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Updated GPS function
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@n-akram
n-akram committed Oct 16, 2023
1 parent d8f707f commit 51013f7
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Showing 2 changed files with 120 additions and 54 deletions.
173 changes: 119 additions & 54 deletions SafeDrones/core/SafeDrones.py
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Original file line number Diff line number Diff line change
Expand Up @@ -593,19 +593,109 @@ def Chip_MTTF_Model(self,MTTFref=None, Tr=None, Ta = None, u=None,b = None, time

return P_Fail.evalf(subs={t: time}), MTTFchip.evalf(subs={t: time})

def GPS_Failure_Risk_Calc(self, SatStatus=None, time=None, Lambda = None, ):
# def GPS_Failure_Risk_Calc(self, SatStatus=None, time=None, Lambda = None, ):

# #%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
# # Program Name : Markov-based Drone's Reliability and MTTF Estimator %
# # Author : Koorosh Aslansefat %
# # Version : 1.0.0 %
# # Description : A Markov Process-Based Approach for Reliability %
# # Evaluation of the GPS System for Drones %
# #%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

# '''

# SatStatus: is an integer between 0 and 11. 0 means no satellite is available and 14 means fully satellite coverage.

# Lambda: Failure Rate of the GPS System.

# time: Time of the mission
# '''

# import numpy as np # linear algebra
# import pandas as pd # data processing, CSV file I/O (e.g. pd.read_csv)
# import sympy as sym # Symbolic Calculation

# t = sym.Symbol('t')

# if SatStatus == None:
# SatStatus = self.SatStatus
# if Lambda == None:
# Lambda = self.GPS_Lambda
# L = Lambda

# if SatStatus == 14:
# P0_GPS = sym.Matrix([[1],[0],[0],[0],[0],[0],[0],[0],[0]])
# Sflag = 7
# elif SatStatus == 13:
# P0_GPS = sym.Matrix([[0],[1],[0],[0],[0],[0],[0],[0],[0]])
# Sflag = 6
# elif SatStatus == 12:
# P0_GPS = sym.Matrix([[0],[0],[1],[0],[0],[0],[0],[0],[0]])
# Sflag = 5
# elif SatStatus == 11:
# P0_GPS = sym.Matrix([[0],[0],[0],[1],[0],[0],[0],[0],[0]])
# Sflag = 4
# elif SatStatus == 10:
# P0_GPS = sym.Matrix([[0],[0],[0],[0],[1],[0],[0],[0],[0]])
# Sflag = 3
# elif SatStatus == 9:
# P0_GPS = sym.Matrix([[0],[0],[0],[0],[0],[1],[0],[0],[0]])
# Sflag = 2
# elif SatStatus == 8:
# P0_GPS = sym.Matrix([[0],[0],[0],[0],[0],[0],[1],[0],[0]])
# Sflag = 1
# elif SatStatus == 7:
# P0_GPS = sym.Matrix([[0],[0],[0],[0],[0],[0],[0],[1],[0]])
# Sflag = 0
# else:
# P_Fail = 1
# MTTF = 0
# return P_Fail, MTTF

# M_GPS = sym.Matrix([[-14*L, 0, 0, 0, 0, 0, 0, 0, 0],
# [ 14*L, -13*L, 0, 0, 0, 0, 0, 0, 0],
# [ 0, 13*L, -12*L, 0, 0, 0, 0, 0, 0],
# [ 0, 0, 12*L, -11*L, 0, 0, 0, 0, 0],
# [ 0, 0, 0, 11*L, -10*L, 0, 0, 0, 0],
# [ 0, 0, 0, 0, 10*L, -9*L, 0, 0, 0],
# [ 0, 0, 0, 0, 0, 9*L, -8*L, 0, 0],
# [ 0, 0, 0, 0, 0, 0, 8*L, -7*L, 0],
# [ 0, 0, 0, 0, 0, 0, 0, 7*L, 0]])

# P_GPS = sym.exp(M_GPS*t)*P0_GPS

# P_GPS_Fail = P_GPS[-1]

# N_GPS = sym.Matrix([[-14*L, 0, 0, 0, 0, 0, 0, 0],
# [ 14*L, -13*L, 0, 0, 0, 0, 0, 0],
# [ 0, 13*L, -12*L, 0, 0, 0, 0, 0],
# [ 0, 0, 12*L, -11*L, 0, 0, 0, 0],
# [ 0, 0, 0, 11*L, -10*L, 0, 0, 0],
# [ 0, 0, 0, 0, 10*L, -9*L, 0, 0],
# [ 0, 0, 0, 0, 0, 9*L, -8*L, 0],
# [ 0, 0, 0, 0, 0, 0, 8*L, -7*L]])

# tt = -1*N_GPS.inv()

# MTTF_GPS = sum(tt[Sflag,:])

# return P_GPS_Fail.evalf(subs={t: time}), MTTF_GPS.evalf(subs={t: time})


def GPS_Failure_Risk_Calc(self, SatStatus=None, time=None, Lambda = None, MaxSat = 28, MinSat = 7):

#%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
# Program Name : Markov-based Drone's Reliability and MTTF Estimator %
# Author : Koorosh Aslansefat %
# Version : 1.0.0 %
# Version : 1.0.5 %
# Description : A Markov Process-Based Approach for Reliability %
# Evaluation of the GPS System for Drones %
#%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

'''
SatStatus: is an integer between 0 and 11. 0 means no satellite is available and 14 means fully satellite coverage.
SatStatus: is an integer between 0 and MaxSat. 0 means no satellite is available and 14 means fully satellite coverage.
Lambda: Failure Rate of the GPS System.
Expand All @@ -617,71 +707,46 @@ def GPS_Failure_Risk_Calc(self, SatStatus=None, time=None, Lambda = None, ):
import sympy as sym # Symbolic Calculation

t = sym.Symbol('t')

if SatStatus == None:
SatStatus = self.SatStatus
if Lambda == None:
Lambda = self.GPS_Lambda
L = Lambda

if SatStatus > MaxSat:
print("The satellite status can not be more than maximum number of satellites. ")
raise ValueError
return None, None

if SatStatus == 14:
P0_GPS = sym.Matrix([[1],[0],[0],[0],[0],[0],[0],[0],[0]])
Sflag = 7
elif SatStatus == 13:
P0_GPS = sym.Matrix([[0],[1],[0],[0],[0],[0],[0],[0],[0]])
Sflag = 6
elif SatStatus == 12:
P0_GPS = sym.Matrix([[0],[0],[1],[0],[0],[0],[0],[0],[0]])
Sflag = 5
elif SatStatus == 11:
P0_GPS = sym.Matrix([[0],[0],[0],[1],[0],[0],[0],[0],[0]])
Sflag = 4
elif SatStatus == 10:
P0_GPS = sym.Matrix([[0],[0],[0],[0],[1],[0],[0],[0],[0]])
Sflag = 3
elif SatStatus == 9:
P0_GPS = sym.Matrix([[0],[0],[0],[0],[0],[1],[0],[0],[0]])
Sflag = 2
elif SatStatus == 8:
P0_GPS = sym.Matrix([[0],[0],[0],[0],[0],[0],[1],[0],[0]])
Sflag = 1
elif SatStatus == 7:
P0_GPS = sym.Matrix([[0],[0],[0],[0],[0],[0],[0],[1],[0]])
Sflag = 0
if MinSat < SatStatus <= MaxSat:
P0_GPS = sym.zeros(MaxSat-MinSat+1, 1)
P0_GPS[SatStatus - MinSat] = 1
Sflag = MaxSat - SatStatus
else:
P_Fail = 1
MTTF = 0
return P_Fail, MTTF

M_GPS = sym.Matrix([[-14*L, 0, 0, 0, 0, 0, 0, 0, 0],
[ 14*L, -13*L, 0, 0, 0, 0, 0, 0, 0],
[ 0, 13*L, -12*L, 0, 0, 0, 0, 0, 0],
[ 0, 0, 12*L, -11*L, 0, 0, 0, 0, 0],
[ 0, 0, 0, 11*L, -10*L, 0, 0, 0, 0],
[ 0, 0, 0, 0, 10*L, -9*L, 0, 0, 0],
[ 0, 0, 0, 0, 0, 9*L, -8*L, 0, 0],
[ 0, 0, 0, 0, 0, 0, 8*L, -7*L, 0],
[ 0, 0, 0, 0, 0, 0, 0, 7*L, 0]])


M_GPS_updated = sym.zeros(MaxSat-MinSat+1, MaxSat-MinSat+1)
start_value = -1*MaxSat

for i in range(MaxSat-MinSat+1):
if i == (MaxSat-MinSat):
M_GPS_updated[i, i] = (start_value + i) * L
else:
M_GPS_updated[i, i] = (start_value + i) * L
M_GPS_updated[i+1, i] = -(start_value + i) * L

M_GPS = sym.Matrix(M_GPS_updated)

P_GPS = sym.exp(M_GPS*t)*P0_GPS

P_GPS_Fail = P_GPS[-1]

N_GPS = sym.Matrix([[-14*L, 0, 0, 0, 0, 0, 0, 0],
[ 14*L, -13*L, 0, 0, 0, 0, 0, 0],
[ 0, 13*L, -12*L, 0, 0, 0, 0, 0],
[ 0, 0, 12*L, -11*L, 0, 0, 0, 0],
[ 0, 0, 0, 11*L, -10*L, 0, 0, 0],
[ 0, 0, 0, 0, 10*L, -9*L, 0, 0],
[ 0, 0, 0, 0, 0, 9*L, -8*L, 0],
[ 0, 0, 0, 0, 0, 0, 8*L, -7*L]])

N_GPS = M_GPS[:-1, :-1]

tt = -1*N_GPS.inv()

MTTF_GPS = sum(tt[Sflag,:])

return P_GPS_Fail.evalf(subs={t: time}), MTTF_GPS.evalf(subs={t: time})

def calculate_collision_risk(self, uav_1_trajectory, uav_2_trajectory, danger_threshold=-1, collision_threshold=-1): # self.danger_threshold, self.collision_threshold
# Check that both trajectories have the same length
assert len(uav_1_trajectory) == len(uav_2_trajectory), "Trajectories must have the same length"
Expand All @@ -699,7 +764,7 @@ def calculate_collision_risk(self, uav_1_trajectory, uav_2_trajectory, danger_th

if distance < self.collision_threshold:
collision_zone_count += 1
elif distance < self.danger_threshold:
if distance < self.danger_threshold:
danger_zone_count += 1

danger_zone_risk = danger_zone_count / len(uav_1_trajectory)
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