GPS issue, unable to stay fixed.

I’ve been using the note for quite sometime now. My GPS seems to have accuracy problem, it locks on pretty quick but it won’t stay fixed. Meaning, when using Google Map for navigation, it only stays for several minutes, or sometime, less than a minute, it will lost the fix. Sometime, it’s even said “GPS Signal Lost”. This happens even in the open area, stabled position (like in the middle soccer field or low-speed open high way).
I’m running version. Using Google Map latest and GPS status app. I’ve tried “Engineer Mode” but nothing looks unusual in the setting. I always redownloaded A-GPS but it won’t help.

Any idea what’s happening?

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