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  • Richard Weremiuk

What is tracking and how does it work?


You often hear terms ‘GPS tracking’ and ‘satellite navigation’. These terms are sometimes confused by consumers. ‘Satellite navigation’ refers to a device which provides turn-by-turn instructions to guide you to a destination. ‘GPS tracking’ refers to a device sharing your location, typically via a weblink, so remote viewers can see where you are.


We all commonly use the term “GPS”. GPS is the American satellite constellation which became live in 1993. Other constellations now exist too; in 1993 Russia launched GLONASS. China launched BeiDou in 2015, and The European Space Agency has recently completed their Galileo constellation.


Most modern tracking and navigation devices do not rely only on “GPS”, they use “GNSS”, which means they can receive signals from some or all those other constellations.



Photo Credit: https://globalgpssystems.com/


A mobile phone, or a dedicated tracker calculates your position by “receiving” broadcast signals from those satellites. If your device has sight of at least 3 satellites, then it can calculate your 2D position (longitude and latitude). If your device receives signals from 4 satellites, then it can calculate your 3D position – this adds your elevation.

OK, now that your phone or tracker “knows where it is” in the world, it needs to send that information somewhere i.e., typically to a server on the internet, to display your location to viewers. This is where the critical difference splits the devices. Most mobile phones are connected to one network (in the UK; EE, O2, Three, Vodafone). If your mobile phone is taken into an area where it has no signal, then it will be unable to send your location to the internet. This raises a key issue for safety.


Dedicated tracking devices sometimes use mobile signal to send their data, or in some cases transmit directly to satellites and thus have no reliance on mobile network availability.


Should you use a tracking app or a dedicated tracker? This is a popular question, or you may often see a common argument, “Why should I use a tracker when I can just use my mobile phone and an app?” Let us look at what is available and the pros and cons of each.


Mobile Phone and a Tracking App

There are many mobile applications that will track your location and share it via a weblink. Some of these applications are free, and others have a one-off cost and/or a monthly subscription.


Strava Beacon



Photo Credit: https://blog.strava.com/beacon/

Strava Beacon is free-to-use without a Strava subscription, providing you carry your mobile phone with you to record the activity. If you want to use Strava Beacon via an Apple Watch or a Garmin device, then you will require a premium Strava subscription.

Once activated, Strava Beacon sends your location every 15 seconds to a unique weblink that you can share with your contacts. Your current location is shown on a Google map, along with the time of the last location update, as well as a breadcrumb trail of your recorded route. Your contacts do require Strava installed to see this information.



Other mobile Apps

Find My is free functionality built into Apple devices so you can share your location. Android Find My Device is the equivalent. There are also paid apps such as FollowMee, which have a small cost to purchase, and then there are various paid features you can unlock. All of these will share your location to a basic map in a similar way to Beacon.



Pros and cons of mobile app-based tracking

Pros

· Free to use in most cases. Well, “free” in so far as you are leveraging the £500 to £1000 investment you made in a smartphone

· Easy to use. Typically, use involves activating the sharing feature and this prompts an outbound SMS with a URL to your contacts

· Accurate and “live”. Your location is updated often, usually every 15 seconds


Cons

· If your planned route roams into an area of no mobile coverage, your location will not be shared until you emerge back into coverage

· Use of tracking apps will run down your mobile phone battery much faster. Strava Beacon, broadcasting at 15 second intervals will deplete a phone after only a few hours use

· Most free apps share your location on a basic map type, such as Google Maps, which lack the route and elevation detail shown on Ordnance Survey maps. It is not easy to discern if your location is a public right of way or otherwise


Dedicated Trackers

There are many dedicated trackers available to hire or buy. Here we will discuss the three most popular types; LTE/GSM, SPOT, Iridium.


GSM (and more recently LTE)



If you have ever been given a tracker to use on an organised mass hiking/running event, it will almost certainly have been a GSM tracker. These devices are fitted with a multi-network SIM card, so they will transmit on any of: EE, O2 or Vodafone (Not Three), and they will send your location via the old 2G band. Worldwide, some countries have already completely phased out 2G. The UK networks have announced that 2G is to be phased out from 2025. If you are in the market to buy a dedicated tracker of this type, ensure it is one of those recently manufactured that transmits on 4G/LTE.


GSM/LTE devices do not have a screen. They will transmit their location every minute with battery life of a few days. The update frequency can be set as low as 10 seconds, but the battery will expire in under 24 hours. The devices are lightweight, usually under 100 grams. They are usually secured on the shoulder in a pouch or pocket. The batteries are fitted lithium cells, usually charged from USB or by wireless charging. Their SOS button will usually trigger SMS to one or more contacts that you can specify.


Pros

· Small, lightweight, under 100g

· Lowest cost to hire or buy

· They provide the fastest location updates (as fast as 10s)

· They will work reliably under heavy tree canopy

· Location can be sent to a 3rd party tracking platform and displayed on advanced maps (OS), and viewed alongside multiple other trackers (for example in a race)


Cons

· Rely on the availability of at least one network’s 2G (or LTE in some cases) mobile coverage

· Purchased LTE trackers require an active subscription (typically £10 a month)

· Do not directly request a rescue service in event of SOS


SPOT Trackers



A SPOT tracker transmits its location via the Globalstar constellation of satellites. There are 24 Globalstar satellites in orbit. The SPOT advantage is that they are not reliant on mobile networks. However, there may not always be a Globalstar satellite in line of sight for a successful location transmission. SPOTs work in most areas all over the world with the following exceptions: no coverage in the Polar regions, and intermittent coverage around the equator and some oceans. SPOT do not transmit under tree canopy or anywhere they are unable to get line of sight to one of the satellites in their constellation; this can include hilly/steep sided terrain and valleys; for example, you will not a location update every 5 minutes whilst on the Lake District or Snowdonia mountains.


SPOT Trackers can send OK messages, preset custom or help messages, and have a dedicated SOS button. They use 4 x AAA batteries which typically last a couple of weeks, depending on use.


Pros

· Excellent battery life, replaceable batteries

· Fairly small and lightweight; around 150g

· Do not require mobile network to transmit their location

· Dedicated SOS button for emergency rescue

· Location data can be sent to a 3rd party tracking platform and displayed on advanced maps (OS), and viewed alongside multiple other trackers (for example in a race)


Cons

· Only send one update every 5 minutes unless you pay more

· Require line of sight to satellite (do not work under trees)

· Does not provide 100% global coverage

· Purchased SPOT trackers require an active subscription (typically £20 a month on a flexible contract)

· Location data is not buffered/stored on the device if it is unable to transmit on schedule; instead the location point is “forgotten”

· SPOT maps are basic (no OS maps)


Iridium Trackers



Popular examples of such devices are Garmin inReach, and Yellowbrick. These trackers transmit location via the Iridium constellation of satellites. There are 82 of these in orbit, providing 100% global coverage. Iridium devices still require line of sight, so may not work under heavy tree canopy, though with more satellites on orbit they are more reliable under tree cover and in hilly areas than SPOT devices. This reliability is reflected in the high cost of purchase and the high cost of satellite data plans. Many Iridium devices are also two-way communicators. Either natively, using the device controls, or by connecting a mobile phone via Bluetooth, the user can send preset or freeform SMS to any mobile phone (or another Iridium device), and they can also send email and in some cases update social media. Some devices have screens and mapping, so can provide navigation, and can also receive weather reports. Iridium’s have a dedicated SOS device to request rescue.


Iridium devices usually have a fitted lithium battery, which can last 2-4 days, if screen use is minimized.


Pros

· 100% global coverage

· Smallest device weighs 100g (inReach Mini)

· Feature dedicated SOS button for emergency rescue

· Location data can be sent to a 3rd party tracking platform and displayed on advanced maps (OS), and viewed alongside multiple other trackers (for example in a race)


Cons

· Only send one update every 10 minutes unless you pay more

· Some devices weight 250g or more

· Require line of sight to satellite

· Purchased Iridium trackers require an active subscription (typically £40 - £90 a month on a flexible contract)

· Manufacturer maps are basic (no OS maps)


Summary

If you are out in a local urban area, or a hike/run of a few hours in length in an area with good mobile coverage, use your mobile phone with an app such as Strava Beacon.


If you regularly hike in more rural areas (including Lakes, Peaks, Dartmoor, Exmoor) where there is 2G coverage on at least one mobile network, or need a device which can last many days, LTE tracker is a good choice.


If you regularly hike in the most remote areas (Cairngorms, Brecon, Snowdonia, Yorkshire Dales) where there are very large gaps in mobile coverage then a SPOT device is useful.


If money is no object, and you want the most reliable communication, including two-way SMS, then choose an Iridium device.


You can Rent a GPS Tracker or Purchase a GPS Tracker here

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