User's Guide

ATOP3.5G Product Description
80447ST10636A rev.10 – 2015-03-03
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Reserved. Page 25 of 66
Mod. 0808 2011-07 Rev.2
8.3 Position processing
8.3.1 Key features
ATOP 3.5 G features GNSS reception used for positioning services. This support is provided in
software integrated on the application processor with the following key features:
 Supports both GPS and GLONASS
 “All in view” tracking capability
 Dual antenna support with internal switching:
o passive antenna input with internal separate LNA
o active antenna input with internal LNA bypass
 Supports following Satellite Based Augmentation Systems: WAAS, EGNOS, MSAS
 Receiver Autonomous Integrity Monitoring (RAIM) & Fault Detection and Exclusion
(FDE) support
 Support of assistance data (Ephemerides, location, time...) provided by customer
application to ensure faster Time To First Fix (TTFF)
 1 Pulse Per Second (1PPS) output for synchronization with GPS system clock
 Software upgradable
 CEP50 < 2 m
8.3.2 Sensitivity
Table 4 shows acquisition and tracking sensitivity measurements for a passive antenna.
Table 4 Sensitivity
Symbol Parameter Conditions Min Typ Max Unit
t
TTFF
time to first fix time
open sky, hot start, 130 dBm signal
- 1.5 - s
open sky,warm start, 130 dBm signal
- < 27 - s
open sky, cold start, 130 dBm signal
- < 36 - s
P
i(acq)
minimum acquisition
input
power
ephemeris decode, cold start -
145
- dBm
hot start -
152
- dBm
P
i(trck)
minimum tracking
input power
-
160
- dBm
P
i(reacq)
minimum
reacquisition input
power
-
159
- dBm
An active antenna should have an integrated LNA with a noise figure of 1.6dB, or lower, and a
gain of 17dB, or higher, to achieve the same sensitivity as measured on the passive antenna
input. A higher (or lower) noise figure results in a one to one worse (or better) sensitivity.