Monitoring API

Note

The Monitoring API is provided on TCP port 5305.

The Monitoring API provides system-level information about the GRX device, including GNSS synchronization, system health, resource usage, and device metadata.

Service Methods

The Monitoring API (Monitord) provides the following RPC methods:

GNSS / GPS

// Full GNSS status: position, timing, satellite details, hardware monitoring
rpc GetGNSSInformation (Empty) returns (GNSSInformation);

System Resources

rpc GetCPUUsage (Empty) returns (CPUUsage);
rpc GetCPUUsageHistory (Empty) returns (GetCPUUsageHistoryReply);
rpc GetMemoryUsage (Empty) returns (MemoryUsage);
rpc GetMemoryUsageHistory (Empty) returns (GetMemoryUsageHistoryReply);
rpc GetSwapUsage (Empty) returns (SwapUsage);
rpc GetSwapUsageHistory (Empty) returns (GetSwapUsageHistoryReply);
rpc GetMountedFilesystemUsage (Empty) returns (GetMountedFilesystemUsageReply);
rpc GetProcessList (Empty) returns (GetProcessListReply);
rpc GetSystemLoad (Empty) returns (SystemLoad);
rpc GetSystemLoadHistory (Empty) returns (GetSystemLoadHistoryReply);

Network

rpc GetNetworkUsage (Empty) returns (GetNetworkUsageReply);
rpc GetNetworkUsageHistory (Empty) returns (GetNetworkUsageHistoryReply);
rpc GetNetworkCounters (Empty) returns (GetNetworkCountersReply);

System Information

// Health monitoring (CPU temperature, DC input voltage)
rpc GetSystemHealth (Empty) returns (SystemHealth);
rpc GetSystemHealthHistory (Empty) returns (GetSystemHealthHistoryReply);

// System metadata (uptime, serial number, versions, reset reasons)
rpc GetSystemInformation (Empty) returns (SystemInformation);

// Clear accumulated reset reasons (acknowledge events)
rpc ClearResetReasons (Empty) returns (Empty);

// Installed Debian packages
rpc GetSystemPackages (Empty) returns (GetSystemPackagesReply);

// Systemd service units and their states
rpc GetUnitList (Empty) returns (GetUnitListReply);

// System log messages (from journald)
rpc GetLogMessages (GetLogMessagesRequest) returns (GetLogMessagesReply);

Combined Status

// Single call that combines the 7 most common queries
rpc GetFullSystemStatus (Empty) returns (GetFullSystemStatusReply);

GNSS Position and Timing

GetGNSSInformation returns a comprehensive GNSSInformation message containing:

Position

Check the fix_type field before using position data:

Fix Type	Description
None (0)	No GNSS fix. Antenna may be disconnected or obstructed.
Pos2D (2)	2D fix (latitude, longitude). Rare – usually enough satellites are visible for a 3D fix.
Pos3D (3)	3D fix (latitude, longitude, height). This is the normal operating state.
TimeOnly (5)	Stationary mode. Position was set manually or determined via survey-in. GNSS is used only for time synchronization.

When fix_type >= 2, the latitude (degrees), longitude (degrees), and height (meters above WGS-84 ellipsoid) fields are valid. Accuracy estimates are in horizontal_accuracy and vertical_accuracy (meters).

Timing

The timing sub-message provides:

• UTC time (year, month, day, hour, minute, second)

• Time pulse lock status and tolerance

• GNSS time accuracy estimate (nanoseconds)

• Internal oscillator frequency offset and uncertainty

• Disciplining source (Internal, GNSS, external input)

Holdover Oscillator

If the device is equipped with an external holdover oscillator (e.g., CSAC), the holdover_oscillator field provides:

• Holdover duration (seconds active)

• Readiness for holdover

• Estimated time accuracy during holdover

• Warning and failure flags

Satellite Details

The optional satellite_information field provides per-satellite tracking data including GNSS constellation, signal quality, elevation, azimuth, and health status.

Tip

For best GNSS performance, use a dedicated GNSS antenna with unobstructed 360° sky view. Indoor GNSS reception is generally not possible.

System Health

GetSystemHealth returns:

• CPU temperature (°C)

• DC input voltage (V) – only on devices with voltage sensing hardware

Use GetSystemHealthHistory for historical data with timestamps.

Protocol Buffer Definition

• Monitord.proto

syntax = "proto3";

import "google/protobuf/empty.proto";

package serosystems.proto.v3.grx.monitord;
option java_package = "de.serosystems.proto.v3.grx.monitord";
option java_outer_classname = "MonitorDProto";
// Go package is relative to the web-ui package
// This will result in "golang.sero-systems.de/grx/web-ui/proto/.../v3
option go_package = "proto/monitord/v3";

/* CPU Usage */
message CPUUsage {
	/*
	 * CPU Usage information for a single CPU/core (or aggregated over all).
	 * All values are percent of time spent in the given states within the last
	 *  measurement period.
	 */
	message SingleCPUUsage {
		float total = 1;
		float user = 2;
		float nice = 3;
		float sys = 4;
		float idle = 5;
		float iowait = 6;
		float irq = 7;
		float softirq = 8;
	}

	/* Total CPU usage (of all CPUs/cores) as average. */
	SingleCPUUsage total = 1;

	/* CPU Usage broken down for each CPU/core. */
	repeated SingleCPUUsage per_cpu = 2;
}

/* Memory usage. All values are in bytes. */
message MemoryUsage {
	uint64 total = 1;
	uint64 used = 2;
	uint64 free = 3;
	uint64 shared = 4;
	uint64 buffer = 5;
	uint64 cached = 6;
	uint64 user = 7;
	uint64 locked = 8;
}

/* Swap memory usage. All values are in bytes. */
message SwapUsage {
	uint64 total = 1;
	uint64 used = 2;
	uint64 free = 3;
}

/* File system usage. */
message FileSystemUsage {
	/* Mount point. */
	message MountEntry {
		/* Probably not needed, what is it anyways? */
		//uint64 dev = 1;
		reserved 1;

		/* Device name. */
		string devname = 2;

		/* Mount point. */
		string mountdir = 3;

		/* Filesystem type. */
		string type = 4;
	}

	/* Mount point for this usage info. */
	MountEntry mount = 1;

	/* Total number of blocks. */
	uint64 blocks = 2;

	/* Free blocks available to non-superuser. */
	uint64 bavail = 3;

	/* Size of a block [b]. */
	uint32 block_size = 4;
}

/* Process info. */
message ProcessInfo {
	/* Process ID. */
	uint64 pid = 1;

	/* User name. */
	string user = 2;

	/* Kernel scheduling priority. */
	int32 priority = 3;

	/* Standard unix nice level of process. */
	int32 nice = 4;

	/* The state, as defined by the GLIBTOP_PROCESS_* macros. */
	int32 state = 5;

	/* Command name. */
	string command = 6;

	/* Command Arguments. */
	repeated string argument = 7;

	/* Parent process ID. */
	uint64 ppid = 8;

	/* Total number of pages of virtual memory. */
	uint64 mem_virt = 9;

	/* Number of resident set (non-swapped) pages. */
	uint64 mem_res = 10;

	/* Number of pages of shared memory. */
	uint64 mem_shared = 11;

	/* Start time of the process [s since epoch UTC]. */
	uint64 start_time = 12;

	/* User-mode CPU time [s]. */
	float utime = 13;

	/* Kernel-mode CPU time [s]. */
	float stime = 14;

	/* TODO: possibly missing: %cpu, %mem */
}

/* Representation of a Debian Package. */
message SystemPackage {
	/* Debian package states. */
	enum Status {
		NOTINSTALLED = 0;
		CONFIGFILES = 1;
		HALFINSTALLED = 2;
		UNPACKED = 3;
		HALFCONFIGURED = 4;
		TRIGGERSAWAITED = 5;
		TRIGGERSPENDING = 6;
		INSTALLED = 7;
	};

	/* Debian package state. */
	Status status = 1;

	/* Package name. */
	string name = 2;

	/* Package version. */
	string version = 3;

	/* Package architecture. */
	string architecture = 4;
}

/*
 * Representation of of a single log message.
 * See also SYSTEMD.JOURNAL-FIELDS(7) for details.
 */
message LogMessage {
	/* TODO: there can be many, many fields, which are usually organized in
	 * key-value pairs, we only extract some here. */

	/* Log message. */
	string message = 1;

	/* Value between 0 (emergency) and 7 (debug). */
	uint32 priority = 2;

	/* File of the code where the messages originates (if known). */
	string code_file = 3;

	/* Line of the code where the messages originates (if known). */
	string code_line = 4;

	/* Function of the code where the messages originates (if known). */
	string code_func = 5;

	/* Value of errno (if available). */
	uint32 causing_errno = 6;

	/* Syslog facility, see RFC 3164. */
	uint32 syslog_facility = 7;

	/*
	 * Systemd SyslogIdentifier, defaulting to process name.
	 * See also systemd.exec(5).
	 */
	string syslog_identifier = 8;

	/* Syslog PID. */
	uint32 syslog_pid = 9;

	/* Time [ms since epoch UTC] this entry was received in the journal. */
	uint64 realtime_timestamp = 10;
}

/* Representation of a systemd unit. */
message Unit {
	/* ID/name of the unit. */
	string id = 1;

	/* Description of the unit. */
	string description = 2;

	/* Load state, e.g. "loaded", "not-found",etc. */
	string load_state = 3;

	/* Active state, e.g. "active", "inactive", etc. */
	string active_state = 4;

	/* Sub-state, e.g. "running", "exited", etc. */
	string sub_state = 5;

	string following = 6;

	/* SD-Bus path of the unit. */
	string unit_path = 7;

	uint32 job_id = 8;
	string job_type = 9;
	string job_path = 10;
}

/*
 * Network device usage: rates for the measurement period, i.e.
 * packets/s, bytes/s, errors/s and collisions/s.
 */
message NetworkDeviceUsage {
	/* Name of the device. */
	string device = 1;

	uint32 packets_in = 2;
	uint32 packets_out = 3;
	uint32 packets_total = 4;
	uint32 bytes_in = 5;
	uint32 bytes_out = 6;
	uint32 bytes_total = 7;
	uint32 errors_in = 8;
	uint32 errors_out = 9;
	uint32 errors_total = 10;
	uint32 collisions = 11;
}

/*
 * Network device counters.
 * Very similar to NetworkDeviceUsage, but gives absolute counter values instead
 *  of rates.
 * Make sure to take care of overflows. Currently, Linux uses 32 bit counters
 *  for (probably most of) these values.
 */
message NetworkDeviceCounters {
	/* Name of the device */
	string device = 1;

	uint32 packets_in = 2;
	uint32 packets_out = 3;
	uint32 packets_total = 4;
	uint32 bytes_in = 5;
	uint32 bytes_out = 6;
	uint32 bytes_total = 7;
	uint32 errors_in = 8;
	uint32 errors_out = 9;
	uint32 errors_total = 10;
	uint32 collisions = 11;

}

/* System health information. */
message SystemHealth {
	/* CPU temperature [Deg. Celcius]. */
	float temperature_cpu = 1;

	/* Voltage at the DC input [V]. */
	float voltage_dc_in = 2;
}

/* Overall system information. */
message SystemInformation {
	/* Current system time [s since epoch UTC]. */
	uint64 system_time = 1;

	/* Uptime of the system [s]. */
	uint32 uptime = 2;

	/* Reset reasons. */
	enum ResetReason {
		/*
		 * Power on Reset, i.e. device has been connected to power. Does not
		 *  indicate a problem.
		 */
		PowerOnReset = 0;

		/*
		 * System level controller reset. Happens e.g. if the device is
		 *  rebooted manually. Usually does not indicate a problem.
		 */
		SystemLevelControllerReset = 1;

		/*
		 * System watchdog reset. Happens if the device is reset by the
		 * internal watchdog timer. Indicates a problem.
		 */
		SystemWatchdogReset = 2;

		/*
		 * External system reset. Can happen on development device which have a
		 *  mounted reset switch and if the Zynq is reset by the CPLD. Usually
		 *  indicates a problem.
		 */
		ExternalSystemReset = 3;

		/*
		 * Debug reset. Should only happen during debugging with JTAG
		 *  hardware.
		 */
		DebugReset = 4;

		/* CPU0 APU watchdog timer reset, should never happen. */
		APUWatchdogTimerReset0 = 5;

		/* CPU1 APU watchdog timer reset, should never happen. */
		APUWatchdogTimerReset1 = 6;
	}

	/*
	 * The reset reasons. There can be multiple, as they need to be manually
	 *  cleared.
	 */
	repeated ResetReason reset_reasons = 3;

	/* The serial number of the device. */
	string serial_number = 4;

	/* System version fields. */
	map<string, string> version_information = 5;
}

/*
 * System Load: Number of jobs in run queue or waiting for IO over time.
 * See /proc/loadavg under proc(5) for details.
 */
message SystemLoad {
	/* Load average over last minute. */
	float load_avg_1m = 1;

	/* Load average over last 5 minutes. */
	float load_avg_5m = 2;

	/* Load average over last 15 minutes. */
	float load_avg_15m = 3;
}

/* GNSS Information. */
message GNSSInformation {
	/* Position information. */
	message Position {
		/* Fix type of GNSS receiver. */
		enum FixType {
			/* No fix established. */
			None = 0;
			/* 2D position fix. */
			Pos2D = 2;
			/* 3D position fix. */
			Pos3D = 3;
			/*
			 * Time only fix. Used in "stationary" mode, when the position is
			 *  assumed to be static.
			 */
			TimeOnly = 5;
		}

		/* Type of fix. */
		FixType fix_type = 1;

		/* Number of satellites used in the solution. Actually uint8. */
		uint32 sats_used = 2;

		/* Latitude [degrees]. */
		double latitude = 3;

		/* Longitude [degrees]. */
		double longitude = 4;

		/* Height above WGS-84 ellipsoid [m]. */
		double height = 5;

		/* Estimated horizontal accuracy [m]. */
		double horizontal_accuracy = 6;

		/* Estimated vertical accuracy [m]. */
		double vertical_accuracy = 7;
	}

	/* Further timing-related information. */
	message Timing {
		/* UTC Timing information. */
		message UTC {
			/* UTC standard of GNSS receiver. */
			enum Standard {
				/* Unknown. */
				Unknown = 0;
				/* UTC as operated by the U.S. Naval Observatory (USNO). */
				USNO = 3;
				/* UTC as operated by the former Soviet Union. */
				SU = 6;
				/*
				 * UTC as operated by the National Time Service Center, China.
				 */
				China = 7;
			};

			/* Whether all UTC fields are valid. */
			bool valid = 1;

			/* Used UTC standard. */
			Standard standard = 2;

			/* UTC year. Actually uint16. */
			uint32 year = 3;

			/* UTC month. Actually uint8. */
			uint32 month = 4;

			/* UTC day. Actually uint8. */
			uint32 day = 5;

			/* UTC hour. Actually uint8. */
			uint32 hour = 6;

			/* UTC minute. actually uint8. */
			uint32 min = 7;

			/*
			 * UTC second (may also be 60, if a leap second is present).
			 * Actually uint8.
			 */
			uint32 sec = 8;
		}

		/* Disciplining sources of GNSS receiver. */
		enum DiscipliningSource {
			/* Internal oscillator. */
			Internal = 0;
			/* GNSS. */
			GNSS = 1;
			EXTINT0 = 2;
			EXTINT1 = 3;
			/* Internal oscillator measured by the host. */
			InternalMeasuredByHost = 4;
			/* External oscillator measured by the host. */
			ExternalMeasuredByHost = 5;
		};

		/* UTC timing information. */
		UTC utc = 1;

		/* Whether time pulse is within tolerance limits. */
		bool time_pulse_within_tolerance = 2;

		/* Whether the internal oscillator is within tolerance limits. */
		bool internal_oscillator_within_tolerance = 3;

		/* Disciplining source of the oscillator. */
		DiscipliningSource disciplining_source = 4;

		/*
		 * Whether the Receiver Autonomous Integrity Monitoring Algorithm
		 * (RAIM) system is active.
		 */
		bool raim_active = 5;

		/* Whether coherent pulse generation is in operation. */
		bool coherent_pulse_generation = 6;

		/* Whether the time pulse is locked.
		 * Note: even when locked, it may still be out of tolerance.
		 */
		bool time_pulse_locked = 7;

		/* Offset between preceding pulse and UTC top of second [ns]. */
		int32 preceding_pulse_utc_offset = 8;

		/* Estimated GNSS time accuracy [ns]. If 0, value is invalid.
		 * During holdover, this will usually grow large.
		 * Was previously only named `time_accuracy`, which was inaccurate.
		 */
		uint32 gnss_time_accuracy = 9;

		/* Internal oscillator frequency offset [ppb]. */
		float internal_oscillator_frequency_offset = 10;

		/* Internal oscillator frequency uncertainty [ppb]. */
		float internal_oscillator_frequency_uncertainty = 11;

		/* Estimated overall time accuracy [ns] as reported by the module. If 0, value is invalid.
		 * It is important to note that this may not include external holdover
		 * oscillator uncertainties, but can only represent a module-internal
		 * state.
		 * During non-holdover, this will be similar as the `gnss_time_accuracy`, but
		 * during holdover, this value should NOT be consulted. Instead, use the
		 * field `time_accuracy_estimation` of `holdover_oscillator`.
		 */
		uint32 module_utc_accuracy = 12;

		/* Estimated overall time accuracy [ns]. If 0, value is invalid.
		 * During non-holdover, this will be similar as the `gnss_time_accuracy`, but
		 * during holdover, this value will represent the accuracy of the (external)
		 * holdover oscillator (see also `HoldoverOscillator::time_accuracy_estimation`).
		 */
		uint32 overall_time_accuracy = 13;
	}


	message HoldoverOscillator {

	  /* Describes what kind of holdover oscillator schema is used. */
	  enum Schema {
	    /* Only the built-in oscillator (in most cases, this will be the VCTCXO of the GNSS module) is used */
	    BUILT_IN_ONLY = 0;
	    /* The built-in oscillator is main clock source, but during hold-over
	       it is disciplined by a more stable external oscillator */
	    BUILT_IN_DISCIPLINED_BY_EXTERNAL = 1;
	    /* The external oscillator is main clock source. During non-holdover,
	       it is disciplined by the built-in GNSS module. */
	    EXTERNAL_DISCIPLINED_BY_BUILT_IN = 2;
	    /* The external oscillator is main clock source. It is self-contained, i.e.
	       it does not need to be disciplined by the built-in GNSS module. */
	    EXTERNAL_SELF_CONTAINED = 3;
	  };

	  Schema schema = 1;
	  /* A string describing the model of the external oscillator, e.g. "CSAC SA.45s" */
	  string model = 2;

	  /* For how many seconds the holdover state is active. Holdover is active iff value > 0 */
	  uint32 holdover_active_seconds = 3;

	  /* True iff the external oscillator is considered "ready" to holdover.
	     This usually requires some internal locks to be acquired, device to be sufficiently
	     warmed up and more.
	   */
	  bool is_ready_for_holdover = 4;

	  /* True iff the external oscillator issues a warning.
	     A warning is considered to describe a non-fatal, but possibly degraded state.
	     This could e.g. be the case if the internal temperature cannot be properly maintained.
	   */
	  bool warning_present = 5;

	  /* True iff the external oscillator issues a failure.
	     A failure is considered to describe a fatal state where no operation is possible.
	     This could e.g. be hardware failure.
	   */
	  bool failure_present = 6;

	  /* Estimated accuracy of the time [ns]. If 0, value is invalid. */
	  uint32 time_accuracy_estimation = 7;

	  /* Detailed health information about external oscillator.
	     As this is highly device-specific, we only provide key-value string-pairs here. */
	  //message HealthDetails {
	  // string key;
	  // string value;
	  //};
	  //repeated HealthDetails health_details;

	};


	/* GNSS hardware monitoring related information. */
	message HardwareMonitoring {
		/* Jamming state of GNSS receiver. */
		enum JammingState {
			/* Unknown or feature disabled. */
			UnknownOrDisabled = 0;
			/* OK, no significant jamming. */
			OK = 1;
			/* Warning, interference visible, but fix OK. */
			Warning = 2;
			/* Critical, interference visible and no fix. */
			Critical = 3;
		}

		/* Noise level (as measured by the GPS core), actually uint8. */
		uint32 noise_level = 1;

		/* AGC Monitor (range 0 to 8191). */
		uint32 agc_monitor = 2;

		/* Output of the interference monitor. */
		JammingState jamming_state = 3;

		/*
		 * Continuous wave (CW) jamming indicator: 0 (no CW jamming) to 255
		 *  (strong CW jamming).
		 */
		uint32 jamming_indicator = 4;

		/* Magnitude of the I-part of the complex signal (0..255). */
		uint32 signal_magnitude_i = 5;

		/* Magnitude of the Q-part of the complex signal (0..255). */
		uint32 signal_magnitude_q = 6;

		/* Imbalance of the I-part of the complex signal (-128..127). */
		int32 signal_imbalance_i = 7;

		/* Imbalance of the Q-part of the complex signal (-128..127). */
		int32 signal_imbalance_q = 8;

		/* Number of 100ms timeslots with parity errors. */
		uint32 timeslots_parity_errors = 9;

		/* Number of 100ms timeslots with framing errors. */
		uint32 timeslots_framing_errors = 10;

		/* Number of 100ms timeslots with overrun errors. */
		uint32 timeslots_overrun_errors = 11;

		/* Number of 100ms timeslots with break conditions. */
		uint32 timeslots_break_conditions = 12;

		/* Maximum usage of transmitter buffer during the last sysmon period for all targets [%]. */
		uint32 tx_buffers_usage = 13;

		/* Maximum usage of transmitter buffer for all targets (overall) [%]. */
		uint32 tx_buffers_peak_usage = 14;
	}

	/* Version information. */
	message Versions {
		/* Hardware version of the GNSS module. */
		string module_hw = 1;

		/* Software version of the GNSS module. */
		string module_sw = 2;
	}

	/* GNSS Survey-In (timing mode) related information. */
	message SurveyIn {
		/* Duration of the survey-in process [s]. */
		uint32 duration = 1;

		/* Current mean position in ECEF coordinates (X component) [cm]. */
		int32 mean_ecef_x = 2;

		/* Current mean position in ECEF coordinates (Y component) [cm]. */
		int32 mean_ecef_y = 3;

		/* Current mean position in ECEF coordinates (Z component) [cm]. */
		int32 mean_ecef_z = 4;

		/* Mean variance of the position [mm^2]. */
		uint32 mean_variance = 5;

		/* Number of observations until now. */
		uint32 num_observations = 6;

		/* Whether a valid position has been found. */
		bool valid = 7;

		/* Whether the survey in progress is still active. */
		bool active = 8;
	}

	/* Details about a satellite */
	message SatelliteDetails {

		/* See 21.6. UBX Satellite Numbering */
		enum GNSSIdentifier {
			GPS = 0;
			SBAS = 1;
			Galileo = 2;
			BeiDou = 3;
			IMES = 4;
			QZSS = 5;
			GLONASS = 6;
		}

		/* GNSS identifier */
		GNSSIdentifier gnss_id = 1;
		/* Satellite identifier, actually uint8 */
		int32 satellite_id = 2;
		/* Carrier to noise ratio [dBHz], actually uint8 */
		int32 carrier_noise_ratio = 3;
		/* Elevation -90 deg to +90 deg. Not present if unknown. Actually sint8 */
		optional sint32 elevation = 4;
		/* Azimuth 0 deg to 360 deg. Not present if unknown. Actually sint16 */
		optional sint32 azimuth = 5;
		/* Pseudo range residual [0.1 m], actually sint16 */
		sint32 pseudo_range_residual = 6;


		QualityIndicator quality_indicator = 7;
		enum QualityIndicator {
			NO_SIGNAL = 0;
			SEARCHING_SIGNAL = 1;
			SIGNAL_AQUIRED = 2;
			SIGNAL_DETECTED_BUT_UNUSABLE = 3;
			CODE_LOCKED_AND_TIME_SYNCHRONIZED = 4;
			CODE_AND_CARRIER_LOCKED_AND_TIME_SYNCHRONIZED_5 = 5;
			CODE_AND_CARRIER_LOCKED_AND_TIME_SYNCHRONIZED_6 = 6;
			CODE_AND_CARRIER_LOCKED_AND_TIME_SYNCHRONIZED_7 = 7;
		}

		/* currently being used for navigation? */
		bool satellite_used = 8;

		HealthFlag health = 9;
		enum HealthFlag {
			UNKNOWN = 0;
			HEALTHY = 1;
			UNHEALTHY = 2;
		}

		bool differential_correction_data_available = 10;
		bool carrier_smoothed_pseudorange_used = 11;
		OrbitSource orbit_source = 12;
		enum OrbitSource {
			NO_ORBIT_INFORMATION_AVAILABLE = 0;
			EPHEMERIS_USED = 1;
			ALMANAC_USED = 2;
			ASSIST_NOW_OFFLINE_ORBIT_USED = 3;
			ASSIST_NOW_AUTONOMOUS_ORBIT_USED = 4;
			OTHER_ORBIT_INFORMATION_5 = 5;
			OTHER_ORBIT_INFORMATION_6 = 6;
			OTHER_ORBIT_INFORMATION_7 = 7;
		}

		bool ephemeris_available = 13;
		bool almanac_available = 14;
		bool assist_now_offline_data_available = 15;
		bool assist_now_autonomous_data_available = 16;

	}

	/* Message containing a list of satellite details */
	message DetailedSatelliteInformation {
		repeated SatelliteDetails satellite_details = 1;
	}

	/* Position information. */
	Position position = 1;

	/* Timing-related information, such as UTC time. */
	Timing timing = 2;

	/* GNSS hardware monitoring related information. */
	HardwareMonitoring hardware = 3;

	/* Version information. */
	Versions versions = 4;

	/* GNSS Survey-In (timing mode) related information. */
	SurveyIn survey_in = 5;

	/* Holdover oscillator related information */
	// TODO: this might need to move out of GNSS ...
	HoldoverOscillator holdover_oscillator = 6;

	/* Detailed satellite information. If not present, no detailed satellite infomation are communicated. */
	optional DetailedSatelliteInformation satellite_information = 7;
}

/* Reply for GetCPUUsageHistory() call. */
message GetCPUUsageHistoryReply {
	/* Pair of timestamp [s since epoch UTC] and cpu usage. */
	message Pair {
		uint64 timestamp = 1;
		CPUUsage cpu_usage = 2;
	}

	/* CPU usage history. */
	repeated Pair history = 1;
}

/* Reply for GetMemoryUsageHistory() call. */
message GetMemoryUsageHistoryReply {
	/* Pair of timestamp [s since epoch UTC] and memory usage. */
	message Pair {
		uint64 timestamp = 1;
		MemoryUsage memory_usage = 2;
	}

	/* Memory usage history. */
	repeated Pair history = 1;
}

/* Reply for GetSwapUsageHistory() call. */
message GetSwapUsageHistoryReply {
	/* Pair of timestamp [s since epoch UTC] and swap usage. */
	message Pair {
		uint64 timestamp = 1;
		SwapUsage swap_usage = 2;
	}

	/* Swap usage history. */
	repeated Pair history = 1;
}

/* Request for GetLogMessages() call. */
message GetLogMessagesRequest {
	/* List of matches, same semantics as specified for journalctl(1). */
	repeated string match = 1;

	/* Maximum number of (most recent) entries to fetch. Set to 0 for all. */
	uint32 max_lines = 2;

	/* If set, only show entries after the specified cursor. */
	string after_cursor = 3;

	/*
	 * If set, only show entries since the specified timestamp [ms since epoch
	 *  UTC].
	 */
	uint64 since = 4;

	/*
	 * If set, only show entries until the specified timestamp [ms since epoch]
	.*/
	uint64 until = 5;
}

/* Reply for GetMountedFilesystemUsage() call. */
message GetMountedFilesystemUsageReply {
	/* List of mounted file systems with their usage. */
	repeated FileSystemUsage file_system = 1;
}

/* Reply for GetProcessList() call. */
message GetProcessListReply {
	/* List of processes. */
	repeated ProcessInfo processes = 1;
}

/* Reply for GetSystemPackages() call. */
message GetSystemPackagesReply {
	/* List of (installed) packages */
	repeated SystemPackage package = 1;
}

/* Reply for GetLogMessages() call. */
message GetLogMessagesReply {
	/*
	 * Current cursor in the journal, can be used to only fetch new messages in
	 * the next request.
	 */
	string cursor = 1;

	/* Messages. */
	repeated LogMessage message = 2;
}

/* Reply for GetUnitList() call. */
message GetUnitListReply {
	/* List of systemd units */
	repeated Unit unit = 1;
}

/* Reply for GetNetworkUsage() call. */
message GetNetworkUsageReply {
	/* List of network devices with their usage. */
	repeated NetworkDeviceUsage device_usage = 1;
}

/* Reply for GetNetworkUsageHistory() call. */
message GetNetworkUsageHistoryReply {
	/* Pair of timestamp [s since epoch UTC] and network device usage. */
	message Pair {
		uint64 timestamp = 1;
		repeated NetworkDeviceUsage network_usage = 2;
	}

	/* Network device usage history. */
	repeated Pair history = 1;
}

/* Reply for GetNetworkCounters() call. */
message GetNetworkCountersReply {
	/* List of network devices with their counters. */
	repeated NetworkDeviceCounters device_counters = 1;
}

/* Reply for GetSystemHealthHistory() call. */
message GetSystemHealthHistoryReply {
	/* Pair of timestamp [s since epoch UTC] and system health values. */
	message Pair {
		uint64 timestamp = 1;
		SystemHealth values = 2;
	}
	/* System health value history. */
	repeated Pair history = 1;
}

/* Reply for GetSystemLoadHistory() call. */
message GetSystemLoadHistoryReply {
	/* Pair of timestamp [s since epoch UTC] and system load. */
	message Pair {
		uint64 timestamp = 1;
		SystemLoad load = 2;
	}
	/* System load history. */
	repeated Pair history = 1;
}

/* Reply for GetFullSystemStatus() call. **/
message GetFullSystemStatusReply {
	GNSSInformation gnss_information = 1;
	SystemLoad system_load = 2;
	SystemHealth system_health = 3;
	MemoryUsage memory_usage = 4;
	repeated FileSystemUsage file_system_usage = 5;
	repeated NetworkDeviceUsage network_usage = 6;
	SystemInformation system_information = 7;
}

/* Monitor daemon service definition. Port 5305. */
service Monitord {
	/* Get current CPU usage. */
	rpc GetCPUUsage (google.protobuf.Empty) returns (CPUUsage);

	/* Get history of CPU usage. */
	rpc GetCPUUsageHistory (google.protobuf.Empty) returns (GetCPUUsageHistoryReply);

	/* Get current memory usage. */
	rpc GetMemoryUsage (google.protobuf.Empty) returns (MemoryUsage);

	/* Get history of memory usage. */
	rpc GetMemoryUsageHistory (google.protobuf.Empty) returns (GetMemoryUsageHistoryReply);

	/* Get current swap usage. */
	rpc GetSwapUsage (google.protobuf.Empty) returns (SwapUsage);

	/* Get history of swap usage. */
	rpc GetSwapUsageHistory (google.protobuf.Empty) returns (GetSwapUsageHistoryReply);

	/* Get current file system usage. */
	rpc GetMountedFilesystemUsage (google.protobuf.Empty) returns (GetMountedFilesystemUsageReply);

	/* Get a list of processes. */
	rpc GetProcessList (google.protobuf.Empty) returns (GetProcessListReply);

	/* Get a list of (installed) system packages. */
	rpc GetSystemPackages (google.protobuf.Empty) returns (GetSystemPackagesReply);

	/* Get log messages (without streaming/waiting for new ones). */
	rpc GetLogMessages (GetLogMessagesRequest) returns (GetLogMessagesReply);

	/* Get a list (with states) of systemd units. */
	rpc GetUnitList (google.protobuf.Empty) returns (GetUnitListReply);

	/* Get current network usage. */
	rpc GetNetworkUsage (google.protobuf.Empty) returns (GetNetworkUsageReply);

	/* Get history of network usage. */
	rpc GetNetworkUsageHistory (google.protobuf.Empty) returns (GetNetworkUsageHistoryReply);

	/* Get counters (in contrast to the rates) of the network usage. */
	rpc GetNetworkCounters (google.protobuf.Empty) returns (GetNetworkCountersReply);

	/* Get current system health. */
	rpc GetSystemHealth (google.protobuf.Empty) returns (SystemHealth);

	/* Get history of system health. */
	rpc GetSystemHealthHistory (google.protobuf.Empty) returns (GetSystemHealthHistoryReply);

	/* Get current system load. */
	rpc GetSystemLoad (google.protobuf.Empty) returns (SystemLoad);

	/* Get history of system load. */
	rpc GetSystemLoadHistory (google.protobuf.Empty) returns (GetSystemLoadHistoryReply);

	/*
	 * Get (lower level) information about the system, like e.g. uptime, reset
	 *  reasons or low-level version information.
	 */
	rpc GetSystemInformation (google.protobuf.Empty) returns (SystemInformation);


	/*
	 * Clear all reset resons (see SystemInformation message).
	 *  This can be used to "acknowledge" certain events, such as a watchdog reset
	 *  (or also a simple "power on reset").
	 */
	rpc ClearResetReasons (google.protobuf.Empty) returns (google.protobuf.Empty);

	/*
	 * Get information related to the Global Navigation Satellite System
	 *  (GNSS).
	 *  Note: if the information is not available or outdated, the gRPC
	 *  call will fail with status code ABORTED.
	 */
	rpc GetGNSSInformation (google.protobuf.Empty) returns (GNSSInformation);

	/* Get full system status (single call for 7 most used calls).
	 *  Note: submessages may be omitted if the "sub calls" fail, e.g.
	 *  if GNSS information are invalid, the `gnss_information` submessage
	 *  will not be included.
	 */
	rpc GetFullSystemStatus (google.protobuf.Empty) returns (GetFullSystemStatusReply);
}