Microtransponder Signal Correlation for Low-Power Object Location
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Solution Overview
Problem
Existing object location systems face challenges in accurately determining the location of low-power transmitting sources due to signal corruption from noise, especially when the information signal is of the same order or smaller than the noise signal.
Innovation Solution
A system and method using a remote locator (RL) and a microtransponder (MT) that employs a powerful signal with a repeating sequence for identification, where the MT processes incoming signals to match an ID code and responds with a low-power acknowledgement, allowing for precise distance calculation using round-trip time-of-flight, and incorporates signal processing techniques like Fast Fourier Transform (FFT) to extract the information signal from noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a low-power transmitting source is used for object location, then power consumption is reduced and battery life is extended, but signal corruption from noise increases and detection becomes difficult
Solution Approach 1:
The patent implements periodic transmission of repeating signal sequences by the low-power microtransponder instead of continuous transmission. The signal repeats at regular intervals, allowing the remote locator to accumulate and correlate multiple signal instances over time. This periodic action enables reliable detection of weak low-power signals while maintaining extended battery life, as the device only transmits intermittently rather than continuously.
Solution Approach 2:
The patent uses signal correlation techniques where the remote locator creates a reference copy of the expected repeating signal sequence and compares it against received signals. By copying and correlating the known signal pattern, the system can extract the weak low-power signal from noise, effectively amplifying the detectability without increasing the actual transmitted power.
2Measurement precision
If signal processing techniques like FFT and correlation are used to extract information from noise, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent pre-generates and stores reference copies of the expected repeating signal sequences in both the microtransponder and remote locator before actual signal extraction begins. This preliminary preparation of reference patterns enables the correlation process to proceed efficiently during operation, reducing real-time computational complexity while maintaining high measurement precision for location determination.
3Duration of action of moving object
If the microtransponder operates in sleep mode to conserve power, then battery life is extended, but the ability to detect and respond to location requests is reduced
Solution Approach 1:
The microtransponder alternates between sleep mode and active transmission mode in periodic cycles. During sleep mode, power consumption is minimized to extend battery life. During brief active intervals, the transponder transmits its repeating signal sequence. This periodic operation allows the device to be detectable at regular intervals while maintaining extended operational duration on battery power.
Solution Approach 2:
Although the microtransponder is in sleep mode most of the time, the useful action of signal transmission continues periodically rather than stopping completely. The repeating signal sequence ensures that whenever the transponder is active, it continuously emits the identifiable pattern, maintaining the possibility of detection and location determination throughout its operational lifetime.
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 accurate and efficient location determination of objects, including living beings, with a high degree of precision and extended battery life for the microtransponder, while maintaining security through embedded noise and power conservation.
Implementation Method 1
Periodically, the MT correlates an internally stored ID code against incoming signals and/or noise
Implementation Method 2
The RL processes the acknowledgement signal received from the MT, determines round-trip time-of-flight, and computes the distance to the MT
Implementation Method 3
A variety of signal processing functions are performed on the captured signals to validate that the transmission has been received by the intended MT
Data Source
AI summary
An object locator system utilizes a microtransponder (12) that is used in association with an object to be located. A remote locator (10) transmits an encoded signal in which is embedded an identification code associated with the object to be located. The microtransponder (12) receives the encoded transmitted signal and processes such signal utilizing fast fourier transform techniques. The microtransponder (12) correlates the transformed received signal with a fast fourier transformed version of an identification code associated with the microtransponder (12) and upon detection of a correlation, transmits an acknowledgement signal to the remote locator (10). The remote locator (10) determines the distance to the microtransponder (12) based upon the round trip time from transmission of the coded signal to the microtransponder (12) to the receipt of the acknowledgement signal.