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Feat : RSSI 전처리 로직 추가 #2

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Feat : RSSI 전처리 로직 추가 #2

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49 changes: 41 additions & 8 deletions app/src/main/java/koren/swiftescaper/domain/viewmodel/MainViewModel.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@ package koren.swiftescaper.domain.viewmodel
import android.util.Log
import androidx.lifecycle.ViewModel
import com.minew.beaconset.MinewBeacon
import koren.swiftescaper.domain.remote.LocationService
import koren.swiftescaper.util.KalmanFilter
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
Expand All @@ -28,7 +27,29 @@ class MainViewModel: ViewModel() {
fun setBeacons(beacons: List<MinewBeacon>) {
val filteredBeacons = beacons.filter { it.uuid == "FDA50693-A4E2-4FB1-AFCF-C6EB07647825" }
_beacons.value = filteredBeacons.toList()
estimatePosition(beacons) // 위치 추정 시작
estimatePosition(filteredBeacons) // 위치 추정 시작
}

// RSSI 가우시안 필터 적용 함수
private fun applyGaussianFilter(rssi: Int): Double {
val sigma = 3.0 // 표준편차 설정
val mean = rssi.toDouble()
return (1 / (sigma * kotlin.math.sqrt(2 * Math.PI))) * kotlin.math.exp(-0.5 * ((rssi - mean) / sigma).pow(2.0))
}

// RSSI 스무딩 처리 함수
private fun applySmoothingFilter(currentRSSI: Double, previousRSSI: Double): Double {
val alpha = 0.75 // 스무딩 계수
return alpha * currentRSSI + (1 - alpha) * previousRSSI
}

// 거리 추정 함수 (상대적 거리 추정)
private fun estimateDistanceFromRSSI(rssi: Double): Double {
// 기본 경로 손실 지수 (실험적 값, 환경에 따라 조정 가능)
val pathLossExponent = 2.0

// 임의의 근사치로 계산
return 10.0.pow(-rssi / (10 * pathLossExponent))
}

// 비콘 신호를 바탕으로 위치를 추정하는 함수
Expand All @@ -37,7 +58,7 @@ class MainViewModel: ViewModel() {
"적어도 3개의 비콘과 해당하는 RSSI가 필요합니다."
}

val sortBeacons =beacons.sortedBy { it.rssi }
val sortedBeacons = beacons.sortedBy { it.rssi }
// 칼만 필터 초기화
val processNoise = 0.1 // 프로세스 노이즈(예시 값)
val measurementNoise = 1.0 // 측정 노이즈(예시 값)
Expand All @@ -47,20 +68,34 @@ class MainViewModel: ViewModel() {
val kalmanY = KalmanFilter(processNoise, measurementNoise, estimatedError)

// 비콘 3개를 사용한 삼변측량
val (beacon1, beacon2, beacon3) = sortBeacons
val (beacon1, beacon2, beacon3) = sortedBeacons

// RSSI 보정 및 거리 추정
val rssi1 = applyGaussianFilter(beacon1.rssi)
val smoothedRSSI1 = applySmoothingFilter(rssi1, beacon1.rssi.toDouble())
val distance1 = estimateDistanceFromRSSI(smoothedRSSI1)

val rssi2 = applyGaussianFilter(beacon2.rssi)
val smoothedRSSI2 = applySmoothingFilter(rssi2, beacon2.rssi.toDouble())
val distance2 = estimateDistanceFromRSSI(smoothedRSSI2)

val rssi3 = applyGaussianFilter(beacon3.rssi)
val smoothedRSSI3 = applySmoothingFilter(rssi3, beacon3.rssi.toDouble())
val distance3 = estimateDistanceFromRSSI(smoothedRSSI3)

// 비콘 좌표
val (x1, y1) = 0.0 to 0.0
val (x2, y2) = 0.0 to 200.0
val (x3, y3) = 100.0 to 50.0

// 삼변측량 계산
val A = 2 * (x2 - x1)
val B = 2 * (y2 - y1)
val C = 2 * (x3 - x1)
val D = 2 * (y3 - y1)

val E = beacon1.distance.pow(2) - beacon2.distance.pow(2) + x2.pow(2) - x1.pow(2) + y2.pow(2) - y1.pow(2)
val F = beacon1.distance.pow(2) - beacon3.distance.pow(2) + x3.pow(2) - x1.pow(2) + y3.pow(2) - y1.pow(2)
val E = distance1.pow(2) - distance2.pow(2) + x2.pow(2) - x1.pow(2) + y2.pow(2) - y1.pow(2)
val F = distance1.pow(2) - distance3.pow(2) + x3.pow(2) - x1.pow(2) + y3.pow(2) - y1.pow(2)

val x = (E - F * (A / C)) / (B - D * (A / C))
val y = (E - A * x) / B
Expand All @@ -71,7 +106,5 @@ class MainViewModel: ViewModel() {

_x.value = kalmanX.getEstimate() // x 좌표 갱신
_y.value = kalmanY.getEstimate() // y 좌표 갱신


}
}
2 changes: 1 addition & 1 deletion app/src/main/java/koren/swiftescaper/ui/view/MainActivity.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -225,4 +225,4 @@ class MainActivity : ComponentActivity() {
}
handler!!.post(runnable!!) // Start sending messages
}
}
}