RTK

Updated on Aug 29, 2026

The RTK HAT (NEO-F9P) supports centimeter-level positioning using RTCM3 corrections.

Note
HAT Compatibility — RTK is available only on the L1/L5 RTK HAT (NEO-F9P).

RtkConfig

Field	C++ Type	Description
`mode`	`ERtkMode`	`Base` or `Rover`
`base`	`optional<BaseConfig>`	Base station configuration. Required when `mode = Base`

RTK Modes

Value	C++	Python	Description
Base	`ERtkMode::Base`	`gnsshat.RtkMode.BASE`	Generate RTCM3 corrections
Rover	`ERtkMode::Rover`	`gnsshat.RtkMode.ROVER`	Consume RTCM3 corrections for cm-level fix

Base Configuration

The base station needs to know its precise position. Two modes:

Survey-In

The module auto-determines its position by observing satellites over a configurable period and accuracy threshold.

Field	Type	Description
`minimumObservationTime_s`	`uint32_t`	Minimum observation time in seconds
`requiredPositionAccuracy_m`	`double`	Required 3D position accuracy in meters

Fixed Position

Provide known coordinates directly, skipping the survey phase. Supports ECEF or LLA.

ECEF (Earth-Centered, Earth-Fixed):

Field	Type	Description
`x_m`	`double`	X coordinate in meters
`y_m`	`double`	Y coordinate in meters
`z_m`	`double`	Z coordinate in meters
`positionAccuracy_m`	`double`	Position accuracy in meters

LLA (Latitude, Longitude, Altitude):

Field	Type	Description
`latitude_deg`	`double`	Latitude in degrees
`longitude_deg`	`double`	Longitude in degrees
`height_m`	`double`	Height above ellipsoid in meters
`positionAccuracy_m`	`double`	Position accuracy in meters

Base Examples

C++ (Survey-In)

config.rtk = RtkConfig {
    .mode = ERtkMode::Base,
    .base = BaseConfig {
        .mode = BaseConfig::SurveyIn {
            .minimumObservationTime_s = 60,
            .requiredPositionAccuracy_m = 2.0
        }
    }
};

Python (Survey-In)

config['rtk'] = {
    'mode': gnsshat.RtkMode.BASE,
    'base': {
        'base_mode': gnsshat.BaseMode.SURVEY_IN,
        'survey_in': {
            'minimum_observation_time_s': 60,
            'required_position_accuracy_m': 2.0
        }
    }
}

C++ (Fixed Position — LLA)

config.rtk = RtkConfig {
    .mode = ERtkMode::Base,
    .base = BaseConfig {
        .mode = BaseConfig::FixedPosition {
            .position = BaseConfig::FixedPosition::Lla {
                .latitude_deg = 52.2297,
                .longitude_deg = 21.0122,
                .height_m = 120.0
            },
            .positionAccuracy_m = 0.01
        }
    }
};

C (Fixed Position — LLA)

jp_gnss_gnss_config_t config;
jp_gnss_gnss_config_init(&config);
config.rtk.mode = JP_GNSS_RTK_MODE_BASE;
config.rtk.base.base_mode = JP_GNSS_BASE_MODE_FIXED_POSITION;
config.rtk.base.fixed_position.type = JP_GNSS_FIXED_POSITION_LLA;
config.rtk.base.fixed_position.lla.latitude_deg = 52.2297;
config.rtk.base.fixed_position.lla.longitude_deg = 21.0122;
config.rtk.base.fixed_position.lla.height_m = 120.0;
config.rtk.base.fixed_position.position_accuracy_m = 0.01;
jp_gnss_hat_start(hat, &config);

Python (Fixed Position — LLA)

config['rtk'] = {
    'mode': gnsshat.RtkMode.BASE,
    'base': {
        'base_mode': gnsshat.BaseMode.FIXED_POSITION,
        'fixed_position': {
            'lla': {
                'latitude_deg': 52.2297,
                'longitude_deg': 21.0122,
                'height_m': 120.0
            },
            'position_accuracy_m': 0.01
        }
    }
}

Rover Examples

C++

config.rtk = RtkConfig {
    .mode = ERtkMode::Rover
};

jp_gnss_gnss_config_t config;
jp_gnss_gnss_config_init(&config);
config.rtk.mode = JP_GNSS_RTK_MODE_ROVER;
jp_gnss_hat_start(hat, &config);

Python

config['rtk'] = {
    'mode': gnsshat.RtkMode.ROVER
}

See RTK Feature for runtime correction flow and NTRIP usage.