Automatic GNSS Quality Monitoring NOTAM Station

Abstract

A claim for protection is being asserted for: • A compact all-in-one outdoor station in an outdoor housing for mast or wall mounting, which detects GNSS interference (interference, jamming, or spoofing) via a receiving antenna on the L1 band, analyzes the GPS, Galileo, Beidou, and Glonass constellations, classifies detected interference as interference, jamming, or spoofing, calculates an interference level, and automatically generates a NOTAM message based on the type and level of interference, encodes this message as FIS-B, and transmits the encoded message via UAT978 through the transmitting antenna on the 978MHz frequency.

Description

[0001] The station is an all-in-one outdoor device for automatically warning aviation pilots upon detection of GNSS jamming or spoofing near the ground. The warning is issued by transmitting NOTAM messages on the 978 MHz frequency, which are then received by the pilots in the aircraft via a suitable device. State of the art

[0002] Increasingly frequent and intense incidents of GNSS jamming and spoofing pose a significant risk to aviation. The Global Navigation Satellite System (GNSS) includes navigation services such as GPS, Galileo, GLONASS, and BeiDou. GNSS jamming involves the transmission of stronger signals to disable GNSS receivers. GNSS spoofing involves the deliberate generation and transmission of false signals to mislead GNSS receivers into believing they have an incorrect position. Both pose a serious risk to pilots.

[0003] Currently, pilots can detect jamming or spoofing using the aircraft's built-in navigation systems, for example, by sudden jumps on the map or unjustified ground warning alarms. In this case, they must switch to alternative navigation systems (such as IRS, inertial reference system). problem

[0004] Pilots only recognize GNSS jamming and spoofing through their displays when they are directly affected. They don't know beforehand what the GNSS quality will be near the ground in their target area—for example, at the airport they are flying to—and then have to switch to alternative navigation systems quickly and during the particularly critical flight phase of the approach, which poses safety risks. Problem solving

[0005] The Automatic GNSS Quality Monitoring NOTAM Station described here uses high-frequency analysis (HF analysis) of the GNSS L1 band to detect and classify any GNSS jamming and spoofing. Upon detection, it automatically issues a warning to pilots in the vicinity. This allows pilots to know the reliability of the GNSS signal on the ground, or whether it is disrupted, well before they arrive at their destination airport. They can then switch to alternative navigation systems early to avoid navigational interference during critical phases of flight, especially the approach. Transmitting the warning on the 978 MHz frequency and the presence of suitable receivers in a large number of aircraft currently in operation ensures comprehensive and improved accessibility to the warnings compared to the current state of the art. Technical implementation in general

[0006] Installed near an airport, the station continuously receives high-frequency parameters from the GNSS constellations GPS, Galileo, Beidou, and GLONASS via its L1-band receiving antenna. By analyzing several hundred data points, interference is detected and classified in real time. Based on the calculated intensity of this interference, the control unit generates a plain-text message about the interference and its intensity, which is then integrated into the standardized NOTAM (Notice to Airman) format. This NOTAM message is converted into FIS-B (Flight Information Service Broadcast) and transmitted on the 978 MHz frequency. Many pilots with the appropriate hardware can already receive FIS-B messages on 978 MHz in their aircraft and display them on a screen. These devices are also capable of receiving the interference messages transmitted by the station. Thus, the innovation lies in the combination of these components into an automated, integrated system.Detection + Processing + Classification + Data Preparation + Transmission. Technical implementation in detail and functional sequence

[0007] The automatic GNSS Quality Monitoring NOTAM station is a fully integrated, complete unit in a weatherproof outdoor housing for mast or wall mounting. It is primarily intended for installation near airports or airfields, or at other locations relevant to air traffic.

[0008] The internal workflow is as follows: 1. The GNSS receiving antenna receives the GNSS signal in the L1 band of all constellations such as GPS, Galileo, Beidou or Glonass. 2. The GNSS signal is routed to the GNSS jamming and spoofing detector via a coaxial cable. 3. The GNSS jamming and spoofing detector analyzes the received RF signal in the L1 band with a bandwidth of 60 MHz and a center frequency of 1575 MHz. It analyzes the signal strength (band power, peak power, etc.) and waveforms to detect anomalies in the radio spectrum. Additionally, the decoded GNSS information, such as the number of satellites and deviations (position deviation, latitude error, longitude error, PPS timing, etc.), is recorded and continuously compared to identify potential interference or distortion. From this, the overall signal quality is calculated, and any interference is detected and classified. 4. In the event of a GNSS interference detection (interference, jamming, or spoofing), the acquired data is processed by the processing and control unit. For this purpose, an interference level is calculated, and—depending on a level configurable via the web interface—an error message is initially generated in plain text. 5. This fault message in plain text is embedded in the message field of a NOTAM message. The additional data fields of the NOTAM message depend on the station's installation location, the airport identifier, the time, the validity period, etc., and can also be configured as further message components via the integrated web interface. 6. The fully generated NOTAM message is then converted into the standardized FIS-B format. 7. The resulting FIS-B telegram is then fed into the UAT978 transmitter with RF amplifier. This transmits the message on the 978MHz frequency via the station's transmitting antenna. 8. Aircraft with (integrated) UAT978 transceiver receive the transmitted message, which is then displayed on the display unit in the cockpit. Glossary (alphabetically sorted): • Beidou: Chinese satellite navigation system • FIS-B: Flight Information System Broadcast, a data radio service for transmitting information to pilots. • Galileo: European Satellite Navigation System • GLONASS: Russian satellite navigation system • GNSS: Global Navigation Satellite System, a general term for the global satellite navigation system including GPS, Beidou, Glonass and Galileo. • GPS: Global Positioning System, a satellite navigation system of American origin. • RF: High frequency • Jamming: Emitting interfering signals to disrupt GNSS receivers. • L1 Band: GNSS band around 1575.42 MHz (1563-1587 MHz) standard frequency range for satellite navigation systems and GPS receivers. • MHz: MHz, megahertz, frequency unit • NOTAM: Notice To Airman, Short-term, temporarily valid instructions or information which are of particular interest for safe air traffic in a specific area. • Spoofing: The falsification of signals. In this context, the transmission of false, or the falsification of genuine GNSS information, for the purpose of misleading GNSS receivers within range. • UAT978: Universal Access Transceiver 978MHz, data radio standard and frequency for transmitting messages to suitable receivers and transceivers in aviation. Legend for the sketch: Function Block Diagram: 1 complete system in an outdoor housing 2 GNSS receiving antennas 3 RF signal path 4 GNSS Jamming and Spoofing Analyzer 5 Data connection 6 Processing and control unit, message generator 7 Data connection 8 UAT 978MHz transmitters and amplifiers 9 RF signal path 10 transmitting antenna 11 Mounting mast (not applicable for wall mounting)

Claims

[1] A claim for protection is made for: • A compact all-in-one outdoor station in an outdoor housing for mast or wall mounting, which detects GNSS interference (interference, jamming, or spoofing) via a receiving antenna on the L1 band, analyzes the GPS, Galileo, Beidou, and Glonass constellations, classifies detected interference as interference, jamming, or spoofing, calculates an interference level, and automatically generates a NOTAM message based on the type and level of interference, encodes this message as FIS-B, and transmits the encoded message via UAT978 through the transmitting antenna on the 978MHz frequency.

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