An apparatus of a mobile device comprising: a modem arranged to communicate with an enhanced Node B; a Global Navigation Satellite System, GNSS, receiver arranged to receive satellite positioning signals from a plurality of satellites; and processing circuitry arranged to: generate local fine time assistance using only temporal information provided within the mobile device or obtained from a network with which the mobile device is connected; instruct the modem to provide the local fine time assistance to the GNSS receiver; instruct the GNSS receiver to obtain GNSS satellite positioning signals using the local fine time assistance; instruct the modem to maintain the local fine time assistance during at least one of inter- or intra-Radio Access Technology, RAT, transitions of the mobile device; instruct the GNSS receiver to transmit a request to the modem; instruct the modem to receive the request from the GNSS receiver; instruct the modem to transmit a pulse and pulse timing information to the GNSS receiver as information for the local fine time assistance in response to the modem receiving the request; instruct the GNSS receiver to obtain a GNSS fix after transmitting the request; characterised in that the processing circuitry is further arranged to determine an absolute cellular network time used in generating the local fine time assistance, the absolute cellular network time being determined in modem cellular frame format and comprising: a relative reference time of the pulse timing information, cumulative cell switching time offsets of inter- and intra-RAT transitions of the mobile device since an immediately preceding pulse, and a cumulative number of frame wraparounds for each RAT since the immediately preceding pulse. a modem arranged to communicate with an enhanced Node B; a Global Navigation Satellite System, GNSS, receiver arranged to receive satellite positioning signals from a plurality of satellites; and processing circuitry arranged to: generate local fine time assistance using only temporal information provided within the mobile device or obtained from a network with which the mobile device is connected; instruct the modem to provide the local fine time assistance to the GNSS receiver; instruct the GNSS receiver to obtain GNSS satellite positioning signals using the local fine time assistance; instruct the modem to maintain the local fine time assistance during at least one of inter- or intra-Radio Access Technology, RAT, transitions of the mobile device; instruct the GNSS receiver to transmit a request to the modem; instruct the modem to receive the request from the GNSS receiver; instruct the modem to transmit a pulse and pulse timing information to the GNSS receiver as information for the local fine time assistance in response to the modem receiving the request; instruct the GNSS receiver to obtain a GNSS fix after transmitting the request; characterised in that the processing circuitry is further arranged to determine an absolute cellular network time used in generating the local fine time assistance, the absolute cellular network time being determined in modem cellular frame format and comprising: a relative reference time of the pulse timing information, cumulative cell switching time offsets of inter- and intra-RAT transitions of the mobile device since an immediately preceding pulse, and a cumulative number of frame wraparounds for each RAT since the immediately preceding pulse. generate local fine time assistance using only temporal information provided within the mobile device or obtained from a network with which the mobile device is connected; instruct the modem to provide the local fine time assistance to the GNSS receiver; instruct the GNSS receiver to obtain GNSS satellite positioning signals using the local fine time assistance; instruct the modem to maintain the local fine time assistance during at least one of inter- or intra-Radio Access Technology, RAT, transitions of the mobile device; instruct the GNSS receiver to transmit a request to the modem; instruct the modem to receive the request from the GNSS receiver; instruct the modem to transmit a pulse and pulse timing information to the GNSS receiver as information for the local fine time assistance in response to the modem receiving the request; instruct the GNSS receiver to obtain a GNSS fix after transmitting the request; characterised in that the processing circuitry is further arranged to determine an absolute cellular network time used in generating the local fine time assistance, the absolute cellular network time being determined in modem cellular frame format and comprising: a relative reference time of the pulse timing information, cumulative cell switching time offsets of inter- and intra-RAT transitions of the mobile device since an immediately preceding pulse, and a cumulative number of frame wraparounds for each RAT since the immediately preceding pulse. a relative reference time of the pulse timing information, cumulative cell switching time offsets of inter- and intra-RAT transitions of the mobile device since an immediately preceding pulse, and a cumulative number of frame wraparounds for each RAT since the immediately preceding pulse.