TRANSITIONING FROM A GENERAL PERTURBATIONS TO A SPECIAL PERTURBATIONS SPACE OBJECT CATALOG

Transcription

1 TRANSITIONING FRO A GENERAL PERTURBATIONS TO A SPECIAL PERTURBATIONS SPACE OBJECT CATALOG ahw P. Wilkin 1 Kyl T. Alfind 2 Shannon L. Coffy 3 Alan. Sgman 4 Abac Naval Spac Command mainain a caalog of obial lmn fo pac objc. Elmn a bad on h mhod of gnal pubaion which li on an analyic hoy fo obi popagaion. A mo accua mhod fo popagaing obi i pcial pubaion which i bad on numical ingaion. Th impovd accuacy of pcial pubaion ha ld Naval Spac Command o dvlop and mainain a cond, pcial pubaion caalog, which i diinc fom h gnal pubaion caalog. In h fuu h pcial pubaion caalog may bcom h only caalog mainaind by Naval Spac Command. In ha ca, a mhod mu b dvlopd fo uppoing u wih h adiional lmn. Thi pap dcib on mhod of conucing lmn fom pcial pubaion vco and h uling accuacy of h lmn. Inoducion Naval Spac Command i cunly mainaining wo caalog fo pac objc. Th adiional caalog of lmn mak u of gnal pubaion (GP) popagaion ofwa calld PPT3 which i bad on h analyical hoy of Bouw 1. Typical pdicion accuacy of h gnal pubaion lmn i on h od of 1-5 km ov a fw day. A nw caalog bad on pcial pubaion (SP) which mploy numical ingaion fo obi popagaion i 5-1 im mo accua han GP. Naval Spac Command i coniding aniioning complly o h pcial pubaion caalog a hi pimay caalog. Thi man h innal mchanim of aociaing obvaion wih objc, agging obvaion and pocing uncolad ag (UCT) would b cnd aound h SP caalog. Howv, NSC will ill nd o uppo u wih h adiional lmn. Figu 1. illua h ol ha gnal pubaion play in h caalog mainnanc pocdu a Naval Spac Command. NSC Fnc Unaociad Obvaion PPT3 Ephmi Pdico SSN Obvaion Aociaion Poc Unaociad Obvaion UCT U NSC Fnc Aociad Obvaion Good Obvaion GP DC Elmn SP DC Sa Vco Figu 1: Cun Caalog ainnanc Pocdu a Naval Spac Command Sinc i will b oo xpniv o mainain all h caaloging machiny fo boh caalog i i ncay o hav an alna mhod of upplying lmn o u. On mhod would b o div lmn fom SP vco. Thi would limina h nd fo kping a full caalog of lmn, h quid lmn could b divd on dmand fom h SP vco. If hi mhod i followd hn h pocing diagam in Fig. 1 would b changd by ubiuing h SP ingao fo h PPT3 Ephmi Pdico and h GPDC would b linkd o h SP Sa vco ah han o h Ral Obvaion. Th ulan pocing diagam i givn in Figu 2. 1 Gadua Rach Aian, Txa A& Univiy, Collg Saion, TX , phon: (49) , fax: (49) mail: mwilkin@amu.du 2 Pofo and Had, Dp. of Aopac Engining, Txa A& Univiy, phon: (49) , fax: (49) , mail: alfind@ao.amu.du. 3 Naval Rach Laboaoy, Wahingon, DC GRCI a Naval Rach Laboaoy, Wahingon, D.C

2 NSC Fnc Unaociad Obvaion SP Ingao SSN Obvaion Aociaion Poc Unaociad Obvaion UCT NSC Fnc Aociad Obvaion Good Obvaion conucd fom pudo daa w alway b han h lmn conucd fom al daa. In h ca of low ah alli h impovmn wa 2-3 im b. Fo high alli h impovmn wa 5-1 im b. Conucing lmn fom pudo daa i no a nw concp. I i h andad mhod ud by Naval Spac Command o conuc SGP4 lmn fom PPT3 lmn fo anf o AF Spac Command. U GP DC Elmn SP DC Sa Vco Figu 2: Popod Caaloging Pocdu wih SP a h Pimay Popagao Th chniqu of conucing lmn fom SP vco i no a difficul on in pincipal o in pacic. Wha i mo impoan i h qualiy of h ulan lmn. Thi pap pn om accuacy ul fom on mhod w implmnd. Pocdu Th pocdu w puud wa a follow. Fi w poducd an lmn fo a paicula alli fom al SSN daa uing PPT3. Thn w conucd an SP vco fom h am daa. Th SP vco wa ud o gna a of look ahad pudo daa. Th pudo daa wa gnad in ah fixd, ah cnd xyz coodina fam. Thi pudo daa wa ud o conuc a cond lmn. Th fi and cond lmn w hn compad o uh fnc phmi wih h ul ha h lmn SSN # Nam Pig H. Kilom 7646 Sal Slla Wpac Ajiai Topx Lago Lago Ealon Ealon Tabl 1: Salli Ud fo Compaion Th alli w wokd wih w a ub of h alli ha a ackd wih Salli La Ranging (SLR). Th SLR obvaion fo h alli a pocd ino vco wih h vco ingad o poduc an xmly accua phmi calld a Pciion Obi Ephmi (POE). Th uling POE i accua o a fw m. Thi of alli povid an xclln bd fo mauing h impovmn of h mhod dcibd in hi pap. A imila pocdu ha bn ud pviouly o valida h implmnaion of PPT2 in h Dap R&D GTDS 2. In ha wok, obi w conucd fom pudo daa gnad by h Dap Smianalyical Salli Thoy (DSST). Compaion w alo mad bwn lmn conucd fom h SLR POE and pudo DSST daa conucd fom obi fi o h SLR POE. Thi poducd accuacy on h od of 39 m. In h pn pap, w a no pocing SLR daa, ah w a woking wih h much noii SSN daa. Elmn S Compaion Th of alli w wokd wih a givn by hi SSN numb in Tabl 1. Th gaph ha follow how h impovmn fo ach of h alli. Th fi fiv gaph givn in Fig Fig 7 a fo SLR alli ha a na o h ah. Th common o in h GP phmi a divd fom an lmn bad on al daa wa abou 1.5 km., wha h o fo h GP phmi a divd fom an lmn bad on h pudo daa wa on h od of abou 8 m fo h fiv alli. Alo on ach gaph i h cuv fo h o in h SP phmi. Th SP phmi i alo h pudo daa. Of paicula in wa h ga impovmn divd fom high alli. In paicula fo h alli in Fig. 8 - Fig 11. Th impovmn in accuacy povidd by h pudo daa wn fom o a ga a val kilom o only abou 5 m. Inpaion of h Rul

3 W povid h an inpaion of why h lmn bad on pudo daa a ignificanly b han lmn bad on al daa. Fi of all, h pudo daa xacd fom SP phmi wa xmly clo h acual fuu obi of h objc. Bcau i i daa in h fuu i nabl h uling GP phmi o do a good job of following hi fuu moion of h objc. Thi i infomaion ha i no povidd o an lmn conucd fom al daa in h pa. Th cond advanag ha lmn conucd fom pudo daa njoy i ha h pudo daa i noi f. Th GP fi hav a much b chanc of following h obi han whn hy a fi o noiy daa. Finally h daa i xmly dn wih no daa gap. Th SP ym i abl o fi hough h daa gap of h al daa and ill poduc an xmly good obi. Fom hi good obi h GP ym can b conuc an obi ha follow h SP phmi han i could do fom daa ha i no a unifomly diibud. On may b moivad o ak h quion of why h GP lmn canno b fi h SP phmi. Th mo noicabl iuaion occu fo h low ah objc. Th aon i ha h GP poco i bad on an analyic hoy which only includ zonal hamonic hough J5 and ha a fw nhancmn fo onan al m. Thu h lmn will no b abl o poduc h moion of a alli du o h ho piodic m in h ah' ponial fild. Ju fo h fun of i, w d hi hypohi by fiing pudo daa wih PPT3 and wih h pcial pubaion ym wh h goponial modl wa ducd o only J5 zonal hamonic. W povid in Fig. 12 h ul of on uch ca. In hi ca, i i almo impoibl o dmin h diffnc bwn h SP/J5 phmi and h PPT3 phmi. Coninuing wih ou inpaion of h ul, w can conclud ha fo high alli ha a no pubd a much by h ah' gaviaion, w hould ha h PPT3 obi bad on pudo daa a much b han fo h low alli. Thi i indd h ca. A n in h gaph fo h high aliud alli, in paicula, Lago 1 and 2, and Ealon 1 and 2, h lmn bad on pudo daa com much clo o appoximaing h SP obi han fo h low aliud alli SP (Ral) PPT (NSC) PPT (Pudo) Figu 3: Sal (7646) Poiion Diffnc, p=14.1, =.21, I=49.8 4

4 SP (Ral) PPT (NSC) PPT (Pudo) Figu 4: Slla (22824) Poiion Diffnc (p=1.9, =.1, I=98.4) 5

5 SP (Ral) PPT (NSC) PPT (Pudo) Figu 5: Wpac (25398) Poiion Diffnc (p=11.1, =.1, I=98.7) SP (Ral) PPT (NSC) PPT (Pudo) Figu 6: Ajiai (1698) Poiion Diffnc (p=115.6, =.1, I=5) 6

6 SP (Ral) PPT (NSC) PPT (Pudo) Figu 7: Topx (2276) Poiion Diffnc (p=112.5, =.1, I=66.1) SP (Ral) PPT (NSC) PPT (Pudo) Figu 8: Lago 1 (882) Poiion Diffnc (p=225.5, =.4, I=19.8) 7

7 SP (Ral) PPT (NSC) PPT (Pudo) Figu 9: Lago 2 (22195) Poiion Diffnc (p=222.5, =.14, I=52.6) SP (Ral) PPT (NSC) PPT (Pudo) Figu 1: Ealon 1 (19751) Poiion Diffnc (p=675.5, =.1, I=65.9) 8

8 SP (Ral) PPT (NSC) PPT (Pudo) Figu 11: Ealon 2 (226) Poiion Diffnc (p=675.5, =.1, I=64.8) 7 Ajiai (1698) Poiion Diffnc SP (J5) PPT (Pudo) p=115, =.1, I=5, Pig=1479 Figu 12: Compaion bwn PPT3 and SP/J5 odl 9

9 Applicaion o Idium Salli Th ha bn much dicuion in h la ya abou dobiing h Idium alli. If hi occu hn hy would b bough down hough h obi of numou oh alli and pac dbi. Dobiing uch a lag numb of alli, 66, would pn concn abou poibl colliion wih xiing aciv alli. Th common mhod of dmining clo conjuncion i wih h u of COBO pogam ha mak u of GP lmn. Th high accuacy lmn popod in hi pap would nhanc h accuacy of h conjuncion amn ha would hav o b don fo dobiing h alli. Concluion Wih h advn of h pcial pubaion caalog, an unxpcd bnfi may vy wll b alizd. By baing h andad lmn on SP vco a ignifican impovmn in accuacy on h od of 2-3 im h cun o may ul. Th ul a ill pliminay in ha w hav only analyzd ul fo SLR alli. Th alli a xmly wll ackd, a cicula and xpinc lil dag. Coninud ach i bing plannd o dmin h bnfi alizd by mo common pac objc. Acknowldgmn Th auho wih o xp hi gaiud o Naval Spac Command fo poviding h funding fo hi ach. Spcial hank o. Kih Akin fo hi dilignc in making h compu un ha poducd h daa and h plo pnd in hi pap. Rfnc 1 Bouw, D., "Soluion of h poblm of aificial alli hoy wihou dag, "Aonomical Jounal, Vol. 64, PP Cfola, P.J., Fon, D.J., and Shah, N., "Th Incluion of h Naval Spac Command Salli Thoy PPT2 in h R&D GTDS obi Dminaion Sym," pap , AIAA/AAS Aodynamic Spciali Confnc, San Didgo, CA July,