A system includes a first-in first-out (FIFO) module, a polling module, a data extraction module, and a control module. The FIFO module receives records having dynamic frequency selection (DFS) information generated based on pulses received and generates a control signal for every N of the records received, where N is an integer greater than or equal to 1. The polling module selectively polls the FIFO module and reads M of the records received by the FIFO module, where M is an integer greater than or equal to 1 and less than N. The data extraction module extracts the DFS information from the N records when the control signal is received and selectively extracts the DFS information from the M records. The control module determines whether the pulses are a type of radar based on the DFS information extracted from at least N of the (N+M) of the records.

Systems and methods for detecting radar

A method may include generating for transmission a repeating sequence of N constant-frequency pulses of width t seconds at interpulse intervals of T seconds, with each pulse in the sequence having a particular constant phase according to a quadratic phase sequence, which phase is applied to each pulse in a first sense of modulation. The method may further include modulating the phase of echo energy received from one or more objects reflecting the transmitted repeating sequence of N constant-frequency pulses with a second sense of modulation opposite to the first sense of modulation. The method may further include producing from the modulated received echo energy N unique and discrete frequency translations of the received echo energy as a function of range r of the reflecting objects, of magnitude equal to multiples of 1/NT Hz, which may preserve the spectrum of the received echo energy, forming in combination a composite signal frequency spectrum.

Radar operation with increased doppler capability

A method for extension of unambiguous range and velocity of a weather radar. To avoid pulse overlaying, the pulse repetition time of a single pulse can be extended such that any return echo will arrive at the radar before the next pulse is transmitted. When pulse repetition time is increased, the maximum unambiguous range increases while the maximum unambiguous velocity decreases. The pulse overlaying can be avoided if consecutive pulses are sent on different frequencies that are far enough from each other to allow separation of pulses arriving simultaneously at the radar. When different frequencies are used an unknown phase difference is generated by distributed atmospheric targets to the return signals. This normally prevents use of the shorter pulse repetition time for velocity calculation.

Method for extension of unambiguous range and velocity of a weather radar

A method and system for SNR enhancement in pulse-Doppler coherent target detection. In accordance with the method of the invention, complex signals are obtained for each of two or more sub-intervals of the time-on-target interval, allowing simultaneous rang and Doppler measurements. A coherent integration is then performed on the signals to generate complex-valued folded matrices. The folded matrices are unfolded and target detection is then performed in a process involving one or more of the unfolded matrices. A pulse-Doppler coherent system is also provided configured for target detection by the method of the invention.

Pulse doppler coherent method and system for snr enhancement

A method and system for SNR enhancement in pulse-Doppler coherent target detection for applications in the fields of radar and ultrasound. In accordance with the method of the invention, complex signals are obtained for each of two or more sub-intervals of the time-on-target interval, allowing simultaneous range and Doppler measurements. A coherent integration is the performed on the signals to generate complex-valued folded matrices. The folded matrices are unfolded and target detection is then performed in a process involving one or more of the unfolded matrices. A pulse-Doppler coherent system is also provided configured for target detection by the method of the invention.

Pulse doppler coherent radar or ultrasound detection method and system for SNR enhancement

A radar is arranged to transmit electromagnetic energy in pulse repetition intervals and to receive reflections or echoes from objects in range gates intended for the purpose, which range gates are provided with Doppler filters. The radar is arranged to approve ambiguous echoes that are desirable and to suppress ambiguous echoes that are of no interest or that interfere with the display function of the radar. The radar works with a frequency that varies according to a staggered or wobbling pattern. The respective ambiguous echoes produce only one pulse in the respective range gates concerned, within a predetermined number of periods. The respective Doppler filter concerned is arranged to work with an impulse function response that only consists of a small number of samples. The Doppler filter is also arranged, during the predetermined number of periods, to give rise to a number of independent samples from reflectors within the radar's unambiguous range. When the sad independent samples exceed the small number of samples, the radar approves the ambiguous echo. Otherwise, it is suppressed. In this way, ambiguous echoes are prevented from interfering with the reception or display of the echoes on the display screen. The suppression of asynchronous interferences, for example pulses from other radar stations, can also be made easier in a simple way.

Bergkvist Bengt

Papers

Apparatus for radar