diff --git a/backlog/tasks/task-1 - Implement-navigation-routes.md b/backlog/tasks/task-1 - Implement-navigation-routes.md
index 630442a..34f07ab 100644
--- a/backlog/tasks/task-1 - Implement-navigation-routes.md	
+++ b/backlog/tasks/task-1 - Implement-navigation-routes.md	
@@ -1,10 +1,11 @@
 ---
 id: task-1
 title: Implement navigation routes
-status: To Do
-assignee: []
+status: Done
+assignee: [@claude]
 created_date: '2025-12-15 19:37'
-labels: []
+completed_date: '2025-12-28'
+labels: [feature, navigation]
 dependencies: []
 priority: high
 ---
@@ -14,3 +15,27 @@ priority: high
 <!-- SECTION:DESCRIPTION:BEGIN -->
 Add routing between participants and waypoints using c3nav for indoor routes and OSRM/GraphHopper for outdoor routes
 <!-- SECTION:DESCRIPTION:END -->
+
+## Implementation Notes
+
+### Components Added
+- `/api/routing/route.ts` - API endpoint for route calculation
+- `RouteOverlay.tsx` - Map overlay component for visualizing routes
+- `NavigationPanel.tsx` - UI panel for selecting navigation targets
+
+### Features Implemented
+- **Outdoor routing**: Uses OSRM public API for walking/driving routes
+- **Indoor routing**: Integrates c3nav API for CCC venue navigation
+- **Mixed routes**: Handles transitions between indoor/outdoor
+- **Route visualization**: GeoJSON line layer on MapLibre GL map
+- **Navigation UI**: Click on participant/waypoint to get directions
+- **State management**: Route state integrated into Zustand store
+
+### Technical Details
+- Route segments are typed as `outdoor`, `indoor`, or `transition`
+- Distance/time estimates calculated from OSRM and c3nav responses
+- Route line rendered with outline for visibility
+- Map auto-fits to route bounds when calculated
+
+### Commit
+`a6c124c` - feat: Add navigation routes feature with indoor/outdoor routing
diff --git a/src/app/page.tsx b/src/app/page.tsx
index f448259..45d0b65 100644
--- a/src/app/page.tsx
+++ b/src/app/page.tsx
@@ -1,6 +1,6 @@
 'use client';
 
-import { useState } from 'react';
+import { useState, useEffect } from 'react';
 import { useRouter } from 'next/navigation';
 import { nanoid } from 'nanoid';
 
@@ -17,8 +17,32 @@ export default function HomePage() {
   const [isCreating, setIsCreating] = useState(false);
   const [joinSlug, setJoinSlug] = useState('');
   const [name, setName] = useState('');
-  const [emoji, setEmoji] = useState(EMOJI_OPTIONS[Math.floor(Math.random() * EMOJI_OPTIONS.length)]);
+  const [emoji, setEmoji] = useState('');
   const [roomName, setRoomName] = useState('');
+  const [isLoaded, setIsLoaded] = useState(false);
+
+  // Load saved user info from localStorage on mount
+  useEffect(() => {
+    let loadedEmoji = '';
+    try {
+      const stored = localStorage.getItem('rmaps_user');
+      if (stored) {
+        const user = JSON.parse(stored);
+        if (user.name) setName(user.name);
+        if (user.emoji) {
+          setEmoji(user.emoji);
+          loadedEmoji = user.emoji;
+        }
+      }
+    } catch {
+      // Ignore parse errors
+    }
+    // Set random emoji if none loaded
+    if (!loadedEmoji) {
+      setEmoji(EMOJI_OPTIONS[Math.floor(Math.random() * EMOJI_OPTIONS.length)]);
+    }
+    setIsLoaded(true);
+  }, []);
 
   const handleCreateRoom = async () => {
     if (!name.trim()) return;
diff --git a/src/app/room/[slug]/page.tsx b/src/app/room/[slug]/page.tsx
index 00ddc63..8e3107e 100644
--- a/src/app/room/[slug]/page.tsx
+++ b/src/app/room/[slug]/page.tsx
@@ -208,6 +208,8 @@ export default function RoomPage() {
           currentUserId={currentParticipantId || undefined}
           currentLocation={currentLocation}
           eventId="38c3"
+          isSharing={isSharing}
+          onToggleSharing={handleToggleSharing}
           onParticipantClick={(p) => {
             setSelectedParticipant(p);
             setShowParticipants(true);
diff --git a/src/components/map/DualMapView.tsx b/src/components/map/DualMapView.tsx
index 5e22021..04b3bbd 100644
--- a/src/components/map/DualMapView.tsx
+++ b/src/components/map/DualMapView.tsx
@@ -38,6 +38,10 @@ interface DualMapViewProps {
   onParticipantClick?: (participant: Participant) => void;
   onWaypointClick?: (waypoint: Waypoint) => void;
   onIndoorPositionSet?: (position: { level: number; x: number; y: number }) => void;
+  /** Whether location sharing is active */
+  isSharing?: boolean;
+  /** Callback to toggle location sharing */
+  onToggleSharing?: () => void;
 }
 
 // CCC venue bounds (Hamburg Congress Center)
@@ -58,6 +62,8 @@ export default function DualMapView({
   onParticipantClick,
   onWaypointClick,
   onIndoorPositionSet,
+  isSharing = false,
+  onToggleSharing,
 }: DualMapViewProps) {
   const [mode, setMode] = useState<MapMode>(initialMode);
   const [activeView, setActiveView] = useState<'outdoor' | 'indoor'>('outdoor');
@@ -152,6 +158,42 @@ export default function DualMapView({
         />
       )}
 
+      {/* Location sharing button - floating inside map for mobile visibility */}
+      {onToggleSharing && (
+        <button
+          onClick={onToggleSharing}
+          className={`absolute top-4 right-4 z-30 flex items-center gap-2 px-4 py-3 rounded-full shadow-lg transition-all ${
+            isSharing
+              ? 'bg-rmaps-primary text-white'
+              : 'bg-white text-gray-800 hover:bg-gray-100'
+          }`}
+          title={isSharing ? 'Stop sharing location' : 'Share my location'}
+        >
+          <svg
+            className="w-5 h-5"
+            fill={isSharing ? 'currentColor' : 'none'}
+            stroke="currentColor"
+            viewBox="0 0 24 24"
+          >
+            <path
+              strokeLinecap="round"
+              strokeLinejoin="round"
+              strokeWidth={2}
+              d="M17.657 16.657L13.414 20.9a1.998 1.998 0 01-2.827 0l-4.244-4.243a8 8 0 1111.314 0z"
+            />
+            <path
+              strokeLinecap="round"
+              strokeLinejoin="round"
+              strokeWidth={2}
+              d="M15 11a3 3 0 11-6 0 3 3 0 016 0z"
+            />
+          </svg>
+          <span className="text-sm font-medium hidden sm:inline">
+            {isSharing ? 'Sharing' : 'Share Location'}
+          </span>
+        </button>
+      )}
+
       {/* Indoor Map button - switch to indoor view */}
       {activeView === 'outdoor' && (
         <button
diff --git a/src/lib/sync.ts b/src/lib/sync.ts
index 31fe108..735e457 100644
--- a/src/lib/sync.ts
+++ b/src/lib/sync.ts
@@ -81,6 +81,19 @@ export type SyncMessage =
 type SyncCallback = (state: RoomState) => void;
 type ConnectionCallback = (connected: boolean) => void;
 
+// Validate that coordinates are reasonable (not 0,0 or out of bounds)
+function isValidLocation(location: LocationState | undefined): boolean {
+  if (!location) return false;
+  const { latitude, longitude } = location;
+  // Basic bounds check
+  if (latitude < -90 || latitude > 90 || longitude < -180 || longitude > 180) return false;
+  // Reject (0,0) which is a common invalid default
+  if (latitude === 0 && longitude === 0) return false;
+  // Reject NaN
+  if (isNaN(latitude) || isNaN(longitude)) return false;
+  return true;
+}
+
 export class RoomSync {
   private slug: string;
   private state: RoomState;
@@ -132,10 +145,11 @@ export class RoomSync {
   }
 
   private cleanupStaleParticipants(state: RoomState): RoomState {
-    const STALE_THRESHOLD_MS = 60 * 60 * 1000; // 1 hour
+    const STALE_THRESHOLD_MS = 15 * 60 * 1000; // 15 minutes (was 1 hour)
     const now = Date.now();
     const cleanedParticipants: Record<string, ParticipantState> = {};
     let removedCount = 0;
+    let invalidLocationCount = 0;
 
     for (const [id, participant] of Object.entries(state.participants)) {
       const lastSeen = new Date(participant.lastSeen).getTime();
@@ -144,6 +158,12 @@ export class RoomSync {
 
       // Keep current user (they'll be updated) and non-stale participants
       if (isCurrentUser || !isStale) {
+        // Also clean up invalid locations
+        if (participant.location && !isValidLocation(participant.location)) {
+          console.log(`Removing invalid location for participant ${id}:`, participant.location);
+          delete participant.location;
+          invalidLocationCount++;
+        }
         cleanedParticipants[id] = participant;
       } else {
         removedCount++;
@@ -153,6 +173,9 @@ export class RoomSync {
     if (removedCount > 0) {
       console.log(`Cleaned up ${removedCount} stale participant(s) from room state`);
     }
+    if (invalidLocationCount > 0) {
+      console.log(`Cleaned up ${invalidLocationCount} invalid location(s) from room state`);
+    }
 
     return {
       ...state,
@@ -257,8 +280,17 @@ export class RoomSync {
 
       case 'location':
         if (this.state.participants[message.participantId]) {
-          this.state.participants[message.participantId].location = message.location;
-          this.state.participants[message.participantId].lastSeen = new Date().toISOString();
+          // Validate location before accepting
+          if (message.location && isValidLocation(message.location)) {
+            this.state.participants[message.participantId].location = message.location;
+            this.state.participants[message.participantId].lastSeen = new Date().toISOString();
+          } else if (message.location === null) {
+            // Allow explicit null to clear location
+            delete this.state.participants[message.participantId].location;
+            this.state.participants[message.participantId].lastSeen = new Date().toISOString();
+          } else {
+            console.warn('Ignoring invalid location from participant:', message.participantId, message.location);
+          }
         }
         break;
 
@@ -310,6 +342,11 @@ export class RoomSync {
 
   updateLocation(location: LocationState): void {
     console.log('RoomSync.updateLocation called:', location.latitude, location.longitude);
+    // Validate location before setting
+    if (!isValidLocation(location)) {
+      console.warn('Rejecting invalid location:', location);
+      return;
+    }
     if (this.state.participants[this.participantId]) {
       this.state.participants[this.participantId].location = location;
       this.state.participants[this.participantId].lastSeen = new Date().toISOString();
@@ -346,11 +383,13 @@ export class RoomSync {
     console.log('RoomSync.updateIndoorPosition called:', indoor.level, indoor.x, indoor.y);
     if (this.state.participants[this.participantId]) {
       // Update or create location with indoor data
+      // Use CCH venue center as default when no outdoor location exists
       const existingLocation = this.state.participants[this.participantId].location;
+      const CCH_CENTER = { latitude: 53.5555, longitude: 9.9898 }; // Hamburg CCH venue center
       const location: LocationState = existingLocation || {
-        latitude: 0,
-        longitude: 0,
-        accuracy: 0,
+        latitude: CCH_CENTER.latitude,
+        longitude: CCH_CENTER.longitude,
+        accuracy: 50, // Indoor accuracy
         timestamp: new Date().toISOString(),
         source: 'manual',
       };