Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Aeronautical vehicle
Reexamination Certificate
1999-08-06
2001-04-10
Camby, Richard M. (Department: 3618)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Aeronautical vehicle
C701S301000, C342S029000
Reexamination Certificate
active
06216065
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates in general to creating an approach to a position on the ground for an in flight aircraft or in the flight planning phase and, in particular, to a method and system for utilizing a global positioning system and an onboard computer to create a precision approach procedure to any location on the ground for which digital terrain elevation data is available.
BACKGROUND OF THE INVENTION
Without limiting the scope of the invention, the background will describe the satellite based global positioning system, as an example.
The satellite based global positioning system (GPS) includes twenty-four satellites, orbiting 11,000 miles above the surface of the earth that emit signals to receivers below. By measuring the travel time of a signal transmitted from each satellite, a receiver can calculate its distance from that satellite. Satellite positions are used by a receiver as precise reference points to determine the location of a receiver. When receiving the signals from at least four satellites, a receiver can determine latitude, longitude, altitude and time, each of which are necessary in the navigation of an aircraft. The basic GPS service provides users with approximately 100 meter accuracy ninety-five percent of the time anywhere on or near the surface of the earth.
The benefits of satellite navigation over those of traditional navigation systems are significant. Satellite based systems achieve greater accuracies than most existing land based systems because the satellite signals are propagated independent of the ground making the system less prone to ground derived errors. Furthermore, because the satellite signals are available worldwide, GPS represents an unique opportunity for the international aviation community to start converging toward the goal of a single, integrated Global Navigation Satellite System (GNSS).
GNSS will eventually allow aviation users to reduce the number of different types of receivers required for navigation services for all phases of flight. Coupled with satellite communications, satellite based navigation will contribute to increased safety and efficiency of international civil aviation by supporting real time surveillance of aircraft and reducing the separation requirements.
The transition from various ground based systems to a common satellite based navigation system on a worldwide scale will require tremendous cooperation among international civil aviation authorities, governments, and industry representatives. The FAA is involved in such a transition on a national basis and has made the commitment to move from its own extensive ground based communications, navigation and surveillance system to one which will rely primarily on satellite navigation. This transition will not only prepare the U.S. National Airspace System (NAS) to meet the demands placed upon it by ever increasing aviation operations, but will serve the goals of the international community by beginning the transition to a seamless worldwide global satellite navigation system.
The FAA began the transition to GPS based navigation in 1994 with the approval of GPS as a supplemental navigation aid for en route through nonprecision approach phases of flight. This was followed by approval of GPS as a primary means of navigation in the oceanic environment as well as for remote operations. These two operational approvals are contingent upon the use of a properly certified Technical Standard Order (TSO) C129A GPS receiver which includes the Receiver Autonomous Integrity Monitoring (RAIM) feature to verify system integrity. In addition, to support this capability, GPS procedures were developed.
The next significant step in the FAA's transition to satellite based navigation is a Satellite Based Augmentation System (SBAS) called the Wide Area Augmentation System (WAAS) WAAS will satisfy the FAA requirements to be used as the only radio navigation aid for all flight operations down to and including Category 1 precision approaches. WAAS alone will not satisfy the FAA requirements for Category 2/3 precision approaches, nor will it satisfy the requirements for Category 1 approaches outside the WAAS coverage area.
For this reason, the FAA is also planning to implement a Ground Based Augmentation System (GBAS) called the Local Area Augmentation System (LAAS). LAAS is intended to satisfy FAA precision approach requirements for accuracy, availability, and integrity in order to provide Category 1 precision approach capability where the WAAS cannot, as well as Category 2/3 precision approach capability. In addition, the LAAS signal allows the user to have highly accurate position information anywhere in the airport vicinity, enabling the potential use of LAAS as an all weather surface navigation sensor and an input to surface surveillance/traffic management systems.
It has been found, however, that even with the implementation of the LAAS, only aircraft in the vicinity of an airport will be able to perform Category 2/3 precision approaches. Thus, for such precision approaches of, for example, helicopters or tiltrotors, in areas not covered by the LAAS, a need has arisen for a method and system for utilizing GPS to create a precision approach procedure to a position on the ground using onboard equipment.
SUMMARY OF THE INVENTION
The present invention disclosed herein comprises an onboard computer based method and system that utilizes a global positioning system for creating an approach to a position on the ground for an in flight aircraft. The system includes a display unit onboard the aircraft which may be a touch screen. The display unit provides a display of a digital moving map to the pilot or flight crew. The system also includes a database onboard the aircraft. The database contains digital terrain elevation data and obstacle data. A global positioning receiver that communicates with the global positioning system identifies the in flight position of the aircraft which may be represented by aircraft symbology on the digital moving map displayed on the display unit.
When the pilot wants to land the aircraft, the pilot uses an input device to enter coordinates or to select the desired point on the ground displayed on the digital moving map as well as other information such as desired landing direction. Thereafter, a processor onboard the aircraft creates a precision approach for the aircraft to that position on the ground from the in flight position of the aircraft. The approach is suitable for instrument meteorological conditions or for visual meteorological conditions. The approach includes direction, elevation and distance to the position on the ground. The approach may also include altitude penalties for obstacles and elevation changes in the terrain.
In one embodiment of the present invention, the system includes a real-time mapping device, such as a Doppler radar or a diode laser, that identifies obstacles in the approach. The identified obstacles are then compared to the obstacle data in the database to verify the validity of the obstacle data in the database. This verification allows the system to modify the approach if necessary based upon the identified obstacles.
The method of the present invention involves generating a digital moving map on a display unit onboard the aircraft from digital terrain elevation data and obstacle data stored in a database onboard the aircraft, identifying the in flight position of the aircraft with a global positioning receiver, selecting the desired position on the ground displayed on the digital moving map and creating a precision approach for the aircraft to the position on the ground. The approach may be for instrument meteorological conditions or visual meteorological conditions. The approach includes direction, elevation and distance to the position on the ground and may include altitude penalties for unknown obstacles.
The method also includes displaying aircraft symbology on the digital moving map based upon the in flight position of the aircraft. In one embodiment, the method further includes identify
Bell Ron
Hall Gary W.
Homan Michael
Bell Helicopter Textron Inc.
Camby Richard M.
Gardere Wynne & Sewell LLP
Warren, Jr. Sanford E.
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