some fixes and improvements

data_acq_and_processing/processing/data_processor/include/processing_live_config.hpp

@@ -18,6 +18,14 @@ enum class LegacyGprMode {
     Extended,
 };
 
+enum class LegacyGprReferenceMode {
+    // t_ref = midpoint between the first and last event centers.
+    FrameCenter,
+    // t_ref = center of the first event. Useful when motion offsets should be
+    // accumulated from frame start, e.g. for tagging frames by their head time.
+    FirstTxEvent,
+};
+
 struct ProcessingLiveConfig {
     std::string processor_mode = "pass_through";
     std::string pass_through_channel = "s21";
@@ -42,6 +50,15 @@ struct ProcessingLiveConfig {
     std::string gpr_score_mode = "combined";
     float gpr_speed_m_s = 0.0F;
     float gpr_look_angle_deg = 0.0F;
+    // Motion model parameters for the legacy GPR pipeline. The direction sign
+    // selects which way later Tx-events appear deeper (+1) or shallower (-1).
+    // Intra-sweep phase correction compensates the motion that happens *inside*
+    // one Tx-sweep before the IFFT — it is independent of the per-pair coarse
+    // tau shift and can be disabled without affecting the rest of the pipeline.
+    // The reference mode picks the anchor used to compute dt_ref per event.
+    float gpr_direction_sign = 1.0F;
+    bool gpr_apply_freq_phase_correction = true;
+    LegacyGprReferenceMode gpr_reference_mode = LegacyGprReferenceMode::FrameCenter;
     float gpr_snr_thresh = 4.5F;
     float gpr_snr_comp_max = 25.0F;
     float gpr_start_freq_mhz = 3000.0F;

data_acq_and_processing/processing/data_processor/src/processing_live_config.cpp

@@ -41,6 +41,18 @@ using Json = nlohmann::json;
     throw std::runtime_error(field_name + " must be one of: point, extended");
 }
 
+[[nodiscard]] auto parse_legacy_gpr_reference_mode(
+    const std::string& value, const std::string& field_name
+) -> LegacyGprReferenceMode {
+    if (value == "frame_center") {
+        return LegacyGprReferenceMode::FrameCenter;
+    }
+    if (value == "first_tx_event") {
+        return LegacyGprReferenceMode::FirstTxEvent;
+    }
+    throw std::runtime_error(field_name + " must be one of: frame_center, first_tx_event");
+}
+
 [[nodiscard]] auto parse_gpr_score_mode(const std::string& value, const std::string& field_name) -> std::string {
     if (value == "peak" || value == "combined") {
         return value;
@@ -266,6 +278,25 @@ void apply_legacy_gpr_algorithm_alias(ProcessingLiveConfig& config, const std::s
         }
         config.gpr_look_angle_deg = static_cast<float>(found->get<double>());
     }
+    if (const auto found = root.find("gpr_direction_sign"); found != root.end()) {
+        if (!found->is_number()) {
+            throw std::runtime_error("processing.gpr_direction_sign must be number");
+        }
+        config.gpr_direction_sign = static_cast<float>(found->get<double>());
+    }
+    if (const auto found = root.find("gpr_apply_freq_phase_correction"); found != root.end()) {
+        if (!found->is_boolean()) {
+            throw std::runtime_error("processing.gpr_apply_freq_phase_correction must be bool");
+        }
+        config.gpr_apply_freq_phase_correction = found->get<bool>();
+    }
+    if (const auto found = root.find("gpr_reference_mode"); found != root.end()) {
+        if (!found->is_string()) {
+            throw std::runtime_error("processing.gpr_reference_mode must be string");
+        }
+        config.gpr_reference_mode =
+            parse_legacy_gpr_reference_mode(found->get<std::string>(), "processing.gpr_reference_mode");
+    }
     if (const auto found = root.find("gpr_snr_thresh"); found != root.end()) {
         if (!found->is_number()) {
             throw std::runtime_error("processing.gpr_snr_thresh must be number");