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OS GPS FAQ

1 - Your device

You can find the manuals and quick start guides available to view from our support page.

GLONASS and Galileo are alternative satellite navigation system to GPS. When used in conjunction with GPS it offers more satellites for a device to use, which can improve the speed and precision of a position fix in environments with a restricted view of the sky. Aventura 2, Trail 2 and Trail 2 Bike support GLONASS and Galileo, while earlier devices support GPS only.

You will need access to a Windows PC or Mac to install the software that allows you to download maps and transfer to your device. You will also need a computer to retrieve GPX files for upload into OS Maps. At the moment we don't have support for Linux installations, so an emulator may be required.

Aside from those functions, your GPS device can work without using a computer.

We will occasionally release updates to add or improve GPS features. These will appear as a pop-up message on the main screen when your device is on and connected to WiFi. Accept the update and wait for it to be applied - this may take a few minutes - and do not turn off the device while it is updating. Unfortunately the update cannot be performed via USB connection to a computer, as the update may affect the USB connection itself.

The Horizon and Aventura both accept an optional micro SD card to increase memory capacity. You can access the micro SD card slot by removing the back cover and lifting out the battery. The SD card can be used to store maps and routes. When you download your first map or route file, if an SD card is present you will be given the option to save it to that location.

We recommend class 10 ultra high speed SD cards for both devices. If it is not already formatted, you will need to format the card as FAT32 (for cards up to 32GB) or NTFS (for any size card, especially larger ones).

Yes, you can display the data from both internal and external sensors to show on screen. There are over 110 different measurements to show, including position, altitude, speed, heart rate, pedal power, air pressure and more. This can be configured for each activity type by going to 'Activity Profiles', selecting a profile and then selecting 'Data Pages'.

There are three options:

  • Long press and release on the map. A panel will appear at the top with the location of the point clicked (and distance from where you are now)
  • Tap top bar, then GPS to show current location and satellites in view
  • Add coordinates as a data field on one of the data pages. Switch to the data screen using the left/top left button, long press on one of the current data fields, click 'change this field', select 'GPS', then 'coordinates'. You can also change the data screens from settings.

By default, your device will show GB Grid Ref. For other coordinate systems, like Lat/Long or other countries' grids, go to Main Menu > Settings > System > Coordinates.

Tap the top bar to get the status screen. Scroll to WiFi and select, then tick the box to activate WiFi. Click on 'Scan Now', and when your network appears select it and enter your network password. Wait for the device to connect to WiFi - the icon in the top bar will turn blue.

To extend battery life in use:

  • Turn off WiFi and any external Sensors when not in use (Top Bar > WiFi / Sensors)
  • Turn down screen brightness (Top bar > Brightness)
  • Set screen shutdown to a short interval (Menu > Settings > Display > Shut Down Screen)
  • Reduce GPS checks (Top Bar > Battery > GPS connections interval > Intermittent then set how often to check GPS in minutes)
  • Turn Broadcast off (Top Bar > Broadcast)

The Li-ion battery in the device should last 500 - 1000 recharge cycles before showing any signs of degradation. There's no need to completely discharge the battery before charging again. Like all li-ion batteries, to extend the battery life do not leave continually connected to mains power - disconnect once it is fully charged. If you intend to store the device for an extended period of time without using it, allow it to run down to around 40% of battery remaining before turning off, and then fully charge before use.

If your device is not responding to the normal power off or reset buttons, there is a hard reset feature. For Velo, Horizon, Trail and Aventura, hold down both front buttons (on the Aventura and Trail the bottom two front buttons) for a few seconds. For Trail 2, hold the power button down for around six seconds.

The most common reason is that it is tricky to distinguish some letters and numbers, like I and O, from the printed label. Fortunately, there are two other ways to check the serial number:

  • Use a QR code reader on the small QR code next to the serial number
  • Menu > Settings > System > Device Info > ID to see it on screen

If you are still unable to register the device, please contact support for help, with your device name and serial number.

2 - Maps

To get your free tiles, please register your device with TwoNav at twonav.com/os. Once you have registered your device, follow the instructions to add them.

If this is the first tile you have purchased, you will be prompted to download and install the tile installer program. Ensure your device is connected by USB cable, follow the instructions, and accept any warnings from your browser or computer to allow it to install. The first tile will take a while to download as it also installs the basemap.

Subsequent tiles are installed in the same way, but will be much faster.

You get six free tiles with the Velo, Horizon and Trail devices, and twelve with the Aventura. You get access to the free tiles as soon as you register the device, and can use them all at once, or save some for later.

Once your free tile allowance has been used, you can also pay for additional tiles - for this reason we suggest that you use your free tiles to obtain the more expensive OS Explorer map tiles first.

If you have more than one OS GPS, you can download the tiles you own on to up to five of your devices registered to the same OS Shop account.

25k maps tiles average at 49MB each, while 50K tiles are 14MB. However, there is quite a lot of variation based on the amount of detail shown in the specific tiles chosen.

The total size, if you had all 518 tiles to cover all of GB would be 20.5GB for the OS Explorer 25k mapping and 6.31GB for the OS Landranger 50k mapping. The basemap is around 2.5MB. The below table shows the approximate storage size required for each region:

25k RegionSize
Cumbria, North East2.16GB
Devon and Cornwall2.02GB
East Coast1.85GB
Grampians2.39GB
Midlands, North West2.66GB
Highlands, Argyle1.72GB
Scottish Islands0.78GB
Scottish Lowlands2.05GB
South East, South Central2.51GB
Wales2.36GB

The amount you can fit in memory will also be reduced when you are using space to save recorded tracks or planned routes.

Each map tile is approximately 25km x 25km (15.5 x 15.5 miles), giving an area of 625km² (241 sq miles). There are small overlaps between the tiles, and the same grid is used for both OS Explorer and OS Landranger. As the tiles are on a grid pattern, some coastal tiles will contain limited mapping. Tiles with less than 50% land area are discounted.

Yes, you can open the device memory using a computer and USB connection, navigate to Data>Maps and remove unwanted tiles. The tiles are still available for re-download from your account at any time

The free basemap is the Ordnance Survey 1:250k Road map. It is downloaded automatically when you download your first tile, and will appear when you zoom out.

The GPS will work anywhere on the planet, but you will need to install the appropriate mapping. Ordnance Survey supplies mapping for Great Britain, while mapping for other countries is available from TwoNav. The maps cover Europe, North America, Australia and South Africa. Check the TwoNav site for the latest maps and areas covered.

Non-GB maps are not covered in the free tile allowance.

Please try these steps:

  1. Plug in your GPS to your computer, go back to 'Maps ready to download' and download the tile again
  2. Find the map tile file name by starting your GPS, opening Menu > Maps > GBTopo > List of Tiles then select the tile that is not working to see the file name. Now plug your GPS into your computer. Find the GPS memory under local drives, find the map tile file in Maps > GB_RTMAP and delete the file from the folder. Then re-download as normal.
  3. If you are still getting the error please contact us for further help.

Yes. You can find regional maps here.

The maps used on the GPS devices are specific formats, so you cannot use the maps available with an OS Maps Premium subscription, and must purchase the map tiles designed for them. However, each device does include some free map tiles, and a 3-year OS Maps Premium subscription, worth over £70

The maps used by the OS GPS devices are in a specific format, and also fall under different licensing than the maps used for the OS Maps online service. For this reason they need to be purchased separately, even if you have an existing OS Maps Premium subscription. In recognition of this, we've ensure every GPS purchase includes three years of access to OS Maps for free, which can be added to any existing subscription.

3 - Routes & activities

By default the routes are recorded as .GPX files. You can change this to .TRK files in the option settings per activity type.

OS GPS devices accept files in GPX and TRK format. Connect the GPS by USB to a computer, and copy the file to the Data folder.

In OS Maps, export your route as a GPX file, and then follow the instructions to manually add a route to the device

Go to Menu > Routes > then click on the boxes next to each route. Routes with blue ticks will show, while routes without will be from removed the map screen.

You can have multiple routes active at one time, which is useful to show alternatives or escape points.

Once you have registered your device, you will be emailed a username and password for the TwoNav GO service. Use this to log in, then click your account name in the top right and then 'Settings'. Click the 'connect' button in the Strava section and log in with your Strava details.

Yes. A GPX format GeoCache can be imported to the Data folder on the device using a USB connection. Disconnect the device, restart and go to Menu, Waypoints, and select the file name to turn on Geocache display. You can see details of an individual cache by clicking on it, and caches will be shown on the map view with the geocache symbol and name. You can change the geocache symbol and how it appears on the map by clicking on the file name and selecting 'Modify all waypoints'.

4 - Extra services

FullConnect refers to the breadth of connections options offered by the GPS devices. This includes WiFi, to synchronise routes with OS Maps and GO, Bluetooth and ANT+ to connect to accessories like heart rate monitors and the GPRS to send your position data or emergency signal over the mobile phone network.

SeeMe allows you to transmit your position every 5 minutes or so using the mobile phone network. This can be followed by users you select in the GO by TwoNav back end, once you have registered. It also allows you to use the 'Emergency' button that will transmit your last known location by SMS and email to two predefined emergency contacts. SeeMe will work in most European countries plus North America - see the GO site for the latest coverage information.

SeeMe requires a contract with a mobile phone carrier. The first six months is included with your device, and can be easily extended on the GO site. The cost after the initial 6 months is £26/year.

You need to follow a few steps to get the SeeMe function to work

  • In My OS GPS, follow the link to SeeMe on TwoNav
  • Follow the instructions to create your TwoNav account
  • Create at least one Emergency Contact and get them to verify the email or text
  • On the GPS device in Settings > My Account select 'Add account' and then TwoNav. Enter the username and password you used for the TwoNav account
  • Make sure you have a GPS lock at least once so there is 'last known position' data available

Use the code in the GPS package to get your 3-years OS Maps Premium subscription. If you are a free registered user, this will upgrade your existing account to Premium. If you already have a Premium account, this will extend your next renewal date by three years, even if you are a recurring subscription user. The only exception is if you have subscribed through the app; as we cannot directly control the app stores they will send you reminders or may automatically renew your in-app subscription. You will need to cancel this in your app store account - we cannot access this to do it for you.

If you do accidentally end up paying twice, get in touch with customer services for help.