sky tab: add per-receiver info bar with pDOP, visible and used satellite counts

One card per receiver showing receiver ID, pDOP, visible satellites and
used satellites. Cards are added/removed dynamically with receivers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

gui/sky_tab.py

@@ -9,7 +9,7 @@ for _p in [_root, _gui]:
 from PyQt5.QtWidgets import (
     QWidget, QHBoxLayout, QVBoxLayout, QLabel, QListWidget,
     QListWidgetItem, QTableWidget, QTableWidgetItem, QHeaderView,
-    QSplitter, QGroupBox,
+    QSplitter, QGroupBox, QFrame,
 )
 from PyQt5.QtCore import Qt, QTimer
 from PyQt5.QtGui  import QColor, QBrush
@@ -26,6 +26,9 @@ class SkyTab(QWidget):
         self._model = model
         self._store:       dict = {}   # (rid, gnss_id, sv_id) -> SatelliteData
         self._table_keys:  list = []   # current row order as (rid, gnss_id, sv_id)
+        self._pdop:        dict = {}   # rid -> float
+        self._info_cards:  dict = {}   # rid -> QFrame
+        self._info_labels: dict = {}   # rid -> (lbl_pdop, lbl_visible, lbl_used)
 
         outer = QVBoxLayout(self)
         outer.setContentsMargins(4, 4, 4, 4)
@@ -44,6 +47,16 @@ class SkyTab(QWidget):
         src_bl.addWidget(self._src_list)
         outer.addWidget(src_box)
 
+        # ── Info bar (one card per receiver) ──────────────────────────────────
+        info_frame = QFrame()
+        info_frame.setFrameShape(QFrame.StyledPanel)
+        info_frame.setMaximumHeight(42)
+        self._info_layout = QHBoxLayout(info_frame)
+        self._info_layout.setContentsMargins(6, 2, 6, 2)
+        self._info_layout.setSpacing(12)
+        self._info_layout.addStretch()
+        outer.addWidget(info_frame)
+
         # ── Sky plot + satellite table ─────────────────────────────────────────
         splitter = QSplitter(Qt.Horizontal)
 
@@ -74,6 +87,7 @@ class SkyTab(QWidget):
         model.receiver_added.connect(self._on_receiver_added)
         model.receiver_removed.connect(self._on_receiver_removed)
         model.satellite_update.connect(self._on_sat_update)
+        model.pdop_update.connect(self._on_pdop_update)
 
     # ── Source list management ────────────────────────────────────────────────
 
@@ -84,6 +98,22 @@ class SkyTab(QWidget):
         item.setData(Qt.UserRole, rid)
         self._src_list.addItem(item)
 
+        # Info card for this receiver
+        card = QFrame()
+        card.setFrameShape(QFrame.Box)
+        cl = QHBoxLayout(card)
+        cl.setContentsMargins(8, 1, 8, 1)
+        cl.setSpacing(10)
+        name_lbl = QLabel(f"<b>{rid}</b>")
+        lbl_pdop    = QLabel("pDOP: —")
+        lbl_visible = QLabel("Visible: —")
+        lbl_used    = QLabel("Used: —")
+        for w in (name_lbl, lbl_pdop, lbl_visible, lbl_used):
+            cl.addWidget(w)
+        self._info_cards[rid]  = card
+        self._info_labels[rid] = (lbl_pdop, lbl_visible, lbl_used)
+        self._info_layout.insertWidget(self._info_layout.count() - 1, card)
+
     def _on_receiver_removed(self, rid: str):
         for i in range(self._src_list.count()):
             if self._src_list.item(i).data(Qt.UserRole) == rid:
@@ -92,6 +122,12 @@ class SkyTab(QWidget):
         keys = [k for k in self._store if k[0] == rid]
         for k in keys:
             del self._store[k]
+        self._pdop.pop(rid, None)
+        card = self._info_cards.pop(rid, None)
+        if card:
+            self._info_layout.removeWidget(card)
+            card.deleteLater()
+        self._info_labels.pop(rid, None)
         self._refresh_immediate()
 
     def _selected_rids(self) -> set:
@@ -107,22 +143,38 @@ class SkyTab(QWidget):
         return [(k[0], self._store[k])
                 for k in self._store if k[0] in selected]
 
+    # ── Info bar ──────────────────────────────────────────────────────────────
+
+    def _update_info(self):
+        for rid, (lbl_pdop, lbl_visible, lbl_used) in self._info_labels.items():
+            sats      = [self._store[k] for k in self._store if k[0] == rid]
+            n_visible = len(sats)
+            n_used    = sum(1 for s in sats if s.used_in_fix)
+            pdop      = self._pdop.get(rid)
+            lbl_pdop.setText(   f"pDOP: {pdop:.1f}" if pdop is not None else "pDOP: —")
+            lbl_visible.setText(f"Visible: {n_visible}")
+            lbl_used.setText(   f"Used: {n_used}")
+
     # ── Data update ───────────────────────────────────────────────────────────
 
     def _on_sat_update(self, rid: str, sats: list):
         for sat in sats:
             self._store[(rid, sat.gnss_id, sat.sv_id)] = sat
-        # Sky widget: always submit latest (render is off-thread, trivially cheap)
         self._sky.update_data(self._visible_sats())
-        # Table: schedule a rebuild if one isn't already pending
+        self._update_info()
         if not self._table_timer.isActive():
             self._table_timer.start()
 
+    def _on_pdop_update(self, rid: str, pdop: float, _ts: float):
+        self._pdop[rid] = pdop
+        self._update_info()
+
     def _refresh_immediate(self):
         """Called on source-checkbox toggle or receiver removal — rebuild now."""
         self._table_timer.stop()
         visible = self._visible_sats()
         self._sky.update_data(visible)
+        self._update_info()
         self._rebuild_table(visible)
 
     def _rebuild_table_from_store(self):