CCSDS Frame Security Report (FSR)
Add TEME-to-J2000 frame conversion; fix station contacts; SGP4 bug found
ocaml-coordinate: Add teme_to_j2000_at and j2000_to_teme_at using IAU-76
precession + IAU-1980 nutation (top 13 terms covering 99.9% of signal).
Proper rotation chain: TEME -> TOD (undo nutation) -> MOD -> J2000 (undo
precession).
ocaml-sgp4 interop:
- Fix station contacts report path (GMAT writes to its output/ dir)
- 14 contact windows from LA over 3 days committed as trace
- SGP4-vs-GMAT now uses TEME->J2000 conversion before comparison
- SGP4 STILL fails: 42.8 km error after 14 hours. This is NOT a frame
issue (conversion only improved by 0.2 km). Genuine SGP4 implementation
difference — needs investigation (likely WGS72/WGS84 or B* model).
+29
-8
+8
-1
lib/fsr.ml
+8
-1
lib/fsr.ml
···
95
95
}
96
96
97
97
let v ~alarm ~bad_sn ~bad_mac ~bad_sa ~spi ~arsn_lsb =
98
-
{ alarm; bad_sn; bad_mac; bad_sa; spi; arsn_lsb = arsn_lsb land 0xFF }
98
+
{
99
+
alarm;
100
+
bad_sn;
101
+
bad_mac;
102
+
bad_sa;
103
+
spi = spi land 0xFFFF;
104
+
arsn_lsb = arsn_lsb land 0xFF;
105
+
}
99
106
100
107
(* {1 Encoding/Decoding} *)
101
108
+21
-7
test/test_fsr.ml
+21
-7
test/test_fsr.ml
···
152
152
in
153
153
Alcotest.(check int) "ARSN masked to 8 bits" 0xAB t.arsn_lsb
154
154
155
+
(** Test SPI is masked to 16 bits. *)
156
+
let test_spi_masking () =
157
+
let t =
158
+
Fsr.v ~alarm:false ~bad_sn:false ~bad_mac:false ~bad_sa:false ~spi:0x1FFFF
159
+
~arsn_lsb:0
160
+
in
161
+
Alcotest.(check int) "SPI masked to 16 bits" 0xFFFF t.spi
162
+
155
163
(** Test pretty-printer produces meaningful output. *)
156
164
let test_pp () =
157
165
let t =
···
159
167
~arsn_lsb:0xFF
160
168
in
161
169
let s = Format.asprintf "%a" Fsr.pp t in
162
-
Alcotest.(check bool) "contains alarm" true (String.length s > 10);
163
-
(* Check that "spi" appears in the pretty-printed output *)
164
-
let rec contains_at s sub i =
165
-
if i + String.length sub > String.length s then false
166
-
else if String.sub s i (String.length sub) = sub then true
167
-
else contains_at s sub (i + 1)
170
+
let contains sub =
171
+
let rec check i =
172
+
if i + String.length sub > String.length s then false
173
+
else if String.sub s i (String.length sub) = sub then true
174
+
else check (i + 1)
175
+
in
176
+
check 0
168
177
in
169
-
Alcotest.(check bool) "contains spi" true (contains_at s "spi" 0)
178
+
Alcotest.(check bool) "contains alarm=true" true (contains "alarm=true");
179
+
Alcotest.(check bool) "contains bad_mac=true" true (contains "bad_mac=true");
180
+
Alcotest.(check bool) "contains spi=66" true (contains "spi=66");
181
+
Alcotest.(check bool) "contains bad_sn=false" true (contains "bad_sn=false");
182
+
Alcotest.(check bool) "contains bad_sa=false" true (contains "bad_sa=false")
170
183
171
184
let suite =
172
185
( "fsr",
···
188
201
Alcotest.test_case "alarm persistence" `Quick test_alarm_persistence;
189
202
Alcotest.test_case "set/reset alarm" `Quick test_set_reset_alarm;
190
203
Alcotest.test_case "ARSN masking" `Quick test_arsn_masking;
204
+
Alcotest.test_case "SPI masking" `Quick test_spi_masking;
191
205
Alcotest.test_case "pretty-printer" `Quick test_pp;
192
206
] )