Cooperative FMCW Radar Waveforms for Low-Interference Multiplatform Operation
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Solution Overview
Problem
Current systems for combined radar and communications face challenges in providing simultaneous time transfer and position determination services without satellite-based positioning systems, and they suffer from interference issues when using the same RF spectrum across multiple platforms.
Innovation Solution
A combined radar/communications system utilizing a frequency-modulated continuous waveform (FMCW) that enables simultaneous radar and communications operations with a single waveform, allowing for time transfer and position determination using common antennas and power, and incorporates synchronization and demod/remod filtering to reduce interplatform interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard waveforms are used for simultaneous dispersed multiplatform FMCW radar, then radar operations can be performed on multiple platforms, but the interference between platforms becomes unacceptably high
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the chirp slope and time offset of FMCW waveforms on different platforms. Each platform operates with unique waveform parameters (different slopes and timing offsets) within the same RF band, transforming the constant interference problem into a manageable parameter variation problem that enables simultaneous operation without unacceptably high interference
Solution Approach 2:
The system implements dynamics by continuously adapting waveform parameters in real-time. Platforms dynamically adjust their chirp slopes and time offsets based on system coordination, allowing the radar network to maintain optimal performance while operating simultaneously on multiple platforms within the same RF spectrum
2Reliability
If separate time transfer and position determination hardware is used for operation during GPS outages, then time and position information can be determined without satellite-based positioning systems, but the device complexity increases
Solution Approach 1:
The patent merges time transfer and position determination functions into the existing FMCW radar system. The same radar hardware and waveform infrastructure used for distance measurement are also utilized for time synchronization and position determination, eliminating the need for separate dedicated hardware systems while maintaining reliability during GPS outages
Solution Approach 2:
The FMCW radar system is designed with multi-functionality, serving simultaneously as a radar for distance measurement, a time transfer system for synchronization, and a position determination system for location tracking. This universal approach allows a single system to perform multiple critical functions that would traditionally require separate dedicated hardware
3Object-affected harmful factors
If different radiofrequency bands are used for platforms within range of each other's sidelobe transmissions, then interference is reduced, but the loss of spectrum efficiency increases
Solution Approach 1:
Instead of allocating different RF bands to different platforms, the patent changes waveform parameters (chirp slope and time offset) within the same RF band. This parameter-based differentiation allows platforms to operate simultaneously in the same frequency spectrum while maintaining low interference levels, thereby preserving spectrum efficiency
Solution Approach 2:
The patent transitions from frequency-based interference management (different RF bands) to time-frequency parameter management (different chirp slopes and time offsets). By adding temporal and slope dimensions to the waveform design, the system achieves interference reduction without sacrificing spectrum efficiency, effectively moving the solution from a one-dimensional frequency approach to a multi-dimensional waveform parameter approach
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 efficient time transfer and position determination services at lower signal-to-noise levels, reduces interference between radar systems, and allows simultaneous FMCW operations across multiple platforms using the same RF spectrum, enhancing sensitivity and coverage.
Implementation Method 1
a frequency-modulated continuous waveform (FMCW) that enables simultaneous radar and communications operations
Implementation Method 2
radar systems transmit mutually orthogonal signals from multiple transmit antennas, and these waveforms are extracted from each of multiple receive antennas by a set of matched filters
Implementation Method 3
current weather radar systems are fundamentally constrained in sensitivity, resolution, and lower atmosphere coverage and lack the capability to trace and track the storm cells
Data Source
AI summary
A system and a method that enable two or more dispersed platforms to simultaneously use respective frequency-modulated continuous-wave radar systems in a typical radar application such as synthetic-aperture radar for terrain mapping, moving-target indicator radar to track targets on the ground and air-to-air tracking of other aircraft. The systems use the same RF spectrum in their operation and also communicate through their respective radar systems while simultaneously reducing their interplatform interference through the use of both filters and coded waveforms.