynamic parameter tape provided on the electronic non-linear aircraft dynamic parameter display;  
         [0033]    [0033]FIG. 8 is a diagram which shows a third example of the dynamic parameter tape provided on the electronic non-linear aircraft dynamic parameter display;  
         [0034]    [0034]FIG. 9 is a block diagram which shows a first embodiment of the electronic non-linear aircraft dynamic parameter display where the dynamic parameter is altitude;  
         [0035]    [0035]FIG. 10 is a flowchart which shows how the electronic non-linear aircraft dynamic parameter display operates in the first embodiment of the invention where the dynamic parameter is altitude;  
         [0036]    [0036]FIG. 11 is a picture which shows a first example of the electronic non-linear aircraft dynamic parameter display in the first embodiment of the invention where the dynamic parameter is altitude;  
         [0037]    [0037]FIG. 12 is a picture which shows a second example of the electronic non-linear aircraft dynamic parameter display in the first embodiment of the invention where the dynamic parameter is altitude;  
         [0038]    [0038]FIG. 13 is a block diagram which shows a second embodiment of the electronic non-linear aircraft dynamic parameter display where the dynamic parameter is speed;  
         [0039]    [0039]FIG. 14 is a flowchart which shows how the electronic non-linear aircraft dynamic parameter display operates in the second embodiment of the invention where the dynamic parameter is speed; and  
         [0040]    [0040]FIG. 15 is a picture which shows an example of the electronic non-linear aircraft dynamic parameter display in the second embodiment of the invention where the dynamic parameter is speed. 
     
    
       [0041]    It will be noted that throughout the appended drawings, like features are identified by like reference numerals.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0042]    Now referring to FIG. 4, there is shown a preferred embodiment of an electronic non-linear aircraft dynamic parameter display  5 .  
         [0043]    The electronic non-linear aircraft dynamic parameter display  5  comprises a processing unit  8  and a display unit  10 . In a preferred embodiment of the invention, the processing unit  8  is a digital computer or microprocessor, while the display unit  10  is either an Electronic Flight Instrument System (EFIS), a Multifunction Display (MFD), or a Head-Up Display (HUD), all of which are well known to someone versed in the art.  
         [0044]    The processing unit  8  receives a selected display algorithm signal provided by a user interface  6  and a measured dynamic parameter signal provided by a dynamic parameter measuring device  12 .  
         [0045]    The processing unit  8  provides a dynamic parameter display signal to the display unit  10 .  
         [0046]    Now referring to FIG. 5, there is shown how the electronic non-linear aircraft dynamic parameter display  5  operates in a preferred embodiment of the invention.  
         [0047]    According to step  20 , a display algorithm is selected using the user interface  6 . The selected display algorithm signal is provided by the user interface  6  to the processing unit  8 . In one embodiment, the display algorithm is selected by a pilot of the aircraft while in another embodiment of the invention, the display algorithm is selected by the air-data or display computer, or the like. For simple embodiments, the display algorithm may be a fixed algorithm which is not user-selectable.  
         [0048]    According to step  22 , a dynamic parameter signal is measured using the dynamic parameter measuring device  12  which provides the measured dynamic parameter signal to the processing unit  8 .  
         [0049]    According to step  24 , the dynamic parameter display signal, comprising data for displaying a dynamic parameter tape on the display unit  10 . Prior to displaying the dynamic parameter tape, the processing unit  8  first determines the dynamic parameter display signal using the measured dynamic parameter signal and the selected display algorithm signal and provides the created dynamic parameter display signal to the display unit  10 .  
         [0050]    Now referring to FIG. 6, there is shown a first example of a dynamic parameter tape  30  provided on an electronic non-linear aircraft dynamic parameter display  10 .  
         [0051]    The dynamic parameter tape  30  comprises a dynamic non-linear dynamic parameter scale  34 , a corresponding non-linear dynamic parameter value scale  32  and a pointer  36 .  
         [0052]    By convention, the dynamic non-linear dynamic parameter scale  34  and the corresponding non-linear dynamic parameter value scale  32  are displayed vertically. In alternative embodiments, the dynamic non-linear dynamic parameter scale  34  and the corresponding non-linear dynamic parameter value scale  32  may be displayed horizontally or at any other angles.  
         [0053]    The dynamic non-linear dynamic parameter scale  34  is a dynamic parameter scale that is provided between a first dynamic parameter scale end  38  and a second dynamic parameter scale end  40 .  
         [0054]    The corresponding non-linear dynamic parameter value scale  32  comprises a plurality of corresponding dynamic parameter values and is provided between a first dynamic parameter value  42  corresponding to the first dynamic parameter scale end  38  and a second dynamic parameter value  44  corresponding to the second dynamic parameter scale end  40 .  
         [0055]    The pointer  36  is located substantially at an equal distance between end  38  and end  40  of the dynamic non-linear dynamic parameter scale  34 . The pointer  36  comprises an indication of the measured dynamic parameter signal.  
         [0056]    It will be appreciated that the dynamic non-linear dynamic parameter scale  34  is adapted according to the selected display algorithm signal. As explained below, in one embodiment, the selected display algorithm signal is an exponential factor while in another embodiment of the invention, the selected display algorithm signal is a logarithmic factor. Alternatively, the selected display algorithm signal is a geometric factor.  
         [0057]    Furthermore, it will be appreciated that while a first part of the dynamic non-linear dynamic parameter scale  34 , for example, the part above pointer  36 , is adapted according to a first selected display algorithm signal, a second part of the dynamic non-linear dynamic parameter scale  34 , for example, the part below pointer  36 , may be adapted according to a second selected display algorithm signal.  
         [0058]    In one embodiment, the first dynamic parameter value  42  corresponding to the first dynamic parameter scale end  38  and the second dynamic parameter value  44  corresponding to the second dynamic parameter scale end  40  are provided by the user interface  6  while in another embodiment, the first dynamic parameter value  42  and the second dynamic parameter value  44  are automatically selected.  
         [0059]    Now referring to FIG. 7, there is shown a second example of a dynamic parameter tape  50  provided on an electronic non-linear aircraft dynamic parameter display.  
         [0060]    The dynamic parameter tape  50  comprises a dynamic non-linear dynamic parameter scale  52 , a corresponding non-linear dynamic parameter value scale  54 , a pointer  56  and an adjacent vertical bar  66 .  
         [0061]    By convention, the dynamic non-linear dynamic parameter scale  52  and the corresponding non-linear dynamic parameter value scale  54  are displayed vertically. In an alternative embodiment, the dynamic non-linear dynamic parameter scale  52  and the corresponding non-linear dynamic parameter value scale  54  may be displayed horizontally.  
         [0062]    The dynamic non-linear dynamic parameter scale  52  comprises a dynamic parameter scale that is provided between a first dynamic parameter scale end  58  and a second dynamic parameter scale end  60 .  
         [0063]    The corresponding non-linear dynamic parameter value scale  54  comprises a plurality of corresponding dynamic parameter values and is provided between a first dynamic parameter value  62  corresponding to the first dynamic parameter scale end  58  and a second dynamic parameter value  64  corresponding to the second dynamic parameter scale end  60 .  
         [0064]    The pointer  56  is located substantially at an equal distance between end  58  and end  60  of the dynamic non-linear dynamic parameter scale  52 . The pointer  56  comprises an indication of the measured dynamic parameter signal.  
         [0065]    The adjacent vertical bar  66  is located adjacent on the corresponding non-linear dynamic parameter value scale  54 . Alternatively, the adjacent vertical bar  66  is located adjacent on the dynamic non-linear dynamic parameter scale  52 .  
         [0066]    The adjacent vertical bar  66  comprises a variable end  68  which is adjacent to a corresponding future dynamic parameter value  53 . The adjacent vertical bar  66  therefore provides an indication of a future dynamic parameter value if a current variation of the dynamic parameter is maintained during a predetermined amount of time.  
         [0067]    The skilled addressee will appreciate that the corresponding future dynamic parameter value  53  can easily be seen by a pilot of the aircraft looking at the variable end  68 .  
         [0068]    It will be appreciated that the dynamic non-linear dynamic parameter scale  52  is adapted according to the selected display algorithm signal. As explained below, in one embodiment, the selected display algorithm signal is an exponential factor while in another embodiment of the invention, the selected display algorithm signal is a logarithmic factor. Alternatively, the selected display algorithm signal is a geometric factor.  
         [0069]    Furthermore, it will be appreciated that while a first part of the dynamic non-linear dynamic parameter scale  52 , for example, the part above pointer  56 , is adapted according to a first selected display algorithm signal, a second part of the dynamic non-linear dynamic parameter scale  52 , for example, the part below pointer  56 , may be adapted according to a second selected display algorithm signal.  
         [0070]    In one embodiment, the first dynamic parameter value  62  corresponding to the first dynamic parameter scale end  58  and the second dynamic parameter value  64  corresponding to the second dynamic parameter scale end  60  are provided by the user interface  6  while in another embodiment, the first dynamic parameter value  62  and the second dynamic parameter value  64  are automatically selected. In fact it will be appreciated that the dynamic non-linear dynamic parameter scale  52  expands from the first dynamic parameter value  62  and the second dynamic parameter value  64  toward the pointer  56 .  
         [0071]    Now referring to FIG. 8, there is shown a third example of a dynamic parameter tape  80  provided on an electronic non-linear aircraft dynamic parameter display.  
         [0072]    The dynamic parameter tape  80  comprises a dynamic non-linear dynamic parameter scale  82 , a corresponding non-linear dynamic parameter value scale  84 , a pointer  86 , an adjacent vertical bar  96  and an indication of a dynamic parameter variation with respect to a predetermined amount of time  100 .  
         [0073]    By convention, the dynamic non-linear dynamic parameter scale  82  and the corresponding non-linear dynamic parameter value scale  84  are displayed vertically. In an alternative embodiment, the dynamic non-linear dynamic parameter scale  82  and the corresponding non-linear dynamic parameter value scale  84  are displayed horizontally.  
         [0074]    The dynamic non-linear dynamic parameter scale  82  comprises a dynamic parameter scale that is provided between a first dynamic parameter scale end  88  and a second dynamic parameter scale end  90 .  
         [0075]    The corresponding non-linear dynamic parameter value scale  84  comprises a plurality of corresponding dynamic parameter values and is provided between a first dynamic parameter value  92  corresponding to the first dynamic parameter scale end  88  and a second dynamic parameter value  93  corresponding to the second dynamic parameter scale end  90 .  
         [0076]    The pointer  86  is located substantially in the middle of the dynamic non-linear dynamic parameter scale  82 . The pointer  86  comprises an indication of the measured dynamic parameter signal.  
         [0077]    The adjacent vertical bar  96  is located adjacent on the corresponding non-linear dynamic parameter value scale  84 . Alternatively, the adjacent vertical bar  96  is located adjacent on the dynamic non-linear dynamic parameter scale  82 .  
         [0078]    The adjacent vertical bar  96  comprises a variable end  98  which is adjacent to a corresponding future dynamic parameter value  101 . The adjacent vertical bar  96  therefore provides an indication of a future dynamic parameter value if a current variation of the dynamic parameter is maintained during a predetermined amount of time. The adjacent vertical bar  96  further comprises the indication of a dynamic parameter variation with respect to a predetermined amount of time  100 .  
         [0079]    The skilled addressee will appreciate that the corresponding future dynamic parameter value  101  can easily be seen by a pilot of the aircraft looking at the variable end  98 .  
         [0080]    It will be appreciated that the dynamic non-linear dynamic parameter scale  82  is adapted according to the selected display algorithm signal. As explained below, in one embodiment, the selected display algorithm signal is an exponential factor while in another embodiment of the invention, the selected display algorithm signal is a logarithmic factor. Alternatively, the selected display algorithm signal is a geometric factor.  
         [0081]    Furthermore, it will be appreciated that while a first part of the dynamic non-linear dynamic parameter scale  82  is adapted according to a first selected display algorithm signal, a second part of the dynamic non-linear dynamic parameter scale  82  may be adapted according to a second selected display algorithm signal.  
         [0082]    Now referring to FIG. 9, there is shown a block diagram which shows a first embodiment of the invention where the electronic non-linear aircraft dynamic parameter display is an electronic non-linear aircraft altimeter display  118 .  
         [0083]    The electronic non-linear aircraft altimeter display  118  comprises a processing unit  112  and a display unit  114 .  
         [0084]    Still in this first embodiment of the invention, the processing unit  112  is an air data computer, which is well known to someone versed in the art, while the display unit  114  is either an Electronic Flight Instrument System (EFIS), a Multifunction Display (MFD), or a Head-Up Display (HUD), all of which are well known to someone versed in the art.  
         [0085]    The processing unit  112  receives a selected display algorithm signal and an altitude reference signal provided by the user interface  110  and a measured altitude signal provided by the altitude measuring device  116 .  
         [0086]    The processing unit  112  provides an altitude display signal to the display unit  114 .  
         [0087]    Now referring to FIG. 10, there is shown how the electronic non-linear aircraft altimeter display  118  operates in the preferred embodiment of the invention.  
         [0088]    According to step  120 , a display algorithm is selected using the user interface  110 . The selected display algorithm signal is provided by the user interface  110  to the processing unit  112 . In one embodiment, the display algorithm is selected by a pilot of the aircraft while in another embodiment of the invention, the display algorithm is selected by the air data or display computer, or the like. For simple embodiments, the display algorithm may be a fixed algorithm which is not user-selectable.  
         [0089]    According to step  122 , an altitude reference signal is selected using the user interface  110 . The selected altitude reference signal is provided by the user interface  110  to the processing unit  112 . In one embodiment, the altitude reference signal is selected by a pilot of the aircraft while in the preferred embodiment of the invention, the altitude reference signal is provided by the air data computer or the like. The altitude reference signal typically represents a datum altimeter setting expressed in millibars, inches of Mercury, or as an altitude value in feet or meters.  
         [0090]    According to step  124 , an altitude signal is measured using the altitude measuring device  116  which provides the measured altitude signal to the processing unit  112 .  
         [0091]    According to step  126 , the altitude display signal, comprising an altitude tape is provided on the display unit  114 . The altitude tape is provided by first determining the altitude display signal using the measured altitude signal, the selected altitude reference signal and the selected display algorithm signal and providing the created altitude display signal to the display unit  114 .  
         [0092]    Now referring to FIG. 11, there is shown a first example of an altitude tape  130  provided on an electronic non-linear aircraft altitude display.  
         [0093]    The altitude tape  130  comprises a dynamic non-linear altitude scale  134 , a corresponding non-linear altitude value scale  132 , a pointer  144 , an adjacent vertical bar  146  and an indication of an altitude variation with respect to a predetermined amount of time  150 .  
         [0094]    By convention, the dynamic non-linear altitude scale  134  and the corresponding non-linear altitude value scale  132  are displayed vertically. In an alternative embodiment, the dynamic non-linear altitude scale  134  and the corresponding non-linear altitude value scale  132  may be displayed horizontally.  
         [0095]    The dynamic non-linear altitude scale  134  comprises an altitude scale that is provided between a first altitude scale end  136  and a second altitude scale end  138 .  
         [0096]    The corresponding non-linear altitude value scale  132  comprises a plurality of corresponding altitude values and is provided between a first altitude value  140  corresponding to the first altitude scale end  136  and a second altitude value  142  corresponding to the second altitude scale end  138 .  
         [0097]    The pointer  144  is located substantially in the middle of the dynamic non-linear altitude scale  134 . The pointer  144  comprises an indication of the measured altitude signal. In this example, the measured altitude signal is 5000 ft.  
         [0098]    The adjacent vertical bar  146  is located adjacent on the corresponding non-linear altitude value scale  132 . Alternatively, the adjacent vertical bar  146  is located adjacent on the dynamic non-linear altitude scale  134 .  
         [0099]    The adjacent vertical bar  146  comprises a variable end  148  which is adjacent to a corresponding future altitude value  152 . The adjacent vertical bar  146  is expandable between the measured altitude signal and the variable end  148 . The adjacent vertical bar  146  therefore provides an indication of a future altitude value if a current variation of the altitude is maintained during a predetermined amount of time. The adjacent vertical bar  146  further comprises the indication of an altitude variation with respect to a predetermined amount of time  150 .  
         [0100]    In the preferred embodiment, the predetermined amount of time is 1 min. In this example, the indication of an altitude variation with respect to a predetermined amount of time  150  is 1000 ft/min. Still in this example, the corresponding future altitude value  152  is 6000 ft.  
         [0101]    The skilled addressee will appreciate that the corresponding future altitude value  152  can easily be seen by a pilot of the aircraft looking at the variable end  148 .  
         [0102]    It will be appreciated that the dynamic non-linear altitude scale  134  is adapted according to the selected display algorithm signal.  
         [0103]    In fact, the dynamic non-linear altitude scale  134  is constantly adapted according to various principles detailed below.  
         [0104]    A first principle is the fact that the dynamic non-linear altitude scale  134  is substantially centered on the measured altitude signal. It will be appreciated by someone skilled in the art that this first principle enables a proper presentation of altitude information to the pilot of the aircraft.  
         [0105]    A second principle is the fact that, preferably, the first altitude value  140  represents the altimeter setting datum. The altimeter setting datum may be the mean sea level in one embodiment. In another embodiment, the altimeter setting datum may be a standard pressure datum (29.92 inch of mercury). In another embodiment, the altimeter datum may be the surface itself in the case where the altitude measuring device  118  is a radar altimeter or radio altimetry device. The altimeter setting datum may be manually set or obtained from the air data computer or radar altimeter.  
         [0106]    A third principle relates to the fact that the dynamic non-linear altitude scale  134  is scaled using the selected display algorithm signal in order to fit both the measured altitude signal and the altimeter setting datum  140  in the available display space.  
         [0107]    In one embodiment, the selected display algorithm signal is an exponential factor. In another embodiment of the invention, the selected display algorithm signal is a logarithmic factor. In another alternative embodiment, the selected display algorithm signal is a geometric factor. In a preferred embodiment, the selected display algorithm signal is set so that the scale of the dynamic non-linear altitude scale  134  decreases as it diverges from a current altitude; i.e., the highest resolution in the dynamic non-linear altitude scale  134  is observed immediately adjacent to the measured altitude signal of the aircraft.  
         [0108]    The choice of a geometric factor, a logarithmic factor, an exponential factor or any other non-linear selected display algorithm signal may depend on a desired application and a desired altitude display range.  
         [0109]    A fourth principles relates to the fact that above the measured altitude signal, the dynamic non-linear altitude scale  134  is scaled by a similar geometric factor, logarithmic factor, exponential factor or any other non-linear selected display algorithm signal to the second altitude value  142 . Because of the relative greater significance of altitudes below the aircraft, it is possible to adapt an upper scaling factor to show a smaller altitude scale above the measured altitude signal than below the measured altitude signal. It will be appreciated that as per the third principle, the selected display algorithm signal may also be changed automatically.  
         [0110]    Someone skilled in the art will appreciate that the high resolution is located where it is most important to maintain an accurate altitude in order to comply, for instance, with air traffic controller (ATC) clearances; and simultaneously, a clear graphic indication of the aircraft&#39;s relationship to the first altitude value  140  is given.  
         [0111]    As mentioned previously, it will be appreciated that while a first part of the dynamic non-linear altitude scale  134 , for instance, the part above the pointer  144 , is adapted according to a first selected display algorithm signal, a second part of the dynamic non-linear altitude scale  134 , for instance, the part below the pointer  144  may be adapted according to a second selected display algorithm signal.  
         [0112]    Now referring to FIG. 12, there is shown a second example of the altitude tape  130  provided on an electronic non-linear aircraft altitude display.  
         [0113]    In this example, the pointer  144  displays a measured altitude signal of 5000 ft.  
         [0114]    Still in this example, the indication of an altitude variation with respect to a predetermined amount of time  150  is −3000 ft/min and the corresponding future altitude value  152  will be 2000 ft if the aircraft maintains its rate of descent.  
         [0115]    It will further be appreciated that the dynamic non-linear altitude scale  134  is constantly adapted according to the display algorithm signal in order to emphasize a range of altitude; such constant adaptation enables the pilot of the aircraft to have a good appreciation of the dynamics of the aircraft; more precisely, the skilled addressee will appreciate that in the case of a descent, the dynamic non-linear speed scale  134  increases as there is less altitude in order to “fit” into the available display area. This results in increasing resolution where it is most necessary which is at low altitudes.  
         [0116]    As a corollary, for a given rate of climb or descent, the dynamic non-linear speed scale  134  will move more rapidly at low altitudes than at high altitudes, because the scale factor is greater in the former case. This has a beneficial effect of highlighting high descent rates at low altitudes by giving them greater saliency.  
         [0117]    While it may be argued that the adjacent vertical bar is analogous to existing vertical speed indicator (VSI), it will be appreciated that prior art vertical speed indicators are incapable of showing very high rates of change while maintaining adequate resolution for normal operations. Accordingly, it is not unusual for contemporary vertical speed indicators to be “pegged” particularly during high-speed descents, so the pilot has little idea of the actual descent rate and its relationship with current altitude, particularly for high performance aircraft. This is unfortunately also the case with prior art vertical speed indicator displays which incorporate digital readouts, because the determination of “time-to-impact” still requires a mental division of the measured altitude signal (which is changing very rapidly) by the instantaneous vertical speed indicator reading.  
         [0118]    The mental division is usually an impossible task under dynamic conditions with a high workload.  
         [0119]    The skilled addressee will appreciate that such shortcoming is not possible with the present invention since the only time when vertical speed indicator will be “pegged” will be when ground impact is in less than 1 min.  
         [0120]    In such case, the imminent impact will be obvious, and the digital readout  150  will still provide the required rate information to the pilot.  
         [0121]    It will further be appreciated that a further benefit of such embodiment of the altitude tape  130  is that the pilot may easily achieve the ideal asymptotic level-off at a desired altitude simply by adjusting the rate of climb or descent to anchor the variable end  58  to the desired level-off altitude. Used in this manner, the constant adaptation of the dynamic non-linear altitude scale  134  has the effect of gradually reducing the rate of climb or descent to zero as the difference between the required and current measured altitude signal diminishes.  
         [0122]    Now referring to FIG. 13, there is shown a block diagram which shows a second embodiment of the invention where the electronic non-linear aircraft dynamic parameter display is an electronic non-linear aircraft speed display  162 .  
         [0123]    The electronic non-linear aircraft speed display  162  comprises a processing unit  164  and a display unit  166 .  
         [0124]    Still in this first embodiment of the invention, the processing unit  164  is an air data computer, which is well known to one versed in the art, while the display unit  166  is an airspeed display on an electronic Flight Instrumentation System (EFIS), a multifunction Display (MFD), or a Head-Up Display (HUD), all of which are well known to one versed in the art.  
         [0125]    The processing unit  164  receives a selected display algorithm signal provided by the user interface  160  and a measured speed signal provided by the speed measuring device  168 .  
         [0126]    The processing unit  164  provides a speed display signal to the display unit  166 .  
         [0127]    Now referring to FIG. 14, there is shown how the electronic non-linear aircraft speed display  162  operates in the preferred embodiment of the invention.  
         [0128]    According to step  180 , a display algorithm is selected using the user interface  160 . The selected display algorithm signal is provided by the user interface  160  to the processing unit  164 . In one embodiment, the display algorithm is selected by the pilot of the aircraft while in another embodiment of the invention, the display algorithm is selected by the air data computer or the like.  
         [0129]    According to step  182 , a speed signal is measured using the speed measuring device  168  which provides the measured speed signal to the processing unit  164 .  
         [0130]    According to step  184 , a speed display signal, comprising a speed tape is provided on the display unit  166 . The speed tape is provided by first determining the speed display signal using the measured speed signal and the selected display algorithm signal and providing the created speed display signal to the display unit  166 .  
         [0131]    Now referring to FIG. 15, there is shown an example of a speed tape  190  provided on an electronic non-linear aircraft dynamic parameter display.  
         [0132]    The speed tape  190  comprises a dynamic non-linear speed scale  192 , a corresponding non-linear speed value scale  194 , a pointer  212  and an adjacent vertical bar  214 .  
         [0133]    Preferably, the dynamic non-linear speed scale  192  and the corresponding non-linear speed value scale  194  are displayed vertically.  
         [0134]    The dynamic non-linear speed scale  192  comprises a speed scale that is provided between a first speed scale end  196  and a second speed scale end  198 .  
         [0135]    The corresponding non-linear speed value scale  194  comprises a plurality of corresponding speed values and is provided between a first speed value  200  corresponding to the first speed scale end  196  and a second speed value  210  corresponding to the second speed scale end  210 .  
         [0136]    The pointer  212  is located substantially in the middle of the dynamic non-linear speed scale  192 . The pointer  212  comprises an indication of the measured speed signal.  
         [0137]    The adjacent vertical bar  214  is located adjacent to the corresponding non-linear speed value scale  194 . Alternatively, the adjacent vertical bar  214  is located adjacent to the dynamic non-linear speed scale  192 .  
         [0138]    The adjacent vertical bar  214  comprises a variable end  216  which is adjacent to a corresponding future speed value  218 . The adjacent vertical bar  214  therefore provides an indication of a future speed value if a current variation of the speed is maintained during a predetermined amount of time. In a preferred embodiment, the predetermined amount of time is 10 sec.  
         [0139]    The skilled addressee will appreciate that the corresponding future speed value  218  can easily be seen by the pilot of the aircraft looking at the variable end  216 .  
         [0140]    It will be appreciated that the dynamic non-linear speed scale  192  is constantly adapted according to the selected display algorithm signal. In one embodiment, the selected display algorithm signal is an exponential factor, in another embodiment of the invention, the selected display algorithm signal is a logarithmic factor; in another alternative embodiment, the selected display algorithm signal is a geometric factor.  
         [0141]    In fact, the selected algorithm is set so that the highest resolution is observed immediately adjacent to the measured speed signal.  
         [0142]    Furthermore, it will be appreciated that while a first part of the dynamic non-linear speed scale  192  is adapted according to a first selected display algorithm signal, a second part of the dynamic non-linear speed scale  192  may be adapted according to a second selected display algorithm signal.  
         [0143]    In one embodiment, the first speed value  200  corresponding to the first speed scale end  196  and the second speed value  210  corresponding to the second speed scale end  198  are provided by the user interface  160  while in the preferred embodiment, the first speed value  200  and the second speed value  210  are automatically selected by the air data computer. It will be appreciated that the first speed value  200  and the second speed value  210  may be selected according to the design of the aircraft.  
         [0144]    In this example, the measured speed signal is 205 kts.  
         [0145]    It will be appreciated that alternatively, the speed tape  190  comprises an indication of characteristic speeds of the aircraft such as Vfe, VNe, Vg, Vl, Vr, etc.  
         [0146]    Furthermore speed zones such as the “yellow arc”, the “green arc” and the “white arc” may be added on the speed tape  190 . The skilled addressee will appreciate that the “white arc”  191  is shown on the speed tape  190  disclosed in FIG. 15.  
         [0147]    It will be appreciated by the one skilled in the art that the embodiment enables the scale of the dynamic non-linear speed scale  192  to be maximum in the vicinity of the measured speed signal.  
         [0148]    Furthermore, the corresponding first speed value  200  and the corresponding second speed value  210  are always displayed on the speed tape  190 .  
         [0149]    Moreover, as the aircraft approaches low or high airspeed, where most limitations are encountered, the dynamic non-linear speed scale  192  ensures good legibility in these critical regimes.  
         [0150]    As per the embodiment where the dynamic parameter is altitude, it will be appreciated that the adjacent vertical bar  214  is of great advantage to show very high rate of change without exceeding available display.  
         [0151]    While prior art trend vectors may be “pegged”, the embodiment disclosed therein overcome such shortcoming which is of great advantage in the case of military jets.  
         [0152]    While it has been disclosed the dynamic parameter may be one of speed and altitude, the skilled addressee will appreciate that the dynamic parameter may alternatively be one of rotations per minutes (RPM), oil pressure, oil temperature, fuel flow, tachometer, remaining fuel or the like.  
         [0153]    The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.