converted calcs to functions for easy reuse

lib/aircraft.py

@@ -27,7 +27,7 @@ def __init__(self):
         self.turn_rate = 0
         self.wind_speed = None
         self.wind_dir = None
-        self.norm_wind_dir = 0 #corrected for aircraft heading for wind direction pointer TODO: Add wind direction pointer to HUD screen
+        self.norm_wind_dir = None #corrected for aircraft heading for wind direction pointer TODO: Add wind direction pointer to HUD screen
         self.mag_decl = None #magnetic declination
 
         self.gps = GPSData()

lib/inputs/_utils.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python
+
+##Library of useful functions that can be used inside of input modules
+##02/06/2019 Brian Chesteen
+
+import math
+from lib.geomag import declination
+
+#############################################
+## Function: ias2tas By: Brian Chesteen
+## Converts indicated airspeed to true airspeed based on
+## outside air temp and pressure altitude.
+
+def ias2tas(ias, oat, palt):
+    tas = ias * (math.sqrt((273.0 + oat) / 288.0)) * ((1.0 - palt / 144000.0) ** -2.75)
+
+    return tas
+
+#############################################
+## Function: geomag By: Brian Chesteen 
+## Called Function By: Christopher Weiss cmweiss@gmail.com
+## Looks up magnetic declination dynamically from GPS Lat and Lon
+## Uses coefficients from the World Magnetic Model of the NOAA
+## Satellite and Information Service, National Geophysical Data Center
+## http://www.ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml
+
+def geomag(LatHemi, LatDeg, LatMin, LonHemi, LonDeg, LonMin):
+    if LatHemi == "N":
+        GeoMagLat = LatDeg + (LatMin / 60)
+    else:
+        GeoMagLat = ((LatDeg + (LatMin / 60))  * -1)
+    if LonHemi == "W":
+        GeoMagLon = ((LonDeg + (LonMin/60))  * -1)
+    else:
+        GeoMagLon = LonDeg + (LonMin/60)
+    mag_decl = declination(GeoMagLat, GeoMagLon)
+
+    return mag_decl
+
+#############################################
+## Function: gndspeed By: Brian Chesteen
+## Calculates GPS ground speed in knots from GPS EW NS velocities in meters/sec.
+
+def gndspeed(EWVelmag, NSVelmag):
+    gndspeed = (math.sqrt(((int(EWVelmag) * 0.1)**2) + ((int(NSVelmag) * 0.1)**2))) * 1.94384
+
+    return gndspeed
+
+#############################################
+## Function: gndtrack By: Brian Chesteen
+## Calculates GPS ground track in knots from GPS EW NS quadrant direction and
+## velocities in meters/sec.
+
+def gndtrack(EWVelDir, EWVelmag, NSVelDir, NSVelmag):
+    if EWVelDir == "W":
+        EWVelmag = int(EWVelmag) * -0.1
+    else:
+        EWVelmag = int(EWVelmag) * 0.1
+    if NSVelDir == "S":
+        NSVelmag = int(NSVelmag) * -0.1
+    else:
+        NSVelmag = int(NSVelmag) * 0.1
+
+    gndtrack = (math.degrees(math.atan2(EWVelmag, NSVelmag))) % 360
+
+    return gndtrack
+
+#############################################
+## Function: windSpdDir By: Brian Chesteen
+## Calculates wind speed and direction
+
+def windSpdDir(tas, gndspeed, gndtrack, mag_head, mag_decl):
+    if tas > 30 and gndspeed > 30:
+        crs = math.radians(gndtrack) #convert degrees to radians
+        head = math.radians(mag_head + mag_decl) #convert degrees to radians
+        wind_speed = math.sqrt(math.pow(tas - gndspeed, 2) + 4 * tas * gndspeed * math.pow(math.sin((head - crs) / 2), 2))
+        wind_dir = crs + math.atan2(tas * math.sin(head-crs), tas * math.cos(head-crs) - gndspeed)
+        if wind_dir < 0:
+            wind_dir = wind_dir + 2 * math.pi
+        if wind_dir > 2 * math.pi:
+            wind_dir = wind_dir - 2 * math.pi
+        wind_dir = math.degrees(wind_dir) #convert radians to degrees
+        norm_wind_dir = (wind_dir + mag_head + mag_decl) % 360 #normalize the wind direction to the airplane heading
+
+    else:
+        wind_speed = None
+        wind_dir = None
+        norm_wind_dir = None
+
+    return (wind_speed, wind_dir, norm_wind_dir) 
+
+
+
+
+
+
+
+
+
+
+

lib/inputs/serial_g3x.py

@@ -9,6 +9,7 @@
 from lib import hud_utils
 from lib import hud_text
 from lib import geomag
+import _utils
 import serial
 import struct
 import math
@@ -84,40 +85,14 @@ def readMessage(self, aircraft):
                                 aircraft.gps.NSVelmag = int(NSVelmag) * 0.1
                                 aircraft.gps.VVelDir = VVelDir # U or D
                                 aircraft.gps.VVelmag = int(VVelmag) * 0.1
-                                if aircraft.gps.LatHemi == "N":
-                                    GeoMagLat = aircraft.gps.LatDeg + (aircraft.gps.LatMin / 60)
-                                else:
-                                    GeoMagLat = ((aircraft.gps.LatDeg + (aircraft.gps.LatMin / 60))  * -1)
-                                if aircraft.gps.LonHemi == "W":
-                                    GeoMagLon = ((aircraft.gps.LonDeg + (aircraft.gps.LonMin/60))  * -1)
-                                else:
-                                    GeoMagLon = aircraft.gps.LonDeg + (aircraft.gps.LonMin/60)
-                                aircraft.mag_decl = geomag.declination(GeoMagLat, GeoMagLon)
-                                aircraft.gndspeed = (math.sqrt(((int(EWVelmag) * 0.1)**2) + ((int(NSVelmag) * 0.1)**2))) * 1.94384
-                                if EWVelDir == "W":
-                                    EWVelmag = int(EWVelmag) * -0.1
-                                else:
-                                    EWVelmag = int(EWVelmag) * 0.1
-                                if NSVelDir == "S":
-                                    NSVelmag = int(NSVelmag) * -0.1
-                                else:
-                                    NSVelmag = int(NSVelmag) * 0.1
-                                aircraft.gndtrack = (math.degrees(math.atan2(EWVelmag, NSVelmag))) % 360
-                                if aircraft.tas > 30 and aircraft.gndspeed > 30:
-                                    crs = math.radians(aircraft.gndtrack) #convert degrees to radians
-                                    head = math.radians(aircraft.mag_head + aircraft.mag_decl) #convert degrees to radians
-                                    aircraft.wind_speed = math.sqrt(math.pow(aircraft.tas - aircraft.gndspeed, 2) + 4 * aircraft.tas * aircraft.gndspeed * math.pow(math.sin((head - crs) / 2), 2))
-                                    aircraft.wind_dir = crs + math.atan2(aircraft.tas * math.sin(head-crs), aircraft.tas * math.cos(head-crs) - aircraft.gndspeed)
-                                    if aircraft.wind_dir < 0:
-                                        aircraft.wind_dir = aircraft.wind_dir + 2 * math.pi
-                                    if aircraft.wind_dir > 2 * math.pi:
-                                        aircraft.wind_dir = aircraft.wind_dir - 2 * math.pi
-                                    aircraft.wind_dir = math.degrees(aircraft.wind_dir) #convert radians to degrees
-                                    aircraft.norm_wind_dir = (aircraft.wind_dir + aircraft.mag_head + aircraft.mag_decl) % 360 #normalize the wind direction to the airplane heading
-
-                                else:
-                                    aircraft.wind_speed = None
-                                    aircraft.wind_dir = None
+                                aircraft.mag_decl = _utils.geomag(aircraft.gps.LatHemi, aircraft.gps.LatDeg,
+                                                                 aircraft.gps.LatMin, aircraft.gps.LonHemi,
+                                                                 aircraft.gps.LonDeg, aircraft.gps.LonMin)  
+                                aircraft.gndspeed = _utils.gndspeed(EWVelmag, NSVelmag)
+                                aircraft.gndtrack = _utils.gndtrack(EWVelDir, EWVelmag, NSVelDir, NSVelmag)
+                                aircraft.wind_speed, aircraft.wind_dir, aircraft.norm_wind_dir = _utils.windSpdDir(aircraft.tas, aircraft.gndspeed,
+                                                                                                                  aircraft.gndtrack, aircraft.mag_head,
+                                                                                                                  aircraft.mag_decl)
 
                             else:
                                 aircraft.msg_bad += 1 
@@ -151,7 +126,7 @@ def readMessage(self, aircraft):
                         )  # 0.00108 of inches of mercury change per foot.
                         aircraft.BALT = aircraft.alt
                         aircraft.vsi = int(VertSpeed) * 10
-                        aircraft.tas = aircraft.ias * (math.sqrt((273.0 + aircraft.oat) / 288.0)) * ((1.0 - aircraft.PALT / 144000.0) ** -2.75)
+                        aircraft.tas = _utils.ias2tas(aircraft.ias, aircraft.oat, aircraft.PALT)
                         aircraft.vert_G = int(VertAcc) * 0.1
                         aircraft.turn_rate = int(RateofTurn) * 0.1
                         aircraft.msg_count += 1