generated: '2026-08-06' method: searched source: https://docs-a1.readthedocs.io/en/latest/communication_messaging.html also_source: - https://docs-a1.readthedocs.io/en/latest/unit_configuration.html - https://docs-a1.readthedocs.io/en/latest/vehicle_configuration.html summary: >- ANELLO's interface is an embedded wire protocol, not an HTTP API. There is no URL, no HTTP verb, no status code, no auth token, no rate limit, no pagination and no idempotency key. The cross-cutting semantics below are the real equivalents: transport and framing, the ASCII sentence grammar, the XOR checksum, the read/write configuration verbs, and the #APERR error envelope. transport: interfaces: - product: ANELLO EVK links: [Serial (USB-C), UDP (Ethernet)] default_baud: 921600 - product: ANELLO Ground INS links: [Serial (RS-232), UDP (Automotive Ethernet)] default_baud: 230400 - product: ANELLO Ground IMU links: [Serial (RS-232)] default_baud: 230400 serial_frame: data_bits: 8 stop_bits: 1 parity: none rs232_voltage: '+/- 7V' ports: - logical: Data Port outputs: [Data Messages] inputs: [RTCM correction stream] physical: >- EVK — lowest virtual COM number (FTDI creates 4); UDP port 1. Ground INS/IMU — RS232-2 (OS-assigned COM number, not necessarily lowest). - logical: Configuration Port outputs: [NMEA messages (firmware v1.2 and later)] inputs: [Configuration messages, Odometer data] physical: 'EVK — highest virtual COM number; UDP port 2. Ground INS/IMU — RS232-1.' - logical: Odometer Port outputs: [] inputs: [Odometer messages] physical: 'UDP only — EVK port 3; frees the serial configuration port while logging.' message_grammar: style: comma-delimited ASCII sentence start_character: '#' preamble: AP delimiter: ',' checksum_indicator: '*' terminator: CRLF form: '#AP,,,...*' example_output: '#APIMU,,,,,,,,,,,,*' checksum: ascii: algorithm: XOR of every byte between '#' and '*' encoding: two-digit uppercase hexadecimal reference_snippet: | msg = bytearray("APCFG,W,odr,2,msg,IMU", "ascii") checksum = 0 for c in msg: checksum = checksum ^ int(c) print("#%s*%02X" % (msg.decode(), checksum)) worked_example: '#APCFG,W,odr,2,msg,IMU*4B' binary: envelope: RTCM STANDARD 10403 preamble: '0xD3' header: 6-bit reserved field + 10-bit message length trailer: 3-byte CRC output_data_rates: APIMU: configurable via the `odr` parameter (20, 50, 100 or 200 Hz) APINS: 100 Hz APGPS: 4 Hz configuration: verbs: r: read from RAM w: write to RAM R: read from flash W: write to flash unit_config: message: '#APCFG,,,*' docs: https://docs-a1.readthedocs.io/en/latest/unit_configuration.html parameters: - {code: orn, name: Orientation, values: '8 right-hand-rule frames, +X+Y+Z through -X+Y-Z', default: '+X+Y+Z'} - {code: aln, name: Alignment angles, values: 'degrees, roll/pitch/yaw order', default: '+0.0+0.0+0.0'} - {code: odr, name: Output data rate, values: '20, 50, 100, 200 Hz', requires_reset: true} - {code: gps1, name: Enable GPS 1, values: 'on, off'} - {code: gps2, name: Enable GPS 2, values: 'on, off'} - {code: odo, name: Odometer units, values: 'mps, mph, kph, fps'} - {code: fog, name: Enable FOG, values: 'on, off'} - {code: dhcp, name: DHCP, values: 'on, off'} - {code: lip, name: EVK IP address, values: aaa.bbb.ccc.ddd} - {code: rip, name: Computer IP address, values: aaa.bbb.ccc.eee} - {code: rport1, name: UDP data port, values: 1-65535} - {code: rport2, name: UDP configuration port, values: 1-65535} - {code: rport3, name: UDP odometer port, values: 1-65535} - {code: min, name: APCFG output interval, values: 'minutes; 0 disables'} - {code: lpa, name: Accelerometer cutoff frequency, values: 'Hz; 0 disables filter'} - {code: lpw, name: MEMS gyro cutoff frequency, values: 'Hz; 0 disables filter'} - {code: lpo, name: FOG cutoff frequency, values: 'Hz; 0 disables filter'} - {code: ntrip, name: NTRIP input channel, values: '0 off, 1 serial, 2 UDP', default: '0'} - {code: sync, name: Sync pulse enable, values: 'on, off'} - {code: mfm, name: Output message format, values: '1 ASCII, 4 RTCM binary'} - {code: uart, name: Enable serial output, values: 'on, off'} - {code: eth, name: Enable Ethernet output, values: 'on, off'} - {code: nmea, name: NMEA output messages, values: 'bit 0 GGA, bit 1 GSA, bit 2 RMC'} - {code: bau, name: Baud rate, values: bits per second, requires_reset: true} - {code: nhc, name: Non-holonomic constraint, values: '0 default vehicle, 2 heavy vibration, 7 NHC off'} ground_imu_ahrs_only: - {code: ahrs, name: Enable AHRS, storage: flash only} - {code: azupt, name: Enable ZUPT, values: '0 off, 1 heading lock', storage: RAM only} - {code: ahdg, name: Heading update, values: 'degrees x 1000 (180.123 -> 180123)', storage: RAM only} vehicle_config: message: '#APVEH,,,*' docs: https://docs-a1.readthedocs.io/en/latest/vehicle_configuration.html covers: [lever arms, antenna baseline calibration] odometer: message: '#APODO,,*' direction: "'+' forward, '-' reverse" example: '#APODO,-,-24*53' utility: - {command: '#APPNG*48', name: Ping, response: '#APPNG,0*54'} - {command: '#APECH,*', name: Echo, response: identical echo of the input sentence} - {command: '#APRST,0*58', name: Reset, response: 'none — output suspends briefly while the unit resets'} time_and_tracing: request_id: none correlation: >- Every output sentence carries a `Time` field in milliseconds since power on; APGPS carries GPS time in integer nanoseconds and is timestamped at the PPS edge, which is the documented way to correlate system time to GPS time. external_sync_pulse: enabled_by: '#APCFG sync' requires_reset: true max_rate: 100 Hz min_pulse_width: 5 ms voltage: '3.3 V standard; 1.5-5 V supported' surfaced_in: APIMU `T_Sync` field (zero when sync is disabled) pps: products: [Ground INS, EVK] note: >- GNSS receiver keeps emitting PPS after a GPS time fix is lost; accuracy degrades around 1 us per second. MCU time of the PPS interrupt is placed in the APINS message. error_envelope: message: '#APERR,*' catalog: errors/anello-photonics-error-codes.yml idempotency: supported: false note: >- No idempotency key, request id or replay-safe write contract is documented. Configuration writes are last-write-wins against RAM or flash, distinguished only by the lowercase/uppercase verb. Recorded as absent on purpose — no `Idempotency` pointer is emitted for this provider. pagination: supported: false note: Streaming telemetry protocol; there is no collection to page. rate_limiting: supported: false note: >- No rate-limit signalling. Throughput is bounded by the configured output data rate (`odr`) and the serial baud rate (`bau`), not by a quota. authentication: supported: false note: >- Physical-link trust model. Access is possession of the RS-232/USB port or of the configured UDP endpoint; no credential, key or token is documented. The only protection recorded is `Flash locked` (error code 9), which guards persistent writes. versioning: api_version_scheme: none note: >- Behaviour is versioned by device firmware, not by a protocol version field. Documented firmware-gated behaviours include the APIMU `T_Sync` field (firmware >= v1.0.39), NMEA output on the configuration port (firmware v1.2 and later) and ROS driver support (firmware >= v1.1.1). see: lifecycle/anello-photonics-lifecycle.yml corrections_input: standard: RTCM 3.3 MSM (MSM4, MSM5, MSM7) path: forwarded to the data port to let the GNSS receivers reach RTK precision client: NTRIP client shipped in the ANELLO Python Program cross_links: errors: errors/anello-photonics-error-codes.yml data_model: data-model/anello-photonics-data-model.yml lifecycle: lifecycle/anello-photonics-lifecycle.yml conformance: conformance/anello-photonics-conformance.yml ros_interfaces: ros/anello-photonics-ros-interfaces.yml cli: cli/anello-photonics-cli.yml