# Set Survey-in time & position accuracy limit

**This step-by-step tutorial will let you to manually set the survey-in time and the position accuracy limit for the Base.**

First, connect your GNSS device to a computer using a USB micro cable.

![](/files/-LdEnYZLwhXVFEwUuCNY)

Now start the U-blox “u-center” software. Then on the top left corner of the screen, left-click on the reversed tiny black triangle to select the COM Port related to your GNSS device. (it may differs from COM7 as shown in pictures)

![](/files/-LYbIddBqnC-aXKJ1bxh)

Make sure the connection icon is blinking in the bottom state bar. It indicates that the serial communication between the computer and the GNSS device is working.

![](/files/-LYbHSKTiJZ0j0qAf-5e)

Next go to ‘View’ then click on “Generation 9 Configuration View”

![](/files/-LYbUsIAWEUg8JmCOVN6)

{% tabs %}
{% tab title="Survey-in time" %}
A new window showing by default “**GNSS Configuration**” opens.

1. So first, click on “**Advanced Configuration**” to display all the configuration registers.
2. Then click on the small ‘+’ on the **CFG-TPMODE** line
3. You can now have access to an expanded menu and click on **CFG-TPMODE-SVIN\_MIN\_DUR**
4. Enter a valid position value in seconds (ex : a 60s value = 60)
5. Click consecutively on **RAM**, **BBR** and **Flash** to write changes into RAM and both non-volatile memories (BBR and Flash)
6. Check the 3 corresponding commands are present in the “Ready to send” box and then click on ‘**Send**’

![](/files/-LYbg7Y5DbnCjpv9Zv0C)
{% endtab %}

{% tab title="Position accuracy limit" %}
A new window showing by default “**GNSS Configuration**” opens.

1. So first, click on “**Advanced Configuration**” to display all the configuration registers.
2. Then click on the small ‘+’ on the **CFG-TPMODE** line
3. You can now have access to an expanded menu and click on **CFG-TPMODE-SVIN\_ACC\_LIMIT**
4. Enter a valid position value in millimeter with a 0.1mm scale (ex : a value of 1m = 10000 / a value of 3.2598m = 32598 / a value of 0.0054m = 54, etc... )
5. Click consecutively on **RAM**, **BBR** and **Flash** to write changes into RAM and both non-volatile memories (BBR and Flash)
6. Check the 3 corresponding commands are present in the “Ready to send” box and then click on ‘**Send**’

![](/files/-LYff_1tH-j8bKWfjfPO)
{% endtab %}
{% endtabs %}

{% hint style="success" %}
You have successfully set the Survey-in Time Duration and Position Accuracy limit !
{% endhint %}

> Keep in mind the smaller the position accuracy is, the longer the RTK fix duration.


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