Integration of GPS with Other Sensors and Network Assistance - Understanding GPS: Principles and Applications - page 490

Figure 9.16 Layout of seven-element CRPA antenna.

Antenna elements

W

W WWWW W

Control of
complex
weights

Antenna controller

Combiner

Amp

Downconverter

OR

Power
level

RF IF

GPSI system

Azimuth, elevation

Figure 9.17 CRPA antenna block diagram.

each element, a combiner used to combine the weighed signal from each antenna ele-
ment, a microprocessor (occasionally referred to as an antenna controller), a
combiner to reconstruct the GPS signal, and optionally a downconverter and a
power detector to measure the amount of jamming coming into the receiver if not
available from the GPS receiver. The microprocessor used within the antenna con-
troller executes an iterative algorithm that computes the weight applied to each ele-
ment, which will minimizes the jamming coming in from the antennas. Since the
received power coming in from a jamming source is above the ground floor, the AE
tries to minimize any incoming power. AE used to implement beam forming addi-
tionally must incorporate platform attitude and satellite location information into
the adaptive algorithm, in combination with the measured voltages from each