diff --git a/package.json b/package.json
index 834b5c6..54ee770 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "map-alliance",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "scripts": {
     "ng": "ng",
     "start": "ng serve --host 0.0.0.0",
diff --git a/src/app/map/map.component.html b/src/app/map/map.component.html
index f423883..b377ae4 100644
--- a/src/app/map/map.component.html
+++ b/src/app/map/map.component.html
@@ -8,7 +8,7 @@
         <button mat-icon-button (click)="draw()" [ngClass]="{'selected': drawListener.length}"><mat-icon>create</mat-icon></button>
         <button mat-icon-button><mat-icon>straighten</mat-icon></button>
         <button mat-icon-button (click)="remove = !remove" [ngClass]="{'selected': remove}"><mat-icon>delete</mat-icon></button>
-        <button *ngIf="physicsService.calibrate.value != null" mat-icon-button (click)="calibrate()"><mat-icon>explore</mat-icon></button>
+        <button *ngIf="!isNaN(position?.heading)" mat-icon-button (click)="calibrate()"><mat-icon>explore</mat-icon></button>
         <button mat-icon-button [matMenuTriggerFor]="styleMenu"><mat-icon>layers</mat-icon></button>
         <mat-menu #styleMenu="matMenu">
             <button mat-menu-item (click)="style = 'satellite'" [ngClass]="{'selected': style == 'satellite'}">Satellite</button>
@@ -32,8 +32,8 @@
     <span *ngIf="!position" class="text-danger">No GPS</span>
     <div *ngIf="position" class="text-white">
         Heading:
-        <span *ngIf="!position.heading" class="text-danger">No Heading</span>
-        <span *ngIf="position.heading">{{position.heading | number : '0.0-0'}}°</span>
+        <span *ngIf="isNaN(position.heading)" class="text-danger">No Heading</span>
+        <span *ngIf="!isNaN(position.heading)">{{position.heading | number : '0.0-0'}}°</span>
         <br>
         Latitude: {{position.latitude | number : '0.0-5'}}
         <br>
diff --git a/src/app/map/map.component.ts b/src/app/map/map.component.ts
index 93d2f8f..62de25c 100644
--- a/src/app/map/map.component.ts
+++ b/src/app/map/map.component.ts
@@ -24,9 +24,12 @@ export class MapComponent {
     style: 'satellite' | 'terrain' | 'roadmap' | 'hybrid' = 'terrain';
     version = version;
 
+    isNaN = isNaN;
+
     constructor(private bpObserver: BreakpointObserver, public physicsService: PhysicsService, private snackBar: MatSnackBar, private bottomSheet: MatBottomSheet) {
         bpObserver.observe([Breakpoints.Handset]).subscribe(results => this.mobile = results.matches);
         physicsService.info.pipe(filter(coord => !!coord), debounceTime(50)).subscribe(pos => {
+            console.log('fire');
             if(this.mapApi) {
                 if(!this.position) this.center(pos);
                 this.position = pos;
diff --git a/src/app/physics/physics.service.ts b/src/app/physics/physics.service.ts
index d799b44..f4f637c 100644
--- a/src/app/physics/physics.service.ts
+++ b/src/app/physics/physics.service.ts
@@ -10,7 +10,7 @@ export class PhysicsService {
     private motionTimestamp;
 
     requireCalibration = new EventEmitter();
-    calibrate = new BehaviorSubject(0);
+    calibrate = new BehaviorSubject<number>(Infinity);
 
     info = new BehaviorSubject(null);
     motion = new BehaviorSubject<DeviceMotionEvent>(null);
@@ -54,13 +54,14 @@ export class PhysicsService {
                         speed: data[0].coords.speed
                     };
 
-                    if(info.heading == null && !!data[1] && data[1].alpha) {
-                        if(!data[1].absolute && this.calibrate.value == null) {
-                            this.requireCalibration.emit();
+                    // TODO-debug
+                    if(info.heading == null && data[1]) {
+                        if(!data[1].absolute && data[2] == Infinity) {
                             this.calibrate.next(0);
+                            this.requireCalibration.emit();
                         }
 
-                        info.heading = data[1].alpha + this.calibrate.value;
+                        info.heading = data[1].alpha + (data[2] == Infinity ? 0 : data[2]);
                         if(info.heading > 360) info.heading -= 360;
                         if(info.heading < 0) info.heading += 360;
                     }