Abstract: A slotted waveguide radiator for an antenna array is arranged to receive microwave energy inputs at either end for producing separate radiated beams and has loading slots having predetermined center-to-center spacings in the longitudinal dimension to provide a predetermined squint angle for each radiated beam which is related to the direction in which energy is fed to the waveguide. The radiator includes means for providing a linear phase shift progression in the signal components radiated from the slots from one end of the waveguide to the other to thereby provide an angular tilt to each radiated beam which is independent of the direction in which energy is fed to the waveguide.

Abstract: Radio frequency energy is rapidly switched from a transmitter in a repeating sequence of bursts of radio frequency energy to the different ones of a plurality of radiation beam ports, and the individual bursts of radio frequency energy are modulated in a predetermined program to provide a composite beam energy profile which is a synthesized directional beam which moves at a predetermined desired scanning rate. The energy levels of the successive individual bursts of raido frequency energy from each radiation beam port produces a composite energy profile from that port which is representative of the impulse response function of a low pass filter.

Abstract: High accuracy guidance signals are produced over a wide angle by sequencing in a predetermined sequence through a series of narrow angular sectors while electrically scanning the transmitted signals within each sector.

Abstract: Radio frequency energy is rapidly switched from a transmitter in a repeating sequence of bursts of radio frequency energy to the different ones of a plurality of radiation beam ports, and the individual bursts of radio frequency energy are modulated in a predetermined program to provide a composite beam energy profile which is a synthesized directional beam which moves at a predetermined desired scanning rate.

Abstract: Where a signal reflective fixed obstruction is present in a subsector of a navigation angle sector in which guidance is required, scanning beams are employed including a main scan which is scanned over most of the navigation angle sector and an auxiliary scan which is scanned only over the obstruction subsector. The scan signals are received and correlated by the aircraft to distinguish obstruction subsector signals to thereby avoid reflection interference.

Abstract: Two carriers are gated on and off in an alternating sequence. The same group of different digital sample point values signifying various modulation levels required for each carrier at successive points in time are read out in timed sequence and applied to modify each of the carrier waves by one sample point value during each period when a carrier wave is gated on to thus modify the carriers in a manner recognized by a receiver as modulation.

Abstract: The system includes a passive station dedicated to the control and acquisition of data of an electronic apparatus and arranged for communication with a central station over a non-dedicated voice band-width communication link with connections being established from the central station. The passive station includes means to initiate a call-out operation under alarm conditions, but the communication is limited to the establishment of the connection and the transmission of a ready signal to the central station inviting the central station to issue a command to the passive station to transmit information.

Abstract: In a directional microwave signal radiation system, low angle radiation problems are dealt with by inserting a combined diffraction edge and radiation screen in the lower portion of the radiation field to provide a diffraction pattern of radiation at low and negative radiation angles beyond the diffraction edge.

Abstract: Microwave carrier frequency energy is switched from one beam to another to provide a switched scanning beam for the glide slope function for an instrument landing system. The beams comprise a plurality of upper beams of uniform angular width in elevation and having a uniform angular center-to-center beam spacing in elevation, together with a class of lower beams consisting of at least one beam with each beam of said lower beams having a reduced angular width in elevation and a reduced spacing beneath the center line of the next higher beam which is proportional to the reduced beam width, the peak energy radiated at the center line of each lower beam being inversely proportional to the peak energy radiated in each of said upper beams as a function of the respective beamwidths.

Abstract: An input signal is sampled and stored at a first clock interval, and then the stored sample is compared with the input signal at a second clock interval to determine whether the two are the same in order to confirm that the signal is a true signal rather than transient noise.

Abstract: A multiple element antenna array provides a separate beam of carrier signal from each element in a pattern of beams spaced at different angles above the horizon. The array is adjusted upwardly to avoid obstructions on the horizon, and a program of modulation is applied to the separate beams to define the desired glide slope path while compensating for the mechanical upward adjustment of the array.

Abstract: The antenna array preferably consists of a plurality of slotted wave guide microwave signal radiating elements positioned to directly radiate separate beams of microwave energy at different azimuth angles to a common horizontally aligned cylinder sector reflector, the radiating elements being operable to primarily determine the direction and shape of the resultant reflected beams in azimuth and the reflector being operable to primarily determine the elevation patterns of the resultant reflected beams.

Abstract: Radio guidance signals comprising a carrier having modulation patterns defining a predetermined guidance path plane for a craft to be guided are transmitted, preferably in a scanning beam, from a ground station. A separate standard frequency signal is also transmitted from the ground station which has a predetermined difference in frequency from the guidance signal carrier frequency, the standard frequency being employed to control a local oscillator at the receiver.