Facing Problem in GPS Signal Acquisition

as you know i’m designing a GSM/GPS based device and i’m facing few problems, the problem of power supply has been resolved, and currently i’m facing issue regarding GPS signal acquiring, i’m using a GPS active patch antenna and it takes very long time to acquire GPS signal and sometimes it doesn’t even get the signal, i’m using MC60 from Quectel, it’s a GSM/GPS module, can you please help me with this issue.
i have attached the image of the antenna i’m using

Probably you are missing Antenna bias voltage. Check it

they have recommended 3.3V bias voltage and i have been supplying it through 47nH inductor as recommended by the datasheet but still the results are poor, i have sent a mail to Quectel but they also not responded.
i saw in one of your blog recommending not to use SIM808 for GPS applications since it is a GPS/GSM integrated chip, any particular reason as to why?