diff --git a/stream/mts/psi/psi_test.go b/stream/mts/psi/psi_test.go
index ab173b58..ff0b9034 100644
--- a/stream/mts/psi/psi_test.go
+++ b/stream/mts/psi/psi_test.go
@@ -123,7 +123,7 @@ const (
 
 // GPS string for testing
 // TODO: make these realistic
-var (
+const (
 	locationTstStr1 = "$GPGGA,123519,4807.038,N,01131.0"
 	locationTstStr2 = "$GPGGA,183710,4902.048,N,02171.0"
 )