JPH01500467A - Terrain identification device for ground proximity warning system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Terrain identification device for ground proximity warning system interconnectedness This application is filed by Charles Donald Bateman (Charles Nonax) a. Bateman) on the same date and the same as the assignee of this invention. ``Ground contact when flying at an excessive rate of descent over rough terrain'' transferred to the transferee This is related to the application for "Nearby Alarm Device".

This invention relates generally to ground proximity warning systems, and in particular to warning systems including inappropriate absolute altitude warnings. when the aircraft is flying over rough or mountainous terrain. A type of aircraft ground proximity warning system in which the standards required to issue a warning have been changed. It is related to.

Description of prior art Includes a ground proximity warning device that issues an alert when the absolute altitude indicates a dangerous altitude with the terrain. Various ground proximity warning devices are known. When absolute altitude indicates a dangerous flight condition A typical device for generating an alarm is U.S. Pat. No. 68 and No. 4,030,065. The US patent mentioned above is All assigned to the same assignee as the assignee of this invention and incorporated herein by reference. It is being

The alarm devices described in the above-mentioned US patent specifications provide satisfactory performance in most cases. However, it is designed primarily for situations where the aircraft is flying over relatively flat terrain. It is measured. The alarm device disclosed in the above-mentioned US patent has a battery altitude of 500 Alert for unsuitable absolute altitudes up to 1000 feet. this The FAA flight rules, especially Section 91, Division 91.119, ``Relatively flat terrain 91.119. This subdivision 91.119 states that if a person is not in the process of landing, The minimum permissible altitude for aircraft not on land is 8km (statute miles) from the flight course. 300m from the highest obstacle within a horizontal distance of rich in ups and downs Each flight rule for flying over dry and mountainous terrain states that minimum altitude of 600 m (2000 ft) above any obstacle. . Conventional warning systems, such as those disclosed to date, have been designed to prevent aircraft from flying over rough terrain or over mountains. Fly over rough terrain at a radio altitude of over 300m, and fly over rugged terrain. Does not issue a warning to the pilot when flying at a minimum altitude of 600m or less.

During its flight course, the aircraft flew over rough terrain and over flat ground. Absolute altitude warning systems provide optimal results for all flight situations. give no fruit. Therefore, when an aircraft is flying over rough terrain, is below a specified minimum altitude for rugged or mountainous terrain. alert the pilot, and pre-collision (: to force the pilot to take appropriate action). The need to provide a changeable absolute altitude warning system to provide extra warning time for Therefore, it is an object of the present invention to provide a ground proximity warning system that overcomes the drawbacks of conventional warning systems. The goal is to provide a

Another object of the invention is to enable aircraft to fly over rough or mountainous terrain in a predetermined manner. This is to issue a warning to the pilot when the aircraft is flying below the minimum altitude.

Another object of this invention is to enable aircraft to fly over rough or mountainous terrain. Ground proximity warning with terrain proximity warning device with extended warning time when inside The purpose is to provide equipment.

Still another object of the invention is to enable aircraft to fly over rough or mountainous terrain. Monitor I7 to see if it is in flight, and therefore change the terrain warning range with a ground proximity warning system. It is to provide.

A further object of the invention is to enable aircraft to fly over rough or mountainous terrain. A warning is issued when the aircraft is flying at an altitude below 600m above the ground and at a speed above a specified level. That's true.

Another object of the invention is to enable aircraft to fly over relatively flat terrain for distances of less than 600 m. This is to issue a warning when the aircraft is flying at an altitude above the ground and at a speed above a specified level.

Accordingly, in accordance with a preferred embodiment of the invention, relatively flat terrain and rugged Dangerous absolute altitude conditions provide improved warning to aircraft flying over both terrain A ground proximity warning device for use in a state of the art is disclosed. In the absolute altitude warning device disclosed here, Warning range changes when aircraft is flying over rough or mountainous terrain be done. A signal that represents the aircraft's altitude above sea level and a signal that represents the altitude above the ground. Rough terrain conditions are detected by the responsive circuitry. Both signals mentioned above are compared and integrated over a predetermined period to provide a bias signal to the absolute altitude warning circuit device. supply. Any difference between both signals is a buffer that is added to the absolute altitude warning signal for flat terrain. Generates a bias signal. An aircraft flies over rough terrain at a speed higher than the specified speed. Moreover, the absolute altitude warning signal that is changed while flying at an altitude below 600m above the ground is a warning signal. make a report. The warning device according to the invention therefore allows the aircraft to operate in both conditions, i.e. When flying over relatively flat terrain and when flying over rough terrain. When descending below a predetermined altitude, a warning is issued to the pilot. the result , giving pilots extra warning time when flying over rough terrain. This helps reduce accidents due to insufficient absolute altitude.

These and other objects and advantages of this invention will become apparent in the detailed description and advantages that follow. This will become readily apparent when considering the accompanying drawings.

Figure 1 shows that when an aircraft is flying over rough terrain, there are multiple absolute altitudes. FIG. 2 is a graph showing the time to collision and the altitude above the ground.

FIG. 2 shows an absolute vehicle with gear warning and terrain warning range modified in accordance with the present invention. FIG. 2 is a graph diagram showing the relationship between aircraft ground altitude and aircraft speed for altitude warning.

FIG. 3 shows a flap warning and terrain warning range modified according to the present invention. 1 is a graph diagram showing the relationship between aircraft ground altitude and aircraft speed for absolute altitude warning; Ru.

FIG. 4 shows functions for implementing the alarm ranges of FIGS. 2 and 6 in accordance with the present invention. It is a block diagram.

Figure 5 shows whether an aircraft is flying over rough terrain in accordance with the present invention. FIG. 2 is a functional block diagram of a circuit device for detecting whether or not the vehicle is floating.

Detailed description of the preferred embodiment If you pay attention to the drawings, especially Figure 1, you can see that the aircraft is flying over rough terrain. A graphical representation is shown when you are flying a specific flight path and the absolute altitude changes with a minimum. has been done. The four instantaneous positions of the aircraft, A, B, O and D, are shown in Figure 1. Ru. As shown, the absolute altitude of the aircraft at position A is 900 m (3000 ft). ). As the aircraft progresses along the flight path, the absolute altitude at position B will be as shown in the diagram. 960 m (3200 ft). As the aircraft advances further, its position on the flight path Upon reaching C, the absolute altitude is 600 m (2000 ft).

The position indicates the aircraft position at an absolute altitude of 300 meters (1000 feet).

The horizontal axis is a function of absolute altitude related to the flight path and terrain shown in Figure 1. Indicates the time until collision.

The time to impact depends on the terrain approach rate and the altitude of the aircraft above the terrain. - Examples and When the aircraft flies over the rugged terrain shown in Figure 1, Moreover, if the absolute altitude reaches a position of 600 m, the time until collision is approximately 2 It is 5 seconds. If the aircraft descends to a position where the absolute altitude is 300 m, a collision will occur. It takes only 5 seconds.

Therefore, the conventional warning system does not issue a warning until the absolute altitude is 500m, It only issues an alarm in situations like seconds ago. In the warning device of this invention, the aircraft wakes up. Alerts you if you approach terrain less than 600m while flying over rugged terrain. This changes the alarm range to effectively lengthen the alarm time.

Referring to Figure 1, the position corresponds to the aircraft approaching the terrain up to 600m. When C is reached, a modified alarm range is generated. As shown in Figure 1, The time until collision at position C is 25 seconds. Therefore, under the flight conditions shown in Figure 1, The alarm device of this invention has a shorter alarm time than that given by the conventional device under the same circumstances. It provides pilots with a warning time five times longer than that of a pilot.

Moreover, as mentioned above, flight regulations require a minimum absolute height of 600 m in mountainous terrain. It is prescribed to take precautions. The warning system of this invention is designed to prevent aircraft from alerts when the aircraft descends below the minimum altitude of Helps pilots monitor the absolute altitude of an aircraft while in flight. Conventional The absolute altitude warning device does not issue an alarm when the absolute altitude is 300m or higher.

Additionally, warning systems may also be appropriate when the aircraft is flying over relatively flat terrain. A warning must be issued. The reason is that aircraft fly over relatively flat terrain. They also fly over rough terrain. Disclose to this This invention is also suitable for situations where the aircraft flies over relatively flat terrain. Prepare a warning range. In this invention, the alarm range is as shown in FIGS. 2 and 3. be.

Figure 2 shows when an absolute altitude warning is issued and the aircraft's landing gear is raised and the To issue a warning when the aircraft is lower than a predetermined altitude and speed (=, depending on the Matsuha number) The relationship between the aircraft speed and the aircraft's altitude above the ground is shown as: In Figure 2 As shown, the speed of the aircraft is 0.35 matsuha slower and the aircraft is in the landing gear. Whenever you are at an altitude below 150 m (500 ft) above the ground with the aircraft raised , the "gear too low" alarm is indicated by the hatched area 1o in Figure 2. Sea urchin is served. At aircraft speeds between 0.35 matsuha and 0.457 matsuha, line 12 The warning boundary indicated by is a function of the aircraft's altitude and speed. Figure 2 As shown in Figure 2, between 0.35 and 45, the aircraft speed increases. The lower the altitude, the higher the altitude above the ground at which the warning will be issued. 0.45 Matsuha or more For aircraft speed, the altitude of the aircraft was indicated by the hatched portion 14 of the warning range. Whenever the water is as low as 300m, a warning is issued.

Hatched areas 10 and 14 indicate that the aircraft is flying over relatively flat terrain. Indicates the appropriate aircraft warning range when Cross hatched area of alarm range 16 is the warning range used when an aircraft is flying over rough terrain. Indicates what has changed.

As can be understood from Figure 2, the aircraft is flying at a speed as low as 0.35 matsuha. The warning range is the same as when the aircraft is flying over relatively flat terrain. Ru.

However, at speeds between 0.35 Matsuhachi and 0.45 Man, line 18 The modified warning boundary, indicated by rise The modified warning boundary is for aircraft flying over relatively flat terrain. The slope of the alarm boundary indicated by line 12 is also steep. The modified alarm boundary is The warning will be given at a higher altitude above the ground, prolonging the warning time. Therefore, the As is clear from Figure 2 and its explanation, both flat and rugged terrain A warning range suitable for aircraft flying over the area is provided.

As mentioned above, such warning ranges are useful when flying over rough terrain. This provides a significantly longer warning period during which the pilot can take evasive action. Police The information range also depends on whether the aircraft's altitude above the ground is above the minimum altitude established by the FA, A. It issues a warning when descending and when the aircraft is flying at a speed greater than 0.45 matsuha.

Similar to Figure 2, the graphical representation in Figure 6 indicates that the flaps are not in the landing position and the aircraft is indicates a different warning range for conditions where the altitude above ground is less than 60 m (200 ft). The operation of the absolute altitude warning device will be illustrated. As can be understood from Figure 3, 0.28 mm At aircraft speeds below 200m, the aircraft is at an altitude below 60m and the flaps are in place. A warning is issued when you are not in a land position. This part of the alarm range It is indicated by the attached section 20. The speed of the aircraft is between 0.28 Matsuhachi and 45 Matsuha , the warning boundary marked a22 is as a function of aircraft speed and altitude. Change. Generally, in this area, the higher the aircraft speed, the less likely a warning will be issued. The altitude before falling is high. At speeds above 0.45 Matsuhachi, the aircraft will fly over 600m. If you approach the bottom, a warning will be issued.

This part of the warning area is represented by the serrated area 24 and is is used when flying over relatively flat terrain. Aircraft undulates When flying over rich terrain, the above-mentioned area should be marked with a cross. By adding 26 minutes, the alarm range is changed. In the modified part, At aircraft speeds between 28 Matsu 8 and 0.45 Matsu 1 the warning range was indicated by line 28 It stands up sharply. At speeds above 0.45 Matsuhachi, the aircraft will reach 600m. A warning will be issued if the altitude below the ground level is lowered.

Therefore, as is clear from Figures 2 and 3, the speed of the aircraft and its related The alarm range is a function of the terrain approach and in response to the landing gear and flap posture. The area has been disclosed. Moreover, when the aircraft is flying over rough terrain, the The alarm range is modified to provide a longer alarm time.

In order to implement a terrain warning system having the characteristics shown graphically in Figures 2 and 3, The first functional block diagram is shown in FIG. FIG. 4 shows the ground plane according to this invention. A proximity warning device 60 is shown. This ground proximity warning device 30 includes: Although it is shown in the series gate, comparison circuit, etc., Figure 4 i: It should be understood that this can be implemented using digital or analog circuits. Here The signals used in alarm systems such as those described include radio altitude and pressure altitude signals. signals indicating the aircraft's flap position and landing gear position; Contains a signal representing speed.

These signals include radio altimeters, barometric altimeters, manno-1 meters, and gear and flash can be obtained from a variety of circuit elements that indicate the location of the tap. 'A new type of aircraft consisting of may derive some of these signals from a digital data bus (not shown). stomach.

A signal representing aircraft speed is routed from line 32 from Matsuno 64 or similar. Applied through. This signal is transmitted to several devices, one of which is function generator 66. input). This function generator 36 represents the general characteristics of the alarm range of the device. supply the signal. To be more specific, if a signal indicating a speed below 0.28 Matsuhachi If input to function generator 36, a signal representing 6om (2oo feet) would be Output. Similarly, the input representing the speed between 0.28 Matsuhachi and 0.35 Matsuhachi For signals, it represents an altitude of 60 m or +50 m (500 ft) above the ground. A proportional signal is output. A signal representing the aircraft speed to 0.45 Matsuno is applied. Function generator 66 then provides a signal representing an altitude of 300 m. Therefore, the function Each portion 10 of the alarm range shown in FIGS. 2 and 3 using a generator 36. , 14, 20, 24 directly. Alarm range part 16 and 26 represent the composite signal generated by function generator 36 and the consists of a bias signal that

The output of the function generator 36 is connected to the signal from the radio altimeter 42 and the bias circuit 44. The signal is applied to the summing point 40 together with the signals from these signals. The bias circuit 44 will be explained in detail later. To change the alert range when the aircraft is flying over rough terrain, Ru. Comparison circuit 46 receives the output from summing point 40 on line 48.

Comparator circuit 46 generates a logic signal on line 50 and connects it to AND gate 1. −52, 54 and 56. At least one of landing gear and flaps A positive logic signal is The voltage is applied through pin 50. A positive logic signal from comparator circuit 46 indicates that the aircraft is in flight. It also shows that the altitude is too low for the medium speed.

A signal representative of flap position is provided by an element shown in FIG. 4 as functional block 62. be provided. When the flaps are ready for landing, a positive logic signal therefore the FD signal is on the line. 64. When the flap is up, a positive logic signal therefore FU multiplier signal line 66 is provided.

Another element, indicated by block 68, provides a signal indicative of the attitude of the landing gear. . A positive logic signal applied through line 70 indicates that the landing gear is up. and is named the GU times signal. Positive logic signal applied through line 72 This signal indicates that the landing gear is lowered and is called the GD double signal.

The GD double signal and the FD double signal are applied to AND gate 74. If the landing gear If both flaps are down, a positive logic signal is output to voice generator 58. is applied to This signal from AND gate 74 inhibits the voice generator. thus eliminating noisy alarms during aircraft landing.

The GEAR alarm is generated by the signal from the AND gate 90, the signal from the comparison circuit 46, and the signal from the AND gate 90. and an AND gate 54 which receives the GU and GU times signals. and gate 9 The signal from 0 is applied to the inverting input terminal of AND gate 54. This input is , can be used whenever a zero logic signal is output from the AND gate 90. be done. A logic signal of zero indicates that the gear is in the down position or the aircraft speed is 0.35. Whenever Matsuha is slow, it is output from AND gate 90. GU double trust is applied to the other input terminal of AND gate 54 together with the signal from signal comparison circuit 46. , the aircraft is at a height of 150 m (500 ft) with its landing gear up. GEAR alarm only when the signal from comparator circuit 46 indicates that the vehicle is at a low altitude above the ground. enable use.

A signal representing the speed of the aircraft is also applied to comparator circuit 76 through line 32. . This comparison circuit 76 equalizes the signal from the pine meter to a signal representing 0.28 man-hachi. A positive logic signal is provided to AND gate 80 when the value is greater than or equal to . F The U times signal is applied to AND gate 80. If the speed of the aircraft is 0.28 matsuha AND Gate 80 can be used if it is large enough and the landing gear is up. be made capable. The output of AND gate 80 is connected to the inverting input terminal of AND gate 52. applied. AND gate 52 receives the signal from comparison circuit 46 and the GU multiplied signal. Let's go. This GU multiplier signal is applied to the inverting input terminal of AND gate 52. and - When gate 52 is enabled, a positive logic signal is sent to voice generator 58. is applied to the aircraft at an altitude that is too low and is also below the specified altitude while the aircraft has its flaps up. The FLAPEI signal is issued to indicate that the aircraft is flying at high speed.

A signal representative of the speed of the aircraft is also applied to comparator circuit 86. This comparison circuit 86 , there is a positive output through line 88 when the aircraft speed is greater than 0.35 matsuha. supply the force signal. The output from the comparison circuit 86 is an AND gate for both the GU multiplied signal. 90. A positive logic signal is supplied to both input terminals of AND gate 90 When a positive logic signal is output and output through line 92 to OR gate 84, is applied to This OR gate 84 also receives input from the AND gate 80, Therefore, when receiving a positive logic signal from AND gate 90 or 80, the AND gate A positive logic signal is applied to gate 56. The output of OR gate 84 is an AND game. The AND gate 56 cooperates with the comparator circuit 46 to Starts the RA engineering alarm. This TERRA engineering N alarm starts when When gate 84 is enabled and a positive logic signal is provided from comparator circuit 46 It is. The OR gate 84 can be used under two conditions, the first being that the gear is This is when the reeds are in the raised position and the speed of the aircraft is 0.35 matsuno\ or more. the The second is when the flaps are in the up position and the aircraft speed is 0.28 matsuha or higher. It's time. If either of the two conditions is met, a positive logic signal is passed through line 94. is applied to AND gate 56, thus placing it under the control of comparator circuit 46. , altitude and speed combinations that bring the aircraft within the warning range shown in Figures 2 and 6. In conjunction with this, a TERRAIN warning will be issued during flight.

The outputs of AND gates 52, 54 and 56 are applied to voice generator 58. It will be done. A positive logic signal applied to this voice generator 58 This will cause an alarm to be emitted from mosquitoes, headphones, etc. Typical voice for this purpose -The generator device is described in U.S. Pat. No. 4, incorporated herein by reference. OS　O ,065 and No. 3,925,751.

The above-described logic circuit is shown in the hatched portions 10 and 14 in FIG. 2 and in FIG. necessary to provide the alarm range indicated by the hatched areas 20 and 24. Refers to a logic circuit. These parts of the warning area are where the aircraft is flying over relatively flat terrain. This is for use during flight.

Referring to Figure 5, this occurs when the aircraft is flying over rough terrain. An independent circuit provides a bias signal applied to summing point 40 to change the alarm range. A particular circuit is shown. This circuit is shown within functional block 44. Ba The ias circuit is modified as shown as section 16.26 in FIGS. 2 and 3, respectively. Provides a range of alarms.

Generally, bias circuit 44 detects the terrain below which the aircraft is flying. this is This is done by taking the difference between the aircraft's radio altitude and pressure altitude. any specific time The difference between the aircraft's pressure altitude and radio altitude is the difference between the aircraft's pressure altitude and radio altitude at that particular time. is equal to the pressure altitude of the terrain at the point being flown by. the aircraft is relatively flat The differential signal remains constant while flying over the terrain. However, When an aircraft is flying over rough terrain, the signal will depend on the terrain and the aircraft. It changes over time as a function of speed. This signal will therefore cause the aircraft to Indicates that you are flying over rich terrain. The difference signal is integrated over time and provide a bias signal that is a function of the difference.

To explain in detail, the signal representing the radio altitude is obtained from the radio altimeter 42 and added. It is applied to the positive input terminal of the calculation point 96. Barometric altimeter 97 or air data code The signal obtained from the computer and representing the barometric altitude is printed on the negative input terminal of the summing point 96. added. The output of summing point 96 is applied to the inverting input terminal of amplifier 98.

Integrator 100 is connected to the output terminal and non-inverting input terminal of amplifier 98, and thus Forms a closed feedback loop.

The integrator is a function of the difference between the signal representing radio altitude and the signal representing pressure altitude. It works to supply an ear signal. The integral constant is printed on the inverting input terminal after a predetermined time. selected so as to cancel out the added signal. The output signal from the circuit resets after a predetermined time. Set. In other words, after a predetermined period of time, line 10 is removed from the output terminal of amplifier 98. There is no signal heading towards 2. The preferred embodiment inhibits the bias circuit under the following conditions: It is also desirable to do so. In other words, the following conditions refer to the barometric altimeter or radio altitude. If the radio signal altitude of the aircraft is a certain amount, e.g. 1500 m (5000 ft. g) It is also expensive. Therefore, under these conditions, integrator 100 is disabled. Ru.

The output of amplifier 98 is applied to function generator 104.

This function generator 104 operates at an altitude of 50 m (500 feet) to 300 m (100 m). 0 feet) is amplified by amplifier 106 to provide a signal representing A bias signal based on the amplifier 98 output is provided. This signal connects line 108 to The aircraft is flying over rough terrain. change the alarm range from time to time. Bias signals help aircraft fly over rough terrain. While flying, the hatched part 16 in Figure 2 and the hatched part 16 in Figure 3. Warning range up to 600 m (2000 ft) as indicated by digit 26. Change the enclosure.

In the preferred embodiment, a time of two minutes is chosen for integrator 100. Other than 2 minutes Time works, but 2 minutes covers the distance that spans multiple change points in the terrain. selected for inclusion. In a typical example, an aircraft flying at normal cruising speed It travels approximately 22 km (12 nautical miles) in 2 minutes. In many areas this distance is is sufficient to span multiple change points in the terrain.

Obviously, many modifications and variations of this invention are possible in light of the dual teachings. Ru. Therefore, within the scope of the claims, the invention may be practiced beyond that specifically described above. .

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Claims (32)

[Claims] 1. The aircraft exhibits an inappropriate absolute altitude while flying over relatively flat terrain. alarm signal generating means for supplying a signal; to bias the signal when the aircraft is flying over rough terrain. biasing means responsive to the alarm signal generating means and the biasing means; An absolute altitude warning device for an aircraft, comprising means for generating an absolute altitude warning. 2. The bias means is Detection to detect if the aircraft is flying over rough terrain and, in response to this detection means, detect whether the aircraft is flying over rough terrain. means for supplying a bias signal to the alarm signal generating means when An absolute altitude warning device according to claim 1, comprising: 3. The bias means includes a signal representing the aircraft's altitude above the ground and a signal representing the pressure altitude. An absolute altitude warning device according to claim 1 in response to the above. 4. The biasing means generates a signal that is a function of the difference between the aircraft's ground altitude and pressure altitude. An absolute altitude warning device according to claim 3. 5. The bias means includes a signal representing the aircraft's altitude above the ground and a signal representing the pressure altitude. The absolute altitude alarm according to claim 4, wherein the signal is generated by integrating the difference between Device. 6. The detection means determines whether the aircraft is flying over rough terrain for a predetermined period of time. 3. The absolute altitude warning device according to claim 2, which is suitable for detecting whether or not the altitude is high. 7. 7. Absolute altitude warning system according to claim 6, wherein the predetermined period of time is substantially two minutes. 8. Absolute altitude is determined in response to a signal representing the aircraft's altitude above the ground and the aircraft's speed. for generating a first signal when the aircraft is within a predetermined altitude and speed range; A first means; Responds to the aircraft's ground altitude and pressure altitude during flight, allowing the aircraft to navigate over rough terrain. for supplying a bias signal to the first signal indicating that the aircraft is flying over the sky; A second means; In response to these first means and second means, a bias is applied to the predetermined range and an absolute a third means for issuing an altitude warning; Ground proximity warning system for aircraft equipped with 9. Claim 8, wherein the first means is also responsive to a signal indicative of the position of the landing gear. The ground proximity warning device described. 10. Claim 8, wherein the first means is also responsive to a signal indicative of the position of the flap. The ground proximity warning device described. 11. The maximum altitude at which the first signal is generated is effectively 300 m (1000 ft). ) The ground proximity warning device according to claim 8. 12. The maximum altitude at which the bias signal is generated is effectively 600 m (2000 m). 9. The ground proximity warning device according to claim 8, which is 13. The source of the signal representing the aircraft's altitude above the ground and the signal representing the aircraft's speed. The source of the signal, the source of the signal that represents the pressure altitude of the aircraft, and the altitude of the aircraft above the ground. the source of a signal representative of the airspeed of the aircraft; , a first means for generating a first reference related to speed and altitude of the aircraft; said signal source of a signal representative of the aircraft's altitude above the ground; and a signal representative of the aircraft's pressure altitude. the aircraft is flying over rough terrain in response to said signal source of detection means for providing a signal indicative of said first reference; bias and the aircraft is flying over rough terrain. biasing means for providing a reference; Absolute altitude warning system for aircraft equipped with 14. The detection means detects that the aircraft is flying over rough terrain for a predetermined period of time. 14. The absolute altitude warning device according to claim 13, which is suitable for detecting whether or not the altitude is high. 15. Absolute altitude warning system according to claim 14, wherein the predetermined period is effectively 2 minutes. Place. 16. further comprising a signal source for a signal indicative of the position of the landing gear, responsive to the signal source; , the aircraft is lower than the specified ground altitude while the landing gear is in the up position. The absolute airspeed of claim 13 which generates a warning criterion when the airspeed is Altitude warning device. 17. further comprising a signal source for a signal indicative of the position of the flap, responsive to the signal source; While the flaps are in the up position, the aircraft is lower than the specified altitude above the ground and Absolute height according to claim 13 that causes a warning criterion when the airspeed is lower than a certain airspeed. degree alarm device. 18. The maximum altitude at which the first criterion occurs is effectively 300 m (1000 ft). ) The absolute altitude warning device according to claim 13. 19. The maximum altitude at which the second criterion occurs is effectively 600 m (2000 ft). ) The absolute altitude warning device according to claim 13. 20. Source of the signal representing the position of the landing gear and signal representing the position of the flaps signal source, and in response to both said signal sources, the landing gear and flaps are both lowered. a prohibition means for prohibiting the alarm means when the alarm is on; The absolute altitude warning device according to claim 13, further comprising: 21. The source of the signal representing the aircraft's altitude above the ground, and the signal source representing the aircraft's pressure altitude. signal source and the terrain below the aircraft is rugged in response to both of these signal sources. detection means for supplying a signal indicating that the equipped with equipment to detect whether the aircraft is flying over rough terrain. Place. 22. The detection means detects whether the aircraft is flying over rough terrain for a predetermined period of time. 22. A device according to claim 21, suitable for measuring. 23. 23. The apparatus of claim 22, wherein the predetermined period of time is substantially two minutes. 24. The source of the signal responsive to the detection means and representing the altitude of the aircraft above the ground and the actual aircraft. biasing means for providing a signal related to the source of the signal representing the pressure altitude of the 22. The apparatus of claim 21, further comprising: 25. Bias means are available for 150 m (500 ft) and 300 m (1000 ft). as claimed in claim 24, suitable for providing a signal representative of the altitude between Device. 26. The signal provided by the detection means detects the aircraft's altitude above ground and air pressure for a predetermined period of time. 22. The apparatus of claim 21, wherein the apparatus is associated with an altitude difference. 27. 22. The apparatus of claim 21, wherein the predetermined period of time is substantially two minutes. 28. The signal provided by the detection means is integrated over a predetermined period of time 22. The apparatus of claim 21, wherein the apparatus is related to the difference between ground altitude and pressure altitude. 29. providing a signal source for a signal representative of the aircraft's altitude above the ground; Providing a signal source representing an altitude of the aircraft above a predetermined data altitude. , From a signal representing the aircraft altitude exceeding the data altitude to a signal representing the aircraft's altitude above the ground the step of subtracting, and The difference between two signals is integrated over a predetermined period of time to determine whether the aircraft is flying over rough terrain. obtaining a detection signal indicating that to determine whether an aircraft is flying over rough terrain. Law. 30. A bias signal associated with the detection signal represents a predetermined altitude range. 30. The method of claim 29, further comprising the step of providing an as signal. 31. The predetermined altitude range is between 150 m (500 ft) and 300 m (1000 ft). 31. The method of claim 30, wherein 32. 30. The method of claim 29, wherein the predetermined period of time is substantially two minutes.