diff --git a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc
index e2d93efda..3bc7b0325 100644
--- a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc
+++ b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc
@@ -488,7 +488,7 @@ int gps_l1_ca_telemetry_decoder_gs::general_work(int noutput_items __attribute__
     // 2. Add the telemetry decoder information
     if (d_flag_preamble == true)
         {
-            if (!d_nav.d_TOW == 0)
+            if (!(d_nav.d_TOW == 0))
                 {
                     d_TOW_at_current_symbol_ms = static_cast<uint32_t>(d_nav.d_TOW * 1000.0);
                     d_TOW_at_Preamble_ms = static_cast<uint32_t>(d_nav.d_TOW * 1000.0);