User's Manual

Telit GE863-GPS

Hardware User guide

1vv0300714, Rev. ISSUE#0, - 21/02/06

• If you don't have EM noisy devices around the PCB of GE863-GPS, by using a strip-line on

the superficial copper layer for the antenna line, the line attenuation will be lower than a

buried one;

4.3 GSM Antenna - installation Guidelines

• Install the antenna in a place covered by the GSM signal.

• The Antenna must be installed to provide a separation distance of at least 20 cm from all

persons and must not be co-located or operating in conjunction with any other antenna or

transmitter;

• Antenna shall not be installed inside metal cases

• Antenna shall be installed also according Antenna manufacturer instructions.

4.4 GPS Antenna Requirements

The GE863-GPS module is not provided with an internal LNA amplifier. The use of an active

antenna is suggested to achieve a good performance.

The module is provided of an Antenna supply circuit with the following characteristics:

• Supply voltage referred to VBATT (3.4 to 4.2 V DC)

• Supply enable controlled internally by the BB

• Current measurement circuit (readable also with AT commands)

• Voltage measurement circuit (readable also with AT commands)

• HW Protection for Antenna Short Circuit (if consumption exceeds 40mA)

4.4.1 Combined GPS Antenna

The use of combined GPS antennas is NOT recommended; this solution could generate an

extremely poor GPS reception and also the combination antennas requires additional diplexer

and adds a loss in the RF route.

4.4.2 Linear and Patch GPS Antenna

Immediate 3 dB of loss relative to a circularly polarized (CP) antenna.

Spherical gain response instead of a hemispherical gain response will aggravate the multipath

behavior & create poor position accuracy!! (lucky to achieve 50 m accuracy in some situations)

Poor LHCP relative to RHCP response.

Can have multiple gain nulls & average gain is MUCH lower than a good patch (-9 dB)