Inmarsat Aero

Inmarsat Aero

Frequencies	1545 MHz,1547 MHz,3685 MHz,3687 MHz
Frequency Range	1545 MHz - 3687 MHz
Mode	USB
Modulation	PSK
ACF	—
Emission Designator	—
Bandwidth	10.5 MHz,800 Hz,1.6 kHz
Location	Worldwide
Short Description	Inmarsat Aero is the protocol that's used to link ground stations with aircraft via Inmarsat's satellite link. This protocol carries digital voice, fax and low speed data such as ACARS and ADS-C.
I/Q Raw Recording	Download file
Audio Sample

Inmarsat Aero is the protocol that's used to link ground stations with aircraft via Inmarsat's satellite link. This protocol carries digital voice, fax and low speed data such as ACARS and ADS-C.

Characteristics

Inmarsat Aero in this article is the Forward TDM link from ground station to plane. The links use OBPSK or OQPSK modulated with 600, 1200, and 10500 bpsBits per second (bps) signals. The 600 and 1200 bpsBits per second (bps) links are part of Inmarsat's Classic Aero service which is due to be discontinued in 2018. the 10500 bpsBits per second (bps) link is part of Inmarsat's Aero H and H+ services which are capable of transmitting both data (10.5 kbpsKilobits per second (kbps)) and digital voice (9.6 kbpsKilobits per second (kbps)).

The Inmarsat Aero system has both forward and return links, as well as digital voice channels.

Forward (Ground Station to Plane)

• P-channel packet switched data TDM: 600 bpsBits per second (bps), 1200 bpsBits per second (bps) A-BPSKBinary Phase-Shift Keying (1 bit per symbol) (SDPSK), 10.5 kbpsKilobits per second (kbps) A-QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (OQPSK), convolutional FECForward Error Correction R = ½, k = 7
• Digital Voice circuit mode SCPC: 8.4 kbpsKilobits per second (kbps) A-QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (OQPSK), convolutional FECForward Error Correction R = 2/3, k = 7, 10.5 kbpsKilobits per second (kbps) A-QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (OQPSK), convolutional FECForward Error Correction R = ½, k = 7

Return (Plane to Ground Station)

• R-channel slotted Aloha: 600 bpsBits per second (bps), 1200 bpsBits per second (bps) A-BPSKBinary Phase-Shift Keying (1 bit per symbol) (SDPSK), 4.8 kbpsKilobits per second (kbps), 10.5 kbpsKilobits per second (kbps) A-QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (OQPSK), convolutional FECForward Error Correction R = ½, k = 7
• T-channel TDMATime Division Multiple Access: 600 bpsBits per second (bps), 1200 bpsBits per second (bps) A-BPSKBinary Phase-Shift Keying (1 bit per symbol) (SDPSK), 10.5 kbpsKilobits per second (kbps) A-QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (OQPSK), convolutional FECForward Error Correction R = ½, k = 7
• Digital Voice circuit mode SCPC: 8.4 kbpsKilobits per second (kbps) A-QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (OQPSK), convolutional FECForward Error Correction R = 2/3, k = 7, 10.5 kbpsKilobits per second (kbps) A-QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (OQPSK), convolutional FECForward Error Correction R = ½, k = 7

Inmarsat Forward TDM Link

• 600 bpsBits per second (bps): Aviation-BPSKBinary Phase-Shift Keying (1 bit per symbol) (SDPSK or Pi/2-BPSKBinary Phase-Shift Keying (1 bit per symbol)) modulation at 600 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.. Spans 800 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). of bandwidth.

• 1200 bpsBits per second (bps): Aviation-BPSKBinary Phase-Shift Keying (1 bit per symbol) (SDPSK or Pi/2-BPSKBinary Phase-Shift Keying (1 bit per symbol)) modulation at 1200 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.. Span 1600 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). of bandwidth.

• 10500 bpsBits per second (bps): Aviation-QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (OQPSK) modulation at 10500 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. with convolutional FECForward Error Correction (Raw data throughput is 21000 bpsBits per second (bps), actual data rate with FECForward Error Correction is 10500 bpsBits per second (bps)). This is part of Inmarsat's Aero H and H+ service.

Samples

Forward TDM Link (Ground Station to Plane)

10.5 kbpsKilobits per second (kbps)	600 bpsBits per second (bps)

Frequencies

• L band downlink (Satellite to Plane): 1545 MHzMegaHertz (MHz) 10^6 Hz - 1547 MHzMegaHertz (MHz) 10^6 Hz (600 and 1200 bpsBits per second (bps) signals are usually found around 1545 MHzMegaHertz (MHz) 10^6 Hz, whereas the faster OQPSK channels with 10500 bpsBits per second (bps) are found around 1546 MHzMegaHertz (MHz) 10^6 Hz.)
• C Band downlink (Satellite to ground station): 3600 MHzMegaHertz (MHz) 10^6 Hz - 3629 MHzMegaHertz (MHz) 10^6 Hz

Check UHF Satcom for frequencies.

Decoding Tutorials

• JAERO Updated: Now Supports 10.5k AERO-H and AERO-H+

Decoding Software

Hobby Level Software

• JAERO

Professional Equipment/Software

• go2DECODE
• go2MONITOR
• Wavecom W-Code
• Wavecom W-Spectra

Video Examples

• Receiving AERO-H on L-band (Inmarsat AOR-W)
• Inmarsat C Band aero feed

Additional Links

• WAVECOM Database: SAT-AERO-P, SAT-AERO-R, SAT-AERO-T
• WAVECOM Database: SAT-AERO-C
• RadioScanner.RU Satellite Inmarsat Aero
• Inmarsat Aero Service
• Inmarsat Worldwide Satellite Services: Today and Tommorow, 1993

Additional Images

Inmarsat Aero 10.5 kbpsKilobits per second (kbps) Phase (OQPSK square) Inmarsat Aero 10.5 kbpsKilobits per second (kbps) Phase with synch Baudrate disabled, showing just the 4 phases. Inmarsat Aero 600 bpsBits per second (bps) Phase (SDPSK) Inmarsat Aero 600 bpsBits per second (bps) SDPSK 2/piPSK that Inmarsat's forward TDM link for 600bps and 1200 bpsBits per second (bps) uses. Coverage of Inmarsat Aero, June 2015