Sinusoidal Signal Distance Measurement for Vehicle Access
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Solution Overview
Problem
Current hands-free access and starting systems for vehicles require high energy consumption and power to determine the distance between a vehicle and an identifier using IR-UWB technology, which affects the autonomy of the identifier due to the need for transmitting pulses and receiving weak signals in noise.
Innovation Solution
A method that synchronizes the vehicle and identifier, transmitting a train of sinusoidal signals with varying frequencies, measuring phases and amplitudes, and performing an inverse Fourier transform to calculate distance without pulse transmission, utilizing existing Bluetooth technology for efficient distance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If IR-UWB pulse transmission method is used to determine distance, then distance measurement capability is achieved, but energy consumption increases and identifier autonomy decreases
Solution Approach 1:
The patent uses periodic sinusoidal signal transmission at multiple frequencies instead of continuous pulse transmission. The identifier transmits sinusoidal signals periodically at frequencies f1, f2, ..., fN, allowing distance measurement through phase difference analysis while significantly reducing peak power requirements and energy consumption compared to continuous pulse methods
Solution Approach 2:
The patent changes the transmission parameter from pulse width modulation to frequency-modulated sinusoidal signals. By transmitting signals at multiple discrete frequencies and analyzing phase differences, the system achieves accurate distance measurement without the high energy consumption of traditional pulse-based IR-UWB methods
2Reliability
If high power pulses are transmitted for distance measurement, then signal detection capability is improved, but identifier autonomy is reduced
Solution Approach 1:
The system uses periodic sinusoidal transmission instead of continuous high-power pulses. The identifier can transmit signals continuously at low power levels, maintaining battery autonomy while still enabling reliable signal detection through phase difference measurement over time
Solution Approach 2:
The patent replaces the mechanical pulse transmission system with an electromagnetic sinusoidal signal system. By using frequency-modulated signals and phase difference analysis, the system achieves reliable detection without requiring high peak powers that would deplete the identifier's battery autonomy
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 method reduces energy consumption and power requirements, enhancing the autonomy of the identifier by providing accurate distance measurement for vehicle access and starting without the need for high-energy pulse transmission, thus improving the reliability and efficiency of hands-free systems.
Implementation Method 1
by way of measuring signal propagation time (or 'time-of-flight')
Implementation Method 2
the vehicle and the identifier being synchronized
Implementation Method 3
an inverse Fourier transform, making it possible to obtain a temporal signature
Data Source
AI summary
A method for measuring a distance separating a vehicle and an identifier is disclosed. The method includes transmitting, from the vehicle to the identifier, a first train of first sinusoidal signals, receiving, by the identifier, an image train of second sinusoidal signals corresponding to the first sinusoidal signals, generating, by the identifier, measurements of phases and amplitudes of the second sinusoidal signals that are altered from the first sinusoidal signals by transmission from the vehicle to the identifier, constructing a frequency spectrum based on the measurements and a second image train received by the vehicle from the identifier, where the frequency spectrum is constructed by detecting spectral lines of the first image train and the second image train, performing an inverse Fourier transform of the frequency spectrum to obtain a temporal signature, and calculating the distance on the basis of an intermediate time associated with a maximum of the temporal signature.