FanTOM Chirp MIMO Radar for Angular Resolution
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Solution Overview
Problem
Conventional radar systems face challenges in constructing larger MIMO arrays due to limitations in time-division multiplexing techniques, which result in reduced angular resolution and increased complexity, cost, and difficulty in distinguishing between Linear Frequency Modulation (LFM) waveforms from different transmitters.
Innovation Solution
The implementation of a frequency and time offset modulation (FanTOM) approach, where distinct chirp signals are transmitted with overlapping pulses and separated in the range spectrum domain, allowing for a larger MIMO virtual array construction without the need for prolonged frame durations or increased complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time-division multiplexing techniques are used to separate LFM waveforms from different transmitters, then signals from distinct transmitters can be separated at each receiving channel, but the system is confined to using a small number of transmitters resulting in a relatively small MIMO virtual array
Solution Approach 1:
The patent applies parameter changes by modulating the frequency and time offsets of chirp signals transmitted by different transmitters. Specifically, each transmitter uses a distinct frequency offset and time offset for its chirp signals, allowing the receiving channels to separate and identify signals from different transmitters based on these parameter differences. This enables construction of large MIMO virtual arrays with many transmitters without requiring complex time-division multiplexing schedules, thereby improving angular resolution while managing system complexity.
2Measurement precision
If a larger number of transmitters are used to construct a larger MIMO virtual array, then improved angular resolution is achieved, but it becomes extremely difficult to distinguish between LFM waveforms transmitted by different transmit antennas
Solution Approach 1:
The patent applies local quality by giving each transmitter a unique local characteristic through distinct frequency and time offset parameters. Each transmitter's chirp signals are locally differentiated by their specific frequency offset and time offset values, enabling receiving channels to easily distinguish and separate signals from different transmitters. This local differentiation through parameter modulation allows large MIMO virtual arrays to be constructed without the waveform discrimination difficulties that plague conventional systems.
3Measurement precision
If time-division multiplexing is used to separate transmitters in time, then signal separation is achieved, but the frame duration is prolonged resulting in reduced frame update rates and increased range migration
Solution Approach 1:
The patent applies periodic action by using regular, structured frequency and time offset patterns across multiple transmitters. Each transmitter operates periodically with its assigned frequency and time offsets, creating a predictable signal structure that receiving channels can efficiently process. This periodic parameter modulation allows all transmitters to operate simultaneously or with minimal time separation while maintaining clear signal identification, thereby reducing frame duration and increasing frame update rates without sacrificing signal separation capability.
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
This approach enables the construction of larger MIMO arrays with improved angular resolution and reduced complexity, maintaining orthogonality and unambiguous Doppler performance, while allowing for faster frame update rates and reduced range migration.
Implementation Method 1
77 GHz Frequency Modulation Continuous Wave (FMCW) Fast Chirp Modulation (FCM) radars are used with MIMO arrays as sensors
Implementation Method 2
Frequency and time offset modulation chirp MIMO radar
Implementation Method 3
Radar systems are used to detect the range, velocity, and angle of nearby targets
Data Source
AI summary
A radar system utilizing a linear chirp that can achieve a larger MIMO virtual array than traditional systems is provided. Transmit channels transmit distinct chirp signals in an overlapped fashion such that the pulse repetition interval is kept short and the frame is kept short. This alleviates range migration and aids in achieving a high frame update rate. The chirp signals from differing transmitters can be separated on receive in the range spectrum domain, such that a MIMO virtual array construction is possible. Distinct chirps are delayed versions of the first chirp signal. Chirps overlap in the fast-time domain, but due to delay, there is separation in the range spectrum domain. When the delay is at least the instrument round-trip delay, transmitters are separable. Further, the wavelengths are identical across transmitters such that there is no residual-range versus angle ambiguity issue present in the claimed frequency-offset modulation range division MIMO system.