How Do GPS Speedometers Work? Some Important Facts to Know

There is an on-going debate about which is more accurate: a standard GPS device or a speedometer? Various sources have different answers, but in order to understand this device, you first have to ask yourself: how do GPS speedometers work?

In this article, we will help shed some light on this very question and more. Aside from how they work, we’ll also talk about how they are made, the materials commonly used in making them, their level of accuracy, and what they have in store for us in the future. Before we talk about all of that, though, let us first talk about what GPS speedometers are.

What Are GPS Speedometers?

GPS technology is widely used in smartphones, fitness trackers, vehicles, and other devices. It is popularly used in giving traffic alerts and point-to-point directions. However, when a GPS device starts giving speed measurements, it then becomes a GPS speedometer, which is believed to provide more accurate calculations than traditional GPS devices.

The first GPS speedometer originally patented by Otto Schultze in 1902 used a spinning flexible cable typically driven by gearing connected to the output of the car’s transmission. However, the first models of motorcycles and VW Beetles used a wire operated from a front wheel.

How Do GPS Speedometers Work?

Today, GPS speedometers are also called positional speedometers. They tend to be more accurate than the standard GPS because it runs continuous calculations and shows regular updates. Hence, the user is informed about the most recent data at any specified time.

Many modern speedometers are electronic, and the designs are inspired by previous models. A spinning sensor attached in the conduction brings a sequence of electronic pulses with a frequency that parallels to the average spinning speed of the driveshaft, hence the car’s speed.

The spinning sensor is usually one or more sets of magnets attached to the output shaft or to a toothed metal disk. As it turns, these magnets or teeth pass under the sensor, producing a pulse while affecting the power of the magnetic field being measured.

Most Common Materials Used

The materials that make up a speedometer depend on the intended application and type of gauge. In the earlier models, steel and other metals were used. Later on, 40% of the materials were made of different plastic polymers.

As years passed, the engineers continuously upgraded the plastic polymers; hence, newer models of speedometers are almost entirely made of plastic.

The housing of a speedometer’s main assembly is made of nylon. However, in usually more expensive models, a water-resistant polybutylene terephthalate (PBT) polyester is used. The magnet shaft and worm drive also comprise of nylon as well as the spindles and gear train.

In the earlier models, the display was made of a glass lens. Today, it is now made of a durable, flexible plastic called transparent polycarbonate, which is resistant to shock, heat, and moisture.

The Manufacturing Process of Speedometers

When it comes to the manufacturing process of GPS speedometers, all the steel materials are melted. The different plastic materials come from organic chemical compounds derived from petroleum. These materials are then assembled.

The process and level of human interaction depend on the quality and advancement of the GPS speedometer being manufactured.

The manufacturing process of speedometers does not emit by-products or waste. Only scrap plastics and metals that can be further recycled or reused in other applications are the known waste materials from the process.

Raw materials are processed outside the factory, so there are no harmful or hazardous by-products or industrial wastes after the manufacturing process.

The Accuracy of GPS Speedometers

Unlike the standard GPS devices, the readings of a GPS speedometer are not impacted by the wheel size. The latter is more accurate and reliable because it relies its readings and calculations on GPS satellites. Hence, under a clear sky and other suitable conditions, a GPS speedometer is accurate specifically within 0.2 mph.

One factor that affects the accuracy of a GPS speedometer is when it loses access to GPS satellites. When passing through tunnels, forests, or during adverse weather conditions, a GPS antenna will have a hard time connecting to the GPS satellite. As a result, calculations are either delayed or inaccurate.

For this very reason, some drivers install a combination of a standard GPS device and a GPS speedometer in hopes to achieve the most accurate driving-related information at any given time regardless of the weather condition.

The Future of GPS Speedometers

Engineers and manufacturing firms are continuously looking for ways to improve GPS speedometers in a way that the users reduce or eliminate the need to look down and gauge their driving speed. In this way, distractions on driving will be minimized as well as the risks of vehicular or road accidents.

The future of GPS speedometers will be digital information flashed on the windshields. Prototypes of these newer models show the data as though it is floating on the vehicle’s hood. It appears several feet beyond the steering wheel, so the drivers don’t need to take off their sight on the road when checking or gauging their driving speed.

In this promising device, the mirrors and projection features can be adjusted to suit the user’s needs and driving position. The future GPS speedometers will be integrated with the navigation tools for directional data to appear with the projection.


Looking into the detailed information on how do GPS speedometers work can be quite overwhelming and hard to comprehend. More often than not, they are almost entirely made of plastic materials that are durable and water-resistant. The display lenses are made of transparent polycarbonate for a clearer, more comfortable view.

GPS speedometers have significantly improved since they were first manufactured. Over the years, they have been modified to suit the changing technological devices. Today, its future is a lot more promising as the engineers and manufacturing firms are working towards a projection display on the hood.

If the expected improvements of GPS speedometers are met, the driving experience will be significantly expanded, and road accidents will be hopefully reduced. While GPS speedometers provide driving speed and other data, the drivers have the sole responsibility for their safety on the road.

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