"The messenger of Allah ﷺ was asked during the campaign of Tabuk about the Sutra of one who is praying. He said: "Something as high as the back of a camel saddle."  

سُئِلَ رَسُولُ اللَّهِ ﷺ فِي غَزْوَةِ تَبُوكَ عَنْ سُتْرَةِ الْمُصَلِّي فَقَالَ مِثْلُ مُؤْخِرَةِ الرَّحْلِ  

It was narrated from Ibn Umar concerning the Messenger of Allah ﷺ he said: "He used to set up a short spear then pray facing toward it."  

عَنِ النَّبِيِّ ﷺ قَالَ كَانَ يَرْكُزُ الْحَرْبَةَ ثُمَّ يُصَلِّي إِلَيْهَا