Drone locates lost 92 year old hunter

Posted by: bws48

Drone locates lost 92 year old hunter - 12/19/17 04:39 PM

I think we have discussed using drones in SAR operations in other posts, but here is an article about a recent success.
https://wtop.com/loudoun-county/2017/12/missing-hunter-found-thanks-loudoun-county-drone/slide/1/
Posted by: hikermor

Re: Drone locates lost 92 year old hunter - 12/19/17 07:50 PM

I'll bet stories like this will become common in the future. Drones can often shorten the 'search" phase of SAR, which in olden days, was typically the most time consuming and labor intensive aspect of the operation.
Posted by: Russ

Re: Drone locates lost 92 year old hunter - 12/19/17 08:09 PM

Is there a drone payload that can detect cellphone signals? Not talking about a system like Stingray, just a system that could search for and ping a specific cell phone number, and using the ping determine a distance via the time of the response. Do that a few times from a moving platform and you have a location. Just wondering.
Posted by: hikermor

Re: Drone locates lost 92 year old hunter - 12/19/17 11:15 PM

Can't they do that anyway,from stationary installations? I believe something like that narrowed the search area for the Kim family. In their case, I think they used their phone, recording data that eventually put the searchers in the right ballpark...
Posted by: AKSAR

Re: Drone locates lost 92 year old hunter - 12/20/17 12:09 AM

Originally Posted By: hikermor
Can't they do that anyway,from stationary installations? I believe something like that narrowed the search area for the Kim family. In their case, I think they used their phone, recording data that eventually put the searchers in the right ballpark...
Yes, kinda, sorta, maybe, sometimes fairly accurately, sometimes only a rough location. It depends. These days it is referred to as "cell phone forensics".

Each of those vertical looking things one sees on a cell tower is an antenna, that covers a certain angle or sector. If the phone is detected by several towers, it is possible to triangulate between those antenna and get a position. With more than one tower receiving the signal, I believe they can also do a triangulation, of sorts, using the relative signal strengths received by each tower.

Additionally, using GIS technology and a digital elevation model (DEM), they can tell which areas are masked by terrain, where the phone is not located, which is also useful information, especially if combined with other data.

However, in areas with minimal cell coverage, the phone may only be hitting one tower. In that case, often the best they can do is say "it's over that way, somewhere" or words to that effect.

There are, of course, privacy issues involved. However, here in Alaska, the State Troopers have worked out regulations/procedures/policies with the cell providers so that in an emergency SAR situation they can quickly get whatever location information that can be derived in a particular situation. It is important that these regulations/procedures/policies are in place in advance, since some of this cell tower data is not retained by the providers for more than a couple of days. I suspect most areas in the country have worked out similar agreements.
Posted by: hikermor

Re: Drone locates lost 92 year old hunter - 12/20/17 02:03 AM

Very informative response, AKSAR. I am relly impressed with the technology available for facilitating SAR efforts. The use of drones in national park areas is still being worked out, where their potential is vast, not just for SAR. A drone was used in a search in Grand Canyon NP last year to good effect, so they are available on a limited basis.
Posted by: tangelo

Re: Drone locates lost 92 year old hunter - 12/20/17 07:18 AM

Great news! That will be a wonderful new application of drones.
Posted by: M_a_x

Re: Drone locates lost 92 year old hunter - 12/20/17 01:37 PM

Cell phones ping on their own when they try to log in to stations. There are devices that offer a virtual stations (law enforcement uses them around here). With an array of antennas it is possible to determine the direction of the signal. When using phase shift detection the direction should be fairly accurate.
The distance is not that easy to determine. The phone has some unknown latency when processing and returning the signal. That latency is enough to invalidate the measurement as the signal travels at light speed.
Posted by: chaosmagnet

Re: Drone locates lost 92 year old hunter - 12/20/17 01:50 PM

The only ways to "ping" a specific cellphone number are with the telco's systems ("central office", connections to cell towers, and the cell towers themselves) or with something that emulates those capabilities, such as Stingray.

Smartphones, when connected, can be made to send their precise GPS coordinates to the telco.
Posted by: AKSAR

Re: Drone locates lost 92 year old hunter - 12/20/17 07:06 PM

A couple of further comments regarding cell phone forensics and lost person searches.

These days, in a well run search, an investigation happens simultaneously with field searching. Ideally, this investigation is done by a team, composed of a law enforcement officer and an experienced search team member. The search team member knows what questions to ask that will most help the field teams, and the LE officer has authority to obtain some info that the searcher does not (such as cell phone data). In most areas one of the very first question asked will be "does the subject have a cell phone, and what is the number?". The LE officer will then immediately initiate the cell phone forensic effort.

As I noted earlier, how much info can be obtained from a phone depends on a number of factors, especially on how many cell towers recieved pings from the phone. Unfortunately here in Alaska, cell phone coverage outside of the larger towns is spotty at best. Thus, cell phones often only hit on a single tower. I've personally been involved in at least two searches where the only location info we could get from the cell phone was a very general direction. We successfully found one of these subjects, and one remains missing to this day.

The key to any search is combining all the info and clues that are available, and using that to allocate the always limited search resources to the most likely areas. Sometimes, just knowing when the last time the cell phone pinged a tower can be helpful. We do the best we can with whatever info we have.

You all stay safe and have a Happy Holiday Season!
Posted by: hikermor

Re: Drone locates lost 92 year old hunter - 12/21/17 04:18 AM

War story time. Your post recalls a search in 1970, pre cell phone era. Two guys went hiking in the Santa Catalina range, just north of Tucson. One became ill and his companion went for help. After a week, the ill individual came out of the range, with no idea of where he had been, or how he had gotten out. His companion was nowhere to be found, evidently still in the mountains.

This launched a massive and long lasting search for the missing man. Background research indicated that the person was due for induction into the armed forces within two weeks of his disappearance. Although some of us more cynically inclined thought that our subject had probably reached Canada before the search even began, we continued for weeks. Years later, we would occasionally call out for Donald Lee Curtis, whenever searching in the Catalinas. The range is not as big as Alaska, but it is big, and precipitous enough to present a significant challenge to search efforts, especially with no point last seen.

Search strategy and tactics are well advanced from those early days...
Posted by: BruceZed

Re: Drone locates lost 92 year old hunter - 12/21/17 08:15 PM

Technology, is great when it works and very dangerous when it fails and we are relying on it.
Posted by: hikermor

Re: Drone locates lost 92 year old hunter - 12/21/17 10:35 PM

Originally Posted By: BruceZed
Technology, is great when it works and very dangerous when it fails and we are relying on it.


True enough, and the key is not to "rely" upon any one mode, but to "utilize it, along with other techniques. When I was doing SAR, an area had not been exhaustively searched until a ground party had entered the area, a dog team had sniffed out the area, and a helicopter had flown over - at a minimum. Drone usage would just be another arrow in the quiver, combining characteristics of ground and aerial searching.