190-01115-01
G3X/G3X Touch Installation Manual - GSU 25/25B Installation
Rev. AC
Page 18-1
18 GSU 25/25B (AHRS/AIR DATA SENSOR UNIT) INSTALLATION
NOTE
References to the GSU 25 throughout this manual apply equally to the GSU 25B except
where specifically noted.
The GSU 25 can be installed as part of the G3X system. This section contains general information as well
as installation information for the GSU 25. Use this section to mount the GSU 25 unit.
18.1 Equipment Description
NOTE
There is no TSO/ETSO applicable to the GSU 25.
The GSU 25 is intended for experimental aircraft and LSA (light sport aircraft) markets. The Garmin
GSU 25 Sensor Unit is not a TSO-certified product and has received no FAA approval or endorsement.
The GSU 25 is intended to be used as a part of the G3X system and it is not suitable for installation in type-
certificated aircraft.
The GSU 25 is an LRU that provides AHRS and Air Data information in a single mechanical package.
The GSU 25 interfaces to a remote mounted GMU magnetometer for heading information and also
computes OAT and TAS from inputs provided by the GTP 59. The GSU 25 does not provide engine/
airframe interface, see
for engine/airframe interface using the GEA 24. Up to three GSU 25
units may be installed to provide redundancy and cross-checking of attitude, heading, and air data.
The GSU 25 provides the functions in Table 18-1.
Table 18-1 GSU 25 Functions
Air Data
Interfaces
AHRS
Pressure Altitude
CAN (1)
Magnetic Heading (with input
from GMU
magnetometer
)
Density Altitude
RS-232 (2 TX/2 RX)
Pitch Angle
Vertical speed
OAT Probe (GTP 59)
Roll Angle
Mach Number
Magnetometer (GMU 22)
(1 RS-232 TX/ 1 RS-485 RX)
Linear Accelerations
Indicated Airspeed
Pitch, Roll, Yaw Rotation Rates
True Airspeed
3 axis angular rates
Angle of attack
3 axis accelerations
Outside and total air
temperature (via GTP 59)
