Impulse Correlation Distance Measurement Using Template Signals

The patent replaces the traditional envelope detection method with a correlation-based detection method. Instead of using simple envelope detection, the system generates template signals that match the expected reflected signal waveform and calculates correlation values between the received signal and template signals. This substitution of detection methodology significantly improves the signal-to-noise ratio by leveraging the correlation property to distinguish actual reflected signals from noise, enabling accurate detection of distant objects while maintaining operational simplicity through automated correlation calculation.

The patent changes the fundamental parameter from using high-bit DTC codes to using correlation values derived from template signal matching. Instead of relying on increasing the number of DTC bits to achieve fine time resolution, the system generates multiple template signals with different time delays and calculates correlation values. The time of flight is determined by finding which template signal produces the maximum correlation, thereby achieving high measurement resolution without requiring a large number of DTC bits, thus reducing device complexity and processing requirements.

The patent applies preliminary action by pre-generating template signals with specific time delays corresponding to expected ranges before actual distance measurement begins. These template signals are prepared in advance with known waveforms and delay characteristics. During measurement, the system only needs to calculate correlation values between the received signal and the pre-prepared template signals, rather than generating and processing all possible signal variations in real-time. This preliminary preparation of template signals significantly reduces the computational load and processing time while maintaining high time measurement resolution.