diff --git a/gnss_lib_py/parsers/rinex_nav.py b/gnss_lib_py/parsers/rinex_nav.py
index e693581c..1ad164fc 100644
--- a/gnss_lib_py/parsers/rinex_nav.py
+++ b/gnss_lib_py/parsers/rinex_nav.py
@@ -178,7 +178,7 @@ def postprocess(self):
         self['gnss_id'] = np.asarray(gnss_id)
         self['sv_id'] = np.asarray(gnss_nums, dtype=int)
 
-    def _get_ephemeris_dataframe(self, rinex_path, constellations=None):
+    def _get_ephemeris_dataframe(self, rinex_path, constellations=None, fast=True):
         """Load/download ephemeris files and process into DataFrame
 
         Parameters
@@ -200,10 +200,10 @@ def _get_ephemeris_dataframe(self, rinex_path, constellations=None):
         if constellations is not None:
             data = gr.load(rinex_path,
                                  use=constellations,
-                                 verbose=self.verbose).to_dataframe()
+                                 verbose=self.verbose, fast=fast).to_dataframe()
         else:
             data = gr.load(rinex_path,
-                                 verbose=self.verbose).to_dataframe()
+                                 verbose=self.verbose, fast=fast).to_dataframe()
         data.dropna(how='all', inplace=True)
         data.reset_index(inplace=True)
         data_header = gr.rinexheader(rinex_path)
diff --git a/gnss_lib_py/parsers/rinex_obs.py b/gnss_lib_py/parsers/rinex_obs.py
index 4081e9b2..17737c10 100644
--- a/gnss_lib_py/parsers/rinex_obs.py
+++ b/gnss_lib_py/parsers/rinex_obs.py
@@ -33,7 +33,7 @@ class RinexObs(NavData):
 
 
     """
-    def __init__(self, input_path):
+    def __init__(self, input_path, fast=True):
         """Loading Rinex observation files into a NavData based class.
 
         Should input path to `.yyo` file.
@@ -45,7 +45,7 @@ def __init__(self, input_path):
 
         """
 
-        obs_file = gr.load(input_path).to_dataframe()
+        obs_file = gr.load(input_path, fast=fast).to_dataframe()
         obs_header = gr.rinexheader(input_path)
         obs_measure_types = obs_header['fields']
         rx_bands = []
diff --git a/requirements.txt b/requirements.txt
index e1bdefb7..c6528da5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -24,7 +24,7 @@ executing==2.0.1 ; python_version >= "3.9" and python_version < "3.13"
 fastjsonschema==2.20.0 ; python_version >= "3.9" and python_version < "3.13"
 fonttools==4.53.1 ; python_version >= "3.9" and python_version < "3.13"
 fqdn==1.5.1 ; python_version >= "3.9" and python_version < "3.13"
-georinex==1.16.1 ; python_version >= "3.9" and python_version < "3.13"
+#georinex==1.16.1 ; python_version >= "3.9" and python_version < "3.13"
 h11==0.14.0 ; python_version >= "3.9" and python_version < "3.13"
 hatanaka==2.8.1 ; python_version >= "3.9" and python_version < "3.13"
 httpcore==1.0.5 ; python_version >= "3.9" and python_version < "3.13"