diff --git a/pyModeS/decoder/adsb.py b/pyModeS/decoder/adsb.py
index e509fce..dacce31 100644
--- a/pyModeS/decoder/adsb.py
+++ b/pyModeS/decoder/adsb.py
@@ -166,23 +166,47 @@ def speed_heading(msg):
     return spd, trk_or_hdg
 
 
-def nic(msg):
-    """Calculate NIC, navigation integrity category
+def oe_flag(msg):
+    """Check the odd/even flag. Bit 54, 0 for even, 1 for odd.
+    Args:
+        msg (string): 28 bytes hexadecimal message string
+    Returns:
+        int: 0 or 1, for even or odd frame
+    """
+    msgbin = common.hex2bin(msg)
+    return int(msgbin[53])
+
+# Uncertainty & accuracy
+def nic(msg, *argv):
+    if len(argv) == 1:
+        # assume ads-b v1, only one supplement bit
+        return nic_v1(msg, *argv)
+    elif len(argv) == 3:
+        # assume ads-b v2, three supplement bits
+        return nic_v2(msg, *argv)
+
+
+def nic_v1(msg, nic_sup_b):
+    """Calculate NIC, navigation integrity category for ADS-B version 1
 
     Args:
         msg (string): 28 bytes hexadecimal message string
+        nic_sup_b (int or string): NIC supplement
 
     Returns:
         int: NIC number (from 0 to 11), -1 if not applicable
     """
-    if typecode(msg) < 9 or typecode(msg) > 18:
-        raise RuntimeError("%s: Not a airborne position message, expecting 8<TC<19" % msg)
+    if typecode(msg) < 5 or typecode(msg) > 22:
+        raise RuntimeError("%s: Not a surface position message (5<TC<8), \
+                           airborne position message (8<TC<19), \
+                           or airborne position with GNSS height (20<TC<22)" % msg)
 
-    msgbin = common.hex2bin(msg)
     tc = typecode(msg)
-    nic_sup_b = common.bin2int(msgbin[39])
 
-    if tc in [0, 18, 22]:
+    if nic_sup_b in ['0', '1']:
+        nic_sup_b = int(nic_sup_b)
+
+    if tc in [0, 8, 18, 22]:
         nic = 0
     elif tc == 17:
         nic = 1
@@ -196,7 +220,10 @@ def nic(msg):
     elif tc == 14:
         nic = 5
     elif tc == 13:
-        nic = 6
+        if nic_sup_b:
+            nic = 6
+        else:
+            nic = 6
     elif tc == 12:
         nic = 7
     elif tc == 11:
@@ -204,21 +231,251 @@ def nic(msg):
             nic = 9
         else:
             nic = 8
-    elif tc in [10, 21]:
+    elif tc in [6, 10, 21]:
         nic = 10
-    elif tc in [9, 20]:
+    elif tc in [5, 9, 20]:
         nic = 11
+    elif tc == 7:
+        if nic_sup_b:
+            nic = 9
+        else:
+            nic = 8
     else:
         nic = -1
     return nic
 
 
-def oe_flag(msg):
-    """Check the odd/even flag. Bit 54, 0 for even, 1 for odd.
+def nic_v2(msg, nic_a, nic_b, nic_c):
+    """Calculate NIC, navigation integrity category, for ADS-B version 2
+
     Args:
         msg (string): 28 bytes hexadecimal message string
+        nic_a (int or string): NIC supplement
+        nic_b (int or srting): NIC supplement
+        nic_c (int or string): NIC supplement
     Returns:
-        int: 0 or 1, for even or odd frame
+        int: NIC number (from 0 to 11), -1 if not applicable
     """
+    if typecode(msg) < 5 or typecode(msg) > 22:
+        raise RuntimeError("%s: Not a surface position message (5<TC<8) \
+                           airborne position message (8<TC<19), \
+                           or airborne position with GNSS height (20<TC<22)" % msg)
+
+    tc = typecode(msg)
+
+    if nic_a in ['0', '1']:
+        nic_a = int(nic_a)
+
+    if nic_b in ['0', '1']:
+        nic_b = int(nic_b)
+
+    if nic_c in ['0', '1']:
+        nic_c = int(nic_c)
+
+    if tc in [0, 18, 22]:
+        nic = 0
+    elif tc == 17:
+        nic = 1
+    elif tc == 16:
+        if nic_a:
+            nic = 3
+        else:
+            nic = 2
+    elif tc == 15:
+        nic = 4
+    elif tc == 14:
+        nic = 5
+    elif tc == 13:
+        if nic_a:
+            nic = 6
+        else:
+            if nic_b:
+                nic = 6
+            else:
+                nic = 6
+    elif tc == 12:
+        nic = 7
+    elif tc == 11:
+        if nic_a:
+            nic = 9
+        else:
+            nic = 8
+    elif tc in [6, 10, 21]:
+        nic = 10
+    elif tc in [5, 9, 20]:
+        nic = 11
+    elif tc == 8:
+        if nic_a:
+            if nic_c:
+                nic = 7
+            else:
+                nic = 6
+        else:
+            if nic_c:
+                nic = 6
+            else:
+                nic = 0
+    elif tc == 7:
+        if nic_a:
+            nic = 9
+        else:
+            nic = 8
+    else:
+        nic = -1
+    return nic
+
+
+def nic_s(msg):
+    """Obtain NIC supplement bit, TC=31 message
+
+    Args:
+        msg (string): 28 bytes hexadecimal message string
+
+    Returns:
+        int: NICs number (0 or 1)
+    """
+    tc = typecode(msg)
+
+    if tc != 31:
+        raise RuntimeError("%s: Not a status operation message, expecting TC = 31" % msg)
+
     msgbin = common.hex2bin(msg)
-    return int(msgbin[53])
+    nic_s = int(msgbin[75])
+
+    return nic_s
+
+
+def nic_a_c(msg):
+    """Obtain NICa/c, navigation integrity category supplements a and c
+
+    Args:
+        msg (string): 28 bytes hexadecimal message string
+
+    Returns:
+        (int, int): NICa and NICc number (0 or 1)
+    """
+    tc = typecode(msg)
+
+    if tc != 31:
+        raise RuntimeError("%s: Not a status operation message, expecting TC = 31" % msg)
+
+    msgbin = common.hex2bin(msg)
+    nic_a = int(msgbin[75])
+    nic_c = int(msgbin[51])
+
+    return nic_a, nic_c
+
+
+def nic_b(msg):
+    """Obtain NICb, navigation integrity category supplement-b
+
+    Args:
+        msg (string): 28 bytes hexadecimal message string
+
+    Returns:
+        int: NICb number (0 or 1)
+    """
+    tc = typecode(msg)
+
+    if tc < 9 or tc > 18:
+        raise RuntimeError("%s: Not a airborne position message, expecting 8<TC<19" % msg)
+
+    msgbin = common.hex2bin(msg)
+    nic_b = int(msgbin[39])
+
+    return nic_b
+
+
+def nac_p(msg):
+    """Calculate NACp, Navigation Accuracy Category - Position
+
+    Args:
+        msg (string): 28 bytes hexadecimal message string, TC = 29 or 31
+
+    Returns:
+        int: NACp number (0 or 1)
+    """
+    tc = typecode(msg)
+
+    if tc not in [29, 31]:
+        raise RuntimeError("%s: Not a target state and status message, \
+                           or operation status message, expecting TC = 29 or 31" % msg)
+
+    msgbin = common.hex2bin(msg)
+
+    if tc == 29:
+        nac_p = common.bin2int(msgbin[71:75])
+    elif tc == 31:
+        nac_p = common.bin2int(msgbin[76:80])
+
+    return nac_p
+
+
+def nac_v(msg):
+    """Calculate NACv, Navigation Accuracy Category - Velocity
+
+    Args:
+        msg (string): 28 bytes hexadecimal message string, TC = 19
+
+    Returns:
+        int: NACv number (from 0 to 4), -1 if not applicable
+    """
+    tc = typecode(msg)
+
+    if tc != 19:
+        raise RuntimeError("%s: Not an airborne velocity message, expecting TC = 19" % msg)
+
+    msgbin = common.hex2bin(msg)
+    nac_v = common.bin2int(msgbin[42:45])
+    return nac_v
+
+
+def sil(msg, version):
+    """Calculate SIL, Surveillance Integrity Level
+
+    Args:
+        msg (string): 28 bytes hexadecimal message string with TC = 29, 31
+
+    Returns:
+        (int, int): sil number and sil supplement (only for v2)
+    """
+    tc = typecode(msg)
+
+    if tc not in [29, 31]:
+        raise RuntimeError("%s: Not a target state and status messag, \
+                           or operation status message, expecting TC = 29 or 31" % msg)
+
+    msgbin = common.hex2bin(msg)
+
+    if tc == 29:
+        sil = common.bin2int(msgbin[76:78])
+    elif tc == 31:
+        sil = common.bin2int(msg[82:84])
+
+    if version == 2:
+        if version == 29:
+            sil_sup = common.bin2int(msgbin[39])
+        elif version == 31:
+            sil_sup = common.bin2int(msgbin[86])
+
+    return sil, sil_sup
+
+
+def version(msg):
+    """ADS-B Version
+
+    Args:
+        msg (string): 28 bytes hexadecimal message string, TC = 31
+
+    Returns:
+        int: version number
+    """
+    tc = typecode(msg)
+
+    if tc != 31:
+        raise RuntimeError("%s: Not a status operation message, expecting TC = 31" % msg)
+
+    msgbin = common.hex2bin(msg)
+    version = common.bin2int(msgbin[72:75])
+
+    return version
diff --git a/pyModeS/streamer/stream.py b/pyModeS/streamer/stream.py
index f139bfd..3dee46d 100644
--- a/pyModeS/streamer/stream.py
+++ b/pyModeS/streamer/stream.py
@@ -46,6 +46,11 @@ class Stream():
                     'ias': None,
                     'mach': None,
                     'hdg': None,
+                    'adsb_version' : None,
+                    'nic_s' : None,
+                    'nic_a' : None,
+                    'nic_b' : None,
+                    'nic_c' : None
                 }
 
             self.acs[icao]['t'] = t
@@ -103,6 +108,47 @@ class Stream():
                     self.acs[icao]['alt'] = adsb.altitude(msg)
                     local_updated_acs_buffer.append(icao)
 
+            # Uncertainty & accuracy
+            if (5 <= tc <= 8):
+                if self.acs[icao]['adsb_version']  == 1:
+                    if self.acs[icao]['nic_s'] != None:
+                        self.nic = adsb.nic_v1(msg, self.acs[icao]['nic_s'])
+                elif self.acs[icao]['adsb_version']  == 2:
+                    if self.acs[icao]['nic_a'] != None and self.acs[icao]['nic_b'] != None:
+                        self.nic = adsb.nic_v2(msg, self.nic_a, self.acs[icao]['nic_b'], self.acs[icao]['nic_c'])
+            if (9 <= tc <= 18):
+                if self.acs[icao]['adsb_version']  == 1:
+                    if self.acs[icao]['nic_s'] != None:
+                        self.nic = adsb.nic_v1(msg, self.acs[icao]['nic_s'])
+                elif self.acs[icao]['adsb_version']  == 2:
+                    self.acs[icao]['nic_b'] = adsb.nic_b(msg)
+                    if self.acs[icao]['nic_a'] != None and self.acs[icao]['nic_b'] != None:
+                        self.nic = adsb.nic_v2(msg, self.acs[icao]['nic_a'], self.nic_b, self.acs[icao]['nic_c'])
+            if tc == 19:
+                self.acs[icao]['nac_v'] = adsb.nac_v(msg)
+            if (20 <= tc <= 22):
+                if self.acs[icao]['adsb_version']  == 1:
+                    if self.acs[icao]['nic_s'] != None:
+                        self.nic = adsb.nic_v1(msg, self.acs[icao]['nic_s'])
+                elif self.acs[icao]['adsb_version']  == 2:
+                    if self.acs[icao]['nic_a'] != None and self.acs[icao]['nic_b'] != None:
+                        self.nic = adsb.nic_v2(msg, self.acs[icao]['nic_a'], self.acs[icao]['nic_b'], self.acs[icao]['nic_c'])
+            if tc == 29:
+                if self.acs[icao]['adsb_version'] != None:
+                    self.acs[icao]['sil'] = adsb.sil(msg, self.acs[icao]['adsb_version'])
+                self.acs[icao]['nac_p'] = adsb.nac_p(msg)
+            if tc == 31:
+                self.acs[icao]['adsb_version']  = adsb.version(msg)
+                self.acs[icao]['sil'] = adsb.version(msg)
+                self.acs[icao]['nac_p'] = adsb.nac_p(msg)
+                if self.acs[icao]['adsb_version']  == 1:
+                    self.acs[icao]['nic_s'] = adsb.nic_s(msg)
+                elif self.acs[icao]['adsb_version']  == 2:
+                    self.acs[icao]['nic_a'], self.acs[icao]['nic_c'] = adsb.nic_a_c(msg)
+
+
+
+
         # process ehs message
         for t, msg in zip(ehs_ts, ehs_msgs):
             icao = ehs.icao(msg)