Resolve "Add Novatel raw data stream"

Closes #11 (closed)

src/receiver_raw_base.cpp

+#include "gnss_utils/receiver_raw_base.h"
+
+namespace GnssUtils
+{
+ReceiverRawAbstract::ReceiverRawAbstract() : raw_data_type_(NO)
+{
+  if (init_raw(&raw_data_, STRFMT_UBX) == 0)
+  {
+    assert("Failed when allocating memory for raw_t");
+    return;
+  }
+}
+
+ReceiverRawAbstract::~ReceiverRawAbstract()
+{
+  free_raw(&raw_data_);
+}
+
+void ReceiverRawAbstract::updateObservations()
+{
+  // sort and remove duplicated observations
+  sortobs(&raw_data_.obs);
+
+  obs_.clearObservations();
+  for (int ii = 0; ii < raw_data_.obs.n; ++ii)
+    obs_.addObservation(raw_data_.obs.data[ii]);
+}
+
+}  // namespace GnssUtils
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