FMCW Radar Ramp Sequences for Unambiguous Range and Velocity
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Solution Overview
Problem
Existing FMCW radar systems face challenges in unambiguously determining both the range and velocity of targets due to complex circuitry requirements and high power consumption, often necessitating the use of I/Q demodulators and multiple mixers.
Innovation Solution
The system employs a frequency modulated continuous wave (FMCW) radar system with a series of consecutive ramps, where each ramp covers a fraction of the frequency range, allowing for range and velocity determination using a single mixer without an I/Q demodulator, reducing circuit complexity and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If I/Q demodulators and multiple mixers are used to determine range and velocity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the I/Q demodulator from the radar signal processing chain by using a single mixer architecture. The frequency shifted ramps provide sufficient information to determine both range and velocity without requiring the complex I/Q demodulation process, thereby removing unnecessary circuitry while maintaining measurement capabilities.
Solution Approach 2:
The patent applies frequency shifting to the ramps, where each ramp is offset by a frequency shift relative to the previous ramp. This parameter change in the transmitted signal structure enables the system to extract both range and velocity information from a single mixer output, replacing the need for multiple mixers and I/Q demodulators.
2Measurement precision
If I/Q demodulators and multiple mixers are used, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent removes the I/Q demodulator and reduces the number of mixers from multiple to a single mixer, directly reducing the power-consuming components in the signal processing chain. This extraction of unnecessary components achieves both complexity reduction and power consumption reduction while maintaining measurement precision.
Solution Approach 2:
By changing the frequency parameter of the ramps (applying frequency shifts), the system enables single-mixer operation that can extract both range and velocity information. This parameter modification allows the system to achieve full measurement capability with fewer active components, thereby reducing overall power consumption.
3Device complexity
If frequency shifted ramps are used, then device complexity is reduced, but measurement precision may be affected
Solution Approach 1:
The patent carefully designs the frequency shift parameter applied to each ramp to ensure that the modified signal structure still contains sufficient information for precise range and velocity determination. The frequency shift is chosen to create distinguishable signal characteristics that enable accurate measurement while simplifying the overall system architecture.
Solution Approach 2:
The patent replaces the mechanical/physical complexity of multiple mixers and I/Q demodulators with a signal processing approach using frequency shifted ramps and a single mixer. This substitution moves the complexity from hardware architecture to signal processing algorithms, achieving simpler circuitry while maintaining measurement precision through mathematical processing of the frequency-shifted signals.
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 simplifies the radar system circuitry, reduces power consumption, and provides performance and cost benefits by enabling unambiguous range and velocity measurements while eliminating the need for I/Q demodulators and additional mixers.
Implementation Method 1
radar is a system that uses electromagnetic waves to identity the range, direction, and/or velocity of both moving objects and stationary targets
Implementation Method 2
radar systems include a radar transmitter that transmits electromagnetic waves, such as radio waves, which are scattered or reflected by a target
Implementation Method 3
frequency modulated continuous wave (FMCW) radar systems
Implementation Method 4
a second ramp in the period is transmitted over a second portion of the frequency range that differs from the first portion. The second ramp is offset by a frequency shift relative to the first ramp
Data Source
AI summary
One embodiment of the present invention relates to a method for detecting a range and velocity of a target. In this method, an electromagnetic wave is transmitted over a frequency range, where a period of the wave comprises a number of consecutive ramps. A first ramp in the period is transmitted over a first portion of the frequency range, and a second ramp in the period is transmitted over a second portion of the frequency range that differs from the first portion. The second ramp is offset by a frequency shift relative to the first ramp. A scattered wave is received from the target and processed to determine the range and the velocity of the target. Other methods and systems are also disclosed.