Abstract: A method for communication involving a plurality of communication devices. A common time base is established among the communication devices and the common time base is then arranged into a repeating cycle of time intervals. The time intervals are arranged into a number of time slots. In one embodiment, at least one time slot is designated as unique and the communication devices are tuned from a first frequency to a second frequency on the occurrence of the unique time slot and the communication devices may receive during the unique time slot. In another embodiment, a time slot is assigned to each communication device, the time slot is unique to each communication device. The communication device is tuned from a first frequency to a second frequency on the occurrence of the communication device's unique time slot and the communication device may transmit during the unique time slot.

Abstract: An integrated landing system interleaves signals encoded in a first format such as the microwave landing system that (MLS) format with signals encoded in a second format such as the precision tactical approach guidance (PTAG) format to permit approach guidance information to be transmitted to aircraft having either MLS receivers or PTAG receivers.

Abstract: A guidance system for landing an aircraft is described which uses a source of signals identifiable with the aircraft and a ground station which is linked to the aircraft. Specifically, the ground station includes a receiver which is connected to one or more pairs of antennas having a fixed, overlapping, directional sensitive pattern symmetically located relative to the center of the landing path, a receiver and a processor for measuring the relative sensitivity of the signals received at the antennas and for using the relative signal intensity to determine the location of the aircraft relative to the center of the landing path.

Abstract: A system for landing an aircraft is described, using a ground installation and an airborne installation which are synchronized together using GPS system time. Specifically, the ground installation includes a ground transmitter which radiates the sequence of signals which provide precision guidance information to the aircraft, an aircraft installation which includes a radio receiver and a processor to receive and process the transmitted guidance signals and to provide indications to aid the pilot in landing the aircraft, a GPS receiver in the air and on the ground for producing signals representative of GPS system time, and a channel selector in the aircraft for actuating the processor to synchronize its operation with the ground installation transmitter. Range information is provided by measuring the time interval between the transmission of a reference at the ground and its receipt in the air.

Abstract: The invention provides independent guidance and monitoring integrated into an MLS landing system and a scaled-down MLS take-off or missed approach guidance system useable at small airports. An added fixed beam precision guidance system is integrated into the MLS time sequence format. The fixed beam guidance system is based upon the concept of using paired fixed overlapping beams, sequentially radiated by different fixed antennas (80 and 81), oriented to left and right of a prescribed guidance path. The paired beams overlap at the prescribed guidance path in such a manner that an aircraft departing or making a missed approach on such path will intercept equal signal intensities to indicate an on-course condition.

Abstract: In a single-frequency precision guidance landing system, the use of a DME interrogator in the aircraft and a DME receiver at the ground installation, each tuned to the same DME channel frequency, to uniquely interrogate a selected ground station and hence identify it by virtue of its replies being synchronous in the aircraft with the interrogations, the interrogations and the replies also being used to obtain range to the ground installation. This technique uses airborne already-installed DME interrogators for selective interrogation of a desired landing installation, thereby to eliminate any need to add additional special purpose equipment to the aircraft to accomplish the desired uniqueness of interrogation and ground installation identification achieved by this invention.

Abstract: The invention provides independent guidance and monitoring to be integrated into an MLS landing system and also provides a scaled-down MLS landing guidance system useable at small airports. In both cases an added fixed beam precision guidance system is integrated into the MLS time sequence format. The fixed beam guidance system is based upon the concept of using paired fixed overlapping beams, sequentially radiated by different fixed antennas. One pair is oriented to left and right of the centerline of the runway, and the other pair is oriented above and below the desired glideslope. The first set of paired beams overlap at the centerline of the runway in such a manner that an aircraft approaching exactly on centerline will intercept equal signal intensities to indicate an on-course approach.

Abstract: The instant invention permits a communication function to be performed by utilizing the transmitter/receiver portion of existing navigational equipment such as, for example, DME equipment, TACAN/DME equipment, and VOR/DME equipment. Rather than utilizing the same channel as the navigation function, the communication function utilizes another of the equipment's channels specifically assigned for communication purposes. Specifically, when it is desired to communicate with a communication or master station, the airborne or remote navigational equipment is momentarily turned from the navigational frequency channel to the frequency channel specifically assigned for the communication function. While momentarily tuned to the communication channel, it sends data to, and receives data from, the communication station. Having completed the communication process, the airborne or remote unit tunes back to the navigational channel and resumes its navigational function.

Abstract: An independent landing monitoring system (ILM) for guiding airborne vehicles on final approach to a landing using a ground-based beacon which transmits a sequence of pulse signals including an omnidirectional signal coded to identify its location and used for initial approach, followed by time spaced directionally radiated right/left and up/down signals used for precision guidance along the final approach path. The time spacing of the various beacon signals and their order of succession in the sequence identify the signals, and the relative intensities of paired precision guidance signals as received by the aircraft is used to provide precision indications of the location of the aircraft on the path. The beacon can be either triggered by the weather radar in the aircraft which then receives the beacon signals on its beacon mode receiver, and/or it can be triggered randomly by a noise jittered oscillator in the beacon for use by approaching aircraft equipped only with a beacon receiver but no weather radar.

Abstract: A weather radar calibration system, wherein one or more radar reflectors are located at a known position adjacent to an airport runway. Each of the reflectors are shaped to direct reflective patterns of known radar cross-section in response to radar signals transmitted from an aircraft following a known guidance path to the airport. The aircraft radar detects the radar return signals from the reflectors. Circuitry is responsive thereto for utilizing the radar returns for calibrating the weather radar for precipitation measurement and display purposes. The design of the reflectors is such as to minimize multipath reflections off the ground and prevent them from disturbing the reflective properties for aircraft following the guidance path.

Abstract: An antenna system having a central radiator element and one or more surrounding rings of parasitic elements which can be tuned or actuated separately in each ring by electrical commutation to provide a stepped cardioid radiation or receiving pattern. When the radiator element and a ring of parasitics are used to transmit a cardioid, its stepped pattern contains a fundamental sinusoidal component which can be extracted by a filter at a receiver and used to provide a TACAN/VORTAC bearing determination by comparing its phase with a reference signal transmitted once per revolution of the pattern to mark a predetermined position in its rotation, as is common in TACAN systems. When the cardioid pattern comprises transmitted squitter pulses, care is taken to ensure actual transmissions marking each stepping of the antenna pattern in order to provide optimum bearing information.

Abstract: The invention provides independent guidance and monitoring to be integrated into an MLS landing system and also provides a scaled-down MLS landing guidance system useable at small airports. In both cases an added fixed beam precision guidance system is integrated into the MLS time sequence format. The fixed beam guidance system is based upon the concept of using paired fixed overlapping beams, sequentially radiated by different fixed antennas. One pair is oriented to left and right of the centerline of the runway, and the other pair is oriented above and below the desired glideslope. The first set of paired beams overlap at the centerline of the runway in such a manner that an aircraft approaching exactly on centerline will intercept equal signal intensities to indicate an on-course approach.