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CPR cleanup

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This commit is contained in:
Nick Foster 2011-06-01 20:37:51 -07:00
parent 9b3b296a22
commit bca80f26ad
1 changed files with 25 additions and 38 deletions
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63
src/python/cpr.py
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@ -154,13 +154,13 @@ def cpr_resolve_global(evenpos, oddpos, mostrecent, surface): #ok this is consid
return [rlat, rlon]
def weed_poslist(poslist):
for key, item in poslist.items():
if time.time() - item[2] > 900:
del poslist[key]
def cpr_decode(my_location, icao24, encoded_lat, encoded_lon, cpr_format, evenlist, oddlist, lkplist, surface, longdata):
#this is a stopgap measure to catch those packets which aren't really position packets. what gives?
# if encoded_lat == 0 or encoded_lon == 0:
#print "debug: lat or lon zero for longdata %x" % (longdata,)
# return [None, None, None, None]
#add the info to the position reports list for global decoding
if cpr_format==1:
oddlist[icao24] = [encoded_lat, encoded_lon, time.time()]
else:
@ -169,29 +169,20 @@ def cpr_decode(my_location, icao24, encoded_lat, encoded_lon, cpr_format, evenli
[decoded_lat, decoded_lon] = [None, None]
#okay, let's traverse the lists and weed out those entries that are older than 15 minutes, as they're unlikely to be useful.
for key, item in lkplist.items():
if time.time() - item[2] > 900:
del lkplist[key]
for key, item in evenlist.items():
if time.time() - item[2] > 900:
del evenlist[key]
for key, item in oddlist.items():
if time.time() - item[2] > 900:
del oddlist[key]
weed_poslist(lkplist)
weed_poslist(evenlist)
weed_poslist(oddlist)
#here we perform global/emitter-centered CPR decoding as follows:
#first, check for the ICAO number in the planelist. if there is a decoded position in there, use that for emitter-centered decoding and be done with it.
if surface==1:
validrange = 45
else:
validrange = 180
if icao24 in lkplist:
#print "debug: icao found in LKP table. EC decoding with local position list %s" % str(lkplist[icao24][0:2])
[decoded_lat, decoded_lon] = cpr_resolve_local(lkplist[icao24][0:2], [encoded_lat, encoded_lon], cpr_format, surface) #do emitter-centered local decoding
#do emitter-centered local decoding
[decoded_lat, decoded_lon] = cpr_resolve_local(lkplist[icao24][0:2], [encoded_lat, encoded_lon], cpr_format, surface)
lkplist[icao24] = [decoded_lat, decoded_lon, time.time()] #update the local position for next time
############debug info for plotting strange position reports###############
@ -204,31 +195,26 @@ def cpr_decode(my_location, icao24, encoded_lat, encoded_lon, cpr_format, evenli
#
############debug info for plotting strange position reports###############
else: #no LKP available
#print "debug: icao %x not found. attempting local decode." % icao24
# [local_lat, local_lon] = cpr_resolve_local(my_location, [encoded_lat, encoded_lon], cpr_format, surface) #try local decoding
# print "debug: local resolve gives %.6f, %.6f" % (local_lat, local_lon)
# [rnge, bearing] = range_bearing(my_location, [local_lat, local_lon])
# if rnge < validrange: #if the local decoding can be guaranteed valid
#print "debug: range < 180nm, position valid."
# lkplist[icao24] = [local_lat, local_lon, time.time()] #update the local position for next time
# [decoded_lat, decoded_lon] = [local_lat, local_lon]
# else: #if the local decoding can't be guaranteed valid AND you couldn't find an LKP
if True:
print "debug: range > %inm, attempting global decode." % validrange
#attempt global decode
else if my_location is not None: #if we have a location, use it
[local_lat, local_lon] = cpr_resolve_local(my_location, [encoded_lat, encoded_lon], cpr_format, surface) #try local decoding
[rnge, bearing] = range_bearing(my_location, [local_lat, local_lon])
if rnge < validrange: #if the local decoding can be guaranteed valid
lkplist[icao24] = [local_lat, local_lon, time.time()] #update the local position for next time
[decoded_lat, decoded_lon] = [local_lat, local_lon]
else: #if the local decoding can't be guaranteed valid, attempt a global decode
# print "debug: range > %inm, attempting global decode." % validrange
if (icao24 in evenlist) and (icao24 in oddlist):
print "debug: ICAOs found in both lists."
# print "debug: ICAOs found in both lists."
if abs(evenlist[icao24][2] - oddlist[icao24][2]) < 10: #if there's less than 10 seconds of time difference between the reports
print "debug: valid even/odd positions, performing global decode."
newer = (oddlist[icao24][2] - evenlist[icao24][2]) > 0 #figure out which report is newer
[decoded_lat, decoded_lon] = cpr_resolve_global(evenlist[icao24][0:2], oddlist[icao24][0:2], newer, surface) #do a global decode
if decoded_lat is not None:
lkplist[icao24] = [decoded_lat, decoded_lon, time.time()]
else:
print "debug: timestamps not close enough to be valid."
else:
print "debug: even/odd information not found."
# else:
# print "debug: timestamps not close enough to be valid."
# else:
# print "debug: even/odd information not found."
#print "settled on position: %.6f, %.6f" % (decoded_lat, decoded_lon,)
if decoded_lat is not None:
@ -240,7 +226,8 @@ def cpr_decode(my_location, icao24, encoded_lat, encoded_lon, cpr_format, evenli
return [decoded_lat, decoded_lon, rnge, bearing]
#calculate range and bearing between two lat/lon points
#should probably throw this in the mlat py somewhere or make another lib
def range_bearing(loc_a, loc_b):
[a_lat, a_lon] = loc_a
[b_lat, b_lon] = loc_b