From f3a3f9b5a3e04427feac00a4e1c71b991f2219b8 Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Tue, 19 May 2026 10:38:41 +0200
Subject: [PATCH] parse and show p_dop

---
 gnss_thread.py | 22 +++++++++++-----------
 plot_tab.py    |  5 ++++-
 sky_plot.py    | 20 +++++++++++++-------
 ubx.py         | 29 +++++++++++++++++++++++------
 4 files changed, 51 insertions(+), 25 deletions(-)

diff --git a/gnss_thread.py b/gnss_thread.py
index 4f561b5..7710017 100644
--- a/gnss_thread.py
+++ b/gnss_thread.py
@@ -6,10 +6,10 @@ import socket
 import serial
 from PyQt5.QtCore import QThread, pyqtSignal
 
-from ubx import UbxPacketizer, build_poll, UBX_CLASS_NAV, UBX_ID_NAV_SAT, extract_satellites
+from ubx import UbxPacketizer, build_poll, UBX_CLASS_NAV, UBX_ID_NAV_SAT, UBX_ID_NAV_DOP, extract_satellites
 
 class GnssReader(QThread):
-    satellites_updated = pyqtSignal(list)
+    satellites_updated = pyqtSignal(dict)
     error_occurred     = pyqtSignal(str)
     connected          = pyqtSignal(str)
 
@@ -26,18 +26,18 @@ class GnssReader(QThread):
         try:
             self._transport = self._factory()
             self.connected.emit("Verbunden")
-            poll_msg = build_poll(UBX_CLASS_NAV, UBX_ID_NAV_SAT)
-            self._transport.write(poll_msg)
-
             while self._running:
+                poll_msg = build_poll(UBX_CLASS_NAV, UBX_ID_NAV_SAT)
+                self._transport.write(poll_msg)
+                poll_msg = build_poll(UBX_CLASS_NAV, UBX_ID_NAV_DOP)
+                self._transport.write(poll_msg)
                 chunk = self._transport.read(512)
                 frames = self.packetizer.on_recv(chunk)
-                sats   = extract_satellites(frames)
-                if sats:
-                    self.satellites_updated.emit(sats)
-                else:
-                    # Kein Datum – erneut pollen
-                    self._transport.write(poll_msg)
+                res   = extract_satellites(frames)
+                if 'sat' in res:
+                    self.satellites_updated.emit(res)
+                if 'dop' in res:
+                    self.satellites_updated.emit(res)
 
         except (serial.SerialException, OSError, ConnectionRefusedError,
                 socket.timeout, socket.gaierror) as exc:
diff --git a/plot_tab.py b/plot_tab.py
index a320b19..6dcfa7f 100644
--- a/plot_tab.py
+++ b/plot_tab.py
@@ -165,8 +165,11 @@ class SinglePlotPanel(QWidget):
         active_keys: set[str] = set()
 
         if self._field == "pdop":
+            if pdop is None:
+                return
             active_keys.add("PDOP")
-            self._push("PDOP", ts, pdop if pdop is not None else float("nan"))
+            print(f"PDOP: {pdop}")
+            self._push("PDOP", ts, pdop)
         else:
             for sat in sats:
                 key = f"{GNSS_NAMES.get(sat['gnssId'], '?')}-{sat['svId']}"
diff --git a/sky_plot.py b/sky_plot.py
index d84e209..cad8a4c 100644
--- a/sky_plot.py
+++ b/sky_plot.py
@@ -163,13 +163,19 @@ class MainWindow(QMainWindow):
         self._conn_panel.set_connected(False)
         self._status.showMessage("Verbindung getrennt.")
 
-    def _on_satellites(self, sats: list):
-        visible = [s for s in sats if s["elev"] >= 0]
-        used    = sum(1 for s in sats if s["used"])
-        self._sat_label.setText(f"Satelliten: {len(visible)} sichtbar, {used} genutzt")
-        self._sky_plot.update_satellites(visible)
-        self._table.update_satellites(visible)
-        self._plot_tab.update_data(visible)     # ← neu
+    def _on_satellites(self, msg: dict):
+        if 'sat' in msg:
+            sats = msg['sat']
+            visible = [s for s in sats if s["elev"] >= 0]
+            used    = sum(1 for s in sats if s["used"])
+            self._sat_label.setText(f"Satelliten: {len(visible)} sichtbar, {used} genutzt")
+            self._sky_plot.update_satellites(visible)
+            self._table.update_satellites(visible)
+            self._plot_tab.update_data(visible)     # ← neu
+        if 'dop' in msg:
+            dop = msg['dop']
+            self._plot_tab.update_data([], pdop=dop['p_dop'])     # ← neu
+
 
     def _on_error(self, msg: str):
         self._status.showMessage(f"Fehler: {msg}")
diff --git a/ubx.py b/ubx.py
index 6a189b5..67cced0 100644
--- a/ubx.py
+++ b/ubx.py
@@ -8,6 +8,8 @@ UBX_SYNC2         = 0x62
 UBX_CLASS_NAV     = 0x01
 UBX_ID_NAV_SAT    = 0x35
 UBX_ID_NAV_SVINFO = 0x30
+UBX_ID_NAV_DOP    = 0x04
+
 UBX_SYNC_WORD = b'\xb5\x62'
 
 
@@ -156,12 +158,27 @@ def parse_nav_svinfo(payload: bytes) -> list[dict]:
 		})
 	return sats
 
-def extract_satellites(frames: list[dict]) -> list[dict]:
+def parse_nav_dop(payload: bytes) -> dict:
+	if len(payload) < 18:
+		return {}
+
+	i_tow, p_dop, g_dop, t_dop, v_dop, h_dop, n_dop, e_dop = struct.unpack_from(
+		"<IHHHHHHH", payload
+	)
+	scale = 0.01
+	res = {
+		"p_dop": p_dop*scale, "g_dop": g_dop*scale, "t_dop": t_dop*scale,
+		"v_dop": v_dop*scale, "h_dop": h_dop*scale, "n_dop": n_dop*scale, "e_dop": e_dop*scale
+	}
+
+	return res
+
+def extract_satellites(frames: list[dict]) -> dict:
 	for f in frames:
 		if f["cls"] == UBX_CLASS_NAV and f["id"] == UBX_ID_NAV_SAT:
-			return parse_nav_sat(f["payload"])
+			return {'sat': parse_nav_sat(f["payload"])}
 		if f["cls"] == UBX_CLASS_NAV and f["id"] == UBX_ID_NAV_SVINFO:
-			return parse_nav_svinfo(f["payload"])
-	return []
-
-
+			return {'sat': parse_nav_svinfo(f["payload"])}
+		if f["cls"] == UBX_CLASS_NAV and f["id"] == UBX_ID_NAV_DOP:
+			return {'dop': parse_nav_dop(f["payload"])}
+	return {}