From 557a7f7265d23733abc7b31be3407f8b3c30b6eb Mon Sep 17 00:00:00 2001
From: Carles Fernandez <carles.fernandez@gmail.com>
Date: Wed, 28 Aug 2024 11:13:54 +0200
Subject: [PATCH] Add work on ISM

---
 src/core/system_parameters/galileo_ism.cc | 34 ++++++++++++++++++++++-
 src/core/system_parameters/galileo_ism.h  | 19 +++++++------
 src/tests/test_main.cc                    |  3 ++
 3 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/src/core/system_parameters/galileo_ism.cc b/src/core/system_parameters/galileo_ism.cc
index 847a4ecd6..24b5b6d82 100644
--- a/src/core/system_parameters/galileo_ism.cc
+++ b/src/core/system_parameters/galileo_ism.cc
@@ -184,7 +184,7 @@ bool Galileo_ISM::check_ism_crc(const std::bitset<GALILEO_DATA_JK_BITS>& bits) c
     boost::to_block_range(frame_bits, std::back_inserter(bytes));
     std::reverse(bytes.begin(), bytes.end());
 
-    boost::crc_32_type crc32_ism;
+    boost::crc_optimal<32, 0xC0A0A0D5, 0xFFFFFFFF, 0xFFFFFFFF, true, true> crc32_ism;
     crc32_ism.process_bytes(bytes.data(), GALILEO_ISM_CRC_DATA_BYTES);
     const uint32_t crc_computed = crc32_ism.checksum();
     if (this->ism_crc == crc_computed)
@@ -193,4 +193,36 @@ bool Galileo_ISM::check_ism_crc(const std::bitset<GALILEO_DATA_JK_BITS>& bits) c
         }
 
     return false;
+}
+
+
+bool Galileo_ISM::ism_apply_to_sat(uint32_t prn) const
+{
+    if (prn == 0 || prn > 63)
+        {
+            return false;
+        }
+    std::bitset<32> bs(this->ism_mask);
+    if (this->ism_mask_msb == 0)
+        {
+            if (prn <= 32)
+                {
+                    return bs[prn - 1];
+                }
+            else
+                {
+                    return false;
+                }
+        }
+    else
+        {
+            if (prn > 32)
+                {
+                    return bs[prn - 32];
+                }
+            else
+                {
+                    return false;
+                }
+        }
 }
\ No newline at end of file
diff --git a/src/core/system_parameters/galileo_ism.h b/src/core/system_parameters/galileo_ism.h
index 12436a606..2066fe0ac 100644
--- a/src/core/system_parameters/galileo_ism.h
+++ b/src/core/system_parameters/galileo_ism.h
@@ -57,16 +57,17 @@ public:
     void set_ism_Tvalidity(uint8_t tvalidity);
     void set_ism_crc(uint32_t crc);
 
-    bool check_ism_crc(const std::bitset<GALILEO_DATA_JK_BITS>& bits) const;
+    bool check_ism_crc(const std::bitset<GALILEO_DATA_JK_BITS>& bits) const;  //!< Requires ism_crc to be already set
+    bool ism_apply_to_sat(uint32_t prn) const;                                //!< Returns true if ISM parameters apply to the prn satellite, false otherwise
 
-    double get_pconst_value() const;
-    double get_psat_value() const;
-    float get_ura_m() const;
-    float get_ure_m() const;
-    float get_bnom_m() const;
-    uint16_t get_WN_ISM() const;
-    uint16_t get_t0_ISM() const;
-    uint16_t get_Tvalidity_hours() const;
+    double get_pconst_value() const;       //!< A priori constellation fault probability
+    double get_psat_value() const;         //!< A priori satellite fault probability
+    float get_ura_m() const;               //!< User Range Accuracy, in m, used for integrity
+    float get_ure_m() const;               //!< User Range Error, in m, used for accuracy
+    float get_bnom_m() const;              //!< Maximum nominal bias for a satellite, in m
+    uint16_t get_WN_ISM() const;           //!< ISM Week Number, in weeks
+    uint16_t get_t0_ISM() const;           //!< ISM Time of Week, in seconds
+    uint16_t get_Tvalidity_hours() const;  //!< Validity duration of ISM content, in hours
 
 private:
     // ICD 2.1 Table 97
diff --git a/src/tests/test_main.cc b/src/tests/test_main.cc
index 3769756aa..00f1f9458 100644
--- a/src/tests/test_main.cc
+++ b/src/tests/test_main.cc
@@ -95,6 +95,9 @@ DECLARE_string(log_dir);
 #include "unit-tests/system-parameters/glonass_gnav_ephemeris_test.cc"
 #include "unit-tests/system-parameters/glonass_gnav_nav_message_test.cc"
 #include "unit-tests/system-parameters/has_decoding_test.cc"
+#include "unit-tests/system-parameters/galileo_ism_test.cc"
+
+
 
 #ifndef EXCLUDE_TESTS_REQUIRING_BINARIES
 #include "unit-tests/control-plane/control_thread_test.cc"