PRECISION APPROACH AND LANDING SYSTEM FOR AIRCRAFT

Abstract

An aircraft with a mission computer, a GNSS receiver with a first air interface and a first receiver and a data transmission unit with a second air interface and a second receiver. The data transmission unit can receive data via an encrypted, bidirectional communication path. The mission computer determines a position value for the aircraft based on satellite signals from the GNSS receiver to which a correction term has been applied, which is transmitted to the aircraft by the data transmission unit to determine corrected satellite signals. The corrected satellite signals are the basis for determining corrected position value. The mission computer uses a GNSS receiver and data transmission unit as part of the aircraft. A ground arrangement is provided with an associated ground station and optionally a test unit for checking correct determination of the corrected position value.

Claims

1. An aircraft, comprising: a mission computer; a Global Navigation Satellite System receiver, a GNSS receiver, with a first air interface and a first receiver; a data transmission unit with a second air interface and a second receiver, wherein the data transmission unit is configured to receive data via an encrypted, bidirectional communication path; wherein the first receiver in the GNSS receiver is configured to receive satellite signals from satellites, which enable determination of a signal propagation time between a respective satellite and the GNSS receiver, wherein the satellite signals can be used for determining a position value of the aircraft; wherein the GNSS receiver is configured to transmit the determined signal propagation time to the respective satellite to the mission computer; wherein the data transmission unit is configured to receive a correction term for applying to the satellite signals received from the GNSS receiver from a remote station and to transmit them to the mission computer; wherein the mission computer implements a function module which is configured to determine corrected satellite signals based on the satellite signals transmitted by the GNSS receiver to the mission computer and the correction term and to use the corrected satellite signals for determining a position value of the aircraft; wherein the GNSS receiver is configured to be used for navigation in the aircraft; wherein the data transmission unit is configured to transmit data between the aircraft and the remote station; and wherein the function module in the mission computer is structurally separated from the GNSS receiver and the data transmission unit.

2. The aircraft of claim 1, wherein the function module is implemented as a software module and is configured to be executed on the mission computer.

3. The aircraft of claim 1, wherein the GNSS receiver is configured to receive and process satellite signals from a satellite from a satellite navigation system selected from the group consisting of GPS, Galileo, Glonass, and Beidou.

4. The aircraft of claim 1, wherein the first receiver in the GNSS receiver is configured to determine the signal propagation time between a respective satellite and the GNSS receiver by a pseudo range measurement and optionally a carrier phase measurement on the satellite signals.

5. The aircraft of claim 1, wherein the first receiver is configured to receive encrypted satellite signals for determining a position of the aircraft and to decrypt the encrypted satellite signals.

6. The aircraft of claim 1, wherein the function module of the mission computer is configured as a remote station of a ground-based approach and landing system.

7. The aircraft of claim 1, wherein the data transmission unit is configured to receive flight path-related data for the aircraft.

8. An aircraft of claim 1, wherein the data transmission unit is configured to transmit data to the remote station and/or to other aircraft; wherein the data transmitted to the remote station are one or more elements from: an approach path chosen by the aircraft; corrected signal propagation times determined by the correction term.

9. The aircraft of claim 1, wherein the aircraft is a manned or unmanned military aircraft.

10. A ground arrangement of a ground-based approach and landing system, wherein the ground arrangement comprises a ground station and the ground station comprises: a computing unit; a global navigation satellite system receiver, a GNSS receiver, with a third air interface and a third receiver; a data transmission unit having a fourth air interface and a fourth receiver, wherein the data transmission unit is configured to receive data via an encrypted, bidirectional communication path; wherein the third receiver in the GNSS receiver is configured to receive satellite signals from satellites which enable determination of a signal propagation time between a respective satellite and the GNSS receiver, wherein the satellite signals can be used for determining a position value of the ground station; wherein the GNSS receiver is configured to transmit the satellite signals to the computing unit; wherein the computing unit is configured to determine a correction term for the satellite signals received from the GNSS receiver based on the satellite signals received from the GNSS receiver and a known actual position value of the ground station so that the correction term, after application to the satellite signals transmitted by the GNSS receiver to the computing unit, gives corrected satellite signals corresponding to the actual position value of the ground station; wherein the data transmission unit is configured to transmit the correction term to a remote station; and wherein the computing unit is structurally separated from the GNSS receiver and the data transmission unit.

11. The ground arrangement of claim 10, comprising: a test unit with a second computing unit, a second GNSS receiver, and a second data transmission unit, which is configured to receive data via an encrypted, bidirectional communication path; wherein the test unit is spatially separated from the ground station; wherein the second GNSS receiver is configured to receive satellite signals from satellites, which enable determination of a signal propagation time between a respective satellite and the second GNSS receiver, wherein the satellite signals can be used for determining a position value of the test unit; wherein the second GNSS receiver is configured to transmit the satellite signals to the second computing unit; wherein the ground station is configured to transmit the correction term by the data transmission unit to the second data transmission unit; wherein the second computing unit is configured to determine corrected satellite signals based on the satellite signals transmitted by the second GNSS receiver to the second computing unit and the correction term and to use the corrected satellite signals for determining a corrected position value of the test unit; wherein the ground arrangement is configured to compare the corrected position value of the test unit with a known actual position value of the test unit.

12. The ground arrangement of claim 11, wherein the ground arrangement is configured to generate an alarm signal in an event of a deviation of the corrected position value of the test unit from the known actual position value of the test unit, which indicates an incorrect corrected position value of the test unit.

13. The ground arrangement of claim 10, wherein the third receiver in the GNSS receiver is configured to determine the signal propagation time between a respective satellite and the GNSS receiver by a pseudo range measurement and optionally a carrier phase measurement on the satellite signals.

14. The ground arrangement of claim 10, wherein the ground arrangement is configured to transmit the satellite signals received by the GNSS receiver to the remote station.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In the following, example embodiments are discussed in more detail on the basis of the attached drawings. The representations are schematic and not true to scale. The same reference characters refer to identical or similar elements. In the figures:

[0066] FIG. 1 shows a schematic representation of components of an aircraft according to an example embodiment.

[0067] FIG. 2 shows a schematic representation of components of a ground arrangement with a ground station and a test unit according to a further example embodiment.

[0068] FIG. 3 shows a schematic representation of a ground station and an aircraft approaching a runway according to a further example embodiment.

DETAILED DESCRIPTION

[0069] FIG. 1 shows a schematic representation of the components of an aircraft 100 relevant to the present description. The aircraft 100 comprises a mission computer 110, a GNSS receiver 120, and a Link 16 interface 130.

[0070] The GNSS receiver 120 comprises a first air interface 122 (for example a GPS antenna) and a first receiver 124. The first air interface 122 is designed to receive navigation signals from several satellites 20 (of which only one is shown). The first receiver 124 is designed to determine the respective signal propagation time based on the received navigation signals. The GNSS receiver 120 transmits the satellite data received from the first receiver 124 and the determined and/or measured signal propagation times (pseudo ranges and possibly carrier phases) to the mission computer 110 so that the mission computer determines the position value and its integrity for the aircraft 100 based on these raw data (pseudo ranges and carrier phases) and the correction term from the ground station.

[0071] The Link 16 interface 130 includes a second air interface 132, typically in the form of an antenna, and a second receiver 134 and is designed to receive and/or send data by an encrypted bidirectional communication protocol, such as the Link 16 protocol. For example, military tactical information is transmitted via the Link 16 interface 130. In the present case, the correction term for application to the signal propagation times of the satellite signals is also transmitted.

[0072] In FIG. 1 it can be clearly seen that both the GNSS receiver 120 and the data transmission unit 130 are independent modules, each with an air interface 122, 132 and its own receiver 124, 134. A multi-mode receiver can be dispensed with. The GNSS receiver 120 and the data transmission unit 130 pass on the data determined or received by them directly to the mission computer 110. The GNSS receiver 120, the mission computer 110 and the data transmission unit 130 are structurally separated from each other, i.e. such that these three components are arranged separately in the aircraft and are independently replaceable without another component being structurally affected in the event of a replacement or modification of one of the three components. It is possible that a functional adaptation of another component, for example the mission computer, is necessary when replacing one of the components.

[0073] The mission computer 110 contains a function module 115, which is designed in particular as a software module and is implemented by the mission computer using a processor and a memory. The function module 115 implements the functions for processing the signal propagation times provided by the GNSS receiver 120 and their correction using the correction term.

[0074] The components shown in FIG. 1 are modularly connectable with each other and do not represent a closed assembly that can only be replaced in its entirety. Rather, the function module 115 can be used with changing GNSS receivers 120 or even with different data transmission interfaces. Likewise, the function module 115 can be adjusted or replaced without affecting the other components. In particular, the function module 115 of the mission computer 110 accesses components already existing in the aircraft 100 such as a GNSS receiver 120 and a Link 16 interface 130.

[0075] FIG. 2 shows a schematic representation of the components of a ground arrangement, wherein the ground arrangement consists of a ground station 200 and a test unit 300. The ground station 200 and the test unit 300 are in principle similar in design with regard to the components described and used herein as in the aircraft 100.

[0076] The ground station 200 comprises a computing unit 210, a GNSS receiver 220, and a data transmission unit 230. The GNSS receiver 220 receives satellite signals and determines the signal propagation time in order to determine the position or a position value of the ground station based on this. The GNSS receiver 220 is similar to the GNSS receiver 120 of the aircraft and has a third air interface 222 and a third receiver 224, which operate similarly to the first air interface 122 and the first receiver 124. As regards the function of the GNSS receiver 220, reference is made to the description of the GNSS receiver 120. The data output by the third receiver 224 are passed to the computing unit 210, where they are processed as a position value. The computing unit 210 determines a correction term based on the position value determined by satellite signals and their signal propagation time and an actual position value of the ground station in order to compensate for an error in the determined signal propagation time, so that the compensated (or corrected) signal propagation times result in the actual position. The computing unit 210 controls the data transmission unit 230 such that the correction term is transmitted by the data transmission unit 230 to a remote station, for example the aircraft 100 from FIG. 1, in order to be used there for the correction of the signal propagation times determined at the remote station. The data transmission unit 230 in this example comprises a third air interface 232 and a third receiver 224. The ground station 200 is thus also of a modular design because the GNSS receiver 220, the data transmission unit 230, and the computing unit 210 operate independently and in particular the GNSS receiver 220 and the data transmission unit 230 are independent modules with an air interface (antenna) and a receiver. The GNSS receiver 220 and the data transmission unit 230 are designed, for example, for receiving encrypted GPS signals or communication signals, as described with reference to the aircraft in FIG. 1.

[0077] The ground station 200 may be set up, for example, near a prepared or unprepared runway or generally near a location to be approached by the aircraft 100.

[0078] The ground arrangement further comprises a test unit 300 whose functional design corresponds to the functional design of the aircraft 100 with respect to a computing unit 310, a GNSS receiver 320 with a fifth air interface 322 and a fifth receiver 324, and a data transmission unit 330 with a sixth air interface 332 and a sixth receiver 334. The test unit comprises a second computing unit 310, a second GNSS receiver 320, and a second data transmission unit 330. Thus, the test unit 300 is designed to receive the correction term from the ground station 200 and to apply it to the signal propagation times received or determined by the test unit.

[0079] In the test unit, the same functions run as in the aircraft 100: the second GNSS receiver 320 receives satellite signals and determines their signal propagation times and, if appropriate, a position value for its own position, the second computing unit 310 applies a correction value, which was received via the second data transmission unit 330, to the signal propagation times in order to determine a corrected position value.

[0080] It should be noted, however, that the actual position value of the test unit 300 is known. Thus, the corrected position value can be compared with the actual position value of the test unit 300 in order to determine whether the determination of the corrected position value leads to a meaningful result (i.e. that the corrected position value coincides with the actual position value or deviates from it by less than a predetermined threshold value).

[0081] The ground station 200 and the test unit 300 may be connected for this purpose by a separate data connection 250, wherein the separate data connection 250 is in particular a wired data connection. The test unit 300 receives the correction term transmitted by the ground station 200 wirelessly by the second data transmission unit 330. The corrected position value of the test unit 300, on the other hand, is transmitted via the data connection 250 to the ground station 200, where the comparison of the corrected position value of the test unit with the actual position value of the test unit is carried out. Thus, with recourse to the test unit 300, it can be determined whether there is an error in the position determination or in the communication in the system network consisting of the ground station, the test unit and the aircraft.

[0082] FIG. 3 shows an example use case of a ground station 200, which is set up near a runway 10 and prepared for data exchange with an aircraft 100 approaching the runway 10. The ground station 200 is fixed to the ground at a known position with a predetermined and known position value and determines a correction term for the signal propagation times of the satellite signals based on the signal propagation times determined by satellite signals and expected target signal propagation times, which correspond to the known position. This correction term is transmitted wirelessly to the aircraft 100 approaching the runway 10 and the aircraft 100 corrects its signal propagation times determined based on satellite signals with the correction term. Thus, the aircraft 100 receives a very accurate corrected position value and an approach to the runway 10 is possible even in poor visibility or with zero visibility.

[0083] The subject matter disclosed herein can be implemented in or with software in combination with hardware and/or firmware. For example, the subject matter described herein can be implemented in or with software executed by a processor or processing unit. In one example implementation, the subject matter described herein can be implemented using a computer readable medium having stored thereon computer executable instructions that when executed by a processor of a computer control the computer to perform steps. Example computer readable mediums suitable for implementing the subject matter described herein include non-transitory devices, such as disk memory devices, chip memory devices, programmable logic devices, and application specific integrated circuits. In addition, a computer readable medium that implements the subject matter described herein can be located on a single device or computing platform or can be distributed across multiple devices or computing platforms.

[0084] While at least one example embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

REFERENCE CHARACTER LIST

[0085] 10 runway [0086] 20 satellite [0087] 100 aircraft [0088] 110 mission computer [0089] 115 function module [0090] 120 GNSS receiver [0091] 122 first air interface [0092] 124 first receiver [0093] 130 data transmission unit [0094] 132 second air interface [0095] 134 second receiver [0096] 200 ground station [0097] 210 computing unit [0098] 220 GNSS receiver [0099] 222 third air interface [0100] 224 third receiver [0101] 230 data transmission unit [0102] 232 fourth air interface [0103] 234 fourth receiver [0104] 250 data connection [0105] 300 test unit [0106] 310 computing unit [0107] 320 GNSS receiver [0108] 322 fifth air interface [0109] 324 fifth receiver [0110] 330 data transmission unit [0111] 332 sixth air interface [0112] 334 sixth receiver