def next(self, quantum=1):
"State after quantum."
self.time += quantum
avspeed = (2 * self.speed + self.h_acc * quantum) / 2
avclimb = (2 * self.climb + self.v_acc * quantum) / 2
self.alt += avclimb * quantum
self.speed += self.h_acc * quantum
self.climb += self.v_acc * quantum
distance = avspeed * quantum
# Formula from <http://williams.best.vwh.net/avform.htm#Rhumb>
# Initial point cannot be a pole, but GPS doesn't work at high.
# latitudes anyway so it would be OK to fail there.
# Seems to assume a spherical Earth, which means it's going
# to have a slight inaccuracy rising towards the poles.
# The if/then avoids 0/0 indeterminacies on E-W courses.
tc = gps.Deg2Rad(self.course)
lat = gps.Deg2Rad(self.lat)
lon = gps.Deg2Rad(self.lon)
lat += distance * math.cos(tc)
dphi = math.log(
math.tan(lat / 2 + math.pi / 4) /
math.tan(self.lat / 2 + math.pi / 4))
if abs(lat - self.lat) < math.sqrt(1e-15):
q = math.cos(self.lat)
else:
q = (lat - self.lat) / dphi
dlon = -distance * math.sin(tc) / q
self.lon = gps.Rad2Deg(
math.mod(lon + dlon + math.pi, 2 * math.pi) - math.pi)
self.lat = gps.Rad2Deg(lat)
def __init__(self, gpstype):
self.ksv = ksv()
self.ksv.lat = gps.Rad2Deg(0.592539)
self.ksv.lon = gps.Rad2Deg(2.066470)
self.ksv.alt = 250
self.ksv.speed = 0.629650
self.ksv.distance = gps.Deg2Rad(3.5 / 60.0)
self.ksv.course = 79.3
self.ephemeris = {}
# This sets up satellites at random. Not really what we want.
for PRN in self.active_PRNs:
for (prn, satellite) in self.ephemeris.items():
self.skyview[prn] = (random.randint(-60, +61),
random.randint(0, 359))
self.have_ephemeris = False
self.channels = {}
self.output = None
self.status = gps.STATUS_NO_FIX
self.mode = gps.MODE_NO_FIX
self.validity = "V"
self.satellites_used = 0
self.filename = None
self.lineno = 0
self.gpstype = gpstype
def next(self, quantum=1):
"State after quantum."
#self.time += quantum
#avspeed = (2*self.speed + self.h_acc*quantum)/2
#avclimb = (2*self.climb + self.v_acc*quantum)/2
#self.alt += avclimb * quantum
#self.speed += self.h_acc * quantum
#self.climb += self.v_acc * quantum
#distance = avspeed * quantum
# Formula from <http://williams.best.vwh.net/avform.htm#Rhumb>
# Initial point cannot be a pole, but GPS doesn't work at high.
# latitudes anyway so it would be OK to fail there.
# Seems to assume a spherical Earth, which means it's going
# to have a slight inaccuracy rising towards the poles.
# The if/then avoids 0/0 indeterminacies on E-W courses.
tc = gps.Deg2Rad(self.course)
#print "lat, lon: " + str(self.lat) + ", " + str(self.lon)
lat1R = gps.Deg2Rad(self.lat)
lon1R = gps.Deg2Rad(self.lon)
#print "lat, lon: " + str(lat1R) + ", " + str(lon1R)
distance = self.distance
#print "dist: " + str(gps.Rad2Deg(distance))
latR = lat1R + distance * math.cos(tc)
#print "lat, lon: " + str(latR) + ", " + str(lon1R)
if abs(latR) > math.pi / 2.0:
print "error d too large. You can't go this far along this rhumb line!"
if abs(latR - lat1R) < math.sqrt(1e-15):
q = math.cos(lat1R)
else:
t1 = math.tan(latR / 2.0 + math.pi / 4.0)
t2 = math.tan(lat1R / 2.0 + math.pi / 4.0)
#print "t1, t2: " + str(t1) + ", " + str(t2)
dphi = math.log(t1 / t2)
q = (latR - lat1R) / dphi
dlon = -distance * math.sin(tc) / q
self.lon = gps.Rad2Deg(
math.fmod(lon1R + dlon + math.pi, 2.0 * math.pi) - math.pi)
self.lat = gps.Rad2Deg(latR)
