What purpose do the obelisk of senusret and other obelisks serve

Typically, obelisks were created to represent and honor Ra, the Egyptian god of the sun. In addition, people believed that gods actually inhabited the obelisks. The Obelisk of Senusret, in particular, was created to honor Senusret I of the Twelfth Dynasty of Egypt. It is the earliest obelisk still standing and intact. Hope this helps.