[Upgrading, Modifying and Unlocking] pjd64:
GPS problem is HW related

Hi,

after my previous post (see below) I was able to improve GPS stability and accuracy on my zp998. I'm not saying that there is no SW problem also, but I am now sure there is a HW problem.

Let me tell you why.

I've found posts on other forums (or fora if you prefer) where a zp998 owner wrote that GPS performance was much better after using duct tape as a "spring" to force some of the motherboard pins to make better contact. Another zp998 owner reported having also better GPS performance after tightening all screws and internal contacts.

Unfortunately I dropped my zp998 and broke its screen, so I ordered a replacement screen which arrived yesterday and, immediately, I proceeded to replace the original/broken screen.

I noticed that the motherboard, which is a rectangle placed on the area going from the top of the phone to the battery compartment, has only 3 screws to hold it in place. So one corner of the motherboard is actually loose and you can bend it sideways with the tip of your finger. Near that corner of the motherboard there are 2 sets of contacts, 1 in each side of the motherboard.

Also at the bottom of the phone, in the area near the mic, there is another small circuit board, also with some contacts.

I'm not going to pretend I know which contact or set of contacts connects to the GPS antenna, I really don't know, but after replacing the screen I used a small screwdriver to carefully "pull up" the contact pins, making them stand out a bit more from both circuit boards.

The result is impressive.

I play Ingress a lot and accurate GPS positioning is of extreme importance on Ingress. Let me just say that in Ingress there are virtual portals associated with buildings, monuments, landmarks, etc. You use "resonators" to activate the portals and bring them to your faction and "bursters" to attack the other faction's portals and claim them for your own. You should place the "resonators" as far from the portal as possible (40 meters) and avoid concentrating them so they will better withstand an attack. If you are a low level player, your "bursters" won't have enough power to destroy the other faction's "resonators" unless you fire the "bursters" exactly on top of each "resonator" you want to destroy.

After I received the zp998, immediately I understood I had bought the worst possible phone to play Ingress. I use GPS Locker to get a GPS fix and then I switch to Ingress. After a short while I would be 2 blocks away from my correct location, or I would turn on a intersection and on the Ingress map I would still be driving forward, or I would be attacking a portal and suddenly I would lose GPS fix and the game wouldn't let me continue the attack.

Anyway, I would be constantly losing GPS fix, switching to GPS Locker to recover it and them back to Ingress to proceed with the game. I often had to do that 4 times in less than 5 minutes to complete an attack on a portal,

with me standing absolutely still

. Why GPS Locker recovers the GPS fix and Ingress loses it is beyond my comprehension.

Since yesterday I have been playing Ingress

without ever losing GPS fix

. The GPS is not perfect, I might appear to be outside the road, but never 1 or 2 blocks away, or I might not turn immediately on an intersection, but 1 or 2 seconds later the GPS will correct my position and, most important, now I never have to switch back and forth from Ingress to GPS Locker to recover the GPS fix, because it is never lost.

I believe we, zp998 owners, have bought a poorly designed phone.

Regards,

Paulo