Passive radar system and method of detection of low-profile low altitude targets based on application of Low Earth Orbit (LEO) and Very Low Earth Orbit (VLEO) satellites signals. Staring array of directional antennas cover entire sky and provide continuous illumination (receiving reflected satellite signals) from multiple targets for fast detection, recognition and targets tracking and increasing detection range. Coupling of each directional antenna with separate receiver cannel allows fast continuous process of information from all targets simultaneously. Monopulse processing of signals from reference sub-set of antennas with overlap antenna patterns provides highest directing accuracy and better clutter/noise and media influence suppression. Directional antenna array does not need beam forming module. System has small weight, size, may be portable or mounted on light vehicle or small drone because small size and weight.

A radar apparatus with a transmission antenna array that outputs a high aspect ratio frequency modulation continuous wave (FMCW) transmission beam that illuminates a large field of regard in elevation and may be both electronically and mechanically scanned in azimuth. The weather radar apparatus includes a receive array and receive electronics that may receive the reflected return radar signals and digitally form a plurality of receive beams that may be used to determine characteristics of the area in the field of regard. The receive beams may be used to determine reflectivity of weather systems and provide a coherent weather picture. The weather radar apparatus may simultaneously process the receive signals into monopulse beams that may be used for accurate navigation as well as collision avoidance.

In some examples, a system includes a radar device configured to transmit first X-band radar signals in a weather mode and receive first return X-band radar signals in the weather mode. In some examples, the radar device is further configured to transmit second X-band radar signals in a landing mode and receive second return X-band radar signals in the landing mode. In some examples, the system also includes processing circuitry configured to detect, in the weather mode, weather formations based on the first return X-band radar signals. In some examples, the processing circuitry is further configured to determine, in the landing mode, a position of a transponder based on the second return X-band radar signals received by the radar device and determine a location of a runway based on the position of the transponder.

A hazardous fire detection radar system that may be mounted on a vehicle, such as aan aircraft to detect bullets, grenades and similar projectiles that may pose a danger to the vehicle. The system may observe a wide field-of-regard (FOR) and for each projectile, determine the range of closest approach to the host platform (miss distance) and an approximate direction of origin. The FMCW radar system measures range and Doppler information for targets within its FOR and resolves Doppler ambiguity by estimating angular information (azimuth and elevation) for each target projectile. The system may estimate angular information by using a monopulse antenna pattern with the radar receiver.

A weather radar with a transmission antenna array that outputs a high aspect ratio FMCW transmission beam that illuminates an area in the field of regard in elevation and may be electronically scanned in azimuth. The weather radar includes a receive array and receive electronics that may receive the reflected return radar signals and electronically form a plurality of receive beams that may be used to determine characteristics of the area in the field of regard. The receive beams may be used to determine reflectivity of weather systems and provide a coherent weather picture. The weather radar may simultaneously process the receive signals into monopulse beams that may be used for accurate navigation as well as detection and tracking of objects, such as birds, aircraft, UAVs and the like.

Monopulse radar apparatus is disclosed. The apparatus comprises a digital processor and an antenna having a plurality of receive channels through which signals received by the antenna are passed to the processor. Each receive channel includes an analogue to digital converter, and the processor is arranged to calculate sum and difference signals from the signals received through each receive channel. The processor is also arranged such that, in the event that a malfunction is detected in one of the plurality of receive channels, compensated sum and difference signals are calculated by the processor using the signals from the remaining, functioning receive channels.

A method is provided for operating a monopulse active electronically scanned array (AESA) radar system on an aircraft. This system includes multiple emitter elements each with corresponding radio frequency (RF) channels including beamforming integrated circuits (BFICs). The method includes defining multiple modes, with each mode defining an effective aperture by specifying a different plurality of the emitter elements, and determining a preferred state of the AESA system based on a flight phase or environment of the aircraft. One of the plurality of modes is identified as corresponding to the preferred state, and beam steering is calibrated via a beam steering controller (BCM) to produce sum, azimuth difference, and elevation difference beams under the constraint of illuminating all of and only the plurality of the emitter elements corresponding to the selected one of the plurality of modes. BFICs of the emitter elements are then energized according to this calibrated beam steering.

A monopulse active electronically scanned array (AESA) system includes a phased array of RF channels each having an associated emitter element. A method of operating this system includes identifying a desired nulling location, and computationally optimizing theoretical aperture patterns for the AESA system to align geographically coincident nulls of multiple beams of the AESA system with the desired nulling location, the theoretical aperture patterns including nominal values of gain and a time-based parameter (e.g., phase or time delay) for each of the RF channels. Actual values of the gain and time-based parameter for each RF channel corresponding to these nominal values are calibrated by iteratively bisecting gain and time-based parameter tables, respectively, through successively narrower rangers converging on nominal values. The RF channels are then driven according to these calibrated actual time-based parameter and gain values.

A passive radar system and method of detection of low-profile low altitude targets based on the application of Low Earth Orbit (LEO) and Very Low Earth Orbit (VLEO) satellite signals. The staring array of directional antennas covers the entire sky and provides continuous illumination (receiving reflected satellite signals) from multiple targets for fast detection, recognition, and target tracking and increasing detection range. The coupling of each directional antenna with a separate receiver channel allows the fast continuous process of information from all targets simultaneously. Monopulse processing of signals from reference sub-set of antennas with overlap antenna patterns provides the highest directing accuracy and better clutter/noise and media influence suppression. A directional antenna array does not need a beam-forming module. The system has a small weight, and size may be portable or mounted on a light vehicle or small drone because small size and weight.