why some devices using two GPS devices on the same board?

jpanhalt

Joined Jan 18, 2008
11,088
Welcome to AAC.

Maybe it is to improve accuracy.

Source: https://www.forbes.com/2002/02/15/0215tentech.html#4b897eec7010
And since GPS data is by design a little fuzzy, accuracy is generally good to within about 40 feet or so. The GPS V can pick up additional data from another system called the Wide Area Augmentation System, or WAAS. The system was developed by the Federal Aviation Administration to help GPS readers show more accurate data by broadcasting error-correction signals from a satellite and from a system of ground-based transmitters; the overall effect is to increase the unit's accuracy to about 20 to 25 feet when WAAS reception is turned on.
 

Wolframore

Joined Jan 21, 2019
2,260
Dual gps modules work on two different bands and the two signals are compared for error correction. Current accuracy is down to about 16 ft but using dual band you can get to centimeters and long term measurements in the millimeter level.

 
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Thread Starter

Mans A

Joined Aug 13, 2019
4
@jpanhalt How it can increase accuracy? As you can see from the image, both GPS chips are the same, so they can not capture different things.

@Wolframore : As far as I know the old version of UBlox chips can only wok on one frequency. So this board can not implement two-band frequency GPS

Any other idea?
 

jpanhalt

Joined Jan 18, 2008
11,088
The fact that they look the same doesn't mean they operate at the same frequency nor that the data processing algorithms are the same. Microprocessors/microcontrollers are very versatile.
 

Wolframore

Joined Jan 21, 2019
2,260
The datasheet for that ublox receiver says it's L1 but all satellites transmit L1 and L2. There are more frequencies being added for ionoshperic correction. There would be almost no benefit except redundancy otherwise if it isn't receiving L2.
 

Thread Starter

Mans A

Joined Aug 13, 2019
4
The fact that they look the same doesn't mean they operate at the same frequency nor that the data processing algorithms are the same. Microprocessors/microcontrollers are very versatile.
Do you have any idea, what type of signal processing they may use to improve accuracy?

Apparently, the GPS chips only work on L1 and not any other frequency.
 

Thread Starter

Mans A

Joined Aug 13, 2019
4
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