diff --git a/src/position.ts b/src/position.ts
index 9b61878..14f25fb 100644
--- a/src/position.ts
+++ b/src/position.ts
@@ -57,14 +57,14 @@ export class Position implements IPosition {
 
   public distanceTo(other: IPosition): number {
     const R = 6371e3; // Earth radius in meters
-    const φ1 = this.latitude * Math.PI / 180;
-    const φ2 = other.latitude * Math.PI / 180;
-    const Δφ = (other.latitude - this.latitude) * Math.PI / 180;
-    const Δλ = (other.longitude - this.longitude) * Math.PI / 180;
+    const lat1 = this.latitude * Math.PI / 180;
+    const lat2 = other.latitude * Math.PI / 180;
+    const dLat = (other.latitude - this.latitude) * Math.PI / 180;
+    const dLon = (other.longitude - this.longitude) * Math.PI / 180;
 
-    const a = Math.sin(Δφ/2) * Math.sin(Δφ/2) +
-              Math.cos(φ1) * Math.cos(φ2) *
-              Math.sin(Δλ/2) * Math.sin(Δλ/2);
+    const a = Math.sin(dLat/2) * Math.sin(dLat/2) +
+          Math.cos(lat1) * Math.cos(lat2) *
+          Math.sin(dLon/2) * Math.sin(dLon/2);
     const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
 
     return R * c; // Distance in meters