Method and device for separating echo signals of space-time waveform encoding synthetic aperture radar in elevation

A device for separating echo signals of Space-Time Waveform Encoding Synthetic Aperture Radar (STWE SAR) in elevation, comprising:

• a processor;
• and
• memory storing instructions for execution by the processor,
• wherein the processor is configured to:
• receive aliasing echo signals of a plurality of sub-swaths;
• for a target sub-swath of the plurality of sub-swaths, generate a plurality of sub-beams associated with the target sub-swath, the plurality of sub-beams pointing to different directions of the target sub-swath respectively, and a null of each of the plurality of sub-beams being used for deep nulling suppression on echo signals of sub-swaths except the target sub-swath;
• and
• process the aliasing echo signals based on the plurality of sub-beams and a plurality of nulls corresponding to the plurality of sub-beams to generate a target echo signal of the target sub-swath;
• wherein the processor is further configured to for each of the plurality of sub-beams, extract a partial echo signal of the target sub-swath from the aliasing echo signals by use of the sub-beam, perform deep nulling suppression on the echo signals of the sub-swaths except the target sub-swath by use of the null of the sub-beam, extract a plurality of partial echo signals of the target sub-swath from the aliasing echo signals by use of the plurality of sub-beams, filter the plurality of partial echo signals and synthesize the plurality of filtered partial echo signals to obtain the target echo signal of the target sub-swath.

The device of 9 10, wherein each sub-beam of the plurality of sub-beams corresponds to each null of the plurality of nulls, and an angle between two adjacent nulls of the plurality of nulls is

• Δϑ
• n
• ⁡
• (
• t
• )
• =
• ϑ
• n
• ⁡
• (
• t
• )
• M
• ,
• where ∂n (t) is a pulse downward viewing angle width of the sub-swaths except the target sub-swath, and M is a number of the plurality of sub-beams.

A non-transitory computer-readable storage medium having stored therein computer instructions that when executed by a processor, implement the steps of the method for separating echo signals of Space-Time Waveform Encoding Synthetic Aperture Radar (STWE SAR) in an elevation, wherein the method comprises:

• receiving aliasing echo signals of a plurality of sub-swaths;
• for a target sub-swath of the plurality of sub-swaths, generating a plurality of sub-beams associated with the target sub-swath, the plurality of sub-beams pointing to different directions of the target sub-swath respectively, and a null of each of the plurality of sub-beams being used for deep nulling suppression on echo signals of sub-swaths except the target sub-swath;
• and
• processing the aliasing echo signals based on the plurality of sub-beams and a plurality of nulls corresponding to the plurality of sub-beams to generate a target echo signal of the target sub-swath;
• wherein processing the aliasing echo signals based on the plurality of sub-beams and the plurality of nulls corresponding to the plurality of sub-beams to generate the target echo signal of the target sub-swath comprises:
• for each of the plurality of sub-beams, extracting a partial echo signal of the target sub-swath from the aliasing echo signals by use of the sub-beam, and performing deep nulling suppression on the echo signals of the sub-swaths except the target sub-swath by use of the null of the sub-beam;
• extracting a plurality of partial echo signals of the target sub-swath from the aliasing echo signals by use of the plurality of sub-beams;
• and
• filtering the plurality of partial echo signals, and synthesizing the plurality of filtered partial echo signals to obtain the target echo signal of the target sub-swath.