It was only a mat­ter of time before drones start­ed mon­i­tor­ing sig­nals from mobile devices.

Since ear­ly Feb­ru­ary, sev­er­al small drones fly­ing around the San Fer­nan­do Val­ley in Los Ange­les have been deter­min­ing mobile devices’ loca­tions from Wi-Fi and cel­lu­lar trans­mis­sion signals.

They are part of an exper­i­ment by Sin­ga­pore-based loca­tion mar­ket­ing firm Adnear, which has offices around the world. The firm told me that, to its knowl­edge, this is the first time an adtech com­pa­ny has employed drones to col­lect wire­less data.

The cap­ture does not involve con­ver­sa­tions or per­son­al­ly iden­ti­fi­able infor­ma­tion, accord­ing to direc­tor of mar­ket­ing and research Smri­ti Kataria. It uses sig­nal strength, cell tow­er tri­an­gu­la­tion, and oth­er indi­ca­tors to deter­mine where the device is, and that infor­ma­tion is then used to map the user’s trav­el patterns.

“Let’s say some­one is walk­ing near a cof­fee shop,” Kataria said by way of example.

The cof­fee shop may want to offer in-app ads or dis­count coupons to peo­ple who often walk by but don’t enter, as well as to fre­quent patrons when they are else­where. Adnear’s client would be the cof­fee shop or oth­er retail­ers who want to entice passersby.

Although this exper­i­ment in the Val­ley is cur­rent­ly test­ing loca­tion-map­ping from drones and is not yet used to send ads, Adnear said it cur­rent­ly has over 530 mil­lion user pro­files cov­er­ing var­i­ous Asian mar­kets for its oth­er loca­tion-based campaigns.

Nor­mal­ly, Adnear col­lects these mobile sig­nals on bikes, cars, trains, and, on occa­sion, stairs. It con­ducts this ground-based col­lec­tion so it can read­i­ly map the strength of the sig­nals against the near­by tow­ers or Wi-Fi hotspots. Drones, of course, offer bet­ter cov­er­age than ground-based meth­ods, and can be used in areas inac­ces­si­ble by vehi­cles or foot.

“With drones, it becomes so much eas­i­er,” Kitaria told me.

A mobile user needs to have an app open that is trans­mit­ting via cel­lu­lar or Wi-Fi for this map­ping to occur. The app does not need to be send­ing loca­tion coordinates.

The sys­tem iden­ti­fies a giv­en user through the device ID, and the loca­tion info is used to flesh out the user’s phys­i­cal traf­fic pat­tern in his pro­file. Although anony­mous, the user is “iden­ti­fied” as a code. The com­pa­ny says that no name, phone num­ber, router ID, or oth­er per­son­al­ly iden­ti­fi­able infor­ma­tion is cap­tured, and there is no pho­tog­ra­phy or video.

Kataria told me that “cap­tur­ing pho­tos [via drone] is some­thing which is scary, and that’s not right.” She added that Adnear has “no need” for pho­tos or videos.

Sev­er­al drone mod­els are being used in this tri­al, includ­ing the Phan­tom 2 Vision, and they fly no high­er than 500 feet. One oper­a­tor is assigned to each drone. The tri­al will con­tin­ue through this quar­ter, after which there may be com­mer­cial deployments.

Data col­lec­tion and loca­tion map­ping is going well so far, she said, but there are issues with drone bat­tery life. The next tests will be in Asia, prob­a­bly Singapore.

“Very few com­pa­nies world­wide — and no oth­ers in Asia — have a tech­nol­o­gy” to map loca­tions from these kinds of sig­nals, she said.

Researchers have shown that drones can read­i­ly take the snoop­ing fur­ther. Mobile devices are con­stant­ly look­ing for Wi-Fi hotspots, and a drone can emu­late a Wi-Fi trans­ceiv­er and cap­ture all transmissions.

And, while Adnear may not be inter­est­ed in visu­al or iden­ti­fi­able infor­ma­tion, drone evo­lu­tion will inevitably include that unless there are clear reg­u­la­tions otherwise.