Calculating position from raw GPS data (2017)
The article explains GPS position calculation using satellites and coordinate systems like ECEF and WGS 1984. It covers height definition, ellipsoid models, latitude, longitude, and GPS system details, emphasizing accuracy.
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The article discusses the process of calculating positions using raw GPS data. It explains how GPS works, including the use of satellites and different coordinate systems like ECEF and WGS 1984. The post delves into the importance of defining height and the models used for this purpose, such as the reference ellipsoid and geoid. It also covers concepts like latitude, longitude, and geodetic height, as well as the conversion between ellipsoidal and Cartesian coordinates. The article emphasizes the significance of understanding these concepts for accurate position estimation and how GPS systems operate. Additionally, it provides insights into the history of GPS, its applications, and the interoperability of different global navigation systems like GLONASS, Galileo, and BeiDou. The post aims to educate readers on the technical aspects of GPS and offers Matlab code for implementing positioning algorithms based on real-world GPS data.
- Several comments provide links to resources for building or understanding GPS receivers, including open-source projects and interactive explanations.
- Discussions on advanced GPS applications, such as precise relative positioning using carrier phase access and combining GNSS with accelerometers and gyroscopes.
- Mentions of innovative uses of GPS, like tracking aquatic creatures with minimal satellite signal exposure.
- Questions and clarifications about the role of relativistic effects in GPS data.
- Humorous and critical takes on GPS technology, including a challenge to flat-earthers to explain GPS without satellites.
13 commentsThat alone isn't too fancy; it gets good once you throw in the accelerometer and gyroscope in each device. Because with that you get this not only in realtime, but also with only minor degradation due to the changes in the GNSS pseudo-range measurements being predictable despite not holding still.
Other interesting things enabled by it are e.g. auto-land of a model plane in a truck bed without needing wheels on the plane (and still preventing it from getting scratched up/depending on a grass landing strip).
Even fairly good GNSS receivers aren't expensive to build, as long as power consumption isn't very critical, so why can't I just buy a pair for a hundred bucks?
Now I'm wishing there was a setting in mapping applications on my phone that changed that the shape used for position uncertainty, from a circle to these arc-intersection shapes.