diff --git a/src/app/services/physics.service.ts b/src/app/services/physics.service.ts
index d4619e4..68152f8 100644
--- a/src/app/services/physics.service.ts
+++ b/src/app/services/physics.service.ts
@@ -46,13 +46,13 @@ export class PhysicsService {
                     };
 
                     if(this.mode == null) this.mode = info.heading ? 'gps' : 'orientation';
-                    if(this.mode == 'orientation' && data[1]) {
-                        if(!data[1].absolute && data[2] == Infinity) {
+                    if(this.mode == 'orientation') {
+                        if((!data[1] || !data[1].absolute) && data[2] == Infinity) {
                             this.calibrate.next(0);
                             this.requireCalibration.emit();
                         }
 
-                        info.heading = -data[1].alpha + (data[2] == Infinity ? 0 : data[2]);
+                        info.heading = -(data[1] ? data[1].alpha : 0) + (data[2] == Infinity ? 0 : data[2]);
                         if(info.heading < 0) info.heading += 360;
                         if(info.heading >= 360) info.heading -= 360;
                     }
diff --git a/src/app/views/map/map.component.ts b/src/app/views/map/map.component.ts
index e313a2e..3742f38 100644
--- a/src/app/views/map/map.component.ts
+++ b/src/app/views/map/map.component.ts
@@ -119,7 +119,8 @@ export class MapComponent implements OnDestroy, OnInit {
             if (!this.position) this.center({lat: pos.latitude, lng: pos.longitude});
             if (this.positionMarker.arrow) this.map.delete(this.positionMarker.arrow);
             if (this.positionMarker.circle) this.map.delete(this.positionMarker.circle);
-            this.positionMarker.arrow = this.map.newMarker({latlng: {lat: pos.latitude, lng: pos.longitude}, noSelect: true, noDelete: true, noDeleteTool: true, icon: 'arrow', rotationAngle: pos.heading, rotationOrigin: 'center'});
+            console.log(pos.heading / 2);
+            this.positionMarker.arrow = this.map.newMarker({latlng: {lat: pos.latitude, lng: pos.longitude}, noSelect: true, noDelete: true, noDeleteTool: true, icon: 'arrow', rotationAngle: (pos.heading / 2), rotationOrigin: 'center'});
             this.positionMarker.circle = this.map.newCircle({latlng: {lat: pos.latitude, lng: pos.longitude}, color: '#2873d8', noSelect: true, noDelete: true, noDeleteTool: true, radius: pos.accuracy, interactive: false});
             let ignore = this.syncService.addMyLocation({latlng: {lat: pos.latitude, lng: pos.longitude}, label: this.name, noDeleteTool: true});
             this.position = pos;