"""Copyright 2015 Roger R Labbe Jr.
FilterPy library.
http://github.com/rlabbe/filterpy
Documentation at:
https://filterpy.readthedocs.org
Supporting book at:
https://github.com/rlabbe/Kalman-and-Bayesian-Filters-in-Python
This is licensed under an MIT license. See the readme.MD file
for more information.
"""
from __future__ import (absolute_import, division, print_function,
unicode_literals)
import math
from numpy.random import randn
def GetRadar(dt):
""" Simulate radar range to object at 1K altidue and moving at 100m/s.
Adds about 5% measurement noise. Returns slant range to the object.
Call once for each new measurement at dt time from last call.
"""
if not hasattr (GetRadar, "posp"):
GetRadar.posp = 0
vel = 100 + .5 * randn()
alt = 1000 + 10 * randn()
pos = GetRadar.posp + vel*dt
v = 0 + pos* 0.05*randn()
slant_range = math.sqrt (pos**2 + alt**2) + v
GetRadar.posp = pos
return slant_range
if __name__ == "__main__":
for i in range (100):
print(GetRadar (0.1))
