# 1. Reference Station Setup The primary purpose of a GNSS reference station is to collect GNSS data in the form of raw observations. Raw observations are all measurements recorded by the reference station. If you want to post-process the rover's trajectory, raw observations from the reference station are needed. [Set up the GNSS reference station to log differential corrections at intervals of 1 Hz](https://www.phoenixlidar.com/wp-content/uploads/2019/10/PLS_Stonex_S900_Static_Base_Configuration_Via_Web_User_Interface.pdf). A direct connection to the rover is NOT required if you wish to post process your trajectory through PPK [NavLab or Intertial Explorer processing](https://docs.phoenixlidar.com/lidarmill-desktop/post-processing/workflow-kk/trajectory-processing). If you wish to transmit real time differential corrections from a GNSS reference station to your rover, make sure the reference station’s communication and protocol parameters have been configured to match the rover’s corresponding parameters within [Spatial Lighthouse](https://docs.phoenixlidar.com/rover/theory-and-workflow/reference-station-setup/spatiallighthouse). We recommend mounting the reference station antenna onto a survey-grade tripod with a clear view of the sky away from buildings and powerlines. To prevent any discrepancies when measuring the Antenna Reference Point (ARP) height, we recommend a fixed height survey grade tripod. This will ensure a uniform measurement throughout all scanning missions. 1\. Set up the tripod and mount the reference station antenna onto the tripod. 2\. Document the Antenna Reference Point (ARP) height above the ground. Refer to SpatialLightHouse’s [Position](https://docs.phoenixlidar.com/rover/theory-and-workflow/reference-station-setup/spatiallighthouse/connect-to-a-private-reference-station/position#reference-station-height) for a more detailed explanation on how to calculate the ARP height. 3\. Power the reference station and begin logging GNSS raw observations at 1 Hz. This will allow you to post-process the trajectory in software such as Inertial Explorer or LiDARMill. {% hint style="warning" %} When powering a CHC X900+ GNSS reference station, make sure to ONLY use a 4 cell LiPo battery. Using a LiPo battery with more than 4 cells will electrically overload the Reference Station’s circuits, causing irreparable damage. {% endhint %} 4a. **Stonex S900**: The Stonex can be set to manually log upon establishing a connection through the Web UI Config. Alternatively, it can be set to log automatically based on a minimum number of satellites. Please reference our [**Stonex S900 Static Base Configuration Via Web User Interface**](https://www.phoenixlidar.com/wp-content/uploads/2019/10/PLS_Stonex_S900_Static_Base_Configuration_Via_Web_User_Interface.pdf) User manual for more details. 4b. **CHC X900**: Set to manually log upon pressing a button or auto log based on a minimum number of satellites. A secondary method of connection is to set up a portable computer (base station) and connect it to the GNSS reference station via Bluetooth or USB/Serial communication. If you are pairing via Bluetooth, the GNSS reference station Bluetooth passkey is 1234. ## SpatialLightHouse (Optional) {% hint style="success" %} **If you want to add differential corrections to your raw observations, SpatialLightHouse can be used. However, post processing your trajectory eliminates the need to add this complexity in real-time.** {% endhint %} 5\. Launch SpatialLightHouse and configure the input to receive differential corrections from the reference station (USB/Serial or TCP/IP) and the output to transmit differential corrections to the rover. Refer to [SpatialLightHouse](https://docs.phoenixlidar.com/rover/theory-and-workflow/reference-station-setup/spatiallighthouse) for more information. {% hint style="info" %} The most common configuration used is to have the input (laptop) receive differential corrections from the reference station over USB/Serial. Make sure to select the correct outgoing COM port in SpatialLightHouse. To transmit differential corrections to the rover, you can select as TCP client with Rover Hostname as rover-wifi if using Wi-Fi or via the Phoenix LiDAR Systems connection service if using a 3G/4G cellular connection. {% endhint %} 6\. Start the SpatialLightHouse session and wait until the session is configured. 7\. If you want to verify the reference station’s configuration, you can launch SpatialExplorer and connect to the rover. Make sure the rover is powered on. If connecting to the rover as a TCP client, make sure to use the correct Rover Hostname; via ethernet use rover-wire and via Wi-Fi use rover-wifi. Once connected, within SpatialExplorer, verify the Position Status (PosStatus) as Computed and the Differential Corrections (CorrAge) received as 0. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs-6.phoenixlidar.com/rover/theory-and-workflow/reference-station-setup.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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