Swift Navigation Support

A real-time Skylark GNSS corrections are distributed over the Internet in RTCM v3.x format using NTRIP v1.0 protocol. A reliable Internet access is required for good navigation performance.

Skylark provides corrections in ITRF2020 and NAD83 (Skylark Nx only) reference frames.

The GNSS receiver needs a properly configured NTRIP Client software to receive corrections from Skylark. NTRIP Client settings include:

Endpoint
- Host address
- Port
Mountpoint
NMEA GGA output
Authentication
- Username
- Password

Skylark Endpoints

The endpoint specifies the corrections server (caster) address.

Endpoint name is not case sensitive.

Skylark endpoint format:

<rr>.<freq>.skylark.swiftnav.com:<port>

Where

<rr> is the region, which is one of:

NA for North America
EU for Europe
AP for Asia Pacific

<freq> represents the GNSS frequencies that the corrections are for:

L1L2 for L1/L2
L1L5 for L1/L5
all-freq for L1/L2/L5

<port> is one of:

2101 for standard connection
2102 for TLS encrypted connection
2103 for mTLS encrypted connection

Skylark Mountpoints

The mountpoint selects the correction stream from the NTRIP caster.

Mountpoint name is case sensitive.

Skylark Dx mountpoint:

DX-MSM1 - DGNSS corrections in standard MSM1 messages, ITRF2020

Skylark Cx mountpoints:

MSM4 - wide-lane RTK corrections in standard MSM4 messages, ITRF2020
MSM5 - wide-lane RTK corrections in standard MSM5 messages, ITRF2020
OSR - wide-lane RTK corrections in Swift proprietary messages, ITRF2020
SSR - State Space Representation corrections in Swift proprietary messages, ITRF2020
SSR-integrity - State Space Representation corrections with integrity in Swift proprietary messages, ITRF2020
SSR-integrity-AES-CMAC - State Space Representation corrections with integrity in Swift proprietary messages, uses AES-CMAC message signing algorithm, ITRF2020

Skylark Nx RTK mountpoints:

NXRTK-MSM5 - RTK corrections in standard MSM5 messages, ITRF2020
NXRTK-NAD83-MSM5 - RTK corrections in standard MSM5 messages, NAD83(2011) epoch 2010.0, available in contiguous United States only
NXRTK-DREF91-MSM5 - RTK corrections in standard MSM5 messages, ETRS89 DREF91(2016), available in Europe only
NXRTK-ETRF2000-MSM5 - RTK corrections in standard MSM5 messages, ETRS89 ETRF2000, available in Europe only
NXRTK-RTCM31 - RTK corrections in standard RTCM v3.1 messages (GPS signals only), ITRF2020

Former mountpoints:

DGNSS-MSM1 new name: DX-MSM1
RTK-MSM5 new name: NXRTK-MSM5
RTK-RTCM31 new name: NXRTK-RTCM31
CRS new name: MSM5

Although mountpoints with the former name are still operational, it's recommended to use new mountpoint name. The data provided by each mountpoint stream has not been changed.

NMEA GGA Output

The NMEA GGA message provides receiver's (rover's) approximate location to Skylark NTRIP caster and is used by Skylark to provide corrections for the given location. Skylark will not provide any corrections without the GGA message.

It's recommended to send updated GGA every 10 seconds.

Authentication

A basic NTRIP authentication with username and password is required to obtain corrections.

Credentials can be obtained from Swift Navigation by creating an account on Skylark Portal or by contacting Swift Sales Team.

Notes

Upon connection, ahead of GGA being received, Skylark sends a block of ephemeris data for all satellites in RTCM message 1019(GPS), 1046(Galileo), and 1042 (BeiDou). It enables receiver to compute a first fix quicker and with more satellites. Ephemeris data block is about 7 KB total. Subsequent ephemeris updates are sent only for the satellites in view.
Skylark expects that NTRIP client will send the initial GGA message within 60 seconds of a connection. If the connections is reset, dropped and re-established, Skylark expects an updated GGA. If Skylark does not receive a properly formatted GGA within 60 seconds it drops the connection.
Skylark will accept NTRIP v2.0 as an input but the responses are in NTRIP v1.0 format.