ALTITUDE MONITORING SYSTEM FOR AIRCRAFT

• US 20080177429A1
• Filed: 10/11/2006
• Published: 07/24/2008
• Est. Priority Date: 10/25/2005
• Status: Abandoned Application

• Current Assignee: Saab AB
• Original Assignee: Saab AB
• Inventors: Berglund, Ingmar, Nordgren, Borje, Hedman, Bernt-Ove
• Application Number:
  US11/548,291
• Publication Number:
  US 20080177429A1
• Time in Patent Office: Days
• US Class Current: 701/8
• CPC Class Codes: G01C 21/005 with correlation of navigation data from several sources, e.g. map or contour matching G01C21/30 takes precedence
• CPC Class Codes: G01C 23/00 Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed or acceleration
• CPC Class Codes: G08G 5/0086 for monitoring terrain radar or analogous systems specially adapted for terrain avoidance G01S13/935
• CPC Class Codes: G08G 5/045 Navigation or guidance aids, e.g. determination of anti-collision manoeuvers radar or analogous systems specially adapted for anti-collision between aircraft G01S13/933

Abstract

An altitude monitoring system for an aircraft, comprising an input unit that makes it possible to receive or enter cleared flight level and cleared maximum and minimum altitudes into the system, and interfaces or other means to gain access to present altitude and speed, said system being provided with a calculator unit for calculating a future altitude and a comparator unit that compare said future altitude with said maximum and minimum altitude limits, and/or with a cleared flight level plus/minus a tolerance, and also an alerting unit capable of issuing a warning to an aircraft pilot of said aircraft a certain time before an altitude limit is violated, said certain time being calculated such that an evasive manoeuvre using a specified load factor can be performed within said certain time with no or little margin.

Claims

1. An altitude monitoring system for an aircraft, comprising an input unit that makes it possible to receive or enter cleared flight level and cleared maximum and minimum altitudes into the system, and interfaces or other means to gain access to present altitude and speed, said system also comprising a calculator unit for calculating a future altitude and a comparator unit that compare said future altitude with said maximum and minimum altitude limits, and/or with a cleared flight level plus/minus a tolerance, and also an alerting unit capable of issuing a warning to an aircraft pilot of said aircraft a certain time before an altitude limit is violated, said certain time being calculated such that an evasive manoeuvre using a specified load factor can be performed within said certain time with no or little margin.

2. The system of claim 1, wherein said system also comprises means to advise the pilot of the proper direction of evasive manoeuvre.

3. The system of claim 2, wherein said certain time is calculated by continuously calculating an altitude loss/gain for an evasive manoeuvre, using a load factor suitable to the aircraft type in question, and in that said calculation also takes into consideration the pilot'"'"'s reaction time, time for load factor build-up and time to roll to 0 or 180 degrees (depending on the evasive manoeuvre in question).

4. The system of claim 2, wherein said alert comprises an audio signal, and in that the proper direction of evasive manoeuvre is indicated by an arrow pointing in the desired direction.

5. The system of claim 4, where said arrow is space stabilized.

6. A method for altitude monitoring, comprising the following steps:

receiving altitude limit data,

presenting altitude limit data,

calculating regularly if an evasive manoeuvre is necessary to perform to keep the aircraft within altitude limits,

if an evasive manoeuvre is necessary, alerting the pilot about this at a certain time before the estimated time of violation, such that the evasive manoeuvre can be performed within said certain time, i.e. avoid the imminent violation.

7. The method of claim 6, where said certain time is calculated by repeated calculation of an altitude loss/gain for an evasive manoeuvre, using a load factor suitable for the aircraft in question, and in said calculations also taking into consideration the pilot'"'"'s reaction time, the time for load factor build-up and time to roll to 0 or 180 degrees.

8. The method of claim 6, where the load factor used is between 2 and 9 g.

9. The method of claim 6, where said alerting comprises the steps of:

issuing an audible signal, and

displaying and arrow pointing in the desired direction of the evasive manoeuvre.

10. The method of claim 9, where said arrow has a total length of between 2.0 and 3.0 degrees, and is shown on a head-up display.

11. The method of claim 10, where said arrow comprises a vertical line and four angles arranged in two groups, such that the vertical line extends beyond both the first and the fourth angle.

12. The method of claim 11, where the audible signal comprises a number of voice frequency impulses.

13. The method of claim 12, where the audible signal comprises four voice frequency impulses of approximately 900 Hz, with a duration of approximately 1.0 second each, and a very short break between them.