Mode-S BDS Register Decoder

Select BDS or press ADS-B Auto

		CLR
ADS-B Auto

Results Region: enter BDS value, then select desired decode option

Comment:

Log decode to browser tab

01	x	09	x	17	x	25	x	33	x	41	x	49	x
02	x	10	x	18	x	26	x	34	x	42	x	50	x
03	x	11	x	19	x	27	x	35	x	43	x	51	x
04	x	12	x	20	x	28	x	36	x	44	x	52	x
05	x	13	x	21	x	29	x	37	x	45	x	53	x
06	x	14	x	22	x	30	x	38	x	46	x	54	x
07	x	15	d	23	x	31	x	39	x	47	x	55	x
08	x	16	x	24	x	32	x	40	x	48	x	56	x

Register decoding per RTCA/DO‑181E
and RTCA/DO‑260B
(ICAO Doc 9871, 1090ES v2).

Software Version: 1.09
(last change: July 2026)

Software coding by:
A. Hege, Retired Systems Engineer,

Disclaimer: decoding of BDS registers in this app is meant to be a guide and not a substitute for any requirements document(s). Always refer to the latest to the latest documentation to determine spec compliance.

SW Vers Description

v1.09 [draft version]

Happy 250th Independance Day, America.
cleaned up custom-hex-keypad UI.

v1.08 [July 2026]

fixed Track Angle Rate in BDS 5,0 decoding, and
Fixed Interial Vertical Velocity in BDS 6,0 decoding.

v1.07 [July 2021]

Fixed issue with 2's complement decoding.
Other bug fixes reported by users.

v1.06 [May 2018]

changed hexadecimal keypad

v1.05 [???date???]

Added comment section to decode for logging.

v1.04 [9 Dec 2016]

Finished decoding of ADS-B BDS registers, except for Compact Position Reporting (CPR). All ADS-B registers for 1090ES v2 are decoded now.
Fixed EHS registers with negative values.
Added ADS-B register auto-detection.
Added SVD section.

Moved 'Send Report to Tab' button inside the BDS Register Decode section.

Keyboard shortcuts:

'0' - '9', 'A' - 'F',
<Del> clears hex scratchpad,
<BS> delete rightmost key,
<Ent> submits hex scratchpad to main program,
<SP> submits hex scratchpad to main program, and executes the ADS-B auto-detection,
<ESC> exits hex keypad without saving changes.


D	E	F	clr
A	B	C	back
7	8	9	ADS-B
4	5	6	ADS-B
1	2	3	↩
0			↩

01	x	09	x	17	x	25	x	33	x	41	x	49	x
02	x	10	x	18	x	26	x	34	x	42	x	50	x
03	x	11	x	19	x	27	x	35	x	43	x	51	x
04	x	12	x	20	x	28	x	36	x	44	x	52	x
05	x	13	x	21	x	29	x	37	x	45	x	53	x
06	x	14	x	22	x	30	x	38	x	46	x	54	x
07	x	15	d	23	x	31	x	39	x	47	x	55	x
08	x	16	x	24	x	32	x	40	x	48	x	56	x

01	x	09	x	17	x	25	x	33	x	41	x	49	x
02	x	10	x	18	x	26	x	34	x	42	x	50	x
03	x	11	x	19	x	27	x	35	x	43	x	51	x
04	x	12	x	20	x	28	x	36	x	44	x	52	x
05	x	13	x	21	x	29	x	37	x	45	x	53	x
06	x	14	x	22	x	30	x	38	x	46	x	54	x
07	x	15	d	23	x	31	x	39	x	47	x	55	x
08	x	16	x	24	x	32	x	40	x	48	x	56	x

01	x	09	x	17	x	25	x	33	x	41	x	49	x
02	x	10	x	18	x	26	x	34	x	42	x	50	x
03	x	11	x	19	x	27	x	35	x	43	x	51	x
04	x	12	x	20	x	28	x	36	x	44	x	52	x
05	x	13	x	21	x	29	x	37	x	45	x	53	x
06	x	14	x	22	x	30	x	38	x	46	x	54	x
07	x	15	d	23	x	31	x	39	x	47	x	55	x
08	x	16	x	24	x	32	x	40	x	48	x	56	x