This disclosure describes systems, methods, and devices related to uplink (UL) null data packet (NDP) format for passive location. A device may cause to send a trigger frame that solicits poll response to one or more anchor stations involved in a passive ranging measurement. The device may identify one or more polling response frames received from the one or more anchor stations. The device may cause to send a trigger frame that solicits uplink null data packet (NDP) to the one or more anchor stations, wherein the uplink NDP comprises an indication of a high efficiency (HE) single user (SU) frame type. The device may identify one or more uplink NDPs received from the one or more anchor stations.