Emergency calls via cell phone

To Ian H-SAR doesn`t have direction finding equipment.It needs to be airborne,so Rescue choppers have them & some private chopper outfits.I believe they`re quite pricey too.

Thanks lewshaw, nice to hear direct from someone in the know

So, @lewshaw, anyone else involved in SAR, at the point that they are putting in an air search, do they generally have cell phone direction finding equipment on board? Or is it capability that exists that police might bring in if they thought it might help in a given situation? Just trying to get an idea of how prevalent this technology is, whether it is deployed as a matter of course in a search where it might help locate someone.

SAR exercise with new GPS tracking technology http://www.newshub.co.nz/nznews/search-teams-tackle-stewart-island-cold-case-25-years-on-2016100911#.V_tCjDEYTE8.facebook

I'm in Tauranga SAR and we don't have any such thing as mini cell towers. More & more of our searches are solved by a cell phone locate that the Police can initiate but I believe that requires cell reception from the lost party. That's getting better & better, especially in our area of the Kaimai ranges. The other weekend our cells were more reliable than our radios. We don't have much gear though, we still use Garmin GPSMAP 60's and only recently our group brought four 64s's. Other than Jackets, Radios & GSP's everything else is our own gear.

Ricochet, may I ask why not use GPS on your phone?

IMO using a phone as a GPS lacks many of the features of a dedicated GPS and may contain more bugs as they are not "commited" as a single GPS unit. Where as A GPS unit is dedicated for navigation, you can replace the batteries easily and are built for outdoor use so will be less prone to environment damage

A LandSAR rep could answer this with more authority, but I'm sure one thing you'd definitely get with stock-standard provision of a particular GPS model is consistency for something that's probably now fairly critical to LandSAR operations when it comes to keeping track of where people have been and where they're going. That'd be consistency with training, reliability and expectations, and compatibility with all the processes and documentation in place. My smartphone has an okay GPS. Most people I know probably have one and with the right software they could probably read off grid references and whatever. But they probably have different antenna (and so many manufactures don't prioritise clear descriptions of their internal GPS hardware) and other hardware, different battery lives. They'd also react differently when different software is installed (if it installs at all) depending both on the phone itself and whatever other random software and treatment people have given the phone during their own personal use.

As far as I know cellphones use standard gps receivers working down to about -160dBW (-130dBm). This gives them about 5db of margin from the ideal signal of -155dBw arriving at the earths surface from the gps satellites. A raincloud, heavy fog, trees, reflected signals of valkeys/buildings, electrical intrrference can all easily knock enough off the incoming signal to stop it working. High sensitivity gps receivers such as those using the MTK chipset (used by my qstarz receiver) receive down to -195dBW (-165dBm) - meaning they can still work with a 30dB lower (1000 times weaker) signal. They achieve this by using powerful digital processing algorythms to pick the gps signal out of the background noise - and so are also more immune to interference, reflections, etc. Some info here: https://en.m.wikipedia.org/wiki/GPS_navigation_device https://www.google.co.nz/url?sa=t&source=web&rct=j&url=http://www.canadagps.com/KB_04.html&ved=0ahUKEwiInpT-ttLPAhVDND4KHTadDgEQFggiMAE&usg=AFQjCNEIEirXpl2O5DdQGo2PZJE94Zr-9A&sig2=Evs25HtXzp10KVVzGpHwiw Edit: Things may be improving. The latest Samsungs for example use the BCM5741 chipset which claims to be high-sensitivity. But they are really quiet in all their advertising and even specificationd, not saying how sensitive the chip actually is.... weird as that is the main selling point of high sensitivity chipsets: https://www.broadcom.com/press/release.php?id=s443754

The new Samsung Note can also be used as an emergency fire lighter Sorry, I couldn't resist:)