MAX-7 - Data Sheet

UBX-13004068 - R05

Production Information

Functional description

Page 9 of 24

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 MAX-7

series 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 be stored 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 GPS satellite orbits. GPS 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.

For more details see the u-blox 7 Receiver Description Including Protocol Specification [2].

1.6.3 Satellite-Based Augmentation System (SBAS)

u-blox MAX-7 positioning modules support SBAS. These systems supplement GPS data with additional regional

or wide area GPS augmentation data. The system broadcasts augmentation data via satellite which can be used

by GPS receivers to improve the resulting GPS precision. SBAS satellites can be used as additional satellites for

ranging (navigation), further enhancing precision. The following SBAS are supported with MAX-7 modules:

WAAS, EGNOS and MSAS.

For more details see the u-blox 7 Receiver Description Including Protocol Specification [2]

1.7 EXTINT: External interrupt

EXTINT is an external interrupt pin with fixed input voltage thresholds with respect to VCC_IO. It can be used for

Control of the receiver or for Aiding.

For more information about how to implement and configure these features see the u-blox 7 Receiver

Description including Protocol Specification [2] and the MAX-7 / NEO-7 Hardware Integration Manual [1].

1.7.1 Pin Control

The pin control feature allows overriding the automatic active/inactive cycle of Power Save Mode. The state of

the receiver can be controlled through the EXTINT pin.

The receiver can also be turned off and sent into Backup Mode using EXTINT when Power Save Mode is not

active.