Active-Antenna Radar Imaging for Rapid Wide-Angle Refresh
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Solution Overview
Problem
Existing radar systems face challenges in producing an instantaneous image of a wide angular scene with high resolution while minimizing digital processing requirements, particularly when the carrier is moving or the scene is changing rapidly, and they often require complex computations or high power transmission.
Innovation Solution
A radar imaging method using an active antenna with N transmission and M reception channels that transmits in bursts, sequentially focusing on De pointing directions during a detection time unit, allowing for digital beam-forming and oversampling to enhance angular resolution and reduce computational load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mechanical or electronic scanning with a narrow beam is used to scan the field of observation, then angular resolution is improved, but the cycle time required to refresh the information increases
Solution Approach 1:
The field of observation is divided into multiple discrete angular positions that are scanned sequentially. Instead of continuously scanning the entire field, the radar divides the angular range into a finite number of positions and cycles through them, allowing for rapid refresh while maintaining fine angular discrimination at each position.
Solution Approach 2:
The radar implements periodic scanning cycles through the discrete angular positions. By repeatedly cycling through the same set of angular positions in a periodic manner, the system achieves rapid information refresh while maintaining high angular resolution at each position, avoiding the need for continuous slow scanning.
2Productivity
If beam forming by computation with a single wide-field antenna is used, then instantaneous observation of the angular range is achieved, but angular discrimination deteriorates
Solution Approach 1:
The wide-field antenna beam is effectively segmented into multiple discrete directional beams by electronically steering the beam to specific angular positions. This segmentation allows the system to maintain the instantaneous observation capability of a wide beam while achieving the angular discrimination of narrow beams at each discrete position.
Solution Approach 2:
The radar uses dynamic electronic beam steering to change the beam direction from pulse to pulse or recurrence to recurrence. This dynamic beam steering allows the single wide-field antenna to achieve narrow beam angular discrimination by rapidly switching between different beam directions, maintaining instantaneous observation capability.
3Productivity
If beam forming by computation with a single wide-field antenna is used, then instantaneous observation is achieved, but transmission power requirements increase
Solution Approach 1:
The transmission energy is segmented and concentrated into discrete angular directions rather than being spread uniformly across the entire wide field. By focusing energy into narrow beams at specific angular positions, the system achieves instantaneous observation of the angular range while reducing the total transmission power required compared to illuminating the entire field with a wide beam.
Solution Approach 2:
Instead of providing uniform illumination across the entire angular range, the system provides concentrated energy locally at specific angular positions through electronic beam steering. This local quality approach allows instantaneous observation capability while reducing overall power requirements by avoiding energy waste in regions where no targets are present.
4Power
If MIMO radar with multiple transmission channels is used, then individual transmission power can be reduced, but computation volume increases
Solution Approach 1:
The MIMO system segments the transmission across multiple channels, with each channel transmitting at lower power. The patent applies this by using multiple transmission channels that are sequentially focused in different pointing directions, reducing individual power requirements while managing computation through structured scanning patterns.
Solution Approach 2:
The system uses dynamic electronic steering to focus each transmission channel in different directions over time. This dynamic focusing reduces the need for complex simultaneous processing of all MIMO channels, as the system cycles through different pointing directions in a structured manner, reducing computation volume while maintaining low individual transmission power.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid, high-resolution imaging of a wide angular scene with reduced computational demands and improved detection of scene boundaries, even in dynamic conditions.
Implementation Method 1
A radar imaging method using an active antenna with N transmission channels and M reception channels, transmitting in bursts
Implementation Method 2
allowing for digital beam-forming and oversampling to enhance angular resolution
Data Source
AI summary
A radar imaging method using an active antenna comprising N transmission channels and M reception channels, transmitting in bursts of pointing cycles, is disclosed. The antenna covers a given angular range during a detection time unit of duration T, said time unit corresponds to a burst in which the N transmission channels are focused successively in a number De of pointing directions (di) such that:the pointing direction on transmission (di) is modified from recurrence to recurrence;each time unit of duration T comprising a periodic repetition of a number C of identical pointing cycles, each of these cycles comprising a number P of recurrences, the set of these P recurrences covers the De pointing directions (di);at least one beam is formed in reception on each recurrence in a direction included in the angular range focused on transmission in the pointing direction corresponding to said recurrence.