Also look closer at the above link and note that there are two (2) antenna cables. They must have decided that both their modules required antennas that they could place at optimal positions. You may consider an alternate GPS unit with a remote antenna option.

Andy has a very good point regarding the EMI screening cans. These likely provide more than just the shielding necessary to pass required agency test requirements. If they do provide module to module isolation we probably wouldn't actually know for sure unless we talked to some of the engineers on the team that prepared the design and validation of the product.

Mahmood - In your situation you certainly have the opportunity to experiment. There are some products available that can help in the determination. One is copper tape that has very conductive glue on it - you often see this at EMI test labs. :-)

Let me comment about post processing the power out of the switching power supply. I suspect that adding post linear regulators may not be really necessary. One may try that option if the main power conversion has to be done with one switcher but you need to have separate cleaner power to two separate down stream devices. On the other hand you may be better off to consider another approach. A first way is to study your power delivery and corresponding GND return paths. Isolate the separate loads through branched copper runs each with its own ferrite beads and capacitors. (Note that switchers can often be cleaned up on the output with careful copper design and an output pi filter). Another approach may be to consider two separate switchers to provide DC voltages close to the point of load. This can have some advantages due to the fact that the voltage rail copper that supplies the higher input voltage to each regulator can be easier to route around on the board (lower current == less copper required) and easier to filter. In this latter approach it can be useful to have input isolation inductors in front of each switcher the help from having the two interfere with each other or place too much noise on the supply lines.

Michael Karas