Sample Test Cases

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Overview

For reference a sample test case is given for each of the five models.¹ The input used was standard T-cards and the output is given at 360 minute intervals in units of kilometers and seconds.

When implemented on a given computer, the accuracies with which the test cases are duplicated will be dominated by the accuracy of the epoch mean motion. If, after reading and converting, the epoch mean motion has an error $\Delta n = j \times 10^{-k}$ radians/time, then the predicted positions at time t may differ from the test cases by numbers on the order of

$\Delta r = \Delta n (t - t_o)(6{,}378.135) \text{ kilometers}$

¹The test cases were generated on a machine with 8 digits of accuracy. After a one day prediction, the test cases have only 5 to 6 digits of accuracy.

Test Case 1 — SGP (Near-Earth)

Input TLE

1 88888U           80275.98708465  .00073094  13844-3  66816-4 0     8
2 88888  72.8435 115.9689 0086731  52.6988 110.5714 16.05824518   105

Satellite: 88888 (test object) — Near-earth, period < 225 minutes

Predicted Ephemeris (SGP)

Position (km)

TSINCE	X	Y	Z
0.	2328.96594238	-5995.21600342	1719.97894287
360.00000000	2456.00610352	-6071.94232177	1222.95977784
720.00000000	2567.39477539	-6112.49725342	713.97710419
1080.00000000	2663.03179932	-6115.37414551	195.73919105
1440.00000000	2742.85470581	-6079.13580322	-328.86091614

Velocity (km/s)

XDOT	YDOT	ZDOT
2.91110113	-0.98164053	-7.09049922
2.67852119	-0.44705850	-7.22800565
2.43952477	0.09884824	-7.31889641
2.19531813	0.65333930	-7.36169147
1.94707947	1.21346101	-7.35499924

Test Case 2 — SGP4 (Near-Earth)

Input TLE

1 88888U           80275.98708465  .00073094  13844-3  66816-4 0     8
2 88888  72.8435 115.9689 0086731  52.6988 110.5714 16.05824518   105

Satellite: 88888 (test object) — Near-earth, period < 225 minutes

Predicted Ephemeris (SGP4)

Position (km)

TSINCE	X	Y	Z
0.	2328.97048951	-5995.22076416	1719.97067261
360.00000000	2456.10705566	-6071.93853760	1222.89727783
720.00000000	2567.56195068	-6112.50384522	713.96397400
1080.00000000	2663.09078980	-6115.48229980	196.39640427
1440.00000000	2742.55133057	-6079.67144775	-326.38095856

Velocity (km/s)

XDOT	YDOT	ZDOT
2.91207230	-0.98341546	-7.09081703
2.67938992	-0.44829041	-7.22879231
2.44024599	0.09810869	-7.31995916
2.19611958	0.65241995	-7.36282432
1.94850229	1.21106251	-7.35619372

Test Case 3 — SDP4 (Deep-Space)

Input TLE

1 11801U           80230.29629788  .01431103  00000-0  14311-1
2 11801  46.7916 230.4354 7318036  47.4722  10.4117  2.28537848

Satellite: 11801 — Deep-space, period >= 225 minutes

Predicted Ephemeris (SDP4)

Position (km)

TSINCE	X	Y	Z
0.	7473.37066650	428.95261765	5828.74786377
360.00000000	-3305.22537232	32410.86328125	-24697.17675781
720.00000000	14271.28759766	24110.46411133	-4725.76837158
1080.00000000	-9990.05883789	22717.35522461	-23616.89062501
1440.00000000	9787.86975097	33753.34667969	-15030.81176758

Velocity (km/s)

XDOT	YDOT	ZDOT
5.10715413	6.44468284	-0.18613096
-1.30113538	-1.15131518	-0.28333528
-0.32050445	2.67984074	-2.08405289
-1.01667246	-2.29026759	0.72892364
-1.09425066	0.92358845	-1.52230928

Test Case 4 — SGP8 (Near-Earth)

Input TLE

1 88888U           80275.98708465  .00073094  13844-3  66816-4 0     8
2 88888  72.8435 115.9689 0086731  52.6988 110.5714 16.05824518   105

Satellite: 88888 (test object) — Near-earth, period < 225 minutes

Predicted Ephemeris (SGP8)

Position (km)

TSINCE	X	Y	Z
0.	2328.87265015	-5995.21289063	1720.04884338
360.00000000	2456.04577637	-6071.90490722	1222.84086609
720.00000000	2567.68383789	-6112.40881348	713.29282379
1080.00000000	2663.49508667	-6115.18182373	194.62816810
1440.00000000	2743.29238892	-6078.90783691	-329.73434067

Velocity (km/s)

XDOT	YDOT	ZDOT
2.91210661	-0.98353850	-7.09081554
2.67936245	-0.44820847	-7.22888553
2.43992555	0.09893919	-7.32018769
2.19525236	0.65453661	-7.36308974
1.94680957	1.21500109	-7.35625595

Test Case 5 — SDP8 (Deep-Space)

Input TLE

1 11801U           80230.29629788  .01431103  00000-0  14311-1
2 11801  46.7916 230.4354 7318036  47.4722  10.4117  2.28537848

Satellite: 11801 — Deep-space, period >= 225 minutes

Predicted Ephemeris (SDP8)

Position (km)

TSINCE	X	Y	Z
0.	7469.47631836	415.99390792	5829.64318848
360.00000000	-3337.38992310	32351.39086914	-24658.63037109
720.00000000	14226.54333496	24236.08740234	-4856.19744873
1080.00000000	-10151.59838867	22223.69848633	-23392.39770508
1440.00000000	9420.08203125	33847.21875000	-15391.06469727

Velocity (km/s)

XDOT	YDOT	ZDOT
5.11402285	6.44403201	-0.18296110
-1.30200730	-1.15603013	-0.28164955
-0.33951668	2.65315416	-2.08114153
-1.00112480	-2.33532837	0.76987664
-1.11986055	0.85410149	-1.49506933