gps hacks

199 Articles

Historical map of The Netherlands overlayed with clouds

Hacking Global Positioning Systems Onto 16th-Century Maps

November 25, 2024 by 9 Comments

What if GPS had existed in 1565? No satellites or microelectronics, sure—but let’s play along. Imagine the bustling streets of Antwerp, where merchants navigated the sprawling city with woodcut maps. Or sailors plotting Atlantic crossings with accuracy unheard of for the time. This whimsical intersection of history and tech was recently featured in a blog post by [Jan Adriaenssens], and comes alive with Bert Spaan’s Allmaps Here: a delightful web app that overlays your GPS location onto georeferenced historical maps.

Take Antwerp’s 1565 city map by Virgilius Bononiensis, a massive 120×265 cm woodcut. With Allmaps Here, you’re a pink dot navigating this masterpiece. Plantin-Moretus Museum? Nailed it. Kasteelpleinstraat? A shadow of the old citadel it bordered. Let’s not forget how life might’ve been back then. A merchant could’ve avoided morning traffic and collapsing bridges en route to the market, while a farmer relocating his herd could’ve found fertile pastures minus the swamp detour.

Unlike today’s turn-by-turn navigation, a 16th-century GPS might have been all about survival: avoiding bandit-prone roads, timing tides for river crossings, or tracking stars as backup. Imagine explorers fine-tuning their Atlantic crossings with trade winds mapped to the mile. Georeferenced maps like these let us re-imagine the practical genius of our ancestors while enjoying a modern hack on a centuries-old problem.

Although sites like OldMapsOnline, Google Earth Timelapse (and for the Dutch: TopoTijdreis) have been around for a while, this new match of technology and historical detail is a true gem. Curious to map your own world on antique charts? Navigate to Allmaps and start georeferencing!

Crowdsourcing Ionosphere Data With Phones

November 18, 2024 by 19 Comments

How do you collect a lot of data about the ionosphere? Well, you could use sounding rockets or specialized gear. Or maybe you can just conscript a huge number of cell phones. That was the approach taken by Google researchers in a recent paper in Nature.

The idea is that GPS and similar navigation satellites measure transit time of the satellite signal, but the ionosphere alters the propagation of those signals. In fact, this effect is one of the major sources of error in GPS navigation. Most receivers have an 8-parameter model of the ionosphere that reduces that error by about 50%.

However, by measuring the difference in time between signals of different frequencies, the phone can estimate the total electron current (TEC) of the ionosphere between the receiver and the satellite. This requires a dual-frequency receiver, of course.

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GNSS Reception With Clone SDR Board

November 3, 2024 by 14 Comments

We love seeing the incredible work many RF enthusiasts manage to pull off — they make it look so easy! Though RF can be tricky, it’s not quite the voodoo black art that it’s often made out to be. Many radio protocols are relatively simple and with tools like gnuradio and PocketSDR you can quickly put together a small system to receive and decode just about anything.

[Jean-Michel] wanted to learn more about GNSS and USB communication. Whenever you start a project like this, it’s a good idea to take a look around at existing projects for designs or code you can reuse, and in this case, the main RF front-end board is taken from the PocketSDR project. This is then paired with a Cypress FX2 development board, and he re-wrote almost all of the PocketSDR code so that it would compile using sdcc instead of the proprietary Keil compiler. Testing involved slowly porting the code while learning about using Python 3 to receive data over USB, and using other equipment to simulate antenna diversity (using multiple antennas to increase the signal-to-noise ratio): Continue reading “GNSS Reception With Clone SDR Board” →

GPS Tracking In The Trackless Land

October 7, 2024 by 17 Comments

Need a weekend project? [Cepa] wanted a GPS tracker that would send data out via LTE or the Iridium network. Ok, maybe that’s one for a very long weekend. However, the project was a success and saw service crossing the Barents Sea in the Arctic. Not bad.

Apparently, [Cepa] is very involved in sharing tracks to odd and remote places. While you may not have cell service in the middle of the Barents Sea, you can always see Iridium. The device does make some sacrifices to the expense of satellite communications. On LTE, the system pings your location every ten seconds. Without it, it dials up the sat connection once an hour. However, it does store data on a SD card, so — presumably — you get caught up when you have a connection.

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Misleading GPS, Philosophy Of Maps, And You

September 10, 2024 by 19 Comments

The oft-quoted saying “all models are wrong, but some are useful” is a tounge-in-cheek way of saying that at some level, tools we use to predict how the world behaves will differ from reality in some measurable way. This goes well beyond the statistics classroom it is most often quoted in, too, and is especially apparent to anyone who has used a GPS mapping device of any sort. While we might think that our technological age can save us from the approximations of maps and models, there are a number of limitations with this technology that appear in sometimes surprising ways. [Kyle] has an interesting writeup about how maps can be wrong yet still be incredibly useful especially in the modern GPS-enabled world. Continue reading “Misleading GPS, Philosophy Of Maps, And You” →

[Scott Manley] Explains GPS Jamming

May 19, 2024 by 46 Comments

We always think of [Scott Manley] as someone who knows a lot about rockets. So, if you think about it, it isn’t surprising he’s talking about GPS — after all, the system uses satellites. GPS is used in everything these days, and other forms of navigation are starting to fall by the wayside. However, the problem is that the system is vulnerable to jamming and spoofing. This is especially important if you fear GPS allowing missiles or drones to strike precise targets. But there are also plenty of opportunities for malicious acts. For example, drone light shows may be subject to GPS attacks from rival companies, and you can easily imagine worse. [Scott] talks about the issues around GPS spoofing in the video, which you can see below.

Since GPS satellites are distant, blocking the signal is almost too easy, sometimes happening inadvertently. GPS has technology to operate in the face of noise and interference, but there’s no way to prevent it entirely. Spoofing — where you produce false GPS coordinates — is much more difficult.

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GPS At Any Speed

May 13, 2024 by 39 Comments

[Mellow_Labs] was asked to create a GPS speedometer. It seems simple, but of course, the devil is in the details. You can see the process and the result in the video below.

We have to admit that he does things step-by-step. The first step was to test the GPS module’s interface. Then, he tried computing the speed from it and putting the result on a display. However, testing in the field showed that the display was not suitable for outdoor use.

That prompted another version with an OLED screen. Picking the right components is critical. It struck us that you probably need a fast update rate from the GPS, too, but that doesn’t seem to be a problem. Continue reading “GPS At Any Speed” →