diff --git a/src/georinex/nav2.py b/src/georinex/nav2.py
index de985d8..2a43e85 100644
--- a/src/georinex/nav2.py
+++ b/src/georinex/nav2.py
@@ -195,6 +195,8 @@ def rinexnav2(fn: T.TextIO | Path, tlim: tuple[datetime, datetime] | None = None
             nav[name] *= 1e3
 
     # %% other attributes
+    if "LEAP SECONDS" in header:
+        nav.attrs["leap_seconds"] = int(header["LEAP SECONDS"])
     nav.attrs["version"] = header["version"]
     nav.attrs["svtype"] = [svtype]  # Use list for consistency with NAV3.
     nav.attrs["rinextype"] = "nav"
diff --git a/src/georinex/nav3.py b/src/georinex/nav3.py
index 02ed7e8..e2958b9 100644
--- a/src/georinex/nav3.py
+++ b/src/georinex/nav3.py
@@ -78,7 +78,6 @@ def rinexnav3(
                 raw += ln[STARTCOL3:80]
             # one line per SV
             raws.append(raw.replace("D", "E").replace("\n", ""))
-
     # %% parse collected data per SV
     # NOTE: must be 'ns' or .to_netcdf will fail!
     t = np.array([np.datetime64(t, "ns") for t in times])
@@ -153,7 +152,8 @@ def rinexnav3(
             nav.attrs["ionospheric_corr_BDS"] = np.hstack((corr["BDSA"], corr["BDSB"]))
         if "IRNA" in corr and "IRNB" in corr:
             nav.attrs["ionospheric_corr_IRN"] = np.hstack((corr["IRNA"], corr["IRNB"]))
-
+    if "LEAP SECONDS" in header:
+        nav.attrs["leap_seconds"] = int(header["LEAP SECONDS"].split()[0])
     nav.attrs["version"] = header["version"]
     nav.attrs["svtype"] = svtypes
     nav.attrs["rinextype"] = "nav"
@@ -227,9 +227,10 @@ def _sparefields(cf: list[str], sys: str, N: int) -> list[str]:
         elif N == 27:  # no middle or trailing spare fields
             cf = cf[:22] + cf[23:-3]
     elif sys == "I":
-        if N == 28:
+        if N == 26:
+            cf = cf[:22] + cf[23:26] + [cf[27]]
+        elif N == 28:
             cf = cf[:28]
-
     if N != len(cf):
         raise ValueError(f"System {sys} NAV data is not the same length as the number of fields.")
 
diff --git a/src/georinex/obs2.py b/src/georinex/obs2.py
index 292db34..4180abd 100644
--- a/src/georinex/obs2.py
+++ b/src/georinex/obs2.py
@@ -52,13 +52,10 @@ def rinexobs2(
             fast=fast,
             interval=interval,
         )
-
         if len(o.variables) > 0:
             attrs = o.attrs
             obs = xarray.merge((obs, o))
-
     obs.attrs = attrs
-
     return obs
 
 
@@ -253,7 +250,6 @@ def rinexsystem2(
                     data[i, j, isv] = darr[:, k]
     # %% output gathering
     data = data[:, : times.size, :]  # trims down for unneeded preallocated
-
     fields = []
     for field in hdr["fields"]:
         fields.append(field)
@@ -283,19 +279,19 @@ def rinexsystem2(
     obs = obs.dropna(dim="time", how="all")  # when tlim specified
     # %% attributes
     obs.attrs["version"] = hdr["version"]
-
+    
     # Get interval from header or derive it from the data
-    if "interval" in hdr.keys():
+    if "interval" in hdr.keys() and np.isfinite(hdr["interval"]):
         obs.attrs["interval"] = hdr["interval"]
     elif "time" in obs.coords.keys():
         # median is robust against gaps
         try:
             obs.attrs["interval"] = np.median(np.diff(obs.time) / np.timedelta64(1, "s"))
         except TypeError:
-            pass
-    else:
-        obs.attrs["interval"] = np.nan
-
+            print ("Couldn't process interval")
+    # else:
+    #     obs.attrs["interval"] = np.nan
+    
     obs.attrs["rinextype"] = "obs"
     obs.attrs["fast_processing"] = int(fast)  # bool is not allowed in NetCDF4
     obs.attrs["time_system"] = determine_time_system(hdr)
@@ -305,10 +301,14 @@ def rinexsystem2(
         obs.attrs["rxmodel"] = hdr["rxmodel"]
     if "position" in hdr.keys():
         obs.attrs["position"] = hdr["position"]
-
     if "position_geodetic" in hdr.keys():
         obs.attrs["position_geodetic"] = hdr["position_geodetic"]
-
+    if "LEAP SECONDS" in hdr.keys():
+        try:
+            obs.attrs["leap_seconds"] = int(hdr["LEAP SECONDS"])
+        except:
+            pass
+    
     return obs
 
 
@@ -450,11 +450,14 @@ def obsheader2(
     except (KeyError, ValueError):
         pass
 
-    try:  # This key is OPTIONAL
+    try:  
         hdr["interval"] = float(hdr["INTERVAL"][:10])
     except (KeyError, ValueError):
         pass
-
+    try:  
+        hdr["version"] = float(hdr["RINEX VERSION / TYPE"].split()[0])
+    except (KeyError, ValueError):
+        pass
     try:
         s = " "
         hdr["rxmodel"] = s.join(hdr["REC # / TYPE / VERS"].split()[1:-1])
diff --git a/src/georinex/obs3.py b/src/georinex/obs3.py
index a68dc21..03f54f5 100644
--- a/src/georinex/obs3.py
+++ b/src/georinex/obs3.py
@@ -160,7 +160,8 @@ def rinexobs3(
             data.attrs["receiver_clock_offset_applied"] = int(hdr["RCV CLOCK OFFS APPL"])
         except ValueError:
             pass
-
+    if "LEAP SECONDS" in hdr.keys():
+        data.attrs["leap_seconds"] = int(hdr["LEAP SECONDS"].split()[0])
     return data