Data Sheet

NEO-7 - Data Sheet
UBX-13003830 - R04 Early Production Information Functional description
Page 9 of 26
1.6 Augmented GNSS
For more details about augmented GNSS, see the u-blox 7 Receiver Description Including Protocol
Specification [2].
1.6.1 Assisted GNSS (A-GPS)
A-GPS improves GNSS performance by delivering aiding data to the GNSS receiver via wireless networks or the
Internet. Supplying information such as ephemeris, almanac, approximate last position, time and satellite status
and an optional time synchronization signal significantly reduces Time to First Fix (TTFF) and improves acquisition
sensitivity.
AssistNow Online and AssistNow Offline are u-blox’ end-to-end A-GPS services for devices with or without
network connectivity. AssistNow Online and AssistNow Offline can either be used alone or in combination. They
are very easy to implement, require no additional hardware, and generate virtually no CPU load. All u-blox 7
modules support u-blox’ AssistNow Online, AssistNow Offline and AssistNow Autonomous A-GPS services, and
are OMA SUPL compliant.
AssistNow Online
With AssistNow Online, an internet-connected GNSS device downloads assistance data from u-blox’ AssistNow
Online Service at system start-up. AssistNow Online is network operator independent and globally available.
u-blox only sends ephemeris data for those satellites currently visible to the device requesting the data, thus
minimizing the amount of data transferred.
AssistNow Offline
With AssistNow Offline, users download u-blox’ Differential Almanac Correction Data from the Internet at their
convenience. The correction data can either be stored in the GNSS receiver’s Flash memory (available on NEO-7N
only) or in the memory of the application processor. Therefore, the service requires no connectivity at system
start-up and enables a position fix within seconds, even when no network is available.
1.6.2 AssistNow Autonomous
AssistNow Autonomous provides functionality similar to Assisted-GNSS without the need for a host or external
network connection. It is an embedded feature available free-of-charge that accelerates GNSS positioning by
capitalizing on the periodic nature of GNSS satellite orbits. GNSS orbit predictions are directly calculated by the
GNSS receiver and no external aiding data or connectivity is required. AssistNow Autonomous can be used
alone, or together with AssistNow Online or AssistNow Offline for increased positioning speed and accuracy.
1.6.3 Satellite-Based Augmentation System (SBAS)
u-blox 7 positioning modules support SBAS. These systems supplement GNSS data with additional regional or
wide area GNSS augmentation data. The system broadcasts augmentation data via satellite which can be used
by GNSS receivers to improve the resulting GNSS precision. SBAS satellites can be used as additional satellites for
ranging (navigation), further enhancing precision. The following SBAS are supported with u-blox 7: WAAS,
EGNOS and MSAS.
1.7 Data logging (NEO-7N)
New with u-blox 7 is the data logging feature, which enables continuous storage of position, velocity and time
information to an internal 16Mbit SQI FLASH memory. The information can be downloaded from the receiver
later for further analysis or for conversion to a mapping tool. For more information see the u-blox 7 Receiver
Description Including Protocol Specification [2].