diff --git a/Core/Src/global_var.c b/Core/Src/global_var.c
index c17d994..562b51e 100644
--- a/Core/Src/global_var.c
+++ b/Core/Src/global_var.c
@@ -19,4 +19,5 @@ uint8_t U1_TX_buf[UART_BF_SIZE]={0};
 /* define var */
 uint8_t ST_IMU_INT = 0, TDK_IMU_INT = 0; // IMU INT flag
 uint8_t U1_DMA_BUSY = 0;
+double time_scale=1;
 int GPS_week;
diff --git a/Core/Src/stm32f1xx_it.c b/Core/Src/stm32f1xx_it.c
index 5841bd9..723aef9 100644
--- a/Core/Src/stm32f1xx_it.c
+++ b/Core/Src/stm32f1xx_it.c
@@ -67,6 +67,7 @@ extern UART_HandleTypeDef huart1;
 extern UART_HandleTypeDef huart2;
 /* USER CODE BEGIN EV */
 extern TIM_HandleTypeDef htim3;
+extern double time_scale;
 
 /* USER CODE END EV */
 
@@ -371,7 +372,7 @@ void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
 			IMU_mng_ST.ready = 1;
 			IMU_mng_ST.gpstime = SYS_TIME.SYS_GPST_TIME;
 			IMU_mng_ST.utctime = SYS_TIME.SYS_UTC_TIME;
-			IMU_mng_ST.gpstime.sec = IMU_mng_ST.utctime.sec = __HAL_TIM_GET_COUNTER(&htim3) / 10000.0;
+			IMU_mng_ST.gpstime.sec = IMU_mng_ST.utctime.sec = __HAL_TIM_GET_COUNTER(&htim3) / 10000.0*time_scale;
 		}
 		else
 		{
@@ -387,6 +388,9 @@ void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
 	else if (GPIO_Pin == PPS_INT_Pin)
 	{
 		/* Neet to add sec and clean Tim CNT */
+		int timer_count =__HAL_TIM_GET_COUNTER(&htim3);
+		if (timer_count<12000 && timer_count > 8000)
+			time_scale=10000.0/timer_count;
 		__HAL_TIM_SET_COUNTER(&htim3, 0); // clean TIM3 CNT
 		if (SYS_TIME.NMEA_GET == 1)
 		{