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GPS Satellite

Issues Associated with Live Sky GPS Testing

Every GPS device’s developer knows the essence of testing his/her craft before its release into the market. This is the only solution to guarantee that the product you are introducing to your target market is of high quality. If you get your testing right, then you will become the go-to option in your field. Getting your testing wrong will leave you with a warehouse filled with devices that nobody will buy. There are two techniques for testing the accuracy of GPS devices: You can opt to use GPS simulation devices and check the device in the lab or go for live sky testing, which uses the antenna of your invention.

In live sky testing, you will plug in your device’s prototype or take it outside and check if it picks up a signal. Some GPS device manufacturers prefer live sky testing to the use of a simulation device since it involves little to no expenses. The following are the issues associated with live sky testing.

Satellite Clock Errors

You should account for satellite clock errors, which are inherent in GPS systems when testing your device’s accuracy. In live sky testing, it is impossible to account for this error since your test will also be affected by the same. As such, you will introduce a device that has a satellite clock error and decreased output accuracy.

Satellite Orbit Errors

Each satellite’s position is interpreted in navigation messages as different depending on its physical location in the earth’s orbit. The satellite’s position is affected by the gravitational impacts of the Earth, Moon, and Sun, which interfere with its precise location. In a simulation, you will remove all the orbital errors and carry out your test using a ‘’perfect’’ constellation or include quantifiable orbital errors in a controlled manner. In live sky testing, however, this is impossible, and the errors distort your device’s accuracy.

Navigation Data Errors

GPS navigation on phone

Errors occur in live testing owing to the transmission, demodulation and modulation processes of the data transmission system that you will use. Though the final 6 bits of most GPS navigation messages are parity bits designed for bit error detection, navigation data errors will still occur in live sky transmission. In a simulation, on the other hand, there is no transmission system, and the risk of navigation data errors is negated unless you deliberately apply them to your test.

Atmospheric Errors

The GPS signal of your device will pass through the troposphere and ionosphere to the satellite. Free electrons found in the ionosphere which is 70-1000knm above the surface of the earth will cause your GP signal’s delay according to its electron density. In a simulation test unlike in live sky testing, you can disable the atmosphere and hence remove the atmospheric errors. Alternatively, you can apply the mistakes to a recognized model and thus account for them.

In the end, every manufacturer and developer wants to produce a GPS device at the lowest cost possible to maximize returns. While this might work for a few production elements, it will not for the testing of your device’s accuracy. Get a GPS simulation device for your device’s testing to guarantee the highest level of skill and returns.

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