True Ground Speed Sensor (TGSS) 740
14
Technical Specifications
5.
Technical Specifications
5.1.
Microwave Output
The output field strength generated by the TGSS is within the acceptability level set
by the FCC, IC, and EC.
Carrier frequency:
Standard:
24.125 GHz +/ 50 MHz
UK:
24.300 GHz +/ 50 MHz
Maximum Power: 100 mW, EIRP
Beam Width: 13° in the E -plane and 11° in the H -plane,
Side Lobes: nominal –17 dB
5.2.
Speed Output Signal
The frequency of the output signal is proportional to the speed of motion. When
using the standard transceiver frequency of 24.125 GHz, the frequency will be
58.9Hz/mph at 35° mounting angle.
The equation for Doppler shift frequency (fd) is given by
V = target velocity (mph)
fo = transceiver frequency (Hz)
c = speed of light (671 x 10
6
mph)
where
Φ
= angle between beam and path of target (degrees)
The sensor has the capability of scaling the output frequency. The selection is done
during production by programming the scaling factor into the micro-controller.
The selectable scales are:
1.
1.0 scaling - 58.9 Hz/mph (35° mounting angle, 24.125 Ghz)
2.
.75 scaling - 44.2 Hz/mph, approximately 1 pulse per cm (35° mounting
angle, 24.125 Ghz)
The speed range of the sensor is 0.3 to 44 mph.
5.3.
Radar-Present Output
This output signal is connected to the battery. Care should be exercised when
installing the unit into a system to limit the current on this output to less than
100 mA @ 12 V.
