❏♦✉r♥❛❧ ♦❢ ●❡♦❞❡t✐❝ ❙❝✐❡♥❝❡• ✶✭✸✮ • ✷✵✶✶ • ✷✸✸✲✷✸✾ ❉❖■✿ ✶✵✳✷✹✼✽✴✈✶✵✶✺✻✲✵✶✶✲✵✵✵✶✲✸ •

❆ss❡ss♠❡♥t ❙t✉❞② ♦❢ ❯s✐♥❣ ❖♥❧✐♥❡ ✭❈❙❘❙✮●P❙✲PPP ❙❡r✈✐❝❡ ❢♦r ▼❛♣♣✐♥❣ ❆♣♣❧✐❝❛t✐♦♥s✐♥ ❊❣②♣t❘❡s❡❛r❝❤ ❛rt✐❝❧❡

Mohamed Abd-Elazeem1, Ashraf Farah2, Farrag A. Farrag3

1 ❉❡♠♦♥str❛t♦r✱ ❆s✇❛♥✲❋❛❝✉❧t② ♦❢ ❊♥❣✐♥❡❡r✐♥❣✱ ❙♦✉t❤ ❱❛❧❧❡② ❯♥✐✈❡rs✐t②✱ ❊❣②♣t2 ❆ss✐st❛♥t Pr♦❢❡ss♦r✱ ❝♦❧❧❡❣❡ ♦❢ ❊♥❣✐♥❡❡r✐♥❣✱ ❑✐♥❣ ❙❛✉❞ ❯♥✐✈❡rs✐t②✱ ❑✐♥❣❞♦♠ ♦❢ ❙❛✉❞✐ ❆r❛❜✐❛3 Pr♦❢❡ss♦r✱ ❝♦❧❧❡❣❡ ♦❢ ❊♥❣✐♥❡❡r✐♥❣✱ ❆❧✲❏♦✉❢ ❯♥✐✈❡rs✐t②✱ ❑✐♥❣❞♦♠ ♦❢ ❙❛✉❞✐ ❆r❛❜✐❛

❆❜str❛❝t✿

▼❛♥② ❛♣♣❧✐❝❛t✐♦♥s ✐♥ ♥❛✈✐❣❛t✐♦♥✱ ❧❛♥❞ s✉r✈❡②✐♥❣✱ ❧❛♥❞ t✐t❧❡ ❞❡❢✐♥✐t✐♦♥s ❛♥❞ ♠❛♣♣✐♥❣ ❤❛✈❡ ❜❡❡♥ ♠❛❞❡ s✐♠♣❧❡r ❛♥❞ ♠♦r❡ ♣r❡❝✐s❡ ❞✉❡ t♦

❛❝❝❡ss✐❜✐❧✐t② ♦❢ ●❧♦❜❛❧ P♦s✐t✐♦♥✐♥❣ ❙②st❡♠ ✭●P❙✮ ❞❛t❛✱ ❛♥❞ t❤✉s t❤❡ ❞❡♠❛♥❞ ❢♦r ✉s✐♥❣ ❛❞✈❛♥❝❡❞ ●P❙ t❡❝❤♥✐q✉❡s ✐♥ s✉r✈❡②✐♥❣ ❛♣♣❧✐❝❛t✐♦♥s

❤❛s ❜❡❝♦♠❡ ❡ss❡♥t✐❛❧✳ ❚❤❡ ❞✐❢❢❡r❡♥t✐❛❧ t❡❝❤♥✐q✉❡ ✇❛s t❤❡ ♦♥❧② s♦✉r❝❡ ♦❢ ❛❝❝✉r❛t❡ ♣♦s✐t✐♦♥✐♥❣ ❢♦r ♠❛♥② ②❡❛rs✱ ❛♥❞ r❡♠❛✐♥❡❞ ✐♥ ✉s❡

❞❡s♣✐t❡ ♦❢ ✐ts ❝♦st✳ ❚❤❡ ♣r❡❝✐s❡ ♣♦✐♥t ♣♦s✐t✐♦♥✐♥❣ ✭PPP✮ t❡❝❤♥✐q✉❡ ✐s ❛ ✈✐❛❜❧❡ ❛❧t❡r♥❛t✐✈❡ t♦ t❤❡ ❞✐❢❢❡r❡♥t✐❛❧ ♣♦s✐t✐♦♥✐♥❣ ♠❡t❤♦❞ ✐♥ ✇❤✐❝❤

❛ ✉s❡r ✇✐t❤ ❛ s✐♥❣❧❡ r❡❝❡✐✈❡r ❝❛♥ ❛tt❛✐♥ ♣♦s✐t✐♦♥✐♥❣ ❛❝❝✉r❛❝② ❛t t❤❡ ❝❡♥t✐♠❡t❡r ♦r ❞❡❝✐♠❡t❡r s❝❛❧❡✳ ■♥ r❡❝❡♥t ②❡❛rs✱ ♠❛♥② ♦r❣❛♥✐③❛t✐♦♥s

✐♥tr♦❞✉❝❡❞ ♦♥❧✐♥❡ ✭●P❙✲PPP✮ ♣r♦❝❡ss✐♥❣ s❡r✈✐❝❡s ❝❛♣❛❜❧❡ ♦❢ ❞❡t❡r♠✐♥✐♥❣ ❛❝❝✉r❛t❡ ❣❡♦❝❡♥tr✐❝ ♣♦s✐t✐♦♥s ✉s✐♥❣ ●P❙ ♦❜s❡r✈❛t✐♦♥s✳ ❚❤❡s❡

s❡r✈✐❝❡s ♣r♦✈✐❞❡ t❤❡ ✉s❡r ✇✐t❤ r❡❝❡✐✈❡r ❝♦♦r❞✐♥❛t❡s ✐♥ ❢r❡❡ ❛♥❞ ✉♥❧✐♠✐t❡❞ ❛❝❝❡ss ❢♦r♠❛ts ✈✐❛ t❤❡ ✐♥t❡r♥❡t✳ ❚❤✐s ♣❛♣❡r ✐♥✈❡st✐❣❛t❡s t❤❡

❛❝❝✉r❛❝② ♦❢ t❤❡ ❈❛♥❛❞✐❛♥ ❙♣❛t✐❛❧ ❘❡❢❡r❡♥❝❡ ❙②st❡♠ ✭❈❙❘❙✮ Pr❡❝✐s❡ P♦✐♥t P♦s✐t✐♦♥✐♥❣ ✭PPP✮ ✭❈❙❘❙✲PPP✮ s❡r✈✐❝❡ s✉♣❡r✈✐s❡❞ ❜② t❤❡ ●❡♦❞❡t✐❝

❙✉r✈❡② ❉✐✈✐s✐♦♥ ✭●❙❉✮✱ ❈❛♥❛❞❛✳ ❙✐♥❣❧❡ ❢r❡q✉❡♥❝② st❛t✐❝ ●P❙ ♦❜s❡r✈❛t✐♦♥s ❤❛✈❡ ❜❡❡♥ ❝♦❧❧❡❝t❡❞ ❛t t❤r❡❡ ♣♦✐♥ts ❝♦✈❡r✐♥❣ t✐♠❡ s♣❛♥s ♦❢

✻✵✱ ✾✵ ❛♥❞ ✶✷✵ ♠✐♥✉t❡s✳ ❚❤❡s❡ t❤r❡❡ ♦❜s❡r✈❡❞ s✐t❡s ❢♦r♠ ❜❛s❡❧✐♥❡s ♦❢ ✶✳✻✱ ✼✱ ❛♥❞ ✶✵ ❦♠✱ r❡s♣❡❝t✐✈❡❧②✳ ■♥ ♦r❞❡r t♦ ❛ss❡ss t❤❡ ❈❙❘❙✲PPP

❛❝❝✉r❛❝②✱ t❤❡ ❞✐s❝r❡♣❛♥❝✐❡s ❜❡t✇❡❡♥ t❤❡ ❈❙❘❙✲PPP ❡st✐♠❛t❡s ❛♥❞ t❤❡ r❡❣✉❧❛r ❞✐❢❢❡r❡♥t✐❛❧ ●P❙ s♦❧✉t✐♦♥s ✇❡r❡ ❝♦♠♣✉t❡❞✳ ❚❤❡ ♦❜t❛✐♥❡❞

r❡s✉❧ts ✐❧❧✉str❛t❡ t❤❛t t❤❡ PPP ♣r♦❞✉❝❡s ❛ ❤♦r✐③♦♥t❛❧ ❡rr♦r ❛t t❤❡ s❝❛❧❡ ♦❢ ❛ ❢❡✇ ❞❡❝✐♠❡t❡rs❀ t❤✐s ✐s ❛❝❝✉r❛t❡ ❡♥♦✉❣❤ t♦ s❡r✈❡♠❛♥②♠❛♣♣✐♥❣

❛♣♣❧✐❝❛t✐♦♥s ✐♥ ❞❡✈❡❧♦♣✐♥❣ ❝♦✉♥tr✐❡s ✇✐t❤ ❛ s❛✈✐♥❣s ✐♥ ❜♦t❤ ❝♦st ❛♥❞ ❡①♣❡r✐❡♥❝❡❞ ❧❛❜♦r✳

❑❡②✇♦r❞s✿

❆ss❡ss♠❡♥t ❙t✉❞② • CSRS-PPP • Mapping Applications

© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

❘❡❝❡✐✈❡❞ ✶✼ ❋❡❜r✉❛r② ✷✵✶✶❀ ❛❝❝❡♣t❡❞ ✶✼ ▼❛② ✷✵✶✶

1. Introduction

▼♦st ✉s❡rs ♦❢ ●P❙ ❞❛t❛ ✉s❡ t❤❡ ❞✐❢❢❡r❡♥t✐❛❧ t❡❝❤♥✐q✉❡ ❞✉❡ t♦ ✐ts

❤✐❣❤❡r ❛❝❝✉r❛❝②✳ ❍♦✇❡✈❡r✱ t❤❡r❡ ❛r❡ s♦♠❡ ❧✐♠✐t❛t✐♦♥s ✐♥ r❡❧❛t✐✈❡

●P❙ t❡❝❤♥✐q✉❡✿ t✇♦ ♦r ♠♦r❡ r❡❝❡✐✈❡rs ❛r❡ r❡q✉✐r❡❞ t♦ ❜❡ ❛✈❛✐❧❛❜❧❡✱

❛♥❞ t❤❡ tr✉❡ ❝♦♦r❞✐♥❛t❡s ♦❢ t❤❡ r❡❢❡r❡♥❝❡ st❛t✐♦♥ s❤♦✉❧❞ ❜❡ ❦♥♦✇♥✳

▼♦r❡♦✈❡r✱ ✐♥❝r❡❛s✐♥❣ t❤❡ ❞✐st❛♥❝❡ ❜❡t✇❡❡♥ t❤❡ t✇♦ r❡❝❡✐✈❡rs

❝❛✉s❡s ❛ ❞❡❝r❡♠❡♥t ✐♥ t❤❡ q✉❛❧✐t② ♦❢ ♣♦s✐t✐♦♥✐♥❣✳ ❆ ♥❡✇ t❡❝❤♥✐q✉❡

✐♥ ●P❙ ♣♦s✐t✐♦♥✐♥❣ ❦♥♦✇♥ ❛s ♣r❡❝✐s❡ ♣♦✐♥t ♣♦s✐t✐♦♥✐♥❣ ✭PPP✮ s❤♦✇s

t❤❛t ❛ ✉s❡r ✇✐t❤ ❛ s✐♥❣❧❡ r❡❝❡✐✈❡r ❝❛♥ ❛tt❛✐♥ ♣♦s✐t✐♦♥✐♥❣ ❛❝❝✉r❛❝②

❛t ❝❡♥t✐♠❡t❡r ♦r ❞❡❝✐♠❡t❡r ❧❡✈❡❧✱ ❛s ❝♦♠♣❛r❡❞ t♦ ❞✐❢❢❡r❡♥t✐❛❧

t❡❝❤♥✐q✉❡✳ PPP ✐s ✈❡r② ❝♦st✲❡❢❢❡❝t✐✈❡ s✐♥❝❡ t❤❡r❡ ✐s ♥♦ ♥❡❡❞ ❢♦r

♦❜s❡r✈❛t✐♦♥s ❢r♦♠ ❧♦❝❛❧ ♦r r❡❣✐♦♥❛❧ r❡❢❡r❡♥❝❡ st❛t✐♦♥s✳

■♥ r❡❝❡♥t ②❡❛rs✱ ❛ ♥✉♠❜❡r ♦❢ ❢r❡❡ ♦♥❧✐♥❡ ●P❙ ♣r♦❝❡ss✐♥❣ s❡r✈✐❝❡s

t❤❛t ♣r♦✈✐❞❡ t❤❡ ✉s❡r ✇✐t❤ ●P❙ ♣♦s✐t✐♦♥✐♥❣ r❡s✉❧ts ❤❛✈❡ ❜❡❡♥

❡st❛❜❧✐s❤❡❞✳ ❚❤❡s❡ s❡r✈✐❝❡s ❛r❡ ❛✈❛✐❧❛❜❧❡ ❢♦r ✉♥❧✐♠✐t❡❞ ❛❝❝❡ss ❛♥❞

❞♦ ♥♦t r❡q✉✐r❡ ❞❡t❛✐❧❡❞ ❦♥♦✇❧❡❞❣❡ ♦❢ t❤❡ ♣r♦❝❡ss✐♥❣ s♦❢t✇❛r❡✳

❚❤❡s❡ s❡r✈✐❝❡s ❛r❡ t❤❡r❡❢♦r❡ ✉s❡❢✉❧ ❢♦r ●P❙ ✉s❡rs ✇❤♦ ❞♦ ♥♦t ❤❛✈❡

❛♥ ❡①♣❡r✐❡♥❝❡ ✐♥ ●P❙ ♣r♦❝❡ss✐♥❣ s♦❢t✇❛r❡ ♣❛❝❦❛❣❡s✳

❚❤❡ ♠♦t✐✈❛t✐♦♥ ❜❡❤✐♥❞ t❤✐s ♣❛♣❡r ✐s t❤❡ ♥❡❡❞ ❢♦r ❢r❡❡ ●P❙ ♣r♦✲

❝❡ss✐♥❣ t♦♦❧s ❢♦r ✉s❡ ✇✐t❤ ❛ s✐♥❣❧❡ r❡❝❡✐✈❡r t❤❛t ❞♦ ♥♦t r❡q✉✐r❡

❞❡t❛✐❧❡❞ ❦♥♦✇❧❡❞❣❡ ♦❢ ♦r ❡①♣❡r✐❡♥❝❡ ✇✐t❤ ♣r♦❝❡ss✐♥❣ s♦❢t✇❛r❡

❏♦✉r♥❛❧ ♦❢ ●❡♦❞❡t✐❝ ❙❝✐❡♥❝❡234

♣❛❝❦❛❣❡s❀ t❤❡s❡ t♦♦❧s s❤♦✉❧❞ ♦❢❢❡r ❛❝❝✉r❛t❡ r❡s✉❧ts ❢♦r ❧❛♥❞ t✐t❧❡

❞❡❢✐♥✐t✐♦♥s ❛♥❞♠❛♣♣✐♥❣❛♣♣❧✐❝❛t✐♦♥s s✉❝❤❛s♣r❡❧✐♠✐♥❛r② ❝✐t②♣❧❛♥✲

♥✐♥❣✳ ❚❤✐s r❡s❡❛r❝❤ ❛✐♠s t♦ ❛ss❡ss t❤❡ ❈❛♥❛❞✐❛♥ ❙♣❛t✐❛❧ ❘❡❢❡r❡♥❝❡

❙②st❡♠ ✭❈❙❘❙✮ Pr❡❝✐s❡ P♦✐♥t P♦s✐t✐♦♥✐♥❣ ✭PPP✮ ✭❈❙❘❙✲PPP✮ s❡r✈✐❝❡

s✉♣❡r✈✐s❡❞ ❜② t❤❡ ●❡♦❞❡t✐❝ ❙✉r✈❡② ❉✐✈✐s✐♦♥ ✭●❙❉✮✱ ❈❛♥❛❞❛✳ ❙✐♥❣❧❡

❢r❡q✉❡♥❝② st❛t✐❝ ●P❙ ♦❜s❡r✈❛t✐♦♥s ❤❛✈❡ ❜❡❡♥ ❝♦❧❧❡❝t❡❞ ❢r♦♠ t❤r❡❡

♣♦✐♥ts ❝♦✈❡r✐♥❣ ❞✐❢❢❡r❡♥t t✐♠❡ ✇✐♥❞♦✇s ♦❢ ✻✵✱ ✾✵ ❛♥❞ ✶✷✵♠✐♥✉t❡s✳

❚❤❡s❡ t❤r❡❡ ♣♦✐♥ts ❢♦r♠ t❤r❡❡ ❜❛s❡❧✐♥❡s ✇✐t❤ ❧❡♥❣t❤s ♦❢ ✶✳✻✱ ✼ ❛♥❞

✶✵ ❦♠✱ r❡s♣❡❝t✐✈❡❧②✳ ❚❤❡s❡ ♦❜s❡r✈❛t✐♦♥s ✇❡r❡ ♣r♦❝❡ss❡❞ ❜② ✉s✐♥❣

t❤❡ t✇♦ ♠❡t❤♦❞s ✭t❤❡ ❞✐❢❢❡r❡♥t✐❛❧ t❡❝❤♥✐q✉❡ ❛♥❞ t❤❡ ❈❙❘❙✲PPP

s❡r✈✐❝❡✮ ✇❤✐❝❤ ✇❡r❡ t❤❡♥ ❝♦♠♣❛r❡❞ t♦ ♦♥❡ ❛♥♦t❤❡r✳ ❚❤❡ ❛tt❛✐♥❡❞

r❡s✉❧ts s❤♦✇ t❤❛t t❤❡ PPP ♣r♦❞✉❝❡s ❛ ♣❧❛♥❡ ❡rr♦r ❛t t❤❡ ❧❡✈❡❧ ♦❢ ❛

❢❡✇ ❞❡❝✐♠❡t❡rs✳

2. GPS positioning techniques

❚❤❡ ❞❡t❡r♠✐♥❛t✐♦♥ ♦❢ ❛ ●P❙ ✉s❡r✬s ♣♦s✐t✐♦♥ ❝❛♥ ❜❡ ❝❛t❡❣♦r✐③❡❞ ✐♥

t✇♦♠♦❞❡s✿ ❛❜s♦❧✉t❡ ♣♦s✐t✐♦♥✐♥❣ ❛♥❞ r❡❧❛t✐✈❡ ♣♦s✐t✐♦♥✐♥❣✳ ❘❡❧❛t✐✈❡

♣♦s✐t✐♦♥✐♥❣ ✭❞✐❢❢❡r❡♥t✐❛❧ ♣♦s✐t✐♦♥✐♥❣✮ ❡♠♣❧♦②s t✇♦ r❡❝❡✐✈❡rs t❤❛t

tr❛❝❦ t❤❡ s❛♠❡ s❛t❡❧❧✐t❡s s✐♠✉❧t❛♥❡♦✉s❧②✱ ♦♥❡ ❛s r❡❢❡r❡♥❝❡ st❛t✐♦♥

❛♥❞ t❤❡ ♦t❤❡r ❛s ❛ r♦✈❡r ✭❡st✐♠❛t❡❞✮ st❛t✐♦♥✳ ❙♦♠❡ ❡rr♦r s♦✉r❝❡s

❝❛♥ ❜❡ ❡❧✐♠✐♥❛t❡❞ ❜② ❝❛❧❝✉❧❛t✐♥❣ t❤❡ ❞✐❢❢❡r❡♥❝❡ ❜❡t✇❡❡♥ t❤❡

❡st✐♠❛t❡❞ ❛♥❞ t❤❡ ❦♥♦✇♥ ❝♦♦r❞✐♥❛t❡s ❢♦r t❤❡ r❡❢❡r❡♥❝❡ st❛t✐♦♥

❛♥❞ t❤❡♥ ❡♠♣❧♦②✐♥❣ ❝♦rr❡❝t✐♦♥s ❢♦r t❤❡ ✉♥❦♥♦✇♥ st❛t✐♦♥✳ ❚❤❡

❞✐❢❢❡r❡♥t✐❛❧ t❡❝❤♥✐q✉❡ ✐s ✉s❡❞ ✐♥ s✉r✈❡②✐♥❣ ❛♣♣❧✐❝❛t✐♦♥s t❤❛t ♥❡❡❞

❤✐❣❤ ❛❝❝✉r❛❝②✳ ❍♦✇❡✈❡r✱ t❤❡r❡ ❛r❡ ❧✐♠✐t❛t✐♦♥s t♦ ✉s✐♥❣ ❞✐❢❢❡r❡♥t✐❛❧

♠♦❞❡✱ s✉❝❤ ❛s t❤❡ ❞❡♣❡♥❞❡♥❝❡ ♦❢ t❤❡ ❛❝❝✉r❛❝② ♦♥ t❤❡ ❞✐st❛♥❝❡

❜❡t✇❡❡♥ t❤❡ r❡❢❡r❡♥❝❡ ❛♥❞ r♦✈❡r st❛t✐♦♥s✳ ■♥ ❛❞❞✐t✐♦♥✱ t❤❡ ♥❡❡❞

❢♦r ❛t ❧❡❛st t✇♦ s✐♠✉❧t❛♥❡♦✉s❧② ♦♣❡r❛t✐♥❣ r❡❝❡✐✈❡rs ❞✉r✐♥❣ ❞❛t❛

❝♦❧❧❡❝t✐♦♥ ❝♦♠♣❧✐❝❛t❡s ❢✐❡❧❞ ♣r♦❝❡❞✉r❡s ❛♥❞ ❛❞❞s ❛ ❣r❡❛t ❞❡❛❧ ♦❢

❡①♣❡♥s❡✳

❆❜s♦❧✉t❡ ♣♦s✐t✐♦♥✐♥❣✱ ❛❧s♦ ❦♥♦✇♥ ❛s st❛♥❞❛❧♦♥❡✱ ❛✉t♦♥♦♠♦✉s✱ ♦r

s✐♥❣❧❡ ♣♦✐♥t ♣♦s✐t✐♦♥✐♥❣✱ ✐♥✈♦❧✈❡s ❛ s✐♥❣❧❡ ●P❙ r❡❝❡✐✈❡r ✐♥ ♥♦♥✲

❞✐❢❢❡r❡♥t✐❛❧ ♠♦❞❡✳ ❚❤✐s r❡❝❡✐✈❡r tr❛❝❦s ❢♦✉r ♦r ♠♦r❡ ●P❙ s❛t❡❧❧✐t❡s

✐♥ ♦r❞❡r t♦ ❞❡t❡r♠✐♥❡ ✐ts ♣♦s✐t✐♦♥ r❡❧❛t✐✈❡ t♦ t❤❡ r❡❢❡r❡♥❝❡ ❢r❛♠❡ ♦❢

t❤❡ ❦♥♦✇♥ s❛t❡❧❧✐t❡ ♦r❜✐ts ✭✉s✉❛❧❧② ●P❙ ❜r♦❛❞❝❛st ❢r❛♠❡ ❲●❙✽✹✮✳

■t ✐s ♣♦ss✐❜❧❡ t♦ ✐♠♣r♦✈❡ t❤❡ ❛❝❝✉r❛❝② ♦❢ s✐♥❣❧❡ ♣♦✐♥t ♣♦s✐t✐♦♥✐♥❣

✇✐t❤ t❤❡ ❛✈❛✐❧❛❜✐❧✐t② ♦❢ ♣r❡❝✐s❡ ❡♣❤❡♠❡r✐s ❛♥❞ ❝❧♦❝❦ ♣r♦❞✉❝ts ❢r♦♠

✭■●❙✮ ❛♥❞ ♦t❤❡r ♦r❣❛♥✐③❛t✐♦♥s✱ t❤❡ ✉s❛❣❡ ♦❢ ❜♦t❤ ❝❛rr✐❡r✲♣❤❛s❡

❛♥❞ ❝♦❞❡ r❛♥❣❡ ♠❡❛s✉r❡♠❡♥ts✱ ❛♥❞ ♦t❤❡r ❝♦rr❡❝t✐♦♥s s✉❝❤ ❛s

s❛t❡❧❧✐t❡ ❛♥t❡♥♥❛ ♦❢❢s❡t✱ ♦❝❡❛♥ t✐❞❡ ❧♦❛❞✐♥❣✱ ❛t♠♦s♣❤❡r❡ ❧♦❛❞✐♥❣

❛♥❞ s✐t❡ ❞✐s♣❧❛❝❡♠❡♥t ❡❢❢❡❝t✳ ❚❤✐s t❡❝❤♥✐q✉❡ ✐s ❦♥♦✇♥ ❛s ♣r❡❝✐s❡

♣♦✐♥t ♣♦s✐t✐♦♥✐♥❣ ✭PPP✮✳ PPP ❧❡❛❞s t♦ ♣♦s✐t✐♦♥❛❧ ❛❝❝✉r❛❝② ❛t t❤❡

❝❡♥t✐♠❡t❡r ♦r ❞❡❝✐♠❡t❡r s❝❛❧❡✳

3. Elements of precise point positioning

❚❤❡ ✉♥❞✐❢❢❡r❡♥❝❡❞ ♦❜s❡r✈❛t✐♦♥ ❡q✉❛t✐♦♥s ❢♦r t❤❡ ♠❡❛s✉r❡❞ ♣❤❛s❡

❛♥❞ ❝♦❞❡ ❛r❡ ❣✐✈❡♥ ✐♥ ❢♦r♠✉❧❛s ✶ ❛♥❞ ✷ r❡s♣❡❝t✐✈❡❧② ❬❋❛r❛❤✱ ✷✵✵✹❪✿

λφji = ρ

ji + c(dti − dtj ) − λ∆iono + λ∆tropo − λN + ε (1)

Rji = ρ

ji + c(dti − dtj ) + ∆iono + ∆tropo + ε (2)

❲❤❡r❡ ✈❛r✐❛❜❧❡s ❛r❡ ❛s ❣✐✈❡♥ ✐♥ ❚❛❜❧❡ ✶✳ ❋r♦♠ t❤❡ ♣r❡✈✐♦✉s

❡①♣r❡ss✐♦♥s✱ ✇❡ ❝❛♥ s❡❡ t❤❛t t❤❡r❡ ❛r❡ ✐♠♣♦rt❛♥t ❢❛❝t♦rs t❤❛t ❛❢❢❡❝t

t❤❡ ♣❡r❢♦r♠❛♥❝❡ ♦❢ ♣r❡❝✐s❡ ♣♦✐♥t ♣♦s✐t✐♦♥✐♥❣ ✭PPP✮✳ ❚❤❡s❡ ❛r❡

❡①♣❧❛✐♥❡❞ ❜❡❧♦✇✳

Table 1. Variables for equations (1) and (2).

Symbol Meaning

φji measured phase between satellite and station,

Rji measured pseudorange between satellite and station,

ρji true range between satellite and station,

N integer ambiguity,

λ carrier wavelength,

c velocity of light,

dtj satellite clock error,

dti receiver clock error,

∆iono ionosphere delay,

∆tropo troposphere delay,

ε noise and multipath.

3.1. Satellite position and clock corrections

❚❤❡ q✉❛❧✐t② ♦❢ ●P❙ ♦r❜✐ts ❛♥❞ ❝❧♦❝❦ ✐♥❢♦r♠❛t✐♦♥ ❛❢❢❡❝ts t❤❡ ❞❡r✐✈❡❞

❡st✐♠❛t❡s ♦❢ PPP✳ ❚❤❡ ♣r❡❝✐s❡ ●P❙ ♦r❜✐ts ❛♥❞ ❝❧♦❝❦ ♣r♦❞✉❝ts ❛r❡

❛✈❛✐❧❛❜❧❡ ✐♥ ❙P✸ ❢♦r♠❛t ❢r♦♠ ■●❙ ❛❢t❡r ✶✸ ❞❛②s ❧❛t❡♥❝②✱ ❛♥❞ ❛r❡

❦♥♦✇♥ ❛s ■●❙✲❢✐♥❛❧✳

3.2. Geometric strength

❋❛❝t♦rs ✐♥❢❧✉❡♥❝✐♥❣ ❣❡♦♠❡tr✐❝ str❡♥❣t❤ ❛r❡ t❤❡ ♥✉♠❜❡r ♦❢ ❛❝❝❡s✲

s✐❜❧❡ s❛t❡❧❧✐t❡s✱ ❞✐str✐❜✉t✐♦♥ ♦❢ ❛❝❝❡ss✐❜❧❡ s❛t❡❧❧✐t❡s✱ ❡❧❡✈❛t✐♦♥ ♠❛s❦

❛♥❣❧❡ ❛♥❞ ❧❡♥❣t❤ ♦❢ t✐♠❡ s♣❛♥ ♦❢ ❝❛rr✐❡r ♣❤❛s❡ ♦❜s❡r✈❛t✐♦♥s✳

3.3. Antenna information

PPP ❞❡t❡r♠✐♥❡s t❤❡ ❤❡✐❣❤t✱ ❧❛t✐t✉❞❡ ❛♥❞ ❧♦♥❣✐t✉❞❡ ♦❢ t❤❡ ❛♥t❡♥♥❛

♣❤❛s❡ ❝❡♥tr❡ ✭❆P❈✮ r❡❛❧✐③❡❞ ❜② t❤❡ ♣r♦❝❡ss❡❞ ♦❜s❡r✈❛t✐♦♥s✳ ❚♦

❝♦♠♣✉t❡ t❤❡ ♣♦s✐t✐♦♥ ♦❢ t❤❡ ❣r♦✉♥❞ ♣♦✐♥t✱ t❤❡ ✈❡rt✐❝❛❧ ❞✐st❛♥❝❡

❜❡t✇❡❡♥ t❤❡ ❣r♦✉♥❞ ♣♦✐♥t ❛♥❞ t❤❡ ❛♥t❡♥♥❛ r❡❢❡r❡♥❝❡ ♣♦✐♥t ✭❆❘P✮

❛s ✇❡❧❧ ❛s t❤❡ ❞✐st❛♥❝❡ ❜❡t✇❡❡♥ ❆❘P ❛♥❞ t❤❡ ❆P❈ ♠✉st ❜❡ ❦♥♦✇♥✳

✶✳ ❆❘P t♦ t❤❡ ♠❛r❦❡r✿

❚❤✐s ✐s t❤❡ ✈❡rt✐❝❛❧ ❞✐st❛♥❝❡ ❜❡t✇❡❡♥ t❤❡ ❣r♦✉♥❞ ♣♦✐♥t ❛♥❞

t❤❡ ❛♥t❡♥♥❛ r❡❢❡r❡♥❝❡ ♣♦✐♥t ✭❆❘P✮✱ ✇❤✐❝❤ ✐s r❡❧❡✈❛♥t ❢♦r

t❤❡ ✐♥st❛❧❧❛t✐♦♥ ♦❢ t❤❡ ❛♥t❡♥♥❛✳ ❚❤✐s ❞✐st❛♥❝❡ s❤♦✉❧❞ ❜❡

❡♥t❡r❡❞ ✐♥ t❤❡ ❍ ❝♦♠♣♦♥❡♥t ♦❢ t❤❡ ❛♥t❡♥♥❛ ❞❡❧t❛ ❍✴❊✴◆ ✐♥

t❤❡ ❘■◆❊❳ ❤❡❛❞❡r✳

✷✳ ❆❘P t♦ ❆P❈✿

❚❤❡ ❞✐st❛♥❝❡ ❜❡t✇❡❡♥ t❤❡ ❆❘P ❛♥❞ t❤❡ ❆P❈ ✐s ❛ ❢✉♥❝t✐♦♥

❏♦✉r♥❛❧ ♦❢ ●❡♦❞❡t✐❝ ❙❝✐❡♥❝❡ 235

♦❢ t❤❡ ❡❧❡❝tr♦♥✐❝ ♣r♦♣❡rt✐❡s ♦❢ t❤❡ ❛♥t❡♥♥❛ ❛s ✇❡❧❧ ❛s t❤❡

❡❧❡✈❛t✐♦♥ ❛♥❞ ❛③✐♠✉t❤ ♦❢ t❤❡ ✐♥❝♦♠✐♥❣ s❛t❡❧❧✐t❡ s✐❣♥❛❧✳ ❚❤✐s

❞✐st❛♥❝❡ ✐s ❞❡t❡r♠✐♥❡❞ ❜② ❧❛❜♦r❛t♦r② ♦r ❢✐❡❧❞ ❝❛❧✐❜r❛t✐♦♥

❛♥❞ ✐ts ✈❛❧✉❡ r❡♠❛✐♥s ❝♦♥st❛♥t ❢♦r ❛♥② ❣✐✈❡♥ ♠♦❞❡❧✳

3.4. Ionospheric delay

❚❤❡ ✐♦♥♦s♣❤❡r❡ ✐s ❛ ❧❛②❡r ♦❢ ✐♦♥✐③❡❞ ❛t♠♦s♣❤❡r❡ s✉rr♦✉♥❞✐♥❣ t❤❡

❡❛rt❤ ❡①t❡♥❞✐♥❣ ❢r♦♠ ✺✵ ❦♠ t♦ ✶✵✵✵ ❦♠ ❛❜♦✈❡ t❤❡ s✉r❢❛❝❡✳ ❚❤❡

✐♦♥♦s♣❤❡r❡ ✐s ❛❞✐s♣❡rs✐✈❡♠❡❞✐✉♠❢♦r t❤❡ ❢r❡q✉❡♥❝②❜❛♥❞s✉s❡❞❜②

❣❧♦❜❛❧ ♥❛✈✐❣❛t✐♦♥ s❛t❡❧❧✐t❡ s②st❡♠ ✭●◆❙❙✮ s✐❣♥❛❧s✳ ❚❤❡ ✐♠♣❛❝t ♦❢ t❤❡

✐♦♥♦s♣❤❡r❡ ❞❡❝r❡❛s❡s ✇✐t❤ t❤❡ r❡❝✐♣r♦❝❛❧ sq✉❛r❡ ♦❢ t❤❡ ❢r❡q✉❡♥❝②

♦❢ t❤❡ s✐❣♥❛❧✳ ❚❤❡ ✐♦♥♦s♣❤❡r✐❝ ❞❡❧❛② ✐s ♣r♦♣♦rt✐♦♥❛❧ t♦ t❤❡ t♦t❛❧

❡❧❡❝tr♦♥✐❝ ❝♦♥t❡♥t ✭❚❊❈✮✳ ■♥ ♦r❞❡r t♦ ❡❧✐♠✐♥❛t❡ t❤❡ ✐♦♥♦s♣❤❡r✐❝ ❜✐❛s✱

✐t ✐s ♣♦ss✐❜❧❡ t♦ ✉s❡ ❛♥ ✐♦♥♦s♣❤❡r❡✲❢r❡❡ ❝♦❞❡ ❛♥❞ ❝❛rr✐❡r ♣❤❛s❡

❝♦♠❜✐♥❛t✐♦♥ ❜② ✉s✐♥❣ ❞✉❛❧ ❢r❡q✉❡♥❝② ♦❜s❡r✈❛t✐♦♥s✳

3.5. Tropospheric delay

❚❤❡ tr♦♣♦s♣❤❡r❡ ✐s t❤❡ ❜♦tt♦♠ ❧❛②❡r ♦❢ ❡❛rt❤✬s ❛t♠♦s♣❤❡r❡✳ ■ts

t❤✐❝❦♥❡ss ✈❛r✐❡s ❢r♦♠ ✽ t♦ ✶✻ ❦♠ ❜❡t✇❡❡♥ t❤❡ ♣♦❧❡s ❛♥❞ t❤❡

❡q✉❛t♦r✳ ❚❤❡ tr♦♣♦s♣❤❡r✐❝❞❡❧❛② ✐s❜❛s❡❞♦♥ t❡♠♣❡r❛t✉r❡✱ ♣r❡ss✉r❡✱

❤✉♠✐❞✐t②✱ ❛♥❞ ✇❛t❡r ✈❛♣♦r ❛♥❞ ✐s ❛ ❢✉♥❝t✐♦♥ ♦❢ ❡❧❡✈❛t✐♦♥ ❛♥❞

❧❛t✐t✉❞❡ ♦❢ t❤❡ r❡❝❡✐✈❡r✳ ❚r♦♣♦s♣❤❡r✐❝ ♠♦❞❡❧s ❛r❡ ✉s❡❞ t♦ ♠✐t✐❣❛t❡

t❤❡ tr♦♣♦s♣❤❡r✐❝ ❡❢❢❡❝ts ❛❜♦✉t ✾✷✪ t♦ ✾✺✪ ❛♥❞ t❤❡ r❡♠❛✐♥✐♥❣ ♣❛rt

❝❛♥ ❜❡ r❡♠♦✈❡❞ ❜② ✉s✐♥❣ ❛ s❤♦rt ❜❛s❡❧✐♥❡ ❞✐❢❢❡r❡♥t✐❛❧ t❡❝❤♥✐q✉❡

❬❲❡❧❧s ❡t ❛❧✳✱ ✶✾✾✾❪✳

4. On-line gps processing services

■♥ r❡❝❡♥t ②❡❛rs ♠❛♥② ♦r❣❛♥✐③❛t✐♦♥s ❤❛✈❡ ✐♥tr♦❞✉❝❡❞ ♦♥❧✐♥❡ ●P❙

t♦♦❧s t❤❛t ♣r♦✈✐❞❡ ✉♥❧✐♠✐t❡❞ ♥✉♠❜❡rs ♦❢ ●P❙ ♣r♦❝❡ss✐♥❣ ❡st✐♠❛t❡s

t♦ t❤❡ ✉s❡r ❢r❡❡ ♦❢ ❝❤❛r❣❡✳ ❚❤❡ ✉s❡r s❡♥❞s ❛ ❢✐❧❡ ✐♥ ❘❡❝❡✐✈❡r

■♥❞❡♣❡♥❞❡♥t ❊①❝❤❛♥❣❡ ❢♦r♠❛t ✭❘■◆❊❳✮ t♦ t❤❡ s❡r✈✐❝❡ ❛♥❞ t❤❡

♣♦s✐t✐♦♥ ♦❢ t❤❡ ✉s❡r✬s r❡❝❡✐✈❡r ✇✐❧❧ ❜❡ s❡♥t ❜❛❝❦ ✇✐t❤✐♥ ❛ s❤♦rt

t✐♠❡❢r❛♠❡ ♥♦t t♦ ❡①❝❡❡❞ s❡✈❡r❛❧ ♠✐♥✉t❡s✳ ❆♥ ♦✉t❧✐♥❡❞ ❝♦♠♣❛r✐s♦♥

❜❡t✇❡❡♥ t❤❡s❡ s❡r✈✐❝❡s ✐s ♣r❡s❡♥t❡❞ ❤❡r❡ ❬❢♦r ♠♦r❡ ❞❡t❛✐❧s✱ s❡❡

❉❛r❡✱ ✷✵✵✻ ❛♥❞ ❉❛✇♦❞ ❡t ❛❧✳ ✷✵✵✼❪✳

4.1. AUSPOS service

❚❤❡ ●❡♦s❝✐❡♥❝❡ ❆✉str❛❧✐❛ ❬❢♦r♠❡r❧② t❤❡ ❆✉str❛❧✐❛♥ s✉r✈❡②✐♥❣ ❛♥❞

▲❛♥❞ ■♥❢♦r♠❛t✐♦♥●r♦✉♣✬s ✭❆❯❙▲■●✮❪ ❖♥❧✐♥❡ ●P❙ Pr♦❝❡ss✐♥❣ ❙❡r✈✐❝❡

✭❆❯❙P❖❙✮ ✇❛s ♦❢❢✐❝✐❛❧❧② ❧❛✉♥❝❤❡❞ ✐♥ ❧❛t❡ ✷✵✵✵✳ ❚❤❡ ❆❯❙P❖❙ s❡r✈✐❝❡

❤❛s t❤❡ ❢♦❧❧♦✇✐♥❣ ❛❞✈❛♥t❛❣❡s✿ ❛♥ ❡❛s② t♦ ✉s❡ ✇❡❜ s✐t❡✱ ❞✉❛❧

❢r❡q✉❡♥❝② ●P❙ ❞❛t❛ ♣r♦❝❡ss✐♥❣ ❛❜✐❧✐t②✱ q✉✐❝❦ t✉r♥ ❜❛❝❦ ♦❢ r❡s✉❧ts✱

❣❧♦❜❛❧ ❛✈❛✐❧❛❜✐❧✐t②✱ ❛♥❞ r❡s✉❧ts t❤❛t ❛r❡ r❡❢❡r❡♥❝❡❞ ❡✐t❤❡r t♦ t❤❡

■♥t❡r♥❛t✐♦♥❛❧ ❚❡rr❡str✐❛❧ ❘❡❢❡r❡♥❝❡ ❋r❛♠❡ ✭■❚❘❋✮ s②st❡♠ ♦r t♦ t❤❡

●❉❆✾✹ ❢♦r ❆✉str❛❧✐❛♥ ✉s❡rs✳ ❚❤❡ ❆❯❙P❖❙ s♦❧✉t✐♦♥ ✉s❡s ❞✐❢❢❡r❡♥t✐❛❧

●P❙ t♦ t❤❡ ♥❡❛r❡st t❤r❡❡ ■♥t❡r♥❛t✐♦♥❛❧ ●◆❙❙ ❙t❛t✐♦♥s ✭■●❙✮ ❛♥❞ ✐♥

❛❞❞✐t✐♦♥ ✉s❡s ■●❙ ♣r❡❝✐s❡ ♦r❜✐t ♣r♦❞✉❝ts✳ ❚❤✐s s❡r✈✐❝❡ ✐s ❛✈❛✐❧❛❜❧❡ ❛t

http://www.ga.gov.au✳

4.2. CSRS-PPP service

❚❤❡ ●❡♦❞❡t✐❝ ❙✉r✈❡② ❉✐✈✐s✐♦♥ ✭●❙❉✮ ♦❢ ❈❛♥❛❞❛ ❞❡✈❡❧♦♣❡❞ t❤❡

❈❛♥❛❞✐❛♥❙♣❛t✐❛❧❘❡❢❡r❡♥❝❡❙②st❡♠✭❈❙❘❙✮Pr❡❝✐s❡P♦✐♥tP♦s✐t✐♦♥✐♥❣

✭PPP✮ s❡r✈✐❝❡✳ ❚❤✐s s❡r✈✐❝❡ ♣r♦✈✐❞❡s ❛ s✐♥❣❧❡✲♣♦✐♥t ♣♦s✐t✐♦♥✐♥❣

s♦❧✉t✐♦♥ ❢♦r ✉s❡rs ✐♥ st❛t✐❝ ♦r ❦✐♥❡♠❛t✐❝ ♠♦❞❡s✳ ❚❤❡ ❈❙❘❙ ❡st✐♠❛t❡s

❛r❡ ♣r♦❝❡ss❡❞ ❢r♦♠ ❝❛rr✐❡r ♣❤❛s❡ ♦r ❝♦❞❡ r❛♥❣❡ ♦❜s❡r✈❛t✐♦♥s ♦❢

❜♦t❤ s✐♥❣❧❡ ❛♥❞ ❞♦✉❜❧❡ ❢r❡q✉❡♥❝② r❡❝❡✐✈❡rs✳ PPP ❝♦♦r❞✐♥❛t❡s

❛r❡ r❡❢❡rr❡❞ t♦ t❤❡ ◆♦rt❤ ❆♠❡r✐❝❛♥ ❉❛t✉♠ ✭◆❆❉ ✶✾✽✸✮ ❛s ✇❡❧❧

❛s t♦ t❤❡ ✭■❚❘❋✮ s②st❡♠✳ PPP r❡s✉❧ts ❛r❡ ❜❛s❡❞ ♦♥ ♣r❡❝✐s❡ ●P❙

♦r❜✐ts ❛♥❞ ❝❧♦❝❦ ♣r♦❞✉❝ts✳ ❘❡s✉❧ts ❝❛♥ ❜❡ ✐♠♣r♦✈❡❞ t❤r♦✉❣❤ t❤❡

✉s❡ ♦❢ ❜❡tt❡r ✉s❡r✲❡♥❞ ❡q✉✐♣♠❡♥t✱ ❛♥❞ t❤r♦✉❣❤ t❤❡ ❞②♥❛♠✐❝s

❛♥❞ ❞✉r❛t✐♦♥ ♦❢ t❤❡ ♦❜s❡r✈❛t✐♦♥s✳ ❚❤✐s s❡r✈✐❝❡ ✐s ❛❝❝❡ss✐❜❧❡ ❛t

http://www.geod.nrcan.gc.ca✳

4.3. SCOUT service

❚❤❡ ❙❝r✐♣♣s ❈♦♦r❞✐♥❛t❡ ❯♣❞❛t❡ ❚♦♦❧ ✭❙❈❖❯❚✮ ✇❛s ❞❡✈❡❧♦♣❡❞

❜② t❤❡ ❙❝r✐♣♣s ❖r❜✐t ❛♥❞ P❡r♠❛♥❡♥t ❆rr❛② ❈❡♥t❡r ✭❙❖P❆❈✮✳ ❚❤❡

❝♦♦r❞✐♥❛t❡s ♦❢ t❤✐s s❡r✈✐❝❡ ❛r❡ ❣✐✈❡♥ ✐♥ r❡❢❡r❡♥❝❡ t♦ t❤❡ ♥❡❛r❡st

t❤r❡❡ ■●❙ st❛t✐♦♥s✳ ❍♦✇❡✈❡r✱ t❤❡ s❡r✈✐❝❡ ♣❡r♠✐ts t❤❡ ✉s❡r t♦ ❝❤♦♦s❡

✉♣ t♦ ❢♦✉r r❡❢❡r❡♥❝❡ st❛t✐♦♥s✳ ❚❤❡ s❡r✈✐❝❡ ✉s❡s ●❆▼■❚ ♣r♦❝❡ss✐♥❣

s♦❢t✇❛r❡✳ ❚❤❡ s❡r✈✐❝❡✬s ✇❡❜s✐t❡ ✐s http://sopac.ucsd.edu✳

4.4. OPUS service

❚❤❡ ❯♥✐t❡❞ ❙t❛t❡s✬ ◆❛t✐♦♥❛❧ ●❡♦❞❡t✐❝ ❙✉r✈❡② ❞❡✈❡❧♦♣❡❞ t❤❡ ❖♥✲

❧✐♥❡ P♦s✐t✐♦♥✐♥❣ ❯s❡r ❙❡r✈✐❝❡ ✭❖P❯❙✮✳ ❚❤❡ r❡s✉❧ts ♦❢ ❖P❯❙ ❛r❡

❝♦♠♣✉t❡❞ ❢r♦♠ t❤r❡❡ ❈♦♥t✐♥✉♦✉s❧② ❖♣❡r❛t✐♥❣ ❘❡❢❡r❡♥❝❡ ❙t❛t✐♦♥s

✭❈❖❘❙✮✳ ❚❤❡ ❈❖❘❙ s✐t❡s ❛r❡ ❝❤♦s❡♥ ♥♦t ❛❝❝♦r❞✐♥❣ t♦ ❝❧♦s❡st ♣r♦①✲

✐♠✐t② ❜✉t ❛❝❝♦r❞✐♥❣ t♦ ❝♦♠♣❛t✐❜✐❧✐t② ❜❡t✇❡❡♥ t❤❡ ✉s❡r✬s ❞❛t❛ ❛♥❞

t❤❡ ❈❖❘❙ s✐t❡✳ ❚❤❡r❡ ✐s ❛❧s♦ ❛♥ ♦♣t✐♦♥ t❤❛t ❛❧❧♦✇s t❤❡ ✉s❡r t♦

❝❤♦♦s❡ t❤❡ ❈❖❘❙ st❛t✐♦♥s t♦ ❜❡ ✉s❡❞✳ ❚❤❡ s❡r✈✐❝❡✬s ✇❡❜s✐t❡ ✐s

http://www.ngs.noaa.gov✳

4.5. Auto-GIPSY service

❚❤✐s ✐s ❛♥ ❡✲♠❛✐❧✴❋❚P ✐♥t❡r❢❛❝❡ t♦ t❤❡ ●P❙ ■♥❢❡rr❡❞ P♦s✐t✐♦♥✐♥❣

❙②st❡♠ ✭●■P❙❨✮ ❞❡✈❡❧♦♣❡❞ ❜② ❏P▲✳ ❚❤✐s s❡r✈✐❝❡ ♣❡r❢♦r♠s s✐♥❣❧❡

♣♦✐♥t ♣♦s✐t✐♦♥✐♥❣ ❛♥❞ ✐t ✐s ♥♦t ❞❡♣❡♥❞❡♥t ♦♥ ❈❖❘❙✴■●❙ ❞❛t❛✳

❚❤❡ ❋❚P ❛❞❞r❡ss ♦❢ ✉s❡r✬s ❞❛t❛ s❤♦✉❧❞ ❜❡ s✉❜♠✐tt❡❞ ❜② ❡♠❛✐❧

t♦✿ ag@cobra.jpl.nasa.gov✳ ❚❤✐s s❡r✈✐❝❡ ✇❛s r❡♣❧❛❝❡❞ ❜② ❏P▲✬s

♥❡✇ ❆✉t♦♠❛t✐❝ Pr❡❝✐s❡ P♦s✐t✐♦♥✐♥❣ ❙❡r✈✐❝❡ ✭❆PP❙✮✱ ❛✈❛✐❧❛❜❧❡ ❛t

http://apps.gdgps.net/ ♦♥ ❆✉❣✉st ✶✺✱ ✷✵✵✾ ❬❆✉t♦✲●■P❙❨✱ ✷✵✶✶❪

❛♥❞ ❤❛s ❜❡❝♦♠❡ ❛❝❝❡ss✐❜❧❡ ❢♦r ❞✉❛❧ ❢r❡q✉❡♥❝② ♦❜s❡r✈❛t✐♦♥s✳

4.6. Comparison between on-line services

❚❤❡r❡ ❛r❡ ❣❡♥❡r❛❧ ❛s♣❡❝ts t♦ ❜❡ ❝♦♥s✐❞❡r❡❞ ✐♥ t❤❡ ❛ss❡ss♠❡♥t ♦❢

❡❛❝❤ s❡r✈✐❝❡ s✉❝❤ ❛s t❤❡ ❛♣♣r♦❛❝❤ ♦❢ s❡♥❞✐♥❣ ❛♥❞ r❡❝❡✐✈✐♥❣ ❞❛t❛✱

t✐♠❡ ❞❡❧❛② ✐♥ r❡❝❡✐✈✐♥❣ r❡s✉❧ts✱ ❛❝❝❡ss✐❜❧❡ ♦♣t✐♦♥s ❛♥❞ t❤❡ s❡r✈✐❝❡✬s

❧✐♠✐t❛t✐♦♥s✳ ❆♥ ♦✈❡r❛❧❧ ❡✈❛❧✉❛t✐♦♥ ♦❢ ❡❛❝❤ s❡r✈✐❝❡ ✐s ✐❧❧✉str❛t❡❞ ✐♥

❚❛❜❧❡ ✷✳

❏♦✉r♥❛❧ ♦❢ ●❡♦❞❡t✐❝ ❙❝✐❡♥❝❡236

Table 2. Comparison of online GPS processing services. [Dare, 2006]

Name of service Data transfer method Available options Elapsed time to receive

results

Restrictions of length

of GPS data set

limitations

AUSPOS Uploading Antenna

Via anonymous FTP

Antenna height

Antenna type No. of

RINEX files

(maximum)

> 25 min. Minimum of 1 hr. Dual frequency

Static

Scout Via anonymous FTP

Upload the file to

Scripps FTP site

Antenna height

Antenna type

Selection of reference

stations

> 15 min. Minimum of 1 hr. Dual frequency

Static

CSRS-PPP Uploading Mode of processing

Reference systems

(NAD83 or ITRF)

< 3 min. No minimum

Maximum 6 days long

OPUS Uploading Antenna height

Antenna type

> 4 min. Minimum 2 hr.

Maximum 24 hr.

Dual frequency

Static

Only available for use

in Central and North

America

Auto-GIPSY Via sending the

anonymous FTP

address

None < 3 min. At least 1 hr.

❆s ❝❛♥❜❡ s❡❡♥ ❢r♦♠❚❛❜❧❡ ✷✱ t❤❡♠♦st s✉✐t❛❜❧❡ s❡r✈✐❝❡ ❢♦r t❤❡ s✐♥❣❧❡

❢r❡q✉❡♥❝② r❡❝❡✐✈❡r ❞❛t❛ ✉s❡❞ ✐♥ t❤✐s ❡①♣❡r✐♠❡♥t ✐s t❤❡ ❈❙❘❙✲PPP

s❡r✈✐❝❡✱ ❛♥❞ s♦ s✉❜s❡q✉❡♥t s❡❝t✐♦♥s ♦❢ t❤✐s ♣❛♣❡r ✇✐❧❧ ❢♦❝✉s ♦♥ t❤❛t

s❡r✈✐❝❡✳

5. Basics of online (CSRS-PPP) GPS processing service

❚❤❡ ❈❛♥❛❞✐❛♥ ❙♣❛t✐❛❧ ❘❡❢❡r❡♥❝❡ ❙②st❡♠ ✭❈❙❘❙✮ Pr❡❝✐s❡ P♦✐♥t P♦✲

s✐t✐♦♥✐♥❣ ✭PPP✮ s❡r✈✐❝❡ ♣r♦✈✐❞❡s ♣♦st✲♣r♦❝❡ss❡❞ ♣♦s✐t✐♦♥ s♦❧✉t✐♦♥s

✈✐❛ t❤❡ ■♥t❡r♥❡t ❢r♦♠ ●P❙ ♦❜s❡r✈❛t✐♦♥ ❢✐❧❡s s✉❜♠✐tt❡❞ ❜② t❤❡ ✉s❡r✳

Pr❡❝✐s❡ s♦❧✉t✐♦♥s ❛r❡ ❣✐✈❡♥ ✐♥ r❡❢❡r❡♥❝❡ t♦ t❤❡ ❈❙❘❙ st❛♥❞❛r❞◆♦rt❤

❆♠❡r✐❝❛♥ ❉❛t✉♠ ♦❢ ✶✾✽✸ ✭◆❆❉✽✸✮ ❛s ✇❡❧❧ ❛s t♦ t❤❡ ■♥t❡r♥❛t✐♦♥❛❧

❚❡rr❡str✐❛❧ ❘❡❢❡r❡♥❝❡ ❋r❛♠❡ ✭■❚❘❋✮✳ Pr❡❝✐s❡ ♣♦s✐t✐♦♥ ❡st✐♠❛t❡s ❛r❡

❝♦♠♣✉t❡❞ ❢♦r ✉s❡rs ♦♣❡r❛t✐♥❣ ✐♥ st❛t✐❝ ♦r ❦✐♥❡♠❛t✐❝ ♠♦❞❡s ✉s✐♥❣

♣r❡❝✐s❡ ●P❙ ♦r❜✐ts ❛♥❞ ❝❧♦❝❦s✳

5.1. Accessibility of precise orbits and clocks

❚❤❡ ❈❙❘❙✲PPP s❡r✈✐❝❡ ✉s❡s t❤❡ ❡♣❤❡♠❡r✐s ❛✈❛✐❧❛❜❧❡ ❛t t❤❡ t✐♠❡

♦❢ s❡♥❞✐♥❣ ●P❙ ❞❛t❛ ✭❜r♦❛❞❝❛st ❡♣❤❡♠❡r✐s✮✳ ❍♦✇❡✈❡r✱ t❤❡ ❧♦♥❣❡r

♣❡r✐♦❞ ✐♥ s✉❜♠✐tt✐♥❣ ❞❛t❛ ❢♦r ♣r♦❝❡ss✐♥❣ ❧❡❛❞s t♦ ♠♦r❡ ❛❝❝✉r❛t❡

❈❙❘❙✲PPP s♦❧✉t✐♦♥s✳ ❚❤✐s ❞✉❡ t♦ t❤❡ ❢❛❝t t❤❛t ■●❙ ❢✐♥❛❧ ♦r❜✐ts ❛♥❞

❝❧♦❝❦ ♣r♦❞✉❝ts ❛r❡ ❛✈❛✐❧❛❜❧❡ ❛❢t❡r ✶✸ ❞❛②s✳

5.2. Accepted minimum and maximum duration of GPS data set

❚❤❡r❡ ✐s ♥♦ ♠✐♥✐♠✉♠ ❧❡♥❣t❤ ❢♦r ❛ ●P❙ ♦❜s❡r✈❛t✐♦♥ s❡ss✐♦♥✳ ❍♦✇✲

❡✈❡r✱ t❤❡ q✉❛❧✐t② ♦❢ ❛ PPP ❝♦♠♣✉t❡❞ ♣♦s✐t✐♦♥ ✇✐❧❧ ♥♦t ❜❡ ♦♣t✐♠❛❧

✉♥t✐❧ t❤❡ ❝❛rr✐❡r ♣❤❛s❡ ❛♠❜✐❣✉✐t✐❡s ❤❛✈❡ ❝♦♥✈❡r❣❡❞✳ ❋♦r s❤♦rt ❞❛t❛

s❡ts✱ t❤❡ ❡❢❢❡❝t✐✈❡ ❝❛❧❝✉❧❛t✐♦♥ ♦❢ ❛ ♣♦s✐t✐♦♥ ✉s❡s ♦♥❧② t❤❡ ❝♦❞❡

♣s❡✉❞♦✲r❛♥❣❡ ♦❜s❡r✈❛t✐♦♥s✳ ▲♦♥❣❡r ❞❛t❛ s❡ts ♠❛❦❡ ✐t ♣♦ss✐❜❧❡ t♦

r❡s♦❧✈❡ t❤❡ ❛♠❜✐❣✉✐t✐❡s r❡q✉✐r❡❞ t♦ r❡❝♦✈❡r ♣♦s✐t✐♦♥s ✉s✐♥❣ t❤❡

♠♦r❡ ♣r❡❝✐s❡ ❝❛rr✐❡r ♣❤❛s❡ ♦❜s❡r✈❛t✐♦♥s ❬❈❙❘❙✲PPP ❣✉✐❞❡✱ ✷✵✵✹❪✳

❚❤❡ ❈❙❘❙✲PPP s❡r✈✐❝❡ ❝❛♥ ♣r♦❝❡ss ✉♣ t♦ s✐① ❞❛②s ♦❢ ♦❜s❡r✈❛t✐♦♥

❞❛t❛ ❛♥❞ ❛ ❘■◆❊❳ ❢✐❧❡ ✉♣ t♦ ✶✵✵ ▼❜✳ ❙✉❜♠✐ss✐♦♥ ♦❢ ❛ ❢✐❧❡ ❡①❝❡❡❞✐♥❣

✶✵✵ ▼❜ ✇✐❧❧ r❡s✉❧t ✐♥ ❛♥ ✉♥s✉❝❝❡ss❢✉❧ ❥♦❜ t❡r♠✐♥❛t✐♦♥ ❬❈❙❘❙✲PPP

❣✉✐❞❡✱ ✷✵✵✹❪✳

5.3. Antenna information

❚❤❡♦♥❧✐♥❡❈❙❘❙✲PPP s❡r✈✐❝❡✉s❡s t❤❡❛♥t❡♥♥❛♣❤❛s❡ ❝❡♥tr❡ ❝❛❧✐❜r❛✲

t✐♦♥ ✈❛❧✉❡♣✉❜❧✐s❤❡❞❜② t❤❡ ■♥t❡r♥❛t✐♦♥❛❧ ●◆❙❙ ❙❡r✈✐❝❡ ✭■●❙✮ ❛♥❞❜②

t❤❡◆❛t✐♦♥❛❧●❡♦❞❡t✐❝❙✉r✈❡② ✭◆●❙✮ t❤r♦✉❣❤❝❡rt❛✐♥❛♥t❡♥♥❛♠♦❞❡❧

✐❞❡♥t✐❢✐❝❛t✐♦♥✱ ❢♦✉♥❞ ❛t http://www.ngs.noaa.gov/ANTCAL/

❬●❙❘❙✲PPP ❣✉✐❞❡✱ ✷✵✵✹❪✳ ❚❤❡ ❛♥t❡♥♥❛ t②♣❡♠✉st ❜❡ r❡❝♦r❞❡❞ ✐♥ t❤❡

❤❡❛❞❡r ♦❢ t❤❡ ❘■◆❊❳ ❢✐❧❡✳ ❚❤❡r❡❢♦r❡ ✐❢ t❤❡r❡ ✐s ♥♦ ✐♥❢♦r♠❛t✐♦♥ ❛❜♦✉t

❆P❈ ♦r ✐❢ t❤❡ ❛♥t❡♥♥❛ ♠♦❞❡❧ ❞♦❡s ♥♦t ❡①✐st ✐♥ t❤❡ ■●❙ ♠♦❞❡❧✱ t❤❡r❡

✇✐❧❧ ❜❡ ✉♥❡①♣❡❝t❡❞ s♦❧✉t✐♦♥s ✐♥ t❤❡ ❤❡✐❣❤t ❝♦♠♣♦♥❡♥t ❬❈❙❘❙✲PPP

❣✉✐❞❡✱ ✷✵✵✹❪✳

5.4. Solutions of ionospheric delay

❚❤❡ ✭❈❙❘❙✲PPP✮ s❡r✈✐❝❡ ✉s❡s ✐♦♥♦s♣❤❡r✐❝ ♠❛♣s ♣r♦❞✉❝❡❞ ❛t ✷✲❤♦✉r

✐♥t❡r✈❛❧s ✐♥ ■❖◆❊❳ ❢♦r♠❛t ❜② ■●❙ ✐♥ ❝❛s❡ ♦❢ ▲✶ ♦❜s❡r✈❛t✐♦♥s✳ ❚❤❡

▲✶✫▲✷ ♣r♦❝❡ss✐♥❣ ✉s❡s t❤❡ ▲✶✫▲✷ ✐♦♥♦s♣❤❡r✐❝✲❢r❡❡ ❝♦♠❜✐♥❛t✐♦♥

♦❢ t❤❡ ❝♦❞❡ ❛♥❞ ♣❤❛s❡ ♦❜s❡r✈❛t✐♦♥s ❬●❙❘❙✲PPP ❣✉✐❞❡✱ ✷✵✵✹❪✳ ❋♦r

♠♦r❡ ❞❡t❛✐❧s ❛❜♦✉t ■❖◆❊❳ ❢♦r♠❛t✱ s❡❡ ❬❙❝❤❛❡r ❡t ❛❧✳✱ ✶✾✾✽❪✳

❏♦✉r♥❛❧ ♦❢ ●❡♦❞❡t✐❝ ❙❝✐❡♥❝❡ 237

5.5. Solutions of tropospheric delay

❈❙❘❙✲PPP t♦t❛❧ tr♦♣♦s♣❤❡r✐❝ ③❡♥✐t❤ ❞❡❧❛② ❡st✐♠❛t❡s ❛r❡ ♥♦✇ ❜❛s❡❞

♦♥ t❤❡●❧♦❜❛❧▼❛♣♣✐♥❣ ❋✉♥❝t✐♦♥ ✭●▼❋✮ ❞❡r✐✈❡❞ ❢r♦♠ t❤❡ ❊✉r♦♣❡❛♥

❈❡♥tr❡ ❢♦r ▼❡❞✐✉♠✲❘❛♥❣❡ ❲❡❛t❤❡r ❋♦r❡❝❛sts ♥✉♠❡r✐❝❛❧ ✇❡❛t❤❡r

♠♦❞❡❧ ❛❧♦♥❣ ✇✐t❤ ❞❡❢❛✉❧t s✉r❢❛❝❡ ♠❡t❡♦r♦❧♦❣✐❝❛❧ ❞❛t❛ ❛♥❞ ❛♥

❡❧❡✈❛t✐♦♥♠❛♣♣✐♥❣ ❢✉♥❝t✐♦♥✳ ❚❤❡s❡ s❡r✈❡ t♦ ❝♦rr❡❝t t❤❡ ❛❧♦♥❣✲♣❛t❤

tr♦♣♦s♣❤❡r✐❝ ❞❡❧❛② ❬❑♦✉❜❛ ❡t ❛❧✳✱ ✷✵✵✽❪✳

6. Results of the previous studies

■♥ ♦r❞❡r t♦ ♠❛❦❡ ❛ ❜❛❝❦❣r♦✉♥❞ r❡✈✐❡✇ ❛❜♦✉t ♦♥❧✐♥❡ PPP s❡r✈✐❝❡s

❛♥❞ t❤❡✐r s♦❧✉t✐♦♥s✱ r❡s✉❧ts ♦❢ ♣r❡✈✐♦✉s st✉❞✐❡s ❛r❡ ♠❡♥t✐♦♥❡❞ ❛♥❞

❝♦♠♣❛r❡❞ ❤❡r❡✳ ❬❉❛r❡✱ ✷✵✵✻❪ s✉❜♠✐tt❡❞ ❞✐❢❢❡r❡♥t ❞❛t❛ s❡ts ✈❛r②✐♥❣

✐♥ t✐♠❡ ❛♥❞ ❧♦❝❛t✐♦♥ t♦ ❞✐❢❢❡r❡♥t ♦♥❧✐♥❡ PPP s❡r✈✐❝❡s ❛♥❞ t❤❡♥

❝♦♠♣❛r❡❞ t❤❡✐r r❡s✉❧ts✳ ❚❤❡ ❢✐♥❞✐♥❣s r❡✈❡❛❧ ✶ ❝♠ ❞✐❢❢❡r❡♥❝❡s ✐♥

❤♦r✐③♦♥t❛❧ ❞✐r❡❝t✐♦♥ ❛♥❞ ❛ ❢❡✇ ❝♠✲❧❡✈❡❧ ✐♥ ❤❡✐❣❤t ❢♦r ✽✲✶✵ ❤r ❧❛st✐♥❣

❞❛t❛ s❡ts ♦❢ ❞✉❛❧ ❢r❡q✉❡♥❝② r❡❝❡✐✈❡rs✳ ■♥ ❛❞❞✐t✐♦♥✱ t❤❡ ❆❯❚❖ ●■P❙❨

❛♥❞ PPP s❡r✈✐❝❡s ❛r❡ ♥♦t ❜❛s❡❞ ♦♥ t❤❡ ❧♦❝❛t✐♦♥ ♦❢ t❤❡ s✐t❡✱ ✇❤✐❧❡

❙❈❖❯❚ ❛♥❞ ❆❯❙P❖❙ ✉s❡ t❤❡ ♥❡❛r❡st t❤r❡❡ ■●❙ st❛t✐♦♥s✳ ❍♦✇❡✈❡r

t❤❡s❡ st❛t✐♦♥s ❛r❡ ♥♦t ❞✐str✐❜✉t❡❞ ✉♥✐❢♦r♠❧② ❛r♦✉♥❞ t❤❡ ✇♦r❧❞✳ ❚❤❡

❆❯❚❖ ●■P❙❨ s❡r✈✐❝❡ ♣r♦✈✐❞❡❞ t❤❡ ❝♦♦r❞✐♥❛t❡s ❝❧♦s❡st t♦ t❤❡ tr✉t❤

✇❤✐❧❡ t❤❡ r❡s✉❧ts ♦❢ t❤❡ ♦t❤❡r s❡r✈✐❝❡s ✈❛r② ❛❜♦✉t ✹ ❝♠ ❛❢t❡r ✽ ❤r

t✐♠❡ s♣❛♥s✳

❬❉❛✇♦❞ ❡t ❛❧✳✱ ✷✵✵✼❪ ❤❛✈❡ ❝♦♠♣❛r❡❞ t❤❡ t✇♦ s❡r✈✐❝❡s ❆❯❙P❖❙ ❛♥❞

❈❙❘❙✲PPP ❜② ✉s✐♥❣ ❞✉❛❧ ❢r❡q✉❡♥❝② ●P❙ ❞❛t❛ ♦❢ ❛ ✸✳✽ ❤r ❛✈❡r❛❣❡

t✐♠❡ s♣❛♥ ✇❤✐❝❤ ❤❛s ❜❡❡♥ ❝♦❧❧❡❝t❡❞ ♦♥ ✶✵ ♥❛t✐♦♥❛❧ ●P❙ st❛t✐♦♥s

❡st❛❜❧✐s❤❡❞ ❜② t❤❡ ❊❣②♣t✐❛♥ ❙✉r✈❡② ❆✉t❤♦r✐t② ✭❊❙❆✮✳ ❚❤❡ ❛❝❝✉r❛❝②

♦❢ t❤❡ ❛tt❛✐♥❡❞ PPP r❡s✉❧ts s❤♦✇ ❛♥ ❛✈❡r❛❣❡ ♦❢ ✵✳✶✾ ♠ ✐♥ t❤❡

✷❉ ❞✐r❡❝t✐♦♥ ❛♥❞ ❛♥ ❛✈❡r❛❣❡ ♦❢ ✵✳✷✶ ♠ ✐♥ t❤❡ ✸❉ ❞✐r❡❝t✐♦♥ ✇❤❡♥

❝♦♠♣❛r❡❞ ✇✐t❤ t❤❡ ❊❙❆ ❦♥♦✇♥ ❝♦♦r❞✐♥❛t❡s✳ ❖♥ t❤❡ ♦t❤❡r s✐❞❡✱

t❤❡ ❛❝❝✉r❛❝② ♦❢ t❤❡ ❛❝❤✐❡✈❡❞ ❆❯❙P❖❙ r❡s✉❧ts s❤♦✇ ❛♥ ❛✈❡r❛❣❡ ♦❢

✵✳✷✸ ♠ ✐♥ t❤❡ ✷❉ ❞✐r❡❝t✐♦♥ ❛♥❞ ❛♥ ❛✈❡r❛❣❡ ♦❢ ✵✳✷✹ ♠ ✐♥ t❤❡ ✸❉

❞✐r❡❝t✐♦♥ ✇❤❡♥ ❝♦♠♣❛r❡❞ ✇✐t❤ t❤❡ ❊❙❆ ♣✉❜❧✐s❤❡❞ ❝♦♦r❞✐♥❛t❡s✳

❬❋❡❛t❤❡rst♦♥❡ ❡t ❛❧✳✱ ✷✵✵✽❪ tr❛♥s♠✐tt❡❞ ●P❙ ♦❜s❡r✈❛t✐♦♥s ♦❢

✹✻ ♣♦✐♥ts ♦❢ ❛ ❣❡♦❞❡t✐❝ ♥❡t✇♦r❦ t♦ t❤❡ ❈❙❘❙✲PPP s❡r✈✐❝❡ ❛♥❞

❝♦♠♣❛r❡❞ t❤❡ r❡s✉❧ts ✇✐t❤ ❝♦♦r❞✐♥❛t❡s ♣r♦❝❡ss❡❞ ❜② ♠❡❛♥s ♦❢ t❤❡

❇❡r♥❡s❡ s❝✐❡♥t✐❢✐❝ s♦❢t✇❛r❡ ❱✺✳ ❚❤❡ ❈❙❘❙✲PPP ❡st✐♠❛t❡s ❛❣r❡❡❞

✇✐t❤ t❤❡ ❇❡r♥❡s❡ s♦❧✉t✐♦♥s t♦ ✸✳✸ ♠♠ ✐♥ ❡❛st ❞✐r❡❝t✐♦♥✱ ✹✳✽ ♠♠ ✐♥

♥♦rt❤ ❞✐r❡❝t✐♦♥ ❛♥❞ ✶✶✳✽ ♠♠ ✐♥ ❤❡✐❣❤t ❞✐r❡❝t✐♦♥✳

7. Experimental work

■♥ ♦r❞❡r t♦ ❛ss❡ss t❤❡ ❛❝❝✉r❛❝② ♦❢ t❤❡ ❈❙❘❙✲PPP s❡r✈✐❝❡✱ s✐♥❣❧❡✲

❢r❡q✉❡♥❝② st❛t✐❝ ●P❙ ♦❜s❡r✈❛t✐♦♥s ❤❛✈❡ ❜❡❡♥ ❝♦❧❧❡❝t❡❞ ❛t t❤r❡❡

♣♦✐♥ts ❝♦✈❡r✐♥❣ ✈❛r✐♦✉s t✐♠❡ s♣❛♥s ♦❢ ✻✵✱ ✾✵ ❛♥❞ ✶✷✵ ♠✐♥✉t❡s✳

❚❤❡s❡ t❤r❡❡ ♦❜s❡r✈❡❞ s✐t❡s ❢♦r♠ ❜❛s❡❧✐♥❡s ♦❢ ✶✳✻✱ ✼ ❛♥❞ ✶✵ ❦♠✱

✇❤❡r❡ t❤❡ ❜❛s❡ ♣♦✐♥t ✐s t❤❡ s❛♠❡ ❢♦r ❛❧❧ t❤❡s❡ ❜❛s❡❧✐♥❡s ✭❋✐❣✉r❡ ✶✮✳

❚❤❡ ♣r♦❝❡ss✐♥❣ ♦❢ t❤✐s ❞❛t❛ ✇❛s ❛❝❤✐❡✈❡❞ ❜② ✉s✐♥❣ t✇♦ ♠❡t❤♦❞s✿

✶✮ ✉s❡ ♦❢ ❛ ❞✐❢❢❡r❡♥t✐❛❧ ●P❙ s♦❧✉t✐♦♥ t♦ ❞❡t❡r♠✐♥❡ t❤❡ ♣♦s✐t✐♦♥s ♦❢

❡❛❝❤ ✉♥❦♥♦✇♥ ♣♦✐♥t✱ ❛♥❞ ✷✮ ✉s❡ ♦❢ t❤❡ ❈❙❘❙✲PPP s❡r✈✐❝❡✳

Figure 1. Occupied points.

❚✇♦ s✐♥❣❧❡✲❢r❡q✉❡♥❝②●P❙ r❡❝❡✐✈❡rs ✭Pr♦♠❛r❦✲✸ ✉♥✐ts✮✇❡r❡ ✉s❡❞ t♦

s✉r✈❡② t❤❡ t❤r❡❡ ❜❛s❡❧✐♥❡s✳ ❆ ✶✵ ❞❡❣r❡❡ ❡❧❡✈❛t✐♦♥ ❛♥❣❧❡✱ ✶✵ s❡❝♦♥❞

s❛♠♣❧❡ r❛t❡✱ ❛♥❞ ●◆❙❙ ❙♦❧✉t✐♦♥ s♦❢t✇❛r❡ ✇❛s ✉s❡❞ t♦ ♣r♦❝❡ss t❤❡

✈❡❝t♦rs ✐♥ t❤❡ ❞✐❢❢❡r❡♥t✐❛❧ s♦❧✉t✐♦♥✳ ❚❤❡ ♣r♦❝❡ss❡❞ ❝♦♦r❞✐♥❛t❡s ♦❢

❡❛❝❤ ❜❛s❡❧✐♥❡ ❛♥❞ ✐ts ❝♦rr❡s♣♦♥❞✐♥❣ PPP s♦❧✉t✐♦♥ ✇❡r❡ ❝♦♠♣❛r❡❞✱

❛❧❧♦✇✐♥❣ ❥✉❞❣♠❡♥t ♦❢ t❤❡ q✉❛❧✐t② ♦❢ t❤❡ r❡s✉❧ts ♦❢ t❤❡ PPP s❡r✈✐❝❡✳

8. Results and discussions

❋♦r ❞✐❢❢❡r❡♥t✐❛❧ ●P❙ s♦❧✉t✐♦♥✱ ●◆❙❙ ❙♦❧✉t✐♦♥ s♦❢t✇❛r❡ ✇❛s ✉s❡❞ t♦

❡st✐♠❛t❡ t❤❡ ♣♦s✐t✐♦♥s ♦❢ t❤❡ ✉♥❦♥♦✇♥ ♣♦✐♥ts ❜② ✉s✐♥❣ ♣r❡❝✐s❡

❡♣❤❡♠❡r✐s ❛✈❛✐❧❛❜❧❡ ❢r♦♠ ■●❙ ❛❢t❡r ✶✸ ❞❛②s ❧❛t❡♥❝②✳ ❯❚▼✲✸✻ ◆

♠❛♣ ♣r♦❥❡❝t✐♦♥ s②st❡♠ ✇❛s ✉s❡❞ t♦ ❝♦♠♣✉t❡ t❤❡ ❝♦♦r❞✐♥❛t❡s ♦❢

s✉r✈❡②❡❞ ♣♦✐♥ts ♦♥ ♠❡tr✐❝ ✉♥✐ts✳ ❚❤❡ ❝♦♦r❞✐♥❛t❡s ♦❢ t❤❡ ♣♦✐♥ts ❛r❡

❣✐✈❡♥ ✐♥ ❚❛❜❧❡ ✸✳

❋♦r t❤❡ ❈❙❘❙✲PPP s♦❧✉t✐♦♥✱ t❤❡ ❢✐rst st❛❣❡ ✇❛s t♦ ❝♦♥✈❡rt ●P❙

♦❜s❡r✈❛t✐♦♥s ❢✐❧❡s ❢r♦♠ ❆s❤t❡❝❤ ❢♦r♠❛t t♦ ❘■◆❊❳ ❢♦r♠❛t ❜② ✉s✐♥❣

❘■◆❊❳❝♦♥✈❡rt❡r✉t✐❧✐t② ✐♥●◆❙❙❙♦❧✉t✐♦♥s♦❢t✇❛r❡✳ ❍❡♥❝❡✱ t❤♦s❡ ❢✐❧❡s

✇❡r❡ ✉♣❧♦❛❞❡❞ t♦ t❤❡ ❈❙❘❙✲PPP ✇❡❜s✐t❡✳ ❚❤❡ ❢✐❧❡s ✇❡r❡ s❡♥t t♦ t❤❡

❈❙❘❙✲PPP s❡r✈✐❝❡ ✶✸ ❞❛②s ❛❢t❡r ❝♦❧❧❡❝t✐♥❣ t❤❡ ♦❜s❡r✈❛t✐♦♥s✱ ✇❤❡♥

t❤❡ ■●❙✲❢✐♥❛❧ ❡♣❤❡♠❡r✐s ❛♥❞ ❝❧♦❝❦♣r♦❞✉❝ts ❜❡❝❛♠❡❛❝❝❡ss✐❜❧❡✳ ❚❤❡

♦❜t❛✐♥❡❞ r❡s✉❧ts ❛r❡ s❤♦✇♥ ✐♥ ❚❛❜❧❡ ✹✳

■♥ ♦r❞❡r t♦ ✐♥✈❡st✐❣❛t❡ t❤❡ ❛❝❝✉r❛❝② ♦❢ ❈❙❘❙✲PPP s♦❧✉t✐♦♥s✱ t❤❡

❛tt❛✐♥❡❞ ❝♦♦r❞✐♥❛t❡s ♦❢ ❡❛❝❤ st❛t✐♦♥ ❤❛✈❡ ❜❡❡♥ ❝♦♠♣❛r❡❞✇✐t❤ t❤❡

❡st✐♠❛t❡s ♦❢ ❞✐❢❢❡r❡♥t✐❛❧ ●P❙ s♦❧✉t✐♦♥ ❜② ❝❛❧❝✉❧❛t✐♥❣ t❤❡ ❞✐❢❢❡r❡♥❝❡

✭❊q✉❛t✐♦♥ ✸✮✳ ❆s ❛♠❡❛s✉r❡ ♦❢ ❛❝❝✉r❛❝②✱ t❤❡ ♣❧❛♥❡ ❞✐❢❢❡r❡♥❝❡ ✈❡❝t♦r

✭✷❉✮ ✐s ❝♦♠♣✉t❡❞ ✉s✐♥❣ ❊q✉❛t✐♦♥ ✹✳ ❚❤❡ r❡s✉❧ts ❛r❡ ❧✐st❡❞ ❛❝❝♦r❞✐♥❣

❏♦✉r♥❛❧ ♦❢ ●❡♦❞❡t✐❝ ❙❝✐❡♥❝❡238

Table 3. Processing data for static differential solution.

UTM coordinates

Base line Time span Easting (m) Northing (m) PDOP

60 min 489110.031 2669890.564 1.5

1.6 km 90 min 489110.031 2669890.565 1.5

120 min 489110.031 2669890.565 1.4

60 min 487125.296 2674847.438 1.5

7.0 km 90 min 487125.295 2674847.441 1.5

120 min 487125.295 2674847.443 1.5

60 min 492712.978 2659341.036 1.9

10 km 90 min 492712.978 2659341.037 1.8

120 min 492712.980 2659341.037 1.5

Table 4. Processing data for static CSRS-PPP solution.

UTM coordinates

Base line Time span Easting (m) Northing (m)

60 min 489110.074 2669890.843

1.6 km 90 min 489109.885 2669890.348

120 min 489109.885 2669890.348

60 min 487125.427 2674847.125

7.0 km 90 min 487125.385 2674847.152

120 min 487125.394 2674847.205

60 min 492712.879 2659340.681

10 km 90 min 492713.012 2659340.737

120 min 492713.040 2659340.801

t♦ ❞✐❢❢❡r❡♥t ❜❛s❡ ❧✐♥❡ ❧❡♥❣t❤ ❛♥❞ ✈❛r✐♦✉s t✐♠❡ ✇✐♥❞♦✇s ✐♥ ❚❛❜❧❡ ✺✳

❋✐❣✉r❡ ✷ ✐❧❧✉str❛t❡s t❤❡ ❞✐❢❢❡r❡♥❝❡s ❜❡t✇❡❡♥ PPP ❛♥❞ ❞✐❢❢❡r❡♥t✐❛❧

s♦❧✉t✐♦♥s ❛t ❞✐❢❢❡r❡♥t t✐♠❡ s♣❛♥s✳

Difference (δ) = Differentialsolution−PPP solution

(3)

Horizontal error (2D) =√

δ2E + δ2

N (4)

❚❤❡ ♣r❡✈✐♦✉s r❡s✉❧ts ❞❡♠♦♥str❛t❡ t❤❡ ❢♦❧❧♦✇✐♥❣✿

• ❋♦r ✻✵ ♠✐♥✉t❡s t✐♠❡ s♣❛♥✱ t❤❡ ❤♦r✐③♦♥t❛❧ ❡rr♦r ✭✷❉✮ r❛♥❣❡s

❢r♦♠ ✷✽ ❝♠ t♦ ✸✼ ❝♠✳

Table 5. Differences between CSRS-PPP and differential solutions.

Differences in coordinates (m) Plane error

Base line Time span δE δN (m)

60 min -0.044 -0.279 0.282

1.6 km 90 min 0.146 0.217 0.261

120 min 0.146 0.217 0.261

60 min -0.131 0.313 0.339

7.0 km 90 min -0.090 0.289 0.303

120 min -0.099 0.238 0.258

60 min 0.099 0.355 0.3699

10 km 90 min -0.034 0.300 0.302

120 min -0.060 0.236 0.244

Figure 2. The plane difference between CSRS-PPP solution and dif-ferential solution.

• ❋♦r ✾✵ ♠✐♥✉t❡s t✐♠❡ s♣❛♥✱ t❤❡ ✷❉ ❡rr♦r ✈❡❝t♦rs r❛♥❣❡ ❢r♦♠

✷✻ ❝♠ t♦ ✸✵ ❝♠✳

• ❋♦r ✶✷✵ ♠✐♥✉t❡s t✐♠❡ ✇✐♥❞♦✇✱ t❤❡ ❤♦r✐③♦♥t❛❧ ❞✐❢❢❡r❡♥❝❡

r❛♥❣❡s ❢r♦♠ ✷✹ ❝♠ t♦ ✷✻ ❝♠✳

• ❆s t❤❡ ♦❜s❡r✈❛t✐♦♥ ♣❡r✐♦❞ ✐♥❝r❡❛s❡s✱ t❤❡ ♣❧❛♥❡ ❡rr♦r ❞❡✲

❝r❡❛s❡s✳

• ❚❤❡ ♦✈❡r❛❧❧ ♣❧❛♥❡ ❞✐❢❢❡r❡♥❝❡ ❜❡t✇❡❡♥ PPP s♦❧✉t✐♦♥ ❛♥❞

❞✐❢❢❡r❡♥t✐❛❧ s♦❧✉t✐♦♥ ✐s ❛t t❤❡ s❝❛❧❡ ♦❢ ❛ ❢❡✇ ❞❡❝✐♠❡t❡rs✳

• ❚❤✐s ❧❡✈❡❧ ♦❢ ❛❝❝✉r❛❝② ✐s ❜❛s❡❞ ♦♥ t❤❡ ♦❜s❡r✈❛t✐♦♥ t✐♠❡

s♣❛♥✱ ♠✉❧t✐♣❛t❤✱ q✉❛❧✐t② ♦❢ ✐♥tr♦❞✉❝❡❞ ♦r❜✐ts ❛♥❞ ❝❧♦❝❦s

♣r♦❞✉❝ts✱ ✐♦♥♦s♣❤❡r✐❝✲♠♦❞❡❧✱ tr♦♣♦s♣❤❡r✐❝♠♦❞❡❧❛♥❞t②♣❡

♦❢ ♦❜s❡r✈❛t✐♦♥s✬ ✭s✐♥❣❧❡ ♦r ❞♦✉❜❧❡ ❢r❡q✉❡♥❝②✮ ❝❛rr✐❡r ♣❤❛s❡

♦r ❝♦❞❡ r❛♥❣❡✳

• ❚❤❡ r❡s✉❧ts ❛❝q✉✐r❡❞ ❢r♦♠ ❈❙❘❙✲PPP s❡r✈✐❝❡ ❝❛♥ ❜❡ ✉s❡❞ ✐♥

♣r♦❞✉❝✐♥❣ ❛ ❝❛❞❛str❛❧ ♠❛♣ ❛t ✶✿✶✵✵✵ s❝❛❧❡✳

• ❚❤❡ ♦❜t❛✐♥❡❞ ❛❝❝✉r❛❝② ♦❢ t❤❡ ❝♦♦r❞✐♥❛t❡s ♣r♦✈✐❞❡❞ ❜②

❈❙❘❙✲ PPP s❡r✈✐❝❡ ❝❛♥ ❜❡ ✉s❡❞ ✐♥ s♦♠❡ ❡♥❣✐♥❡❡r✐♥❣ ❛♣♣❧✐✲

❝❛t✐♦♥s s✉❝❤ ❛s ♣r❡❧✐♠✐♥❛r② ❝✐t② ♣❧❛♥♥✐♥❣✱ ❢♦r ❛ ❝❛❞❛str❛❧

♠❛♣ ✇✐t❤ s❝❛❧❡ ✶✿✶✵✵✵✳

9. Conclusions

■♥ r❡❝❡♥t ②❡❛rs✱ ❛ ♥✉♠❜❡r ♦❢ ❢r❡❡ ♦♥❧✐♥❡ ❣❧♦❜❛❧ ♣♦s✐t✐♦♥✐♥❣ ✭●P❙✮

♣r♦❝❡ss✐♥❣ s❡r✈✐❝❡s ❤❛✈❡ ❜❡❝♦♠❡ ❛✈❛✐❧❛❜❧❡ t❤❛t ♣r♦✈✐❞❡ t❤❡ ✉s❡r

✇✐t❤ ●P❙ ♣r♦❝❡ss✐♥❣ r❡s✉❧ts✳ ❚❤❡s❡ s❡r✈✐❝❡s ❛r❡ ❛❝❝❡ss✐❜❧❡ ✈✐❛ t❤❡

✐♥t❡r♥❡t ✇✐t❤♦✉t r❡q✉✐r✐♥❣ ❞❡t❛✐❧❡❞ ❦♥♦✇❧❡❞❣❡ ♦❢ t❤❡ ❡♠♣❧♦②❡❞

♣r♦❝❡ss✐♥❣ s♦❢t✇❛r❡✳

■♥ ♦r❞❡r t♦ ❛ss❡ss ♦♥❡ ♦❢ t❤❡s❡ s❡r✈✐❝❡s ✭♥❛♠❡❧② t❤❡ ❈❙❘❙✲PPP s❡r✲

✈✐❝❡✮✱ s✐♥❣❧❡✲❢r❡q✉❡♥❝② st❛t✐❝●P❙♦❜s❡r✈❛t✐♦♥s❤❛✈❡❜❡❡♥❝♦❧❧❡❝t❡❞

❛t t❤r❡❡ ♣♦✐♥ts ❜✉✐❧❞✐♥❣ ❜❛s❡ ❧✐♥❡s ✇✐t❤ ❞✐❢❢❡r❡♥t ❧❡♥❣t❤s ♦❢ ✶✳✻✱ ✼

❛♥❞ ✶✵ ❦♠ ✇✐t❤✐♥ t✐♠❡ ❢r❛♠❡s ♦❢ ✻✵✱ ✾✵ ❛♥❞ ✶✷✵ ♠✐♥✉t❡s✳ ❚❤❡s❡

❏♦✉r♥❛❧ ♦❢ ●❡♦❞❡t✐❝ ❙❝✐❡♥❝❡

♦❜s❡r✈❛t✐♦♥s ✇❡r❡ ♣r♦❝❡ss❡❞ ❜② ✉s✐♥❣ t✇♦ ❞✐❢❢❡r❡♥t ♣r♦❝❡ss✐♥❣

♠❡t❤♦❞s✿ ❛ ❞✐❢❢❡r❡♥t✐❛❧ t❡❝❤♥✐q✉❡✱ ❛♥❞ t❤❡ ❈❙❘❙✲PPP s❡r✈✐❝❡✳ ❚❤❡

❢✐♥❛❧ r❡s✉❧ts ♦❢ ❜♦t❤ ♣r♦❝❡ss✐♥❣ ❧✐♥❡s ✇❡r❡ ❝♦♠♣❛r❡❞✳ ❚❤❡ ❛tt❛✐♥❡❞

r❡s✉❧ts s❤♦✇ t❤❛t t❤❡ PPP ♣r♦❞✉❝❡s ❛ ❤♦r✐③♦♥t❛❧ ❡rr♦r ❛t t❤❡ s❝❛❧❡

♦❢ ❛ ❢❡✇ ❞❡❝✐♠❡t❡rs✳ ❚❤❡ q✉❛❧✐t② ♦❢ ❈❙❘❙✲PPP s❡r✈✐❝❡ ❞❡♣❡♥❞s ♦♥

t❤❡ ♦❜s❡r✈❛t✐♦♥ t✐♠❡ s♣❛♥✱ t❤❡ q✉❛❧✐t② ♦❢ ✐♥tr♦❞✉❝❡❞ ♦r❜✐ts ❛♥❞

❝❧♦❝❦s ♣r♦❞✉❝ts✱ t❤❡ ✐♦♥♦s♣❤❡r✐❝ ♠♦❞❡❧✱ t❤❡ tr♦♣♦s♣❤❡r✐❝ ♠♦❞❡❧✱

❛♥❞ t❤❡ t②♣❡ ♦❢ ♦❜s❡r✈❛t✐♦♥s✬ ✭s✐♥❣❧❡ ♦r ❞♦✉❜❧❡ ❢r❡q✉❡♥❝②✮ ❝❛rr✐❡r

♣❤❛s❡ ♦r ❝♦❞❡ r❛♥❣❡✳

❚❤❡ ♦❜t❛✐♥❡❞ ❛❝❝✉r❛❝② ♣r♦✈✐❞❡❞ ❜② ❈❙❘❙✲PPP s❡r✈✐❝❡ ✐s s✉❢❢✐❝✐❡♥t

❢♦r s♦♠❡ ♠❛♣♣✐♥❣ ❛♣♣❧✐❝❛t✐♦♥s ❢♦r ❛ ❝❛❞❛str❛❧ ♠❛♣ ✇✐t❤ s❝❛❧❡

✶✿✶✵✵✵✳ ■♥ ❛❞❞✐t✐♦♥✱ t❤✐s s❡r✈✐❝❡ ❛❧❧♦✇s ❢♦r ❛ tr❡♠❡♥❞♦✉s s❛✈✐♥❣s ✐♥

❝♦st ❛♥❞ ❡①♣❡r✐❡♥❝❡❞ ❧❛❜♦r✳

References

❆✉t♦✲●■P❙❨ ✭✷✵✶✶✮✿ ✭❢r❡q✉❡♥t❧② ✉♣❞❛t✐♥❣ ✇❡❜ ♣❛❣❡✮✿

http://milhouse.jpl.nasa.gov/ag/✳

❉❛r❡✱ P✳ ✭✷✵✵✻✮✿ ❵❵❖♥❧✐♥❡ ●P❙ Pr♦❝❡ss✐♥❣ ❙❡r✈✐❝❡s✿ ❛♥ ■♥✐t✐❛❧

❙t✉❞②✬✬✳ ●P❙ s♦❧✉t✐♦♥s✱ ◆♦✳✶✵✱ P✳ ✶✷✲✷✵✳

❉❛✇♦❞✱ ●✳✱ ■s♠❛✐❧✱ ❙✳ ❛♥❞ ▼♦❤❛♠❡❞✱ ❍✳ ✭✷✵✵✼✮✿ ❵❵❆ss❡ss✲

♠❡♥t ♦❢ ❆ ❈♦st✲❊❢❢❡❝t✐✈❡ ●P❙ ❉❛t❛ Pr♦❝❡ss✐♥❣ ❆❧t❡r♥❛t✐✈❡ ■♥

❊❣②♣t ❯t✐❧✐③✐♥❣ ■♥t❡r♥❛t✐♦♥❛❧ ❖♥✲❧✐♥❡ Pr♦❝❡ss✐♥❣ ❙❡r✈✐❝❡s✬✬✳ ❈✐✈✐❧

❊♥❣✐♥❡❡r✐♥❣ ❘❡s❡❛r❝❤ ▼❛❣❛③✐♥❡ ✭❈❘❊▼✮✱ ❆❧✲❆③❤❛r ❈♦❧❧❡❣❡ ♦❢

❊♥❣✐♥❡❡r✐♥❣ ❱✳✷✾✱ ◆♦✳ ✭✷✮✱ ❆♣r✐❧ ✷✵✵✼✳

❊❜♥❡r✱ ❘✳ ❛♥❞ ❋❡❛t❤❡rst♦♥❡✱ ❲✳ ✭✷✵✵✽✮✿ ❵❵❍♦✇ ❲❡❧❧ ❈❛♥ ❖♥✲

❧✐♥❡ ●P❙ PPP P♦st✲♣r♦❝❡ss✐♥❣ ❙❡r✈✐❝❡s ❇❡ ❯s❡❞ ❚♦ ❊st❛❜❧✐s❤

●❡♦❞❡t✐❝ ❙✉r✈❡② ❈♦♥tr♦❧ ◆❡t✇♦r❦s❄✬✬✳ ❏♦✉r♥❛❧ ♦❢ ❆♣♣❧✐❡❞ ●❡♦❞❡s②✱

◆♦✳ ✭✷✮✱ P✳ ✶✹✾✲✶✺✼✳

❋❛r❛❤ ❆✳ ✭✷✵✵✹✮✿ ❵❵●P❙✴●❆▲▲■▲■❖ ❙✐♠✉❧❛t✐♦♥ ❢♦r ❘❡❞✉❝✐♥❣

❉②♥❛♠✐❝ ▲❡♦ ❙❛t❡❧❧✐t❡ ❖r❜✐t ❉❡t❡r♠✐♥❛t✐♦♥✬✬✱ P❍❉✱ ■❊❙❙● ❯♥✐✈❡rs✐t②

♦❢ ◆♦tt✐♥❣❤❛♠✱ ❯♥✐t❡❞ ❑✐♥❣❞♦♠✳

▼✐r❡❛✉❧t✱ ❨✳✱ ❚étr❡❛✉❧t✱ P✳✱ ▲❛❤❛②❡✱ ❋✳✱ ❍ér♦✉①✱ P✳ ❛♥❞ ❑♦✉❜❛✱

❏✳ ✭✷✵✵✽✮✿ ❵❵❖♥❧✐♥❡ Pr❡❝✐s❡ P♦✐♥t P♦s✐t✐♦♥✐♥❣✿ ❆ ◆❡✇✱ ❚✐♠❡❧② ❙❡r✈✐❝❡

❢r♦♠ ◆❛t✉r❛❧ ❘❡s♦✉r❝❡s ❈❛♥❛❞❛✬✬✳ ●P❙ ❲♦r❧❞✱ ❙❡♣t❡♠❜❡r ✷✵✵✽✱

P✳ ✺✾✲✻✹✳

◆❛t✉r❛❧ ❘❡s♦✉r❝❡s ❈❛♥❛❞❛ ●❡♦❞❡t✐❝ ❙✉r✈❡② ❉✐✈✐s✐♦♥ ✭✷✵✵✹✮✿

❵❵❖♥✲▲✐♥❡ Pr❡❝✐s❡ P♦✐♥t P♦s✐t✐♦♥✐♥❣ Pr♦❥❡❝t✲❍♦✇ ❚♦ ❯s❡ ❉♦❝✉✲

♠❡♥t✬✬✳ ❱✳ ✶✳✶✱ ✷✵✵✹✳

❙❝❤❛❡r✱ ❙✳✱ ●✉r♥t❡r✱ ❲✳ ❛♥❞ ❋❡❧t❡♥s✱ ❏✳ ✭✶✾✾✽✮✿ ❵❵■❖◆❊❳✿ ❚❤❡

■❖◆♦s♣❤❡r❡ ▼❛♣ ❊①❝❤❛♥❣❡ ❋♦r♠❛t ❱❡rs✐♦♥ ✶✬✬✳ Pr♦❝❡❡❞✐♥❣ ♦❢ t❤❡

■●❙ ❆❈ ✇♦r❦s❤♦♣✱ ❉❛r♠st❛❞t✱ ●❡r♠❛♥②✳

❲❡❧❧s✱ ❉✳✱ ❇❡❝❦✱ ◆✳✱ ❉❡❧✐❦❛r❛♦❣❧♦✉✱ ❉✳✱ ❑❧❡✉s❜❡r❣✱ ❆✳✱ ❑r❛❦✐✲

✇s❦②✱ ❊✳✱ ▲❛❝❤❛♣❡❧❧❡✱ ●✳✱ ▲❛♥❣❧❡②✱ ❘✳✱ ◆❛❦✐❜♦❣❧✉✱ ▼✳✱ ❙❝❤✇❛r③✱ ❑✳✱

❚r❛♥q✉✐❧❧❛✱ ❏✳ ❛♥❞ ❱❛♥✐❝❡❦✱ P✳ ✭✶✾✾✾✮✿ ❵❵●✉✐❞❡ ❚♦ ●P❙ P♦s✐t✐♦♥✐♥❣✬✬✳

▲❡❝t✉r❡ ♥♦t❡ ◆♦✳✺✽✱ ❉❡♣❛rt♠❡♥t ♦❢ ●❡♦❞❡s② ❛♥❞ ●❡♦♠❛t✐❝s

❊♥❣✐♥❡❡r✐♥❣✱ ❯♥✐✈❡rs✐t② ♦❢ ◆❡✇ ❇r✉♥s✇✐❝❦✱ ❈❛♥❛❞❛✳