Research Of The System Of Position Telemetering Based On Radio Frequency Signal Strength For Micro-Gastrointestinal Endoscope

Micro-Gastrointestinal Endoscope, such as an implantablemicro-capsule,changed the deficiency of original diagnosis method andwould be paid more concern on its advantage of noninvasive，convenientand complete gastrointestinal diagnosis.Considering the location of theMicro-Gastrointestinal Endoscope in the gastrointestinal tract is invisibleto doctors, which influences the diagnosis and treatment, a novellocalization system need be developed to track the microcapsule and thelocalization for Micro-Gastrointestinal Endoscope became a keytechnology needing to be solved.In the background， this paper relies on the National HighTechnology Research&Development Program (863Program) of China(Program No.2006AA04Z368、2007AA04Z234) and National NaturalScience Foundation (Program No.60875061、30800235) to makeresearch on a novel localization system for Micro-GastrointestinalEndoscope. Considering to make the localization method more easier torealized and make the localization system more safe and reliable, it is necessary to use a novel tracking method based on radio frequency(RF)signal strength, which don’t need add other devices forMicro-Gastrointestinal Endoscope. In this method the array of RFreceivers are located over the abdomen of human body, and these RFreceivers can get the radio frequency signal strength (RSSI) by RFcommunication with the Micro-Gastrointestinal Endoscope. Based onthe localization model, the position and orientation ofMicro-Gastrointestinal Endoscope can be calculated from the differenceof the RSSI got by the array of the RF receivers. The contents of thispaper focus on the following aspects：1. Make special research and analyse about the localization methodbased on radio frequency signal strength, and introduce the content fromthe two aspects, one is basic principle, the other one is algorithm model.Especially the RF transmittance model, which provider theory foundationfor localization of the Micro-Gastrointestinal Endoscope using RSSI, isanalyzed.2. Study the design of Micro-Gastrointestinal Endoscope system,and propose a novel scheme to design localization system, What is more,the software and hardware realization of localization system is introduced.The hardware can be introduced from three aspects. The array of RFsensors is responsible for attaining the RSSI value, The Data Collectingand Storing Cell put the information, including RSSI values, time information and tag number of RF sensors, into SD card using the FATfile system. At last, the Data Process Cell analyzes the information fromSD card and calculates the location of Micro-Gastrointestinal Endoscope.3. Construct the basic experiment device to validate this method,especially use Trilateration algorithm and plane track algorithm toanalyze the data gotten by the localization system. The experiments showthe localization method can be effective to tract the position of the targetin some case, but it need more consideration and research about thealgorithm and model for localizing Micro-Gastrointestinal Endoscope inthe human body. At last, propose a improving algorithm model tocombine the advantages between Trilateration algorithm and plane trackalgorithm. The improving algorithm can effectively reduce the theoryerror, which is brought by lacking the precise RF transmittance model inhuman body.