There are three UAV tracking modes as follows (see TS 23.256
for more details):
UAV location reporting mode;
UAV presence monitoring mode; and
Unknown UAV tracking mode.
The first two relate to obtaining location information about a particular UE while the latter one is about obtaining information about all the UEs in a particular geographic region.
For the first two mode before proceeding with the request for information about the particular UE, the UAS NF shall ensure that the requesting USS is the one that authorized the UE.
For the latter mode, a USS is authorized to receive the CAA level ID of all UAVs in a geographic area indicated by the USS. In addition, if the USS performed the UUAA of the UAV, or the UAS NF is configured to know the USS is authorized to receive such information, then the 3GPP UAV ID of such UAVs is also included.
USS may receive the location information which is reported by UAV via the application layer. The USS may decide to check and verify the location information in order to prevent spoofed and forged location information. The location result from 5GS helps to verify the location information reported from UAV side. 5GS provides network-based location information by utilizing the Location Services (LCS) supported by AMF or GMLC as specified in TS 23.273
and TS 23.502
, and the detailed procedures of location information veracity and location tracking authorization are described below.
Step 1-3 shows the procedure for the USS to obtain a network-based location for UAV(s).
The USS sends the location request to UAS NF/NEF to request the UAV location or presence from network. The location request includes the GPSI of the UAV to request the location information or presence about an individual UE, or a geographic area when trying to find the information of all UAVs in an area. The LCS request also indicates the 5GS to obtain reliable UE location information, i.e. the location calculated and provided by the network.
If the USS/TPAE does not specify target 3GPP UAV ID and request UAS NF for a list of the UAVs in the geographic area and served by the PLMN, clauses 220.127.116.11
in TS 23.256
The UAS NF/NEF first verifies the request in step 1 is authorized. When the USS sends a GPSI, this is done by checking whether the identifier of the USS sending the request matches the previously associated mapping between the GPSI and the USS identifier. When the USS request UAS NF for a list of the UAVs in the geographic area, this is done by checking the USS is authorized to receive the CAA level ID of all UAVs in a geographic area indicated by the USS. The UAS NF/NEF gets the relevant UAV(s) location information or presence from AMF or GMLC by the current location services supported by AMF or GMLC if passes the above authorization check. On the condition of the location services provided by AMF, the UE presence status is provided by reusing the Area of Interest mechanism. On the condition of the location services provided by GMLC, the GMLC indicates LMF via AMF to select Network Assisted Positioning method which relies on the location measurement from NG-RAN nodes, if receiving reliable location information request in step 1.
The UAS NF/NEF provides the UAV(s) location information or presence to the USS. When the USS request UAS NF for a list of the UAVs in the geographic area, if the USS performed the UUAA of the UAV, or the UAS NF is authorized to receive such information, then the 3GPP UAV ID of such UAVs is also included. USS may make decisions to control the UAV based on the result output received from UAS NF/NEF.