A method and system for removing ground clutter data from time series data are provided. The method comprises receiving first time series data, dividing the first time series data into a plurality of subsets of first time series data, applying a first regression filter to each respective subset first time series data of the plurality of subsets of first time series data to generate a plurality of regression filtered subsets of first time series data, and concatenating the plurality of regression filtered subsets of first time series data to generate a regression filtered first time series data.

A method for confusing the electronic signature of a signal transmitted by a radar, includes the generation by the radar of at least one pulse, wherein the method comprises a step of modulation, in the pulse, of the polarization of the transmitted signal, according to two orthogonal or opposite polarizations, the modulation of the polarization being performed according to a predetermined modulation code.

The present disclosure relates to position, navigation and timing (PNT) methods, systems, and transmitters. A method comprises receiving radio-frequency (RF) signals from a plurality of virtual transmitters and determining PNT information of a target object based on information obtained from the RF signals. A system comprises a plurality of virtual transmitters and a receiver. The plurality of virtual transmitters is configured to transmit radio-frequency (RF) signals that include PNT information. The receiver is configured to determine PNT information of a target object based on the PNT information. A transmitter comprises a high-frequency (HF) carrier generator, a waveform generator, and an antenna system. The HF carrier generator generates an HF carrier signal. The waveform generator generates a waveform that includes PNT information. The antenna system transmits the HF carrier signal to generate a subject ionospheric duct. The antenna system is further configured to transmit the waveform through the ionospheric duct.

The present disclosure relates to position, navigation and timing (PNT) methods, systems, and transmitters. A method comprises receiving radio-frequency (RF) signals from a plurality of virtual transmitters and determining PNT information of a target object based on information obtained from the RF signals. A system comprises a plurality of virtual transmitters and a receiver. The plurality of virtual transmitters is configured to transmit radio-frequency (RF) signals that include PNT information. The receiver is configured to determine PNT information of a target object based on the PNT information. A transmitter comprises a high-frequency (HF) carrier generator, a waveform generator, and an antenna system. The HF carrier generator generates an HF carrier signal. The waveform generator generates a waveform that includes PNT information. The antenna system transmits the HF carrier signal to generate a subject ionospheric duct. The antenna system is further configured to transmit the waveform through the ionospheric duct.

Radar signals are generated to have signal characteristics that define multiple sub-pulses in each of a plurality of pulse repetition intervals (PRIs) of a single radar dwell. Electromagnetic radiation is emitted according to the radar signals and the emitted electromagnetic radiation is sensed as radar return signals over a receive interval in each PRI. Coherent integration is performed on a set of the radar return signals and non-coherent integration is performed on another set of the radar return signals.

Radar signals are generated to have signal characteristics that define multiple sub-pulses in each of a plurality of pulse repetition intervals (PRIs) of a single radar dwell. Electromagnetic radiation is emitted according to the radar signals and the emitted electromagnetic radiation is sensed as radar return signals over a receive interval in each PRI. Coherent integration is performed on a set of the radar return signals and non-coherent integration is performed on another set of the radar return signals.

The echoes being picked up in the distance-speed domain, the method being wherein it includes a step of producing a mask, in the distance-speed plane, overlying the zone of detection of the ground and/or sea clutter echoes picked up by the sidelobes, the zone being determinable by the antenna parameters of the radar, the waveform emitted by the radar and the environmental context of the radar, all the points of the distance-speed plane which are covered by the mask being assigned a characteristic which is specific to the mask; a step of filtering the received echoes, in which the echoes covered by the mask are rejected from the radar reception processing.

The echoes being picked up in the distance-speed domain, the method being wherein it includes a step of producing a mask, in the distance-speed plane, overlying the zone of detection of the ground and/or sea clutter echoes picked up by the sidelobes, the zone being determinable by the antenna parameters of the radar, the waveform emitted by the radar and the environmental context of the radar, all the points of the distance-speed plane which are covered by the mask being assigned a characteristic which is specific to the mask; a step of filtering the received echoes, in which the echoes covered by the mask are rejected from the radar reception processing.

According to a first aspect, a pulsed radar comprises a transmitter; wherein the pulsed radar is arranged to generate a string of binary values; wherein the transmitter comprises a pulse generator arranged to generate a pulse signal comprising a series of transmit pulses with polarities determined in accordance with the string of binary values; wherein a first substring comprises a first series of values; wherein a second substring comprises a second series of values; wherein the second substring is different from the first substring; and wherein each value in the second series of values is either the same as or different from the corresponding value in the first series of values according to a repeating pattern; and wherein the string of binary values comprises at least the first substring and the second substring concatenated together and each optionally being reversed before concatenation.

According to a first aspect, a pulsed radar comprises a transmitter; wherein the pulsed radar is arranged to generate a string of binary values; wherein the transmitter comprises a pulse generator arranged to generate a pulse signal comprising a series of transmit pulses with polarities determined in accordance with the string of binary values; wherein a first substring comprises a first series of values; wherein a second substring comprises a second series of values; wherein the second substring is different from the first substring; and wherein each value in the second series of values is either the same as or different from the corresponding value in the first series of values according to a repeating pattern; and wherein the string of binary values comprises at least the first substring and the second substring concatenated together and each optionally being reversed before concatenation.