diff --git a/src/core/system_parameters/GLONASS_L1_L2_CA.h b/src/core/system_parameters/GLONASS_L1_L2_CA.h
index e893f7df7..042754742 100644
--- a/src/core/system_parameters/GLONASS_L1_L2_CA.h
+++ b/src/core/system_parameters/GLONASS_L1_L2_CA.h
@@ -238,6 +238,7 @@ const std::vector<int32_t> GLONASS_GNAV_CRC_M_INDEX{20, 21, 22, 23, 24, 25, 26,
 const std::vector<int32_t> GLONASS_GNAV_CRC_N_INDEX{35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65};
 const std::vector<int32_t> GLONASS_GNAV_CRC_P_INDEX{66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85};
 const std::vector<int32_t> GLONASS_GNAV_CRC_Q_INDEX{9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85};
+const std::vector<int32_t> GLONASS_GNAV_ECC_LOCATOR{0, 0, 1, 8, 2, 9, 10, 11, 3, 12, 13, 14, 15, 16, 17, 18, 4, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 5, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 6, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84};
 
 // GLONASS GNAV NAVIGATION MESSAGE STRUCTURE
 // NAVIGATION MESSAGE FIELDS POSITIONS
diff --git a/src/core/system_parameters/glonass_gnav_navigation_message.cc b/src/core/system_parameters/glonass_gnav_navigation_message.cc
index 3f1bcd12e..94ddd9073 100644
--- a/src/core/system_parameters/glonass_gnav_navigation_message.cc
+++ b/src/core/system_parameters/glonass_gnav_navigation_message.cc
@@ -36,7 +36,7 @@ Glonass_Gnav_Navigation_Message::Glonass_Gnav_Navigation_Message()
 }
 
 
-bool Glonass_Gnav_Navigation_Message::CRC_test(const std::bitset<GLONASS_GNAV_STRING_BITS>& bits) const
+bool Glonass_Gnav_Navigation_Message::CRC_test(std::bitset<GLONASS_GNAV_STRING_BITS>& bits) const
 {
     uint32_t sum_bits = 0;
     int32_t sum_hamming = 0;
@@ -128,7 +128,28 @@ bool Glonass_Gnav_Navigation_Message::CRC_test(const std::bitset<GLONASS_GNAV_ST
             return true;
         }
 
-    // All other conditions are assumed errors. TODO: Add correction for case B
+    if (C_Sigma && (sum_bits & 1))
+        {
+            int32_t syndrome = C1;
+            syndrome |= (C2 ? 2 : 0);
+            syndrome |= (C3 ? 4 : 0);
+            syndrome |= (C4 ? 8 : 0);
+            syndrome |= (C5 ? 16 : 0);
+            syndrome |= (C6 ? 32 : 0);
+            syndrome |= (C7 ? 64 : 0);
+            if (syndrome < 85)
+                {
+                    const int32_t locator = GLONASS_GNAV_ECC_LOCATOR[syndrome];
+                    bits[locator] = !bits[locator];
+                    return true;
+                }
+            else
+                {
+                    return false;
+                }
+        }
+
+    // All other conditions are assumed errors.
     return false;
 }
 
@@ -238,7 +259,7 @@ int32_t Glonass_Gnav_Navigation_Message::string_decoder(const std::string& frame
     uint64_t P_1_tmp = 0;
 
     // Unpack bytes to bits
-    const std::bitset<GLONASS_GNAV_STRING_BITS> string_bits(frame_string);
+    std::bitset<GLONASS_GNAV_STRING_BITS> string_bits(frame_string);
 
     // Perform data verification and exit code if error in bit sequence
     flag_CRC_test = CRC_test(string_bits);
diff --git a/src/core/system_parameters/glonass_gnav_navigation_message.h b/src/core/system_parameters/glonass_gnav_navigation_message.h
index fcad9c79f..c51264ad8 100644
--- a/src/core/system_parameters/glonass_gnav_navigation_message.h
+++ b/src/core/system_parameters/glonass_gnav_navigation_message.h
@@ -55,7 +55,7 @@ public:
      * \brief Compute CRC for GLONASS GNAV strings
      * \param bits Bits of the string message where to compute CRC
      */
-    bool CRC_test(const std::bitset<GLONASS_GNAV_STRING_BITS>& bits) const;
+    bool CRC_test(std::bitset<GLONASS_GNAV_STRING_BITS>& bits) const;
 
     /*!
      * \brief Computes the frame number being decoded given the satellite slot number
diff --git a/src/tests/unit-tests/system-parameters/glonass_gnav_crc_test.cc b/src/tests/unit-tests/system-parameters/glonass_gnav_crc_test.cc
index 88fc61e04..2280219d1 100644
--- a/src/tests/unit-tests/system-parameters/glonass_gnav_crc_test.cc
+++ b/src/tests/unit-tests/system-parameters/glonass_gnav_crc_test.cc
@@ -17,14 +17,14 @@
 
 #include "glonass_gnav_navigation_message.h"
 #include <bitset>
-#include <string>
+#include <iostream>
 
 TEST(GlonassCrcTest, GnssSdrCRCTest)
 {
     // test data
     std::string string1Real_14_18_00("0000100000111001001001000011101010101100010101001000001001011101010101110011110110101");
     std::string string1Real_14_18_30("0000100000111001001011000011101010101100010101001000001001011101010101110011100001010");
-    std::string string1Wrong_14_18_00("0000100000111001001001000011101010101100010101001000001001011101010101110011100001010");
+    std::string string1Wrong_14_18_00("0000100000111001001001100011101010101100010101001000001001011101010101110011100001010");
 
     auto gnav_msg = Glonass_Gnav_Navigation_Message();
     std::bitset<GLONASS_GNAV_STRING_BITS> bits;
@@ -34,4 +34,12 @@ TEST(GlonassCrcTest, GnssSdrCRCTest)
     ASSERT_TRUE(gnav_msg.CRC_test(bits));
     bits = std::bitset<GLONASS_GNAV_STRING_BITS>(string1Wrong_14_18_00);
     ASSERT_FALSE(gnav_msg.CRC_test(bits));
+    bits = std::bitset<GLONASS_GNAV_STRING_BITS>(string1Real_14_18_30);
+    for (int k = 8; k < 85; k++)
+        {
+            std::bitset<GLONASS_GNAV_STRING_BITS> corrupt_bits = bits;
+            corrupt_bits[k] = corrupt_bits[k] ? false : true;
+            ASSERT_TRUE(gnav_msg.CRC_test(corrupt_bits));
+            ASSERT_TRUE(corrupt_bits == bits);
+        }
 }