diff --git a/docs/zh_CN/product_documents/modules/module_gps.md b/docs/zh_CN/product_documents/modules/module_gps.md
index ad125873..45c24884 100644
--- a/docs/zh_CN/product_documents/modules/module_gps.md
+++ b/docs/zh_CN/product_documents/modules/module_gps.md
@@ -63,8 +63,6 @@ $GPTXT,01,01,01,ANTENNA OPEN*25
 
 具体例程请点击[这里](https://github.com/m5stack/M5-ProductExampleCodes/tree/master/Modules/GPS/Arduino)。
 
-<!-- ### 2. UIFlow -->
-
 ## 原理图
 
 <img src="assets/img/product_pics/modules/gps_sch.png">
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diff --git a/docs/zh_CN/product_documents/units/unit_gps.md b/docs/zh_CN/product_documents/units/unit_gps.md
index 59e43cd7..163ec822 100644
--- a/docs/zh_CN/product_documents/units/unit_gps.md
+++ b/docs/zh_CN/product_documents/units/unit_gps.md
@@ -55,4 +55,8 @@ float pressure = bme.readPressure();//pressure
 ## 相关链接
 
 - [AT6558](http://www.icofchina.com/d/file/xiazai/2016-12-05/b1be6f481cdf9d773b963ab30a2d11d8.pdf)
-- [MAX2659](https://datasheets.maximintegrated.com/en/ds/MAX2659.pdf)
\ No newline at end of file
+- [MAX2659](https://datasheets.maximintegrated.com/en/ds/MAX2659.pdf)
+
+- [CASIC多模卫星导航接收机协议规范](http://www.icofchina.com/d/file/xiazai/2017-05-02/ea0cdd3d81eeebcc657b5dbca80925ee.pdf)
+
+- [上位机软件GnssToolKit3(Windows版本)](http://www.icofchina.com/d/file/xiazai/2018-05-23/2b29a8da746eec0ef1dcd9deae895298.zip)
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