Course deviation indicator

Abstract: A marine automatic steering apparatus for setting a desired course in a digital fashion is disclosed, in which a course deviation which is a difference between a set course and a ship's heading is indicated in an analog manner on a course deviation indicator whose zero point is set at the position corresponding to the lubber line of a steering repeater card.

Abstract: In good weather, San Francisco International Airport can support approximately 60 landings per hour on its two par-allel runways which are 750 ft apart; however, current navigation and surveillance systems lack the accuracy required for two aircraft to fly through clouds in such close proximity. During even fairly benign instrument meteoro-logical conditions, the airport degrades to a one-runway operation, the landing rate drops to 30 per hour, an air-borne traffic jam ensues, and many passengers become restless. (ILS) for this task is due to the angular nature of its radio beam, typically 3 to 6 deg wide. Farther away from the runway, the resolution of the aircraft's absolute position accuracy degrades; for landings on parallel runways, the two ILS approach beams will eventually overlap some-where on the approach. Special equipment and procedures can allow parallel instrument approaches to runways as lit-tle as 3400 ft apart; however, these solutions are expensive and are not applicable to airports such as San Francisco with 750 ft runway spacing. GPS positioning from the Wide Area Augmentation Sys-tem (WAAS) can be used to create straight instrument approach corridors that are free of the angular dependence ILS. These high-accuracy parallel approaches do not overlap and navigational separation is possible, even far from touchdown. A prototype WAAS-based avionics suite was built at Stanford University and flight tested at Mof-fett Federal Airfield in the fall of 1998 onboard a Beech-craft Queen Air. Pilots flew 27 approaches using the needle-based Course Deviation Indicator (CDI) as well as 3-D "tunnel-in-the-sky” display. Data was gathered on flight technical error (FTE), the pilot's guidance-following accuracy and navigation sensor error (NSE), the accuracy the WAAS-derived guidance. Pilots flew the WAAS-based corridor approaches with less deviation from center-line than that of the ILS approaches. Additional data shows that using a tunnel-in-the-sky display dramatically reduced FTE both horizontally and vertically. Finally, sta-tistical models were generated for both horizontal and ver-tical FTE that may be used in computational models of aircraft approach trajectories.

Abstract: Modern aircraft heavily rely on several wireless technologies for communications, control, and navigation. In this work, we demonstrate the vulnerability of aircraft instrument landing systems to wireless attacks. We show that it is possible to fully and in finegrain control the course deviation indicator, as displayed by the ILS receiver, in real-time, and demonstrate it on aviation-grade ILS receivers. We develop a tightly-controlled closed-loop ILS spoofer that autonomously adjusts the adversary's transmitted signals based on the aircraft's GPS location to cause an undetected off-runway landing. We demonstrate the integrated attack on an FAA certified flight-simulator (X-Plane)'s AI-based auto-land feature and show success rate with offset touchdowns of 18 meters to over 50 meters.

Abstract: Apparatus for a digital averaging filter, particularly suited for use with an aeronautical navigation receiver, for reducing oscillatory deviation errors that appear in a course deviation voltage produced by the receiver and occur as the result of reflected incoming radio-navigation signals and/or interfering signals as described. In essence, this apparatus first amplifies, filters and repetitively samples the course deviation voltage to provide digital representations thereof. Each digital representation is then converted by a digital to pulse count converter into a series of pulses wherein the value of each digital representation is encoded into the number of pulses in the series. Thereafter, these pulses are totalized over a pre-defined interval. The resulting totalized count is then divided to produce an average value, which at the end of the pre-defined interval accurately reflects the average course deviation error. Advantageously, this average value is substantially free of any oscillatory deviation errors. This average value is then converted to an equivalent analog value for eventual display on a course deviation indicator.