# 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.

![](https://3825805345-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LYSZeu4HjB-NrVI4riL%2F-LdEnSI1uNcnTmxfEH77%2F-LdEnYZLwhXVFEwUuCNY%2Fassets_-LYSZeu4HjB-NrVI4riL_-LZ5e77FV8hJoLVGS7xa_-LZ5eg7yAUc-02Xt3jdx_USB_connect-\(1\).png?alt=media\&token=9818d259-dd93-4562-ace6-7d07e705f9f9)

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)

![](https://3825805345-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LYSZeu4HjB-NrVI4riL%2F-LYbICDde_PqBQRMcCsl%2F-LYbIddBqnC-aXKJ1bxh%2FSans-titre-1.png?alt=media\&token=240244db-09d5-40e8-9735-869651b9198e)

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.

![](https://3825805345-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LYSZeu4HjB-NrVI4riL%2F-LYbGvHfj8nIN6gywxBz%2F-LYbHSKTiJZ0j0qAf-5e%2Ficon_blink.png?alt=media\&token=0f35cbc4-ce5a-4d3b-90f4-ecadc5a36821)

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

![](https://3825805345-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LYSZeu4HjB-NrVI4riL%2F-LYbTIvEVGMGLVnSeoFn%2F-LYbUsIAWEUg8JmCOVN6%2Fstep3.png?alt=media\&token=bd43162b-1a87-42b7-b165-c0ce0504ebe4)

{% 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**’

![](https://3825805345-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LYSZeu4HjB-NrVI4riL%2F-LYbfaexRzEQJkoinOLN%2F-LYbg7Y5DbnCjpv9Zv0C%2Fstep4%20change_SV-inTime.png?alt=media\&token=0e12c4ee-e3eb-47fc-9516-de277e74d682)
{% 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**’

![](https://3825805345-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LYSZeu4HjB-NrVI4riL%2F-LYffWVCkdDQKgr9QGNr%2F-LYff_1tH-j8bKWfjfPO%2Fstep4%20change_Accuracy.png?alt=media\&token=25bd4568-9cd7-48f3-ab47-80f91f85b652)
{% 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.