/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.hardware.gnss@1.0;
/** The callback interface to report measurements from the HAL. */
interface IGnssMeasurementCallback {
/**
* Flags to indicate what fields in GnssClock are valid.
*/
@export(name="", value_prefix="GNSS_CLOCK_")
enum GnssClockFlags : uint16_t {
/** A valid 'leap second' is stored in the data structure. */
HAS_LEAP_SECOND = 1 << 0,
/** A valid 'time uncertainty' is stored in the data structure. */
HAS_TIME_UNCERTAINTY = 1 << 1,
/** A valid 'full bias' is stored in the data structure. */
HAS_FULL_BIAS = 1 << 2,
/** A valid 'bias' is stored in the data structure. */
HAS_BIAS = 1 << 3,
/** A valid 'bias uncertainty' is stored in the data structure. */
HAS_BIAS_UNCERTAINTY = 1 << 4,
/** A valid 'drift' is stored in the data structure. */
HAS_DRIFT = 1 << 5,
/** A valid 'drift uncertainty' is stored in the data structure. */
HAS_DRIFT_UNCERTAINTY = 1 << 6
};
/**
* Flags to indicate what fields in GnssMeasurement are valid.
*/
@export(name="", value_prefix="GNSS_MEASUREMENT_")
enum GnssMeasurementFlags : uint32_t {
/** A valid 'snr' is stored in the data structure. */
HAS_SNR = 1 << 0,
/** A valid 'carrier frequency' is stored in the data structure. */
HAS_CARRIER_FREQUENCY = 1 << 9,
/** A valid 'carrier cycles' is stored in the data structure. */
HAS_CARRIER_CYCLES = 1 << 10,
/** A valid 'carrier phase' is stored in the data structure. */
HAS_CARRIER_PHASE = 1 << 11,
/** A valid 'carrier phase uncertainty' is stored in the data structure. */
HAS_CARRIER_PHASE_UNCERTAINTY = 1 << 12,
/** A valid automatic gain control is stored in the data structure. */
HAS_AUTOMATIC_GAIN_CONTROL = 1 << 13
};
/**
* Enumeration of available values for the GNSS Measurement's multipath
* indicator.
*/
@export(name="", value_prefix="GNSS_MULTIPATH_")
enum GnssMultipathIndicator : uint8_t {
/** The indicator is not available or unknown. */
INDICATOR_UNKNOWN = 0,
/** The measurement is indicated to be affected by multipath. */
INDICATOR_PRESENT = 1,
/** The measurement is indicated to be not affected by multipath. */
INDICATIOR_NOT_PRESENT = 2
};
/**
* Flags indicating the GNSS measurement state.
*
* The expected behavior here is for GNSS HAL to set all the flags that applies.
* For example, if the state for a satellite is only C/A code locked and bit
* synchronized, and there is still millisecond ambiguity, the state must be
* set as:
*
* STATE_CODE_LOCK | STATE_BIT_SYNC | STATE_MSEC_AMBIGUOUS
*
* If GNSS is still searching for a satellite, the corresponding state must be
* set to STATE_UNKNOWN(0).
*/
@export(name="", value_prefix="GNSS_MEASUREMENT_")
enum GnssMeasurementState : uint32_t {
STATE_UNKNOWN = 0,
STATE_CODE_LOCK = 1 << 0,
STATE_BIT_SYNC = 1 << 1,
STATE_SUBFRAME_SYNC = 1 << 2,
STATE_TOW_DECODED = 1 << 3,
STATE_MSEC_AMBIGUOUS = 1 << 4,
STATE_SYMBOL_SYNC = 1 << 5,
STATE_GLO_STRING_SYNC = 1 << 6,
STATE_GLO_TOD_DECODED = 1 << 7,
STATE_BDS_D2_BIT_SYNC = 1 << 8,
STATE_BDS_D2_SUBFRAME_SYNC = 1 << 9,
STATE_GAL_E1BC_CODE_LOCK = 1 << 10,
STATE_GAL_E1C_2ND_CODE_LOCK = 1 << 11,
STATE_GAL_E1B_PAGE_SYNC = 1 << 12,
STATE_SBAS_SYNC = 1 << 13,
STATE_TOW_KNOWN = 1 << 14,
STATE_GLO_TOD_KNOWN = 1 << 15,
};
/**
* Flags indicating the Accumulated Delta Range's states.
*/
@export(name="", value_prefix="GNSS_")
enum GnssAccumulatedDeltaRangeState : uint16_t {
ADR_STATE_UNKNOWN = 0,
ADR_STATE_VALID = 1 << 0,
ADR_STATE_RESET = 1 << 1,
ADR_STATE_CYCLE_SLIP = 1 << 2,
};
/**
* Represents an estimate of the GNSS clock time.
*/
struct GnssClock {
/**
* A set of flags indicating the validity of the fields in this data
* structure.
*/
bitfield<GnssClockFlags> gnssClockFlags;
/**
* Leap second data.
* The sign of the value is defined by the following equation:
* utcTimeNs = timeNs - (fullBiasNs + biasNs) - leapSecond *
* 1,000,000,000
*
* If this data is available, gnssClockFlags must contain
* HAS_LEAP_SECOND.
*/
int16_t leapSecond;
/**
* The GNSS receiver internal clock value. This is the local hardware clock
* value.
*
* For local hardware clock, this value is expected to be monotonically
* increasing while the hardware clock remains powered on. (For the case of a
* HW clock that is not continuously on, see the
* hwClockDiscontinuityCount field). The receiver's estimate of GNSS time
* can be derived by subtracting the sum of fullBiasNs and biasNs (when
* available) from this value.
*
* This GNSS time must be the best estimate of current GNSS time
* that GNSS receiver can achieve.
*
* Sub-nanosecond accuracy can be provided by means of the 'biasNs' field.
* The value contains the timeUncertaintyNs in it.
*
* This field is mandatory.
*/
int64_t timeNs;
/**
* 1-Sigma uncertainty associated with the clock's time in nanoseconds.
* The uncertainty is represented as an absolute (single sided) value.
*
* If the data is available, gnssClockFlags must contain
* HAS_TIME_UNCERTAINTY. Ths value is ideally zero, as the time
* 'latched' by timeNs is defined as the reference clock vs. which all
* other times (and corresponding uncertainties) are measured.
*/
double timeUncertaintyNs;
/**
* The difference between hardware clock ('time' field) inside GNSS receiver
* and the true GNSS time since 0000Z, January 6, 1980, in nanoseconds.
*
* The sign of the value is defined by the following equation:
* local estimate of GNSS time = timeNs - (fullBiasNs + biasNs)
*
* This value is mandatory if the receiver has estimated GNSS time. If the
* computed time is for a non-GNSS constellation, the time offset of that
* constellation to GNSS has to be applied to fill this value. The error
* estimate for the sum of this and the biasNs is the biasUncertaintyNs,
* and the caller is responsible for using this uncertainty (it can be very
* large before the GNSS time has been solved for.) If the data is available
* gnssClockFlags must contain HAS_FULL_BIAS.
*/
int64_t fullBiasNs;
/**
* Sub-nanosecond bias.
* The error estimate for the sum of this and the fullBiasNs is the
* biasUncertaintyNs.
*
* If the data is available gnssClockFlags must contain HAS_BIAS. If GNSS
* has computed a position fix. This value is mandatory if the receiver has
* estimated GNSS time.
*/
double biasNs;
/**
* 1-Sigma uncertainty associated with the local estimate of GNSS time (clock
* bias) in nanoseconds. The uncertainty is represented as an absolute
* (single sided) value.
*
* If the data is available gnssClockFlags must contain
* HAS_BIAS_UNCERTAINTY. This value is mandatory if the receiver
* has estimated GNSS time.
*/
double biasUncertaintyNs;
/**
* The clock's drift in nanoseconds (per second).
*
* A positive value means that the frequency is higher than the nominal
* frequency, and that the (fullBiasNs + biasNs) is growing more positive
* over time.
*
* The value contains the 'drift uncertainty' in it.
* If the data is available gnssClockFlags must contain HAS_DRIFT.
*
* This value is mandatory if the receiver has estimated GNSS time.
*/
double driftNsps;
/**
* 1-Sigma uncertainty associated with the clock's drift in nanoseconds (per
* second).
* The uncertainty is represented as an absolute (single sided) value.
*
* If the data is available gnssClockFlags must contain
* HAS_DRIFT_UNCERTAINTY. If GNSS has computed a position fix this
* field is mandatory and must be populated.
*/
double driftUncertaintyNsps;
/**
* When there are any discontinuities in the HW clock, this field is
* mandatory.
*
* A "discontinuity" is meant to cover the case of a switch from one source
* of clock to another. A single free-running crystal oscillator (XO)
* will generally not have any discontinuities, and this can be set and
* left at 0.
*
* If, however, the timeNs value (HW clock) is derived from a composite of
* sources, that is not as smooth as a typical XO, or is otherwise stopped &
* restarted, then this value shall be incremented each time a discontinuity
* occurs. (E.g. this value can start at zero at device boot-up and
* increment each time there is a change in clock continuity. In the
* unlikely event that this value reaches full scale, rollover (not
* clamping) is required, such that this value continues to change, during
* subsequent discontinuity events.)
*
* While this number stays the same, between GnssClock reports, it can be
* safely assumed that the timeNs value has been running continuously, e.g.
* derived from a single, high quality clock (XO like, or better, that is
* typically used during continuous GNSS signal sampling.)
*
* It is expected, esp. during periods where there are few GNSS signals
* available, that the HW clock be discontinuity-free as long as possible,
* as this avoids the need to use (waste) a GNSS measurement to fully
* re-solve for the GNSS clock bias and drift, when using the accompanying
* measurements, from consecutive GnssData reports.
*/
uint32_t hwClockDiscontinuityCount;
};
/**
* Represents a GNSS Measurement, it contains raw and computed information.
*
* All signal measurement information (e.g. svTime,
* pseudorangeRate, multipathIndicator) reported in this struct must be
* based on GNSS signal measurements only. You must not synthesize measurements
* by calculating or reporting expected measurements based on known or estimated
* position, velocity, or time.
*/
struct GnssMeasurement{
/**
* A set of flags indicating the validity of the fields in this data
* structure.
*/
bitfield<GnssMeasurementFlags> flags;
/**
* Satellite vehicle ID number, as defined in GnssSvInfo::svid
* This is a mandatory value.
*/
int16_t svid;
/**
* Defines the constellation of the given SV.
*/
GnssConstellationType constellation;
/**
* Time offset at which the measurement was taken in nanoseconds.
* The reference receiver's time is specified by GnssData::clock::timeNs.
*
* The sign of timeOffsetNs is given by the following equation:
* measurement time = GnssClock::timeNs + timeOffsetNs
*
* It provides an individual time-stamp for the measurement, and allows
* sub-nanosecond accuracy.
* This is a mandatory value.
*/
double timeOffsetNs;
/**
* Per satellite sync state. It represents the current sync state for the
* associated satellite.
* Based on the sync state, the 'received GNSS tow' field must be interpreted
* accordingly.
*
* This is a mandatory value.
*/
bitfield<GnssMeasurementState> state;
/**
* The received GNSS Time-of-Week at the measurement time, in nanoseconds.
* For GNSS & QZSS, this is the received GNSS Time-of-Week at the
* measurement time, in nanoseconds. The value is relative to the
* beginning of the current GNSS week.
*
* Given the highest sync state that can be achieved, per each satellite,
* valid range for this field can be:
* Searching : [ 0 ] : STATE_UNKNOWN
* C/A code lock : [ 0 1ms ] : STATE_CODE_LOCK set
* Bit sync : [ 0 20ms ] : STATE_BIT_SYNC set
* Subframe sync : [ 0 6s ] : STATE_SUBFRAME_SYNC set
* TOW decoded : [ 0 1week ] : STATE_TOW_DECODED set
* TOW Known : [ 0 1week ] : STATE_TOW_KNOWN set
*
* Note: TOW Known refers to the case where TOW is possibly not decoded
* over the air but has been determined from other sources. If TOW
* decoded is set then TOW Known must also be set.
*
* Note: If there is any ambiguity in integer millisecond,
* GNSS_MEASUREMENT_STATE_MSEC_AMBIGUOUS must be set accordingly, in the
* 'state' field.
*
* This value must be populated if 'state' != STATE_UNKNOWN.
*
* For Glonass, this is the received Glonass time of day, at the
* measurement time in nanoseconds.
*
* Given the highest sync state that can be achieved, per each satellite,
* valid range for this field can be:
* Searching : [ 0 ] : STATE_UNKNOWN set
* C/A code lock : [ 0 1ms ] : STATE_CODE_LOCK set
* Symbol sync : [ 0 10ms ] : STATE_SYMBOL_SYNC set
* Bit sync : [ 0 20ms ] : STATE_BIT_SYNC set
* String sync : [ 0 2s ] : STATE_GLO_STRING_SYNC set
* Time of day decoded : [ 0 1day ] : STATE_GLO_TOD_DECODED set
* Time of day known : [ 0 1day ] : STATE_GLO_TOD_KNOWN set
*
* Note: Time of day known refers to the case where it is possibly not
* decoded over the air but has been determined from other sources. If
* Time of day decoded is set then Time of day known must also be set.
*
* For Beidou, this is the received Beidou time of week,
* at the measurement time in nanoseconds.
*
* Given the highest sync state that can be achieved, per each satellite,
* valid range for this field can be:
* Searching : [ 0 ] : STATE_UNKNOWN set.
* C/A code lock : [ 0 1ms ] : STATE_CODE_LOCK set.
* Bit sync (D2) : [ 0 2ms ] : STATE_BDS_D2_BIT_SYNC set.
* Bit sync (D1) : [ 0 20ms ] : STATE_BIT_SYNC set.
* Subframe (D2) : [ 0 0.6s ] : STATE_BDS_D2_SUBFRAME_SYNC set.
* Subframe (D1) : [ 0 6s ] : STATE_SUBFRAME_SYNC set.
* Time of week decoded : [ 0 1week ] : STATE_TOW_DECODED set.
* Time of week known : [ 0 1week ] : STATE_TOW_KNOWN set
*
* Note: TOW Known refers to the case where TOW is possibly not decoded
* over the air but has been determined from other sources. If TOW
* decoded is set then TOW Known must also be set.
*
* For Galileo, this is the received Galileo time of week,
* at the measurement time in nanoseconds.
*
* E1BC code lock : [ 0 4ms ] : STATE_GAL_E1BC_CODE_LOCK set.
* E1C 2nd code lock : [ 0 100ms] : STATE_GAL_E1C_2ND_CODE_LOCK set.
* E1B page : [ 0 2s ] : STATE_GAL_E1B_PAGE_SYNC set.
* Time of week decoded : [ 0 1week] : STATE_TOW_DECODED is set.
* Time of week known : [ 0 1week] : STATE_TOW_KNOWN set
*
* Note: TOW Known refers to the case where TOW is possibly not decoded
* over the air but has been determined from other sources. If TOW
* decoded is set then TOW Known must also be set.
*
* For SBAS, this is received SBAS time, at the measurement time in
* nanoseconds.
*
* Given the highest sync state that can be achieved, per each satellite,
* valid range for this field can be:
* Searching : [ 0 ] : STATE_UNKNOWN
* C/A code lock: [ 0 1ms ] : STATE_CODE_LOCK is set
* Symbol sync : [ 0 2ms ] : STATE_SYMBOL_SYNC is set
* Message : [ 0 1s ] : STATE_SBAS_SYNC is set
*/
int64_t receivedSvTimeInNs;
/**
* 1-Sigma uncertainty of the Received GNSS Time-of-Week in nanoseconds.
*
* This value must be populated if 'state' != STATE_UNKNOWN.
*/
int64_t receivedSvTimeUncertaintyInNs;
/**
* Carrier-to-noise density in dB-Hz, typically in the range [0, 63].
* It contains the measured C/N0 value for the signal at the antenna port.
*
* This is a mandatory value.
*/
double cN0DbHz;
/**
* Pseudorange rate at the timestamp in m/s. The correction of a given
* Pseudorange Rate value includes corrections for receiver and satellite
* clock frequency errors. Ensure that this field is independent (see
* comment at top of GnssMeasurement struct.)
*
* It is mandatory to provide the 'uncorrected' 'pseudorange rate', and
* provide GnssClock's 'drift' field as well. When providing the
* uncorrected pseudorange rate, do not apply the corrections described above.)
*
* The value includes the 'pseudorange rate uncertainty' in it.
* A positive 'uncorrected' value indicates that the SV is moving away from
* the receiver.
*
* The sign of the 'uncorrected' 'pseudorange rate' and its relation to the
* sign of 'doppler shift' is given by the equation:
* pseudorange rate = -k * doppler shift (where k is a constant)
*
* This must be the most accurate pseudorange rate available, based on
* fresh signal measurements from this channel.
*
* It is mandatory that this value be provided at typical carrier phase PRR
* quality (few cm/sec per second of uncertainty, or better) - when signals
* are sufficiently strong & stable, e.g. signals from a GNSS simulator at >=
* 35 dB-Hz.
*/
double pseudorangeRateMps;
/**
* 1-Sigma uncertainty of the pseudorangeRateMps.
* The uncertainty is represented as an absolute (single sided) value.
*
* This is a mandatory value.
*/
double pseudorangeRateUncertaintyMps;
/**
* Accumulated delta range's state. It indicates whether ADR is reset or
* there is a cycle slip(indicating loss of lock).
*
* This is a mandatory value.
*/
bitfield<GnssAccumulatedDeltaRangeState> accumulatedDeltaRangeState;
/**
* Accumulated delta range since the last channel reset in meters.
* A positive value indicates that the SV is moving away from the receiver.
*
* The sign of the 'accumulated delta range' and its relation to the sign of
* 'carrier phase' is given by the equation:
* accumulated delta range = -k * carrier phase (where k is a constant)
*
* This value must be populated if 'accumulated delta range state' !=
* ADR_STATE_UNKNOWN.
* However, it is expected that the data is only accurate when:
* 'accumulated delta range state' == ADR_STATE_VALID.
*/
double accumulatedDeltaRangeM;
/**
* 1-Sigma uncertainty of the accumulated delta range in meters.
* This value must be populated if 'accumulated delta range state' !=
* ADR_STATE_UNKNOWN.
*/
double accumulatedDeltaRangeUncertaintyM;
/**
* Carrier frequency of the signal tracked, for example it can be the
* GPS central frequency for L1 = 1575.45 MHz, or L2 = 1227.60 MHz, L5 =
* 1176.45 MHz, varying GLO channels, etc. If the field is not set, it
* is the primary common use central frequency, e.g. L1 = 1575.45 MHz
* for GPS.
*
* For an L1, L5 receiver tracking a satellite on L1 and L5 at the same
* time, two raw measurement structs must be reported for this same
* satellite, in one of the measurement structs, all the values related
* to L1 must be filled, and in the other all of the values related to
* L5 must be filled.
*
* If the data is available, gnssClockFlags must contain
* HAS_CARRIER_FREQUENCY.
*/
float carrierFrequencyHz;
/**
* The number of full carrier cycles between the satellite and the
* receiver. The reference frequency is given by the field
* 'carrierFrequencyHz'. Indications of possible cycle slips and
* resets in the accumulation of this value can be inferred from the
* accumulatedDeltaRangeState flags.
*
* If the data is available, gnssClockFlags must contain
* HAS_CARRIER_CYCLES.
*/
int64_t carrierCycles;
/**
* The RF phase detected by the receiver, in the range [0.0, 1.0].
* This is usually the fractional part of the complete carrier phase
* measurement.
*
* The reference frequency is given by the field 'carrierFrequencyHz'.
* The value contains the 'carrier-phase uncertainty' in it.
*
* If the data is available, gnssClockFlags must contain
* HAS_CARRIER_PHASE.
*/
double carrierPhase;
/**
* 1-Sigma uncertainty of the carrier-phase.
* If the data is available, gnssClockFlags must contain
* HAS_CARRIER_PHASE_UNCERTAINTY.
*/
double carrierPhaseUncertainty;
/**
* An enumeration that indicates the 'multipath' state of the event.
*
* The multipath Indicator is intended to report the presence of overlapping
* signals that manifest as distorted correlation peaks.
*
* - if there is a distorted correlation peak shape, report that multipath
* is MULTIPATH_INDICATOR_PRESENT.
* - if there is no distorted correlation peak shape, report
* MULTIPATH_INDICATOR_NOT_PRESENT
* - if signals are too weak to discern this information, report
* MULTIPATH_INDICATOR_UNKNOWN
*
* Example: when doing the standardized overlapping Multipath Performance
* test (3GPP TS 34.171) the Multipath indicator must report
* MULTIPATH_INDICATOR_PRESENT for those signals that are tracked, and
* contain multipath, and MULTIPATH_INDICATOR_NOT_PRESENT for those
* signals that are tracked and do not contain multipath.
*/
GnssMultipathIndicator multipathIndicator;
/**
* Signal-to-noise ratio at correlator output in dB.
* If the data is available, GnssMeasurementFlags must contain HAS_SNR.
* This is the power ratio of the "correlation peak height above the
* observed noise floor" to "the noise RMS".
*/
double snrDb;
/**
* Automatic gain control (AGC) level. AGC acts as a variable gain
* amplifier adjusting the power of the incoming signal. The AGC level
* may be used to indicate potential interference. When AGC is at a
* nominal level, this value must be set as 0. Higher gain (and/or lower
* input power) must be output as a positive number. Hence in cases of
* strong jamming, in the band of this signal, this value must go more
* negative.
*
* Note: Different hardware designs (e.g. antenna, pre-amplification, or
* other RF HW components) may also affect the typical output of of this
* value on any given hardware design in an open sky test - the
* important aspect of this output is that changes in this value are
* indicative of changes on input signal power in the frequency band for
* this measurement.
*/
double agcLevelDb;
};
/**
* Represents a reading of GNSS measurements. For devices where GnssSystemInfo's
* yearOfHw is set to 2016+, it is mandatory that these be provided, on
* request, when the GNSS receiver is searching/tracking signals.
*
* - Reporting of GNSS constellation measurements is mandatory.
* - Reporting of all tracked constellations are encouraged.
*/
struct GnssData {
/** Number of GnssMeasurement elements. */
uint32_t measurementCount;
/** The array of measurements. */
GnssMeasurement[GnssMax:SVS_COUNT] measurements;
/** The GNSS clock time reading. */
GnssClock clock;
};
/**
* Callback for the hal to pass a GnssData structure back to the client.
*
* @param data Contains a reading of GNSS measurements.
*/
GnssMeasurementCb(GnssData data);
};