diff --git a/mbtk/mbtk_gnssd/gnss_main.c b/mbtk/mbtk_gnssd/gnss_main.c
index 5b60d93..772cf21 100755
--- a/mbtk/mbtk_gnssd/gnss_main.c
+++ b/mbtk/mbtk_gnssd/gnss_main.c
@@ -46,8 +46,8 @@
 
 int gnss_init_config(int fd);
 
-static char nmea_buff[GNSS_BUFF_SIZE*2] = {0};
-static char data_buff[GNSS_BUFF_SIZE] = {0};
+static char nmea_buff[GNSS_BUFF_SIZE*4] = {0};
+static char data_buff[GNSS_BUFF_SIZE*4] = {0};
 static uint32 nmea_buff_len = 0;
 static uint32 data_buff_len = 0;