Appendix A
Specifications
NI PXI-6682 Series User Manual
A-6
ni.com
Temperature stability (0 to 55 °C) ..........±1 ppm
Aging per year ........................................±1 ppm
GPS
Recommended GPS antenna ..................Trimble Bullet III
DC voltage output for antenna................5 V
RF GPS signal frequency .......................1575.42 MHz ±1.023 MHz
Input impedance .....................................50
Ω
, nominal
Accuracy
PPS ..................................................Within 15 ns to GPS/UTC
(1 Sigma)
Horizontal position ..........................<6 m (50%)
<9 m (90%)
Altitude position ..............................<11 m (50%)
<18 m (90%)
Velocity ...........................................0.06 m/s
Trimble Bullet III
Gain at 1575.42 MHz .............................35 dB ±3 dB
Current requirement (5 V) ......................30 mA maximum
VSWR.....................................................2.0 maximum
Polarization .............................................Right-hand circular
polarization (RHCP)
Signal strength required
at PXI-6682.............................................18 dB
Maximum allowable cable
signal loss at 1575.42 MHz ....................17 dB
Note
The GPS antenna kit offered by National Instruments comes with a 30 m cable
which has a loss of 15 dB/100 ft, making the total loss in the cable approximately 14.8 dB.
If your GPS antenna installation requires a longer cable, ensure that the loss per unit of
distance is lower, such that the total signal loss is under 17 dB.
