Hello everyone!
I did two flight test with exact same flight path to test the performance of my custom GPS.
In one mission I used off the shelf Holybro F9P gps. Here is the Speed Accuracy graph Log1
I observed that the holybro gps has a ground which is attached to outside aluminum casing, the ground gets physically attached to outside aluminum casing once bolted, whereas our custom made gps is open pcb.
Is it necessary to have this kind of aluminum casing connected to pcb ground?
I cannot put aluminum casing around my pcb, is there any alternative way for this?
You might want to ask your question in the u-blox forums. Clive1 there can answer pretty much any question.
I recently asked about if it is better to have an aluminium case around the PCB to reduce RF interference to the receiver. It does help, but it is also good to reduce temperature fluctuations of the receiver. Clive1 also says that the receiver is affected by the noise in the supplied voltage.
Hi again John
That voltage is another interesting point you mention. In Tridges big GPS round-up he found that the supplied voltage was important to performance.
A lot of people would say “but the GNSS unit has a 3.3v converter in it anyway” however I would point out it is incredibly tiny and unlikely to be high performance with fantastic noise immunity. The GNSS unit is expecting a clean +5v supply to work with.
So if someone has an old/cheap pixhawk clone power brick that puts out a noisy 4.7 volts instead of clean 5.2 volts, it’s likely they will have poor GNSS performance too. I’ve seen this plenty of times in logs.
It’s worth the effort to measure the supply voltage at the GNSS unit to ensure you really do have 5 volts there.
