I’ve seen plenty of old Android phones get repurposed as hiking GPS units. My neglected Samsung Galaxy TabPro S made me wonder why I couldn’t give a whole Windows tablet that same job.

Its larger screen gives much more for a zoomed-out map, while its camera could document a trip and its keyboard would allow me to blog about it later. For hikers, off-roaders, and anyone preparing for a day beyond the reach of cell towers, the tablet could easily be used for offline maps, route scoping, and waypoint planning.

I loaded up the maps, switched the Wi-Fi off, and took the ten-year-old Windows tablet outside to see whether its GPS and battery could actually keep up.

The GPS receiver was hiding in plain sight

Ironically, it was Linux that discovered the old hardware that could make this possible

A little while ago, I installed Linux on this tablet and had some issues with the camera and LTE modem drivers. I also vowed never to give up on trying to get the unsupported drivers to work.

It was in the middle of this process that I stumbled upon an unfamiliar Broadcom device. I honestly had no idea the device even existed, but it turned out to be a GNS satellite receiver. At the time, I was more focused on getting the mobile data working, so I made a mental note of it and carried on.

I eventually, and reluctantly, reinstalled Windows 10 on the device to reverse-engineer the LTE driver. Once Windows was back, I remembered what Linux had found. Samsung’s drivers identified a Broadcom GNSS 4752 geolocation sensor and its matching bus driver:

Get-PnpDevice | Where-Object {
    $_.FriendlyName -match 'GNSS|GPS|Location' -or
    $_.InstanceId -match 'SSE.4752'
} | Format-Table Status, Class, FriendlyName -AutoSize

The modem, of course, was still giving me trouble, but now I had a more interesting idea. Could I turn this old tablet into a big-screen hiking and off-roading GPS? While Windows was back in action, this was my chance to find out.

I installed Cartograph Maps 4 and ran an experiment. I chose this app because it could combine the tablet’s position from the Broadcom sensor with incredibly detailed hiking maps, which was precisely the idea I had in mind.

Before I spent time downloading trails and contours, though, I wanted to know whether the Windows location service was actually getting a usable position from the receiver.

At first, Cartograph put me roughly in the right place, but it didn’t follow me around outside. A PowerShell check quickly explained why. Windows reported IPAddress as the location source, with an estimated accuracy of 300 feet. That position stuck around even after turning off cellular and Wi-Fi, so seeing a dot on the map wasn’t exactly conclusive proof GPS worked.

I enabled Cartograph’s “Keep GPS always on” setting after reading a tip on Reddit. I then cleared Windows’ location history, rebooted, and took the tablet out to a clear sky with Wi-Fi turned off.

The time, PowerShell reported what I wanted to see:

This was the proof I needed that the tablet had found its position without Wi-Fi or a SIM.

Developer(s)

Harald Meyer

Platform(s)

Windows 10 64-bit and newer, Android, iOS, and macOS 13 and newer.

Cartograph Maps displays downloaded outdoor maps alongside GPS positions, GPX tracks, landmarks, and elevation information. It supports OpenAndroMaps maps and the Elevate hiking theme.

Downloading the map gave the GPS a purpose

I wanted trails, elevation, and contours waiting for me when the cell towers are left behind

For the sake of full disclosure, it should be noted that from this point on, I spoofed the location data to obscure my real location for the demonstration images. I chose Chain Lakes near Mount Baker in Washington because it’s stunningly beautiful, and because it has a lot of hiking trails.

A satellite fix was great, but a dot on a blank screen wasn’t exactly much use for hiking. I downloaded the OpenAndroMaps map for Washington State and applied its Elevate theme to Cartograph.

I could now see walking tracks winding between lakes and ridges, with contour lines showing how the elevation changed between them. Elevate also made the outdoor details easier to pick out compared to something like Google Maps for PC.

On the TabPro S’s larger screen, I could look at the shape of the whole walk and still zoom in to see the finer details I’d be crossing, like woodlands, rocks, and creeks.

The real check was what happened after I switched off the internet. I reopened Cartograph, panned well away from the spot that was cached, and zoomed in around the area. The map remained fully available because its data was stored on the tablet itself. I didn’t have to rely on a previously loaded patch of screen to make the offline claim.

At this point, I saw the appeal of this setup beyond hiking. A downloaded terrain map could be a handy alternative to Android Auto for an off-road adventure, and offline nautical maps from OpenSeaMap could also be imported for use on the water. I only tested the tablet on foot, though. My immediate payoff was that I could leave the Wi-Fi off and still see both the trails and the surrounding landscape.

I could plan the walk before going anywhere

The GPX track, waypoints, and elevation graph made the map more useful

With the Washington map downloaded, I wanted to see whether Cartograph could also help me plan a walk rather than just show me where I was. I found a public GPX file for a Chain Lakes route and dragged it from Explorer into the app.

Cartograph asked whether it was a map, style, track, overlay, or package. Selecting “Track” overlaid the file on top of the offline map.

I used the tablet’s touchscreen to add custom waypoints in the form of bookmarks along the route. These were landmarks that were of interest to me as photography opportunities, so I replaced the big ugly red map pin with real images.

Being able to see these and recognize places from their pictures made those markers far more helpful than a row of identical pins. I also opened up the elevation graph that came with the GPX file to see where and when I was probably going to need to take a breather.

Together, the track, bookmarks, and graph answered most of the questions I would’ve asked before setting out:

• Where does the router actually go?
• Which landmarks should I look for along the way?
• Am I even fit enough to make the trek?
• What kind of terrain am I likely to encounter?

Cartograph also allowed me to create my own tracks and export them as GPX files. I used a public Chain Lakes track for this experiment, then added in my own landmark bookmarks on the tablet. With the Pro version of the app, I could export it to GPX for later use. This way, I could build my own route and share it with others who might be interested in taking the same route I did.

I loved that all of this could be done on the tablet before even leaving. The route was a plan I could inspect, with landmarks and elevation information available even in the middle of nowhere, with no cellular service.

Then I took it outside with Wi-Fi off

Twenty minutes of actual movement answered the question the screenshots couldn’t

After experimenting with the spoofed location, I finally switched off the override, disabled the Wi-Fi, grabbed my dog, and took the ProTab S for a walk around the block. This was a brief but real 20-minute walk, nowhere near the Chain Lakes route in my screenshots (and not as pretty either).

I kept Cartograph’s “Keep GPS always on” setting enabled, and the marker moved with me and its compass indicator accurately pointed the right way as I turned.

That was a clear improvement on the first attempt outdoors when Windows reported a network-based position with only 300 feet of estimated accuracy. This time, with Wi-Fi off and the override disabled, it tracked my movement with an adequate amount of accuracy.

Since I was already getting strange looks from my neighbors, I didn’t measure its precise accuracy along the sidewalk, but I did take waypoint measurements approximately every 300–400 feet.

The battery was also a pleasant surprise. My experience with smartphones where the GPS sensor is hammered constantly is usually one of a rapidly depleted battery and an overheated phone.

With a screen brightness at 50%, Windows’ battery reading only fell by 5 percentage points in twenty minutes. That’s a useful result for a short test, but I’d still be taking a full-featured power bank on an all-day walk.

There was, regrettably, one feature I couldn’t try out in the free version of Cartograph that would, in my opinion, complete this project. That was the BRouter OSM functionality for offline route calculation. Since I wanted to see how far the free setup would go, I didn’t upgrade just to test the ability to use OpenStreetMap (OSM) route calculation offline.

Even with that limit, this went way further than an offline map demo. I’d verified a satellite source, watched the tablet follow a real walk without Wi-Fi, and prepared a downloaded map and track for a trip with little to no mobile internet.

It’s not going to replace Google Maps for every single journey, especially when there’s a mobile signal. But the ten-year-old tablet did better than I expected. It followed me without Wi-Fi, and I could prepare maps and a route before leaving. For offline navigation, I no longer need to depend on Google Maps.