Global positioning made easy

Paul Boughton

More and more end-products are integrating global positioning as a crucial feature, writes Kim Kaisti.

In addition to familiar navigation systems, Global Navigation Satellite System (GNSS) receivers are required in vehicle and asset tracking systems, personal locators, security systems, vending machines, health monitoring and recreational devices.

Every GNSS receiver requires an antenna. As many customers do not have the RF/antenna tuning expertise or the sourcing capability, a performance optimised GNSS antenna module which combines both satellite receiver chip and antenna on the same module is often a good idea. These modules provide fast time-to-market and an economically viable solution for 'instant' global positioning. A GNSS antenna module is also significantly smaller in size than a GNSS module plus an external antenna.

Typical GNSS antenna module customers purchase GNSS receivers at around 10k pieces per year quantity. Sourcing external antennas in these quantities may not be feasible in terms of cost and lead times. Custom tuning would also be needed, especially with patch antennas. For these customers, pre-tuned GNSS antenna modules are an attractive choice.

Currently u-blox offers two different kinds of GNSS Antenna Modules: PAM (Patch Antenna Module) which is dedicated to GPS positioning, and CAM (Chip antenna Module) which can track GPS, GLONASS or BeiDou satellites. Both types are optimised for best antenna performance independent of orientation. These GNSS Antenna Modules are highly optimized for performance including sensitivity and jamming immunity as they include integrated dual SAW filters.
The PAM-7Q is a highly popular form factor due to its installation flexibility. It can be mounted ‘as is’ in pre-existing designs or soldered with a pin-header to a customized PCB. The 18 x 18 mm patch antenna of PAM-7Q provides RHCP polarisation not achievable with smaller patch antenna elements.

The simple design and easy interfacing keeps installation costs to a minimum. PAM-7Q targets industrial and consumer applications that require a small, fast and cost efficient solution to GPS positioning.

u-blox’ chip antenna module, CAM-M8Q, is a really interesting alternative when customers require both small size and multi-GNSS capability. The chip antenna element used in CAM-M8Q can handle all L1 frequencies ranging from BeiDou (1560 MHz) and GPS (1575 MHz) up to GLONASS (1606 MHz).

Traditional patch antenna solutions cannot achieve the same bandwidth. CAM-M8Q is also extremely low in height making very thin customer designs possible.

Chip antenna modules, however, require care in design implementation as the PCB forms part of the overall antenna (half of the dipole). CAM-M8Q has a feature whereby the internal chip antenna can be used as a backup antenna if the customer chooses to use an external antenna. This is useful in applications where there is a risk that the primary antenna may malfunction or suffer damage. CAM-M8Q is targeted for all applications requiring good Multi-GNSS performance in a compact form factor.

Kim Kaisti, Product Manager GNSS antenna modules, u-blox