Apparatus, method and aircraft for line replaceable units

Abstract

The present disclosure relates to apparatuses, methods, and aircraft for line replaceable units. The apparatus includes a housing, a first interface on a first side of the housing, a second interface on a second side of the housing opposite the first side, and circuitry within the housing. The first interface is configured to couple to a multi-mode receiver (MMR) rack. The second interface is configured to couple to an MMR external to the housing. The circuitry is configured to receive, via the first interface, digital data representative of a navigation signal received at an antenna. The circuitry is configured to perform time, space, and frequency filtering operations using the digital data to generate modified digital data. The circuitry is configured to output, via the second interface, a modified analog navigation signal to the MMR based on the modified digital data.

Description

Technical Field

[0001] This disclosure generally relates to radio devices including controlled reception mode antenna controller plug-ins. Background Technology

[0002] With technological advancements, GPS-based navigation systems, such as Global Navigation Satellite Systems (GNSS), have become a common type of navigation system used by aircraft and other long-range transportation. GPS-based navigation systems use radio communications from satellites to the aircraft to derive its precise position during flight. GPS-based navigation systems are increasingly popular due to their accuracy and reliability, as well as their easier and lower-cost deployment and calibration compared to other types of navigation systems. However, GPS-based navigation systems have some drawbacks, including inability to function in areas with poor satellite signal availability and quality, vulnerability to interference from other wireless communications, and spoofing or jamming by malicious entities.

[0003] One approach to combat drawbacks such as interference, jamming, and spoofing is to use a Controlled Receiver Pattern Antenna (CRPA) capable of modifying its reception pattern to improve navigation signal reception. For example, the reception pattern can be changed to focus on areas with high-quality signal strength, or to deny areas identified as sources of interference. However, the use of CRPA in commercial aircraft is limited by the need to replace antennas, receivers, signal processing components, and so on. This maintenance-intensive operation limits the availability of aircraft to commercial operators. Summary of the Invention

[0004] In one implementation, an apparatus includes a housing. The apparatus also includes a first interface on a first side of the housing. The first interface is configured to be coupled to a multimode receiver (MMR) rack. The apparatus also includes a second interface on a second side of the housing opposite the first side. The second interface is configured to be coupled to an MMR outside the housing. The apparatus also includes circuitry within the housing. The circuitry is configured to receive digital data representing navigation signals received at an antenna via the first interface. The circuitry is further configured to perform temporal, spatial, and frequency filtering operations using the digital data to generate modified digital data. The circuitry is also configured to output modified analog navigation signals to the MMR via the second interface, based on the modified digital data.

[0005] In another specific implementation, an aircraft includes an antenna, a multimode receiver (MMR), an MMR rack coupled to the antenna via a communication link, and a route-changeable unit (LRU) disposed between the MMR and the MMR rack. The LRU includes a housing. The LRU also includes a first interface on a first side of the housing. The first interface is configured to be coupled to the multimode receiver (MMR) rack. The LRU also includes a second interface on a second side of the housing opposite the first side. The second interface is configured to be coupled to an MMR outside the housing. The LRU also includes circuitry within the housing. The circuitry is configured to receive digital data representing navigation signals received at the antenna via the first interface. The circuitry is also configured to perform time, space, and frequency filtering operations using the digital data to generate modified digital data. The circuitry is further configured to output modified analog navigation signals to the MMR via the second interface, based on the modified digital data.

[0006] In another specific implementation, a method includes receiving digital data representing a navigation signal received at an antenna via a first interface on a first side of the housing. The method further includes performing temporal, spatial, and frequency filtering operations using the digital data to generate modified digital data. The method also includes outputting a modified analog navigation signal via a second interface on a second side of the housing to a multimode receiver (MMR) located outside the housing and coupled to the second interface, wherein the modified analog navigation signal is based on the modified digital data.

[0007] The features, functions, and advantages described herein can be implemented independently in various ways or combined in other ways. Further details can be found in the following description and figures. Attached Figure Description

[0008] Figure 1 Examples of systems including a CRPA controller plugin set up within an aircraft, according to one or more examples of this disclosure, are depicted.

[0009] Figure 2 An exemplary system according to some examples of this disclosure is shown, the exemplary system including an exemplary CRPA controller plug-in coupled to an exemplary antenna via a first interface and an MMR bracket.

[0010] Figure 3 An exemplary system according to some examples of this disclosure is shown, which includes an exemplary CRPA controller plugin and an exemplary MMR.

[0011] Figure 4 An exemplary system according to some examples of this disclosure is shown, the exemplary system including an antenna coupled to the MMR via a communication link and a CRPA controller plug disposed between the MMR and the MMR rack.

[0012] Figure 5 This is a flowchart illustrating an example of a method for operating a CRPA controller plugin, according to some examples of this disclosure.

[0013] Figure 6 This is a flowchart illustrating an example of the lifecycle of an aircraft including a CRPA controller plugin, according to some examples of this disclosure.

[0014] Figure 7 Is with Figure 6 A block diagram showing the specific implementation of an aircraft in relation to its lifecycle.

[0015] Figure 8 This is a block diagram of a computing environment according to the present disclosure, which includes computing devices configured to support aspects of computer-implemented methods and computer-executable program instructions (or code). Detailed Implementation

[0016] The aspects disclosed herein describe systems and methods for providing controlled receive mode antenna (CRPA) controller plug-ins. CRPA controller plug-ins can be implemented to provide anti-blocking and anti-spoofing capabilities in a manner that is transparent to existing equipment and requires no wiring changes or impacts on downstream user equipment in the aircraft.

[0017] According to some aspects of this disclosure, a CRPA controller plugin is described for use with Global Navigation Satellite Systems (GNSS) and can be particularly beneficial for the cost-effective retrofitting of commercial transport aircraft. The systems and methods disclosed herein include digital CRPA, in which down-conversion and digitization of radio frequency (RF) signals from antenna elements in the GNSS band are performed in an antenna array near individual antenna elements. The resulting in-phase and quadrature baseband samples (I and Q samples) are then serialized and modulated onto a signal used to transmit information from multiple antenna elements to a GNSS signal processor via a single RF cable. At the processor, the bitstream is demodulated and deserialized to reconstruct the individual I and Q samples for each of the individual antenna elements.

[0018] The specific implementations of the systems and methods disclosed herein simplify and reduce the cost of CRPA installation. For example, a single cable is used to connect the antenna array assembly to the GNSS processing unit. The antenna assembly can replace existing antennas in existing designs, and CRPA processing can be implemented without installing additional Line Replaceable Units (LRUs) near the antenna array and managing the connections of multiple GNSS antenna units. Furthermore, existing RF cables can be used to connect digital CRPA to the CRPA processing unit, significantly reducing the difficulty and cost of retrofitting.

[0019] In certain configurations, the CRPA controller plugin (and methods of operating the CRPA controller plugin) described herein supports resource-saving means of retrofitting commercial aircraft with GNSS antennas using standard Aeronautical Radio, Inc. (ARINC is a registered trademark of Arinc, Inc., a Delaware company.) These standards include the ARINC 743 for GPS antennas and the ARINC 755 for multimode receivers, which are common means of incorporating GNSS receivers into large commercial aircraft.

[0020] The technical advantages of this disclosure include providing a resource-saving means of retrofitting aircraft to better support anti-jamming and anti-spoofing technologies for in-flight navigation. The systems and methods disclosed herein enable digital CRPA as a plug-and-play, line-replaceable technology for retrofitting existing commercial aircraft. Taking an aircraft out of service can be a significant part of the cost of retrofitting any system. By enabling plug-and-play replacement without any wiring changes, the systems and methods disclosed herein enable more cost-effective CRPA for commercial aircraft (and potential military derivatives). For example, the digital CRPA and CRPA controller plug-in described herein can be installed in an aircraft during overnight turnaround without taking the aircraft out of service.

[0021] Another technical advantage of this disclosure includes supporting the anti-jamming and anti-spoofing techniques implemented in the digital CRPA by providing sufficient operating power to the digital CRPA without modifying or replacing the aircraft's existing receivers. Some existing multimode receivers (MMRs) cannot provide sufficient power to the center conductor coupled to the CRPA to power the digital CRPA. Installing DC blocks and alternative power inputs would increase the risk that aircraft modifications might extend beyond overnight turnaround. The CRPA controller plug described herein introduces a new LRU that will be inserted between the existing MMR and the rack connector used for the MMR.

[0022] Another technical advantage of this disclosure includes providing support for those technologies by enabling the anti-blocking and anti-spoofing techniques implemented in digital CRPA to be used at the appropriate time and with appropriate accuracy based on the flight status. For example, the CRPA controller plugin described herein can be controlled according to the operating mode of the MMR. The anti-blocking and anti-spoofing capabilities provided by the CRPA controller plugin may need to be modified according to the operating mode. For example, during flight operations requiring very high position calculation accuracy (e.g., precision approaches), it may be necessary to suppress signal nulling. If the approaching satellite's direction of arrival produces a null trap, a power-minimizing signal nulling algorithm can cause GNSS signal tracking errors. The systems and methods disclosed herein enable the CRPA controller plugin to learn the operating mode or status of the MMR and thus be controlled.

[0023] The accompanying drawings and the following description illustrate specific exemplary embodiments. It should be understood that those skilled in the art will be able to design various arrangements, although not explicitly described or shown herein, that embody the principles described herein and are included within the scope of the claims following this description. Furthermore, any examples described herein are intended to aid in understanding the principles of this disclosure and are not to be construed as limiting. Therefore, this disclosure is not limited to the specific embodiments or examples described below, but is defined by the claims and their equivalents.

[0024] The specific implementation is described herein with reference to the accompanying drawings. Throughout the description, common features are indicated by common reference numerals. In some drawings, multiple instances of a particular type of feature are used. Although these features are physically and / or logically different, the same reference numerals are used for each feature, and different instances are distinguished by the addition of letters to the reference numerals. When a feature is referred to herein as a group or type (e.g., when a specific feature among multiple features is not mentioned), reference numerals are used without distinguishing letters. However, when a specific feature among multiple features of the same type is referred to herein, reference numerals are used along with distinguishing letters.

[0025] As used herein, different terms are used only for the purpose of describing a particular implementation and are not intended to be restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. Furthermore, some features described herein are singular in some implementations and plural in others. For illustration, a system may be described herein as comprising one or more computing devices (“computing devices”), indicating that in some implementations the system comprises a single computing device, while in others the system comprises multiple computing devices. For ease of reference herein, such features are generally introduced as “one or more” features and are subsequently referred to in the singular or optional plural form unless an aspect relating to multiple features is described.

[0026] The terms “comprise,” “comprises,” and “comprising” are used interchangeably with “include,” “includes,” or “including.” Furthermore, the term “wherein” is used interchangeably with the term “where.” As used herein, “exemplary” indicates an example, implementation, and / or aspect, and should not be construed as limiting or indicating a preference or preferred implementation. As used herein, ordinal terms used to modify elements (such as structures, components, operations, etc.) (e.g., “first,” “second,” “third,” etc.) do not themselves indicate any priority or order of that element relative to another element, but merely distinguish that element from another element with the same name (other than the use of ordinal terms). As used herein, the term “set” refers to a grouping of one or more elements, and the term “multiple” refers to multiple elements.

[0027] As used herein, the terms “generate,” “calculate,” “use,” “select,” “access,” and “determine” are interchangeable unless the context otherwise indicates. For example, “generate,” “calculate,” or “determine” a parameter (or signal) can refer to actively generating, calculating, or determining a parameter (or signal) or can refer to using, selecting, or accessing a parameter (or signal) that has already been generated, such as through another component or device. As used herein, “coupled” can include “communication coupling,” “electrical coupling,” or “physical coupling,” and can also (or alternatively) include any combination thereof. Two devices (or components) can be coupled directly or indirectly (e.g., communication coupling, electrical coupling, or physical coupling) via one or more other devices, components, wires, buses, networks (e.g., wired networks, wireless networks, or combinations thereof). Electrically coupled devices (or components) can be in the same or different devices and, by way of illustrative, non-limiting example, can be connected via electronics, one or more connectors, or inductive coupling. In some implementations, two devices (or components) that are communicationally coupled (e.g., in electrical communication) can directly or indirectly send and receive electrical signals (digital or analog signals), for example, via one or more wires, buses, networks, etc. As used herein, "direct coupling" is used to describe two devices coupled (e.g., communication coupling, electrical coupling, or physical coupling) without any intermediate components.

[0028] Figure 1 An example of a system 100 including a CRPA controller plug-in 104, configured within an aircraft according to one or more examples of this disclosure, is depicted. The CRPA controller plug-in 104 can be used as an exemplary modification of an aircraft to implement resource-saving means of providing anti-blocking and anti-spoofing technologies for digital CRPA implementation, as referenced below. Figures 2 to 8 Described in more detail. In exemplary system 100, after the aircraft has been modified, CRPA controller plug-in 104 is coupled to multimode receiver 106 via a first interface and to digital CRPA 112 via a second interface. In some implementations, as described below, the second interface of CRPA controller plug-in 104 may be connected to an MMR rack, which is then coupled to digital CRPA 112 via a communication link. In some aspects, digital CRPA 112 may include, for example, an antenna array, one or more components configured to provide low-noise amplification, digitization, down-conversion, serialization, modulation, etc.

[0029] Figure 1Enlarged views of the multimode receiver 106 before and after aircraft modification are shown. The illustration of system 100 in a first state before aircraft modification includes aircraft 102A, which includes the multimode receiver 106 coupled to antenna 108 via communication link 110. In some configurations, antenna 108 may include a single-frequency antenna, and in others, the antenna may include dual-frequency capability. For example, antenna 108 may include an ARINC Active Single-Channel / Single-Frequency Fixed Receiver Mode Antenna (FRPA) Global Positioning System (GPS) antenna system. In some configurations, multimode receiver 106 may be a receiver conforming to the ARINC 755 standard for multimode receivers. Communication link 110 may include a coaxial cable or other means for transmitting RF signals from antenna 108 to multimode receiver 106. In some implementations, multimode receiver 106 is mounted in an MMR rack providing connectivity from multimode receiver 106 to various other components of system 100.

[0030] The illustration of system 100 in its second state after aircraft modification includes aircraft 102B, which includes a multimode receiver 106 coupled to digital CRPA 112 via an MMR rack, CRPA controller plug-in 104, and communication link 110. In some implementations, digital CRPA 112 may include an active multichannel CRPA GPS antenna system. The multichannel antenna system may be a single-frequency antenna system, a multi-frequency antenna system, or may include one or more of these. In certain configurations, digital CRPA 112 may be compatible with the footprint and / or mounting patterns provided in the ARINC 743 standard for GNSS antennas.

[0031] In some aspects, the digital CRPA 112 may include multiple receiving elements coupled to a digitizer 114. The digitizer 114 may be one or more electronic components configured to digitize and down-convert navigation signals received at one or more of the multiple receiving elements to baseband. The digitizer 114 may also be configured to transmit a series of in-phase and quadrature samples (I and Q samples) to a serializer 116 of the digital CRPA 112. The serializer 116 may include one or more electronic components configured to serialize the I and Q samples received from the digitizer 114 for transmission via a communication link 110 to a CRPA controller plug-in 104. In a particular configuration, the digital CRPA 112 may include at least a twelve-bit analog-to-digital converter to produce a set of twelve-bit I and Q samples. The serializer 116 may be configured to acquire the I and Q samples, place them sequentially, and interleave them to provide a single bit stream.

[0032] As shown in the following reference Figures 2 to 8In more detail, the CRPA controller plug-in 104 may include: a housing; a first interface coupled to the MMR rack 107 on a first side of the housing; and a second interface coupled to the multimode receiver 106 on a second side of the housing. The CRPA controller plug-in 104 may also include circuitry within the housing configured to receive digital data representing navigation signals received at the digital CRPA 112 via the first interface. The circuitry may also be configured to perform time, space, and frequency filtering operations using the digital data to generate modified digital data, and to reconstruct (e.g., via digital-to-analog conversion and up-conversion) an analog RF output containing the modified analog navigation signal to the multimode receiver 106 based on the modified digital data via the second interface. The time, space, and frequency filtering operations may include, for example, beamforming, null control, frequency cutoff, pulse cancellation, and other suitable operations to alter signal reception in time, space, and frequency.

[0033] Figure 2 An exemplary system 200 according to some examples of this disclosure is shown, the exemplary system including an exemplary CRPA controller plug-in 104 coupled to an exemplary antenna rack connector 209 via a first interface 202 and an MMR rack. The CRPA controller plug-in 104 is also coupled to a multimode receiver 106 via a second interface 204. The CRPA controller plug-in 104 includes a housing 205, wherein the first interface 202 is on a first side of the housing 205 and the second interface 204 is on a second side of the housing 205.

[0034] In some implementations, the antenna rack connector 209 may be coupled to, integrated with, or otherwise associated with an MMR rack. The antenna rack connector 209 may include multiple interface connectors. At least one of the interface connectors may be coupled to the digital CRPA 112. For example, the antenna rack connector 209 may be coupled to the digital CRPA 112 via a single coaxial cable.

[0035] In some implementations, the CRPA controller plug-in 104 includes multiple interface connectors. In some aspects, one or more printed circuit boards may be layered between the connectors to house the servicing antenna rack connector 209 and the circuitry required to further servic the MMR rack and digital CRPA 112 (e.g., to perform spatial interference filtering, as referred to below). Figure 4(Described in more detail). Multiple interface connectors allow specific signals input to the CRPA controller plug-in 104 to be transmitted to the output with minimal insertion loss. Other interface connectors allow specific signals input to the CRPA controller plug-in 104 to be intercepted, processed, and used to control the CRPA controller, or in some cases, transmitted to the output. Other interface connectors allow the reading of digital data, which may be transmitted, processed, modified, added, etc., before being transmitted to the output. Specific coaxial connectors in the rack connector assembly connect the multimode receiver 106 to antennas for other systems included in the MMR (i.e., instrument landing system components, such as localizers, VHF omnidirectional beacon receivers, glide slope determination elements, glide slope determination elements, etc.). These coaxial channels enable transmission to the multimode receiver 106 via the second interface 204 of the CRPA controller plug-in 104 with minimal insertion loss, without degrading the functionality of other receivers included in the MMR.

[0036] In some aspects, system 200 includes a first plurality of signal paths 206 corresponding to RF signals transmitted via a first interface 202 from digital CRPA 112 to CRPA controller plug-in 104, via a second interface 204 to multimode receiver 106, or both. CRPA controller plug-in 104 can be configured to receive digital data representing navigation signals received at digital CRPA 112 via the first interface 202. CRPA controller plug-in 104 can be configured to perform temporal, spatial, and frequency filtering operations using the digital data to generate modified digital data, as referred to below. Figure 4 For a more detailed description, the CRPA controller plug-in 104 can also be configured to output modified analog RF navigation signals to the multimode receiver 106 via a second interface 204, based on modified digital data.

[0037] For example, CRPA controller plug-in 104 can receive digital data representing GNSS signals from digital CRPA 112 via first interface 202. This signal can be intercepted and processed (including time, space, and frequency filtering operations) by specific circuitry of CRPA controller plug-in 104, as shown below. Figure 4 For a more detailed description. Then, the CRPA controller plug-in 104 can output the modified analog navigation signal to the multimode receiver 106 via the second interface 204.

[0038] In some implementations, system 200 also includes a second plurality of signal paths 208 corresponding to various digital signals transmitted from various aircraft systems via antenna rack connector 209 and / or from digital CRPA 112 to CRPA controller plug-in 104 via first interface 202, from multimode receiver 106 to CRPA controller plug-in via second interface 204, or both. Signals on the second plurality of signal paths 208 are transmitted through CRPA controller plug-in 104 with or without modification. For example, the voltage on one of the signals in the second plurality of signal paths 208 can be read by CRPA controller plug-in 104 to obtain information. This may include, for example, receiving tags (e.g., receiver status, position information, etc.) from multimode receiver 106, or tags (e.g., pitch, roll, heading, etc.) from other aircraft systems to multimode receiver 106. As another example, specific signals (e.g., ARINC 429 bus signals) can be intercepted, allowing tags to be added, removed, or modified as needed to support specific functions of CRPA controller plug-in 104. In order to read and / or modify signals on one or more of the second plurality of signal paths 208, in some respects, the second interface 204 includes a plurality of connectors, including at least one connector configured to be coupled to an aircraft bus and at least one connector configured to be coupled to a digital CRPA 112.

[0039] In some implementations, system 200 further includes a third plurality of signal paths 210 corresponding to various RF signals transmitted via a first interface 202 from antenna rack connector 209 and / or digital CRPA 112 to CRPA controller plug 104, via a second interface 204 from multimode receiver 106 to CRPA controller plug 104, or both. Signals on the third plurality of signal paths 210 are transmitted through CRPA controller plug 104 with minimal insertion loss. For example, RF connections for other functions of multimode receiver 106 (e.g., VHF connectors for VHF omnidirectional range (VOR), VHF digital broadcast (VDB) functions, etc.) can be transmitted through CRPA controller plug 104 with minimal insertion loss.

[0040] In some implementations, the first interface 202 includes a first plurality of connectors and the second interface 204 includes a second plurality of connectors. The first plurality of connectors are complementary to the connectors of the antenna rack connector 209, and the second plurality of connectors are complementary to the first plurality of connectors. The complementary connectors enable signals from the antenna rack connector 209 and / or the multimode receiver 106 to be transmitted through the CRPA controller plug-in 104.

[0041] although Figure 2The system 200 is shown with specific components arranged in a particular manner, but other components are possible in different configurations without departing from the scope of this disclosure. For example, a particular CRPA controller plug-in 104 may not include the first, second, and third plurality of signals. As another example, the CRPA controller plug-in 104 may also include circuitry configured to supply power to the digital CRPA 112 via the first interface 202 and the antenna rack connector 209.

[0042] Figure 3 An exemplary system 300 is shown according to some examples of the present disclosure, the exemplary system including an exemplary CRPA controller plug-in 104 and an exemplary multimode receiver 106. Figure 3 The illustration shows a landscape view of CRPA controller plug-in 104, which is configured to be coupled to multimode receiver 106 via a first interface 202. Figure 3 It also shows in an aircraft (e.g., Figure 1 A side view of the system 300 in its first state before modification (of the aircraft), including the insertion of the CRPA controller plug-in 104 between the multimode receiver 106 and the MMR rack 107. Figure 3 A side view of system 300 in a second state after aircraft modification is also shown, including the insertion of CRPA controller plug-in 104 between multimode receiver 106 and MMR rack 107. As shown in the modified side view, CRPA controller plug-in 104 is coupled to multimode receiver 106 via second interface 204 and to MMR rack 107 via first interface 202. In some implementations, CRPA controller plug-in 104 may include a line-changeable unit (LRU) disposed between multimode receiver 106 and MMR rack 107.

[0043] Figure 4 An exemplary system 400 according to some examples of this disclosure is shown, the exemplary system including a digital CRPA 112 coupled to a CRPA controller plug-in 104 via a communication link 110, and the CRPA controller plug-in 104 further connecting to... Figures 1 to 3 The multimode receiver 106.

[0044] In some implementations, the digital CRPA 112 may include one or more receiving elements 401 coupled to the digitizer 114. The receiving element 401 may be configured to receive one or more RF signals received at the digital CRPA 112. For example, the receiving element 401 may be configured to receive one or more navigation signals that are part of a Global Navigation Satellite System (GNSS). (Refer to the above...) Figure 1As described, digitizer 114 can be configured to down-convert and digitize the RF signal received at receiving element 401 to baseband. In some implementations, one or more components of the digital CRPA 112 configured to down-convert the RF signal can be part of digitizer 114, separate from digitizer 114, or a combination thereof.

[0045] In some implementations, digitizer 114 can be coupled to serializer 116. (See above reference...) Figure 1 As described, serializer 116 can be configured to serialize the output of digital samples from digitizer 114 for transmission to modulator 402 coupled to serializer 116. Modulator 402 can be configured to modulate the serialized output of serializer 116 onto a signal that can be used to transmit information from a received RF signal via communication link 110.

[0046] As an illustrative operational example, the digital CRPA 112 can be configured to receive a digital CRPA that is part of the navigation signal in GNSS. The digital CRPA 112 can be configured to down-convert and digitize the RF signal (received at receiver 401) in the GNSS band near each receiver element 401. The resulting in-phase and quadrature samples (i.e., I and Q samples) are then serialized and modulated onto a signal used to transmit information to the GNSS signal processor via communication link 110.

[0047] In some implementations, system 400 may also include a communication link 110 (e.g., via...). Figure 2 The first interface 202) is coupled to a CRPA controller plug-in 104 of the digital CRPA 112. The CRPA controller plug-in 104 may include a demodulator 404 configured to demodulate signals received from the digital CRPA 112 via communication link 110. The demodulator 404 may transmit the demodulated signal to a deserializer 406, which may include circuitry configured to deserialize the demodulated signal. The deserializer 406 may transmit the deserialized, demodulated signal to one or more filters 408. In some implementations, the filters 408 may include circuitry configured to perform time, space, and frequency filtering operations using the received digital data to generate modified digital data. The filters 408 may transmit the modified digital data to a modulator 410, which may include modulators configured to modulate the modified digital data to a modulated signal for (e.g., via...) Figure 2 The circuitry that transmits signals from the second interface 204 to the multimode receiver 106.

[0048] For example, demodulator 404 can be configured to communicate via a first interface (e.g., Figure 2 The first interface 202 receives digital data representing navigation signals received at the digital CRPA 112. The received digital data may be received as a first modulated analog signal (e.g., modulated by modulator 402). Demodulator 404 may be configured to generate a bit sequence based on the first modulated analog signal. Deserializer 406 may be configured to generate two or more parallel I and Q sample streams based on the bit sequence, the two or more parallel I and Q sample streams representing the received navigation signals received at two or more receiving elements 401 of the digital CRPA 112, respectively. Time, space, and frequency filters 408 may be configured to perform time, space, and frequency filtering operations based on the two or more parallel sample streams. Modulator 410 may be configured to modulate the reconstructed analog RF signal based on the modified digital data to generate a modified analog navigation signal.

[0049] In some aspects, filter 408 may include circuitry that performs beamforming and null control operations, wherein the circuitry is configured to spatially filter digital data such that components of the received signal from one or more directions received at digital CRPA 112 are attenuated in a modified analog navigation signal based on the modified digital data.

[0050] In similar or alternative configurations, filter 408 may include circuitry performing time, space, and frequency filtering operations, wherein the circuitry is configured to perform interference detection operations based on digital data. In some configurations, the circuitry may be configured to generate nulls pointing towards the interference source. In similar or alternative configurations, to perform the detection operation, the circuitry may be configured to determine the signal power and angle of arrival (AOA) of at least a subset of the navigation signal received at digital CRPA 112 based on digital data. The circuitry may be configured to compare the signal power, AOA, or both of the at least subset of the signal with the expected signal characteristics of the navigation signal. For example, if the signal power, AOA, or both of the at least subset of the signal are higher than the expected signal characteristics of the navigation signal, system 400 may be configured to identify the direction of the interference or spoofing source. In some configurations, the circuitry may be configured to generate nulls pointing towards the identified interference or spoofing source.

[0051] The circuit can also be configured to respond to the detection of navigation signals, including spoofing navigation signals, via a first interface (e.g., Figure 2 First interface 202), second interface (e.g., Figure 2 The second interface 204) or both output data to prevent one or more aircraft systems from using navigation data based on navigation signals.

[0052] The circuit can also be configured to output an alarm in response to the detection of interference (e.g., via...). Figure 2First interface 202, Figure 2 (Second interface 204 or both). For outputting alarms, the circuit can also be configured to add or modify tags on the aircraft data bus, as described above. Figure 2 To describe in more detail, an alarm can indicate, for example, the type of interference, the direction to the source of the interference, the detection time of the interference, or a combination of these.

[0053] In some implementations, the digital CRPA 112 can be configured to receive navigation signals in a first frequency band, and the circuitry of the CRPA controller plug-in 104 can be configured to receive digital data via a modulation signal in a second frequency band different from the first frequency band and output a reconstructed modified analog navigation signal in the first frequency band.

[0054] Referring again to the illustrative operational example above, the received digital data can be demodulated and deserialized to recover the I and Q samples of each receiving element 401 of the digital CRPA 112. The I and Q samples can then be processed to apply signal nulling algorithms (e.g., via time, frequency, and spatial filtering algorithms) to eliminate interference. The processed, sampled signals are combined to generate a single baseband signal, which is then converted into an analog signal that can be up-converted back to the original GNSS frequency. In this way, the set of GNSS signals is reconstructed, with some or all of the interference energy removed. The reconstructed GNSS signal can then be directly transmitted to a conventional GNSS receiver, enabling the CRPA to be used with existing GNSS receivers without requiring modifications to the receiver.

[0055] In some implementations, the CRPA controller plugin 104 can be configured to receive (e.g., via...) Figure 2 First interface 202, Figure 2The second interface 204 (or both) indicates the operating mode of the multimode receiver 106. The circuitry of the CRPA controller plug-in 104 can be configured to determine the specific spatial, temporal, and frequency filtering operations to be performed based on the operating mode of the multimode receiver 106. Knowing the operating mode of the multimode receiver 106 allows the system 400 to operate with higher accuracy than without such knowledge. For example, during operations requiring very high accuracy (e.g., precision approaches), it may be necessary to suppress certain aspects of spatial-temporal and frequency filtering. As a specific example, if the approaching satellite's direction of arrival produces a null, a power-minimizing signal nulling algorithm can cause GNSS tracking errors. Therefore, if the aircraft is operating in an environment requiring very high accuracy, the operating mode of the multimode receiver 106 can indicate that such an operation is in effect, and the circuitry of the CRPA controller plug-in 104 can change the performed spatial, temporal, and frequency operations (e.g., by using different algorithms, avoiding null values ​​in specific environments, stopping operation for a period of time, applying appropriate compensation, etc.).

[0056] While specific components are shown in a particular configuration in exemplary system 400, more, fewer, and / or different components are possible in different configurations without departing from the scope of this disclosure. For example, digital CRPA 112 may include more than Figure 4 The more, fewer, and / or different receiving elements 401 shown are also included. The digital CRPA 112 can transmit four-channel digital RF streams, eight to twelve-channel streams, etc., to the CRPA controller plug-in 104. As another example, the components, functions, etc., described with respect to the CRPA controller plug-in 104 may be wholly or partially integrated within the multimode receiver 106.

[0057] The above reference Figures 1 to 4 The described CRPA controller plug-in 104 simplifies and reduces the cost of installing digital CRPA functionality on existing aircraft. For example, systems 100, 200, 300, and 400 use a single cable (e.g., communication link 110) to connect digital CRPA 112 to CRPA controller plug-in 104. Digital CRPA 112 can replace existing antennas in existing designs and enables CRPA processing without requiring additional line-of-flight replaceable units (LRUs) near the antenna array and managing multiple GNSS antenna unit connections.

[0058] In addition, the above reference Figures 1 to 4 The described CRPA controller plug-in 104 can provide sufficient operating power to the digital CRPA without replacing the aircraft's existing receiver. The LRU, which will be inserted between the multimode receiver 106 and the MMR rack 107, can provide sufficient power to the digital CRPA 112.

[0059] In addition, the above reference Figures 1 to 4 The described CRPA controller plugin 104 can operate at the appropriate time and with appropriate precision according to the flight status. For example, the CRPA controller plugin 104 can control the multimode receiver 106 according to its operating mode or status.

[0060] Figure 5 This illustrates some examples of CRPA controller plugins for operation according to this disclosure (e.g., Figures 1 to 4 The flowchart illustrates an example of method 500 of the CRPA controller plug-in 104. Method 500 can be executed by one or more processors carrying out instructions, or by circuitry configured to cause one or more operations (such as those existing in...). Figures 1 to 4 The CRPA controller plugin 104 or a combination thereof is used to initiate, execute or control.

[0061] In some implementations, method 500 includes, at block 502, receiving digital data representing navigation signals received at the antenna via a first interface on a first side of the housing. For example, Figure 1 The CRPA controller plug-in 104 can be accessed via the first side of the housing 205. Figure 2 The first interface 202 receives digital data representing navigation signals received at the digital CRPA 112.

[0062] Method 500 includes, in block 504, performing temporal, spatial, and frequency filtering operations on the digital data to generate modified digital data. For example, Figure 4 Filter 408 can perform time, space, and frequency filtering operations using digital data to generate modified digital data. Method 500 includes, at block 506, outputting a modified analog navigation signal via a second interface on a second side of the housing to a multimode receiver (MMR) external to the housing and coupled to the second interface, wherein the modified analog navigation signal is based on modified digital data. For example, Figure 1 The CRPA controller plug-in 104 can be accessed via the second side of the housing 205. Figure 2 The second interface 204 outputs the modified analog navigation signal to a multimode receiver 106 located outside the housing 205 and coupled to the second interface 204. The modified analog navigation signal is based on modified digital data.

[0063] In some implementations, method 500 may include more, fewer, and / or different steps without departing from the scope of this disclosure. For example, method 500 may further include: when receiving digital data includes receiving a first modulated analog signal, generating a bit sequence based on the first modulated analog signal; generating two or more parallel sample streams based on the bit sequence, the two or more parallel sample streams representing navigation signals received at two or more antenna elements of an antenna, respectively; performing time, space, and frequency filtering operations based on the two or more parallel sample streams; and modulating a baseband signal based on the modified digital data to generate a modified analog navigation signal.

[0064] The above references can be implemented. Figure 5 The methods described are intended to achieve one or more of the technical advantages described in more detail above. For example, method 500 could enable resource-saving retrofits of commercial aircraft to benefit from the anti-blocking and anti-spoofing technologies implemented by digital CRPA.

[0065] Reference Figure 6 A flowchart, shown and labeled 600, illustrates an example of the lifecycle of an aircraft including CRPA controller plug-in 104. CRPA controller plug-in 104 enables resource-saving retrofits of commercial aircraft to benefit from the anti-blocking and anti-spoofing technologies implemented with digital CRPA. During pre-production, exemplary method 600 includes, at 602, the aircraft (such as...) Figure 1 and Figure 7 The specifications and design of the aircraft. During the specification and design of the aircraft, method 600 may include the specifications and design of a radio device configured to provide anti-jamming and anti-spoofing technologies implemented by digital CRPA. At 604, method 600 includes material procurement, which may include procuring materials for the radio device.

[0066] During production, method 600 includes, at 606, the manufacture of parts and sub-assemblies, and at 608, the system integration of the aircraft. For example, method 600 may include the manufacture of parts and sub-assemblies for CRPA controller plug-in 104 and the system integration of CRPA controller plug-in 104. At 610, method 600 includes the certification and delivery of the aircraft, and at 612, putting the aircraft into service. Certification and delivery may include the certification of CRPA controller plug-in 104 to put CRPA controller plug-in 104 into service. When used by the customer, routine maintenance and overhauls of the aircraft may be scheduled (which may also include resource-saving modifications, modifications, reconfigurations, refurbishments, etc.). At 614, method 600 includes performing maintenance and overhauls on the aircraft, which may include performing maintenance and overhauls on CRPA controller plug-in 104. Alternatively, performing maintenance and overhauls on the aircraft may include replacing the radio altimeter with the CRPA controller plug-in 104 disclosed herein during a modification operation.

[0067] Each process of Method 600 may be performed or implemented by a system integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this specification, a system integrator may include, but is not limited to, any number of aircraft manufacturers and main system subcontractors; a third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, etc.

[0068] Various aspects of this disclosure can be described in the context of examples of means of transport. Specific examples of means of transport are as follows: Figure 7 The aircraft shown is 700. Figure 7 In the example, aircraft 700 includes a fuselage 718 and an interior 722 having multiple systems 720. Examples of the multiple systems 720 include one or more of a propulsion system 724, an electrical system 726, an environmental system 728, a hydraulic system 730, and a CRPA controller plug-in 732. Any number of other systems may be included. Figure 7 In the example, CRPA controller plugin 732 includes a CRPA controller plugin configured to provide anti-blocking and anti-spoofing technologies for digital CRPA implementation, such as... Figures 1 to 4 CRPA controller plug-in 104, included in the... Figure 5 Method 500 is associated with the CRPA controller plug-in in the aircraft, including in conjunction with Figure 6 Method 600 is associated with the CRPA controller plug-in in the aircraft or any combination thereof.

[0069] Figure 8According to a block diagram of a computing environment 800 disclosed herein, the computing environment includes computing device 810 configured to support aspects of computer-implemented methods and computer-executable program instructions (or code). For example, computing device 810 or portions thereof is configured to execute instructions to initiate, execute, or control references. Figures 1 to 7 One or more operations as described.

[0070] The computing device 810 includes one or more processors 820. The processors 820 are configured to communicate with system memory 830, one or more storage devices 840, one or more input / output interfaces 850, one or more communication interfaces 860, or any combination thereof. System memory 830 includes volatile memory devices (e.g., random access memory (RAM) devices), non-volatile memory devices (e.g., read-only memory (ROM) devices, programmable read-only memory, and flash memory), or both. System memory 830 stores operating system 832, which may include a basic input / output system for booting computing device 810 and a complete operating system enabling computing device 810 to interact with users, other programs, and other devices. System memory 830 stores program data 836 (system data), such as digital data 837, modified digital data 839, modified analog navigation signals 841, or combinations thereof. Digital data 837 may include or correspond to data received via a first interface and represented in... Figures 1 to 7 The digital data of the navigation signals received at the digital CRPA 112. The modified digital data 839 may include or correspond to the modified digital data generated by the CRPA controller plugin when performing time, space, and frequency filtering operations using digital data 837, as referenced above. Figures 1 to 7 A more detailed description follows. The modified analog navigation signal 841 may include or correspond to the modified analog navigation signal output to the MMR via the second interface from the CRPA controller plug-in, wherein the modified analog navigation signal 841 is based on modified digital data 839, as referred to above. Figures 1 to 7 More detailed description.

[0071] System memory 830 includes one or more application programs 834 (e.g., instruction sets) that can be run by processor 820. As an example, one or more application programs 834 include those that can be run by processor 820 to initiate, control, or execute references. Figures 1 to 7 Instructions for one or more operations described. For illustration, one or more application programs 834 include instructions that can be run by processor 820 to initiate, control, or perform one or more operations described with reference to CRPA controller plug-in 104, the circuitry of CRPA controller plug-in 104, or a combination thereof.

[0072] In one particular implementation, system memory 830 includes a non-transitory computer-readable medium storing instructions that, when executed by processor 820, cause processor 820 to initiate, execute, or control operations to implement anti-spoofing and anti-blocking techniques for digital CRPA. Operations include receiving digital data representing navigation signals received at the antenna via a first interface on a first side of the housing. Operations include performing temporal, spatial, and frequency filtering operations using the digital data to generate modified digital data. These operations also include outputting modified analog navigation signals via a second interface on a second side of the housing to a multimode receiver (MMR) external to the housing and coupled to the second interface, wherein the modified analog navigation signals are based on the modified digital data.

[0073] One or more storage devices 840 include non-volatile storage devices, such as disks, optical disks, or flash memory devices. In a particular example, storage device 840 includes both removable and non-removable memory devices. Storage device 840 is configured to store an operating system, images of the operating system, applications (e.g., one or more of applications 834), and program data (e.g., system program data 836). In a particular aspect, system memory 830, storage device 840, or both include tangible computer-readable media. In a particular aspect, one or more of storage devices 840 are external to computing device 810.

[0074] One or more input / output interfaces 850 enable computing device 810 to communicate with one or more input / output devices 870 to facilitate user interaction. For example, one or more input / output interfaces 850 may include a display interface, an input interface, or both. For example, input / output interface 850 is adapted to receive input from a user, input from another computing device, or a combination thereof. In some implementations, input / output interface 850 conforms to one or more standard interface protocols, including serial interfaces (e.g., Universal Serial Bus (USB) interfaces or Institute of Electrical and Electronics Engineers (IEEE) interface standards), parallel interfaces, display adapters, audio adapters, or custom interfaces (“IEEE” is a registered trademark of the Institute of Electrical and Electronics Engineers of Piscatway, New Jersey). In some implementations, input / output device 870 includes one or more user interface devices and displays, including some combination of buttons, keyboards, pointing devices, displays, speakers, microphones, touchscreens, and other devices.

[0075] The processor 820 is configured to communicate with the device or controller 880 via one or more communication interfaces 860. For example, the one or more communication interfaces 860 may include a network interface. The device or controller 880 may include, for example... Figures 1 to 7 Multimode receiver 106 Figures 1 to 7The number CRPA 112 or any combination thereof.

[0076] In conjunction with the described systems and methods, an apparatus is disclosed comprising a component for receiving digital data representing navigation signals received at an antenna via a first interface on a first side of a housing. In some implementations, the component for receiving corresponds to system 100, system 200, system 300, CRPA controller plug-in 104, first interface 202, demodulator 404, one or more other circuits or devices configured to receive digital data, or combinations thereof.

[0077] The device also includes components for performing time, space, and frequency filtering operations using digital data to generate modified digital data. For example, the components for performing time, space, and frequency filtering operations may correspond to system 100, system 200, system 300, CRPA controller plug-in 104, filter 408, processor 820, one or more other circuits or devices configured to perform time, space, and frequency filtering operations, or combinations thereof.

[0078] The device also includes components for outputting modified analog navigation signals via a second interface on a second side of the housing to a multimode receiver (MMR) located outside the housing and coupled to the second interface, wherein the modified analog navigation signals are based on modified digital data. For example, the components for output may correspond to system 100, system 200, system 300, system 400, CRPA controller plug-in 104, modulator 410, one or more other circuits or devices configured to output modified analog navigation signals, or combinations thereof.

[0079] In some implementations, a non-transitory computer-readable medium stores instructions that, when executed by one or more processors, cause one or more processors to initiate, execute, or control operations to perform some or all of the functions described above. For example, the instructions can be executed to implement... Figures 1 to 8 One or more operations or methods. In some implementations, this can be carried out by one or more processors executing instructions (e.g., one or more central processing units (CPUs), one or more graphics processing units (GPUs), one or more digital signal processors (DSPs)), by dedicated hardware circuitry, or any combination thereof. Figures 1 to 8 Some or all of one or more operations or methods.

[0080] The illustrations of the examples described herein are intended to provide a general understanding of the structure of various implementations. These illustrations are not intended to serve as a complete description of all elements and features of devices and systems utilizing the structures or methods described herein. Many other implementations will be apparent to those skilled in the art upon review of this disclosure. Other implementations may be utilized and derived from this disclosure, allowing structural and logical substitutions and changes to be made without departing from the scope of this disclosure. For example, method operations may be performed in a different order than those shown in the figures, or one or more method operations may be omitted. Therefore, this disclosure and the accompanying drawings are to be considered illustrative rather than restrictive.

[0081] Furthermore, while specific examples have been shown and described herein, it should be understood that any subsequent arrangements designed to achieve the same or similar results may replace the specific implementations shown. This disclosure is intended to cover any and all subsequent adaptations or variations of the various implementations. After reviewing this description, combinations of the above implementations, as well as other implementations not specifically described herein, will be apparent to those skilled in the art.

[0082] The abstract of this disclosure is provided to be understood not to be construed as limiting the scope or meaning of the claims. Furthermore, in the foregoing detailed embodiments, various features may be combined together or described in a single implementation for the purpose of simplification. The foregoing examples are illustrative but not limiting of this disclosure. It should also be understood that many modifications and variations are possible based on the principles of this disclosure. As reflected in the following claims, the claimed subject matter may involve fewer features than all features of any of the disclosed examples. Therefore, the scope of this disclosure is defined by the appended claims and their equivalents.

[0083] Furthermore, this disclosure includes implementations according to the following examples: According to Example 1, an apparatus includes: a housing; a first interface on a first side of the housing, wherein the first interface is configured to be coupled to a multimode receiver (MMR) rack; a second interface on a second side of the housing opposite to the first side, wherein the second interface is configured to be coupled to an MMR outside the housing; and circuitry within the housing, the circuitry being configured to receive digital data representing navigation signals received at an antenna via the first interface, perform time, space, and frequency filtering operations using the digital data to generate modified digital data, and output modified analog navigation signals to the MMR based on the modified digital data via the second interface.

[0084] Example 2 includes the apparatus according to Example 1, wherein the circuitry includes a modem configured to receive digital data as a first modulated analog signal via a first interface and generate a bit sequence based on the first modulated analog signal. The circuitry includes a deserializer configured to generate two or more parallel sample streams based on the bit sequence, the two or more parallel sample streams representing navigation signals received at two or more antenna elements of an antenna, respectively. The circuitry includes time, space, and frequency filters configured to perform time, space, and frequency filtering operations based on the two or more parallel sample streams. The circuitry includes a modulator configured to modulate a baseband signal based on modified digital data to generate a modified analog navigation signal.

[0085] Example 3 includes an apparatus according to Example 1 or Example 2, wherein, in order to perform time, space and frequency filtering operations, the circuitry is configured to spatially filter the digital data such that components of the navigation signal received at the antenna from one or more directions are attenuated in a modified analog navigation signal based on the modified digital data.

[0086] Example 4 includes an apparatus according to any one of Examples 1 to 3, wherein the circuitry is further configured to perform an interference detection operation based on digital data.

[0087] Example 5 includes an apparatus according to Example 4, wherein the circuitry is further configured to output an alarm via a first interface, a second interface, or both in response to the detection of interference.

[0088] Example 6 includes the apparatus according to Example 5, wherein, in order to output an alarm, the circuitry is configured to add or modify tags on the aircraft data bus.

[0089] Example 7 includes an apparatus according to any one of Examples 5 to 6, wherein the alarm indicates the type of interference, the direction to the source of interference, the detection time of the interference, or a combination thereof.

[0090] Example 8 includes an apparatus according to any one of Examples 4 to 7, wherein, in order to perform time, space and frequency filtering operations in response to the detection of interference, the circuit is configured to generate null traps pointing to the source of interference.

[0091] Example 9 includes an apparatus according to any one of Examples 4 to 8, wherein, in order to perform an interference detection operation, the circuitry is further configured to determine, based on digital data, the signal power and angle of arrival (AOA) of at least a subset of the navigation signal received at the antenna; and to compare the signal power, AOA, or both of the at least subset of the signal with the expected signal characteristics of the navigation signal.

[0092] Example 10 includes an apparatus according to any one of Examples 4 to 9, wherein the circuitry is further configured to output data via a first interface, a second interface, or both in response to the detection of a navigation signal including a spoofing navigation signal, to prevent one or more aircraft systems from using navigation data based on the navigation signal.

[0093] Example 11 includes an apparatus according to any one of Examples 1 to 10, wherein the circuitry is further configured to receive data indicating an operating mode of the MMR via a first interface, a second interface, or both; and to determine specific time, space, and frequency filtering operations to be performed based on the operating mode of the MMR.

[0094] Example 12 includes an apparatus according to any one of Examples 1 to 11, wherein the antenna is configured to receive a navigation signal in a first frequency band, and wherein the circuitry is configured to receive digital data via a modulation signal in a second frequency band different from the first frequency band and output a modified analog navigation signal in the first frequency band.

[0095] Example 13 includes an apparatus according to any one of Examples 1 to 12, wherein the second interface includes a plurality of connectors, the plurality of connectors including at least one connector configured to be coupled to an aircraft bus and at least one connector configured to be coupled to an MMR.

[0096] Example 14 includes an apparatus according to any one of Examples 1 to 13, wherein a first interface includes a first plurality of connectors and a second interface includes a second plurality of connectors, and wherein the first plurality of connectors are complementary to the connectors of the MMR rack, and the second plurality of connectors are complementary to the first plurality of connectors.

[0097] Example 15 includes an apparatus according to any one of Examples 1 to 14, wherein the antenna includes a digitally controlled receive mode antenna comprising a plurality of antenna elements configured to receive navigation signals and generate digital data representing the navigation signals.

[0098] Example 16 includes an apparatus according to any one of Examples 1 to 15, wherein the circuitry is further configured to provide power to the antenna via a first interface.

[0099] According to Example 17, the aircraft includes: an antenna; a multimode receiver (MMR); an MMR rack coupled to the antenna via a communication link; and a route-changeable unit (LRU) disposed between the MMR and the MMR rack. The LRU includes: a housing; a first interface coupled to the MMR rack on a first side of the housing; a second interface coupled to the MMR on a second side of the housing; and circuitry within the housing configured to receive digital data representing navigation signals received at the antenna via the first interface, perform time, space, and frequency filtering operations using the digital data to generate modified digital data, and output modified analog navigation signals to the MMR via the second interface based on the modified digital data.

[0100] Example 18 includes the aircraft of Example 17, wherein the circuitry includes: a modem configured to receive digital data as a first modulated analog signal via a second interface and generate a bit sequence based on the first modulated analog signal; a deserializer configured to generate two or more parallel sample streams based on the bit sequence, the two or more parallel sample streams representing navigation signals received at two or more antenna elements of the antenna, respectively; time, space, and frequency filters configured to perform time, space, and frequency filtering operations based on the two or more parallel sample streams; and a modulator configured to modulate a baseband signal based on modified digital data to generate a modified analog navigation signal.

[0101] Example 19 includes the aircraft of Example 17 or Example 18, wherein, in order to perform time, space and frequency filtering operations, the circuitry is configured to spatially filter the digital data such that components of the navigation signal received at the antenna from one or more directions are attenuated in a modified analog navigation signal based on the modified digital data.

[0102] Example 20 includes an aircraft of any of Examples 17 to 19, wherein the circuitry is further configured to perform interference detection operations based on digital data.

[0103] Example 21 includes the aircraft of Example 20, wherein the circuitry is further configured to output an alarm via a first interface, a second interface, or both in response to the detection of interference.

[0104] Example 22 includes the aircraft of Example 21, wherein, in order to output an alarm, the circuitry is configured to add or modify tags on the aircraft data bus.

[0105] Example 23 includes the aircraft of Example 21 or Example 22, wherein the alarm indicates the type of interference, the direction to the source of interference, the detection time of the interference, or a combination thereof.

[0106] Example 24 includes an aircraft of any of Examples 20 to 23, wherein, in order to perform time, space, and frequency filtering operations in response to the detection of interference, the circuitry is configured to generate null traps pointing toward the source of the interference.

[0107] Example 25 includes an aircraft of any one of Examples 20 to 24, wherein, in order to perform interference detection operations, the circuitry is further configured to determine, based on digital data, the signal power and angle of arrival (AOA) of at least a subset of the navigation signal received at the antenna; and to compare the signal power, AOA, or both of the at least subset of the signal with the expected signal characteristics of the navigation signal.

[0108] Example 26 includes an aircraft of any one of Examples 20 to 25, wherein the circuitry is further configured to output data via a first interface, a second interface, or both in response to the detection of navigation signals, including spoofed navigation signals, to prevent one or more aircraft systems from using navigation data based on navigation signals.

[0109] Example 27 includes an aircraft of any of Examples 17 to 26, wherein the circuitry is further configured to receive data indicating the operating mode of the MMR via a first interface, a second interface, or both; and to determine specific time, space, and frequency filtering operations to be performed based on the operating mode of the MMR.

[0110] Example 28 includes an aircraft of any of Examples 17 to 27, wherein the antenna is configured to receive navigation signals in a first frequency band, and wherein the circuitry is configured to receive digital data via a modulated signal in a second frequency band different from the first frequency band and output a modified analog navigation signal in the first frequency band.

[0111] Example 29 includes an aircraft of any of Examples 17 to 28, wherein the second interface includes a plurality of connectors, the plurality of connectors including at least one connector configured to be coupled to an aircraft bus and at least one connector configured to be coupled to an antenna.

[0112] Example 30 includes an aircraft of any of Examples 17 to 29, wherein a first interface includes a first plurality of connectors and a second interface includes a second plurality of connectors, and wherein the first plurality of connectors are complementary to the connectors of the MMR rack, and the second plurality of connectors are complementary to the first plurality of connectors.

[0113] Example 31 includes an aircraft of any of Examples 17 to 30, wherein the antenna includes a digitally controlled receive mode antenna comprising a plurality of antenna elements configured to receive navigation signals and generate digital data representing the navigation signals.

[0114] Example 32 includes an aircraft of any of Examples 17 to 31, wherein the circuitry is further configured to provide power to the antenna via a second interface.

[0115] Example 33 includes an aircraft of any of Examples 17 to 32, wherein the communication link between the antenna and the MMR rack includes a coaxial cable.

[0116] Example 34 includes an aircraft of any of Examples 17 to 33, wherein the antenna includes: a plurality of antenna elements; one or more digitizers configured to generate a digital representation of a signal received at the antenna elements; one or more serializers configured to generate a sample stream based on the digital representation; and a modem configured to transmit the sample stream to an LRU via a communication link.

[0117] According to Example 35, a method includes: receiving digital data representing a navigation signal received at an antenna via a first interface on a first side of the housing; performing time, space, and frequency filtering operations using the digital data to generate modified digital data; and outputting the modified analog navigation signal to a multimode receiver (MMR) located outside the housing and coupled to the second interface via a second interface on a second side of the housing, wherein the modified analog navigation signal is based on the modified digital data.

[0118] Example 36 includes the method of Example 35, wherein receiving digital data includes receiving a first modulated analog signal, and the method further includes generating a bit sequence based on the first modulated analog signal; generating two or more parallel sample streams based on the bit sequence, the two or more parallel sample streams representing navigation signals received at two or more antenna elements of an antenna, respectively; performing time, space, and frequency filtering operations based on the two or more parallel sample streams; and modulating a baseband signal based on the modified digital data to generate a modified analog navigation signal.

[0119] Example 37 includes a method according to Example 35 or Example 36, wherein performing time, space, and frequency filtering operations includes spatial filtering of digital data such that components of the navigation signal received at the antenna from one or more directions are attenuated in a modified analog navigation signal based on the modified digital data.

[0120] Example 38 includes the method of any one of Examples 35 to 37, and further includes performing an interference detection operation based on digital data.

[0121] Example 39 includes the method of Example 38, and further includes outputting an alarm via a first interface, a second interface, or both in response to the detection of interference.

[0122] Example 40 includes a method according to Example 40, wherein outputting an alarm includes adding or modifying a tag on the aircraft data bus.

[0123] Example 41 includes the method according to Example 39 or Example 40, wherein the alarm indicates the type of interference, the direction to the source of interference, the detection time of the interference, or a combination thereof.

[0124] Example 42 includes a method according to any one of Examples 38 to 41, wherein performing temporal, spatial, and frequency filtering operations in response to the detection of interference includes generating null traps pointing to the source of interference.

[0125] Example 43 includes a method according to any one of Examples 38 to 42, wherein performing the interference detection operation includes determining the signal power and angle of arrival (AOA) of at least a subset of the navigation signal received at the antenna based on digital data; and comparing the signal power, AOA, or both of the at least subset of the signal with the expected signal characteristics of the navigation signal.

[0126] Example 44 includes the method of any one of Examples 38 to 43, and further includes outputting data via a first interface, a second interface, or both in response to detecting that a navigation signal includes a spoofing navigation signal, to prevent one or more aircraft systems from using navigation data based on the navigation signal.

[0127] Example 45 includes the method of any one of Examples 35 to 44, and further includes receiving data indicating the operating mode of the MMR via a first interface, a second interface, or both; and determining specific time, space, and frequency filtering operations to be performed based on the operating mode of the MMR.

[0128] Example 46 includes any of the methods in Examples 35 to 45, and further includes receiving a navigation signal in a first frequency band at an antenna; receiving digital data via a modulation signal in a second frequency band different from the first frequency band; and outputting a modified analog navigation signal in the first frequency band.

[0129] Example 47 includes a method according to any one of Examples 35 to 46, and further includes receiving a navigation signal; and generating digital data representing the navigation signal.

[0130] Example 48 includes the method of any one of Examples 35 to 47, and further includes providing power to the antenna via a second interface.

Claims

1. An apparatus for a line-changeable unit, comprising: case; A first interface is located on a first side of the housing, wherein the first interface is configured to be coupled to a multimode receiver rack. A second interface is located on a second side of the housing opposite to the first side, wherein the second interface is configured to be coupled to a multimode receiver outside the housing; and The circuit, within the housing, is configured as follows: Digital data representing the navigation signal received at the antenna is received via the first interface; Perform temporal, spatial, and frequency filtering operations using the digital data to generate modified digital data; and The modified analog navigation signal is output to the multimode receiver via the second interface based on the modified digital data.

2. The apparatus according to claim 1, wherein, The circuit includes: A modem is configured to receive the digital data as a first modulated analog signal via the first interface and generate a bit sequence based on the first modulated analog signal; A deserializer is configured to generate two or more parallel sample streams based on the bit sequence, the two or more parallel sample streams representing navigation signals received at two or more antenna elements of the antenna, respectively; The filter is configured to perform the time, space, and frequency filtering operations based on the two or more parallel sample streams; and A modulator is configured to modulate a baseband signal based on the modified digital data to generate the modified analog navigation signal.

3. The apparatus according to claim 1, wherein, In order to perform the time, space, and frequency filtering operations, the circuit is configured to spatially filter the digital data such that components of the navigation signal received at the antenna from one or more directions are attenuated in the modified analog navigation signal based on the modified digital data.

4. The apparatus according to claim 1, wherein, The circuit is further configured to perform interference detection operations based on the digital data.

5. The apparatus according to claim 4, wherein, The circuit is further configured to output an alarm via the first interface, the second interface, or both in response to the detection of interference.

6. The apparatus according to claim 5, wherein, In order to output the alarm, the circuit is configured to add or modify tags on the aircraft data bus.

7. The apparatus according to claim 5, wherein, The alarm indicates the type of interference, the direction to the source of the interference, the detection time of the interference, or a combination thereof.

8. The apparatus according to claim 4, wherein, In order to perform the time, space, and frequency filtering operations in response to the detection of interference, the circuit is configured to generate null traps pointing to the source of interference.

9. The apparatus according to claim 4, wherein, In order to perform the interference detection operation, the circuit is further configured as follows: Based on the digital data, determine the signal power and angle of arrival of at least a subset of the navigation signals received at the antenna; and The signal power, angle of arrival, or both of at least the subset of signals are compared with the expected signal characteristics of the navigation signal.

10. The apparatus according to claim 4, wherein, The circuitry is further configured to output data via the first interface, the second interface, or both in response to detecting that the navigation signal includes a spoofing navigation signal, to prevent one or more aircraft systems from using navigation data based on the navigation signal.

11. The apparatus according to claim 1, wherein, The circuit is further configured as follows: Receive data indicating the operating mode of the multimode receiver via the first interface, the second interface, or both; and The specific time, space, and frequency filtering operations to be performed are determined based on the operating mode of the multimode receiver.

12. The apparatus according to claim 1, wherein, The antenna is configured to receive the navigation signal in a first frequency band, and the circuit is configured to receive the digital data via a modulation signal in a second frequency band different from the first frequency band and output the modified analog navigation signal in the first frequency band.

13. The apparatus according to claim 1, wherein, The second interface includes a plurality of connectors, including at least one connector configured to be coupled to an aircraft bus and at least one connector configured to be coupled to the multimode receiver.

14. The apparatus according to claim 1, wherein, The first interface includes a first plurality of connectors, and the second interface includes a second plurality of connectors, wherein the first plurality of connectors are complementary to the connectors of the multimode receiver rack, and the second plurality of connectors are complementary to the first plurality of connectors.

15. The apparatus according to claim 1, wherein, The antenna includes a digitally controlled receive mode antenna, which includes multiple antenna elements configured to receive the navigation signal and generate digital data representing the navigation signal.

16. The apparatus according to claim 1, wherein, The circuit is further configured to provide power to the antenna via the first interface.

17. An aircraft comprising: antenna; Multimode receiver; A multimode receiver rack is coupled to the antenna via a communication link; as well as A route-changeable unit is disposed between the multimode receiver and the multimode receiver rack, the route-changeable unit comprising: case; A first interface is coupled to the multimode receiver rack on a first side of the housing; A second interface is coupled to the multimode receiver on a second side of the housing; and The circuit, within the housing, is configured as follows: Receive digital data representing the navigation signal received at the antenna via the first interface; Perform temporal, spatial, and frequency filtering operations using the digital data to generate modified digital data; and The modified analog navigation signal is output to the multimode receiver via the second interface based on the modified digital data.

18. The aircraft according to claim 17, wherein, The circuit includes: The modem is configured to receive the digital data as a first modulated analog signal via the second interface and generate a bit sequence based on the first modulated analog signal; A deserializer is configured to generate two or more parallel sample streams based on the bit sequence, the two or more parallel sample streams representing navigation signals received at two or more antenna elements of the antenna, respectively; The filter is configured to perform the time, space, and frequency filtering operations based on the two or more parallel sample streams; and A modulator is configured to modulate a baseband signal based on the modified digital data to generate the modified analog navigation signal.

19. The aircraft according to claim 17, wherein, In order to perform the time, space, and frequency filtering operations, the circuit is configured to spatially filter the digital data such that components of the navigation signal received at the antenna from one or more directions are attenuated in the modified analog navigation signal based on the modified digital data.

20. A method for a line-swappable unit, comprising: Digital data representing navigation signals received at the antenna is received via a first interface on the first side of the housing; The digital data is used to perform temporal, spatial, and frequency filtering operations to generate modified digital data; as well as A modified analog navigation signal is output to a multimode receiver outside the housing and coupled to the second interface via a second interface on the second side of the housing, wherein the modified analog navigation signal is based on the modified digital data.

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