Merge pull request #5 from nsirola/i245_tropo_rebase

UNB3M tropospheric model and iono/tropo Python bindings

Author: ljbade

include/libswiftnav/time.h

@@ -102,4 +102,6 @@ static inline bool is_leap_year(s32 year)
 
 gps_time_t glo_time2gps_time(u16 nt, u8 n4, u8 h, u8 m, u8 s);
 
+u16 gps2doy(const gps_time_t *t);
+
 #endif /* LIBSWIFTNAV_TIME_H */

include/libswiftnav/tropo.h renamed to include/libswiftnav/troposphere.h

@@ -10,10 +10,12 @@
  * WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#ifndef LIBSWIFTNAV_TROPO_H
-#define LIBSWIFTNAV_TROPO_H
+#ifndef LIBSWIFTNAV_TROPOSPHERE_H
+#define LIBSWIFTNAV_TROPOSPHERE_H
 
-double tropo_correction(double elevation);
+#include <libswiftnav/time.h>
 
-#endif /* LIBSWIFTNAV_TROPO_H */
+double calc_troposphere(const gps_time_t *t_gps, double lat, double h,
+                        double el);
 
+#endif /* LIBSWIFTNAV_TROPOSPHERE_H */

python/setup.py

@@ -63,6 +63,7 @@ def make_extension(ext_name):
     'swiftnav.memory_pool',
     'swiftnav.prns',
     'swiftnav.sats_management',
+    'swiftnav.iono',
     'swiftnav.tropo',
     'swiftnav.set',
     'swiftnav.bit_sync',

python/swiftnav/iono.pxd

@@ -0,0 +1,22 @@
+# Copyright (C) 2016 Swift Navigation Inc.
+#
+# This source is subject to the license found in the file 'LICENSE' which must
+# be be distributed together with this source. All other rights reserved.
+#
+# THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
+# EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+
+from common cimport *
+from time cimport gps_time_t
+
+cdef extern from "libswiftnav/ionosphere.h":
+  double calc_ionosphere(const gps_time_t *t_gps,
+                       double lat_u, double lon_u,
+                       double a, double e,
+                       const ionosphere_t *i);
+
+  ctypedef struct ionosphere_t:
+    double a0, a1, a2, a3;
+    double b0, b1, b2, b3;
+

python/swiftnav/iono.pyx

@@ -0,0 +1,43 @@
+# Copyright (C) 2016 Swift Navigation Inc.
+#
+# This source is subject to the license found in the file 'LICENSE' which must
+# be be distributed together with this source. All other rights reserved.
+#
+# THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
+# EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+
+from time cimport *
+from time import GpsTime
+
+def calc_iono_correction(GpsTime t, lat, lon, azimuth, elevation, alpha, beta):
+  """
+  Wraps function :libswiftnav:`calc_ionosphere`.
+
+  Parameters
+  ----------
+  t : GpsTime
+    GPS time for iono computation (only time of day used)
+  lat, lon : float
+    User latitude and longitude (rad)
+  elevation, azimuth : float
+    Satellite az-el (rad)
+  alpha, beta : (float, float, float, float)
+    ionospheric parameters
+
+  Returns
+  -------
+  out : float
+    Ionospheric delay in meters
+
+  """
+  assert len(alpha) == 4 and len(beta) == 4, "Ionospheric parameter vectors alpha and beta must have 4 elements each."
+  
+  cdef ionosphere_t i
+  
+  i.a0, i.a1, i.a2, i.a3 = alpha[0], alpha[1], alpha[2], alpha[3]
+  i.b0, i.b1, i.b2, i.b3 = beta[0], beta[1], beta[2], beta[3]
+  return calc_ionosphere(&t._thisptr, 
+                         lat, lon,
+                         azimuth, elevation,
+                         &i);

python/swiftnav/tropo.pxd

@@ -8,6 +8,7 @@
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 
 from common cimport *
+from time cimport gps_time_t
 
-cdef extern from "libswiftnav/tropo.h":
-  double tropo_correction(double elevation)
+cdef extern from "libswiftnav/troposphere.h":
+  double calc_troposphere(const gps_time_t *t, double lat, double h, double el)

python/swiftnav/tropo.pyx

@@ -6,3 +6,30 @@
 # THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
 # EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+
+from time cimport *
+from time import GpsTime
+
+def calc_tropo_correction(GpsTime t, lat, h, el):
+  """
+  Wraps function :libswiftnav:`calc_troposphere`.
+
+  Parameters
+  ----------
+  t : GpsTime 
+    Time at which to calculate tropospheric delay (only doy matters)
+  lat : float
+    Latitude of the receiver [rad]
+  h : float
+    Orthometric height of the receiver [m]
+  el : float
+    Elevation of the satellite [rad]
+
+  Returns
+  -------
+  out : float
+    Tropospheric delay in meters
+
+  """
+  
+  return calc_troposphere(&t._thisptr, lat, h, el)

src/CMakeLists.txt

@@ -20,7 +20,7 @@ set(libswiftnav_SRCS
   ephemeris.c
   nav_msg.c
   pvt.c
-  tropo.c
+  troposphere.c
   track.c
   correlate.c
   coord_system.c

src/ionosphere.c

@@ -18,7 +18,7 @@
 #include <libswiftnav/ionosphere.h>
 
 /** \defgroup ionosphere Ionospheric models
- * Implemenations of ionoshperic delay correction models.
+ * Implemenations of ionospheric delay correction models.
  * \{ */
 
 /** Calculate ionospheric delay using Klobuchar model.
@@ -33,7 +33,7 @@
  * \param e Elevation of the satellite [rad]
  * \param i Ionosphere parameters struct from GPS NAV data
  *
- * \return  Ionospheric delay distance for GPS L1 frequency [m]
+ * \return Ionospheric delay distance for GPS L1 frequency [m]
  */
 double calc_ionosphere(const gps_time_t *t_gps,
                        double lat_u, double lon_u,

src/time.c

@@ -13,6 +13,7 @@
 #include <assert.h>
 #include <math.h>
 #include <stdio.h>
+#include <time.h>
 
 #include <libswiftnav/time.h>
 #include <libswiftnav/constants.h>
@@ -188,4 +189,16 @@ gps_time_t glo_time2gps_time(u16 nt, u8 n4, u8 h, u8 m, u8 s)
   return gps_t;
 }
 
+/** GPS time to day of year.
+ *
+ * \param t GPS time
+ * \return The day of year (days since Jan 1st)
+ */
+u16 gps2doy(const gps_time_t *t)
+{
+  time_t unixtime = gps2time(t);
+  struct tm* ptm = ptm = gmtime(&unixtime);
+  return ptm->tm_yday;
+}
+
 /** \} */