Semtech LR1110 - LR1110 GNSS Scanning Results Description

LR1110
User Manual Rev.1.0
UM.LR1110.W.APP March 2020
98 of 130
Semtech
www.semtech.com
• ResultMask: bit mask indicating which information is added in the output payload.
Set to 0x03. Other values are RFU.
• NbSvMax defines the maximum number of satellites to detect.
If NbSvMax=0, all the detected satellites will be returned. Otherwise, only the NbSvMax satellites with higher C/N will
be returned.
Please note that calling this command resets the previous GNSS results, if any.
11.3.5 GnssSetAssistancePosition
The command GnssSetAssistancePosition( ) allows configuring the approximate position for the GNSS assisted mode.
• Latitude: Latitude, coded on 12bits (resolution of 0.044°)
Latitude= latitude in degrees (decimal value)* 2048/90.
For example for 47.006° latitude: 47.006*2048/90=1070 (rounded)=0x042E.
• Longitude: Longitude, coded on 12bits (resolution of 0.088°)
Longitude= longitude in degrees (decimal value)* 2048/180.
For example, for 6.966°longitude: 6.966*2048/180=79 (rounded)=0x004F.
11.4 GNSS Scanning Results Description
GNSS scanning results are formatted in NAV messages, of variable length depending on the number of satellites detected
and on the GnssMode (single or dual scanning). The NAV messages destination can be either to the host (for status
information), to the Solver (for geolocation cloud calculation), or to the DMC (for almanac management).
In order to read back the GNSS scanning results, the size of results stream to read has to be determined first using the
command GnssGetResultSize( ). Afterwards, the results can be read using the command GnssReadResult( ).
11.4.1 NAV Message Description
The NAV message format is shown in Figure 11-2: NAV Message Format It is composed of a DestinationID field, followed by
a Payload of variable length:
Table 11-5: GnssSetAssistancePosition Command
Byte 0 1 2 3 4 5
Data from Host 0x04 0x10
Latitude
(15-8)
Latitude
(7-0)
Longitude
(15-8)
Longitude
(7:0)
Data to Host Stat1 Stat2
IrqStatus
(31:24)
IrqStatus
(23:16)
IrqStatus
(15:8)
IrqStatus
(7:0)