Satellite navigation method
First Claim
1. Satellite navigation system having a mobile user receiver and a reference station, whose position is known, wherein the signals emitted by a plurality of satellites are received and evaluated in the user receiver and the reference station, and the position of the user receiver is thereby determined, whereinthe signals received from a plurality of satellites (Si, Sj) and/or pseudo-satellites are evaluated in the user receiver and reference station (Ref) by means of a carrier-phase measurement according to the formula
whereφ
)·
(R.sub.E.sup.S +Δ
R.sup.S +Δ
R.sub.E +ε
.sub.E.sup.S)+N.sub.E.sub.S
ES is the measured carrier phase;
λ
is the wavelength of the emitted GNSS carrier signal;
RES is the geometric distance from the satellite to the receiver;
Δ
RS are errors correlated between satellites;
Δ
RE are errors correlated between receivers;
ε
ES are errors such as multiple-path propagation and dynamic influences;
NES is the phase ambiguity at an initial time t0 andtriple difference is formed from the carrier phases determined at the initial time (t0) and a current time (t where t>
t0) according to the formula
space="preserve" listing-type="equation">ovΔ
.o slashed.={ ¥
.sub.F (t)-.o slashed..sub.R (t)!- .o slashed..sub.F.sup.j (t)-.o slashed..sub.R.sup.j (t)!}-{ .o slashed..sub.F (t.sub.0)-.o slashed..sub.R (t.sub.0)!- .o slashed..sub.F.sup.i (t.sub.0)-.o slashed..sub.R.sup.j (t.sub.0)!}where.o slashed. is the carrier phase,Δ
is the difference shown in square brackets,∇
is the difference shown in wavy brackets,δ
is the difference between the sets of wavy brackets,t is the current time,t0 is the initial time,φ
Ri (t) is the carrier phase of the satellite Si measured at the reference station Ref at time t,φ
Fi (t) is the carrier phase of the satellite Si measured at the user receiver F at time t,φ
Rj (t) is the carrier phase of the satellite Sj measured at the reference station Ref at time t,φ
Fj (t) is the carrier phase of the satellite Sj measured at the user receiver F at time t,φ
Ri (t) is the carrier phase of the satellite Si measured at the reference station Ref at initial time t0,φ
Fi (t0) is the carrier phase of the satellite Si measured at the user receiver F at initial time t0,φ
Rj (t0) is the carrier phase of the satellite Sj measured at the reference station Ref at initial time t0,φ
Fj (t0) is the carrier phase of the satellite Sj measured at the user receiver F at initial time t0,characterized in thatthe positions of the user receiver at times t and t0 are determined from the triple difference using an analytical method with at least six triple-difference equations that have been linearized around an estimation point, whereinthe position of the user receiver at an initial time (t0) is evaluated statistically based on its temporally-unchanged characteristic, that the values of the position at the initial time (t0), which have been determined with the use of the position solution with six unknowns, are smoothed by low-pass filtering,the statistically-evaluated position of the user receiver at the initial time (t0) is inserted as a known position into the observation equations, and only the current position of the user receiver is subsequently determined at a predefinable, current time (t).
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Accused Products
Abstract
A satellite navigation process, in particular for an automatic landing process for aircraft, according to the ICAO requirements under the CAT-II or CAT-III terms. The necessary degrees of accuracy are achieved by analytical phase evaluation of the carrier signals of at least seven satellites (GPS and/or GLONASS and/or reference stations).
18 Citations
6 Claims
- 1. Satellite navigation system having a mobile user receiver and a reference station, whose position is known, wherein the signals emitted by a plurality of satellites are received and evaluated in the user receiver and the reference station, and the position of the user receiver is thereby determined, wherein
the signals received from a plurality of satellites (Si, Sj) and/or pseudo-satellites are evaluated in the user receiver and reference station (Ref) by means of a carrier-phase measurement according to the formula - space="preserve" listing-type="equation">.o slashed..sub.E.sup.S=( 1/λ
)·
(R.sub.E.sup.S +Δ
R.sup.S +Δ
R.sub.E +ε
.sub.E.sup.S)+N.sub.E.sub.S
where φ
ES is the measured carrier phase;λ
is the wavelength of the emitted GNSS carrier signal;RES is the geometric distance from the satellite to the receiver; Δ
RS are errors correlated between satellites;Δ
RE are errors correlated between receivers;ε
ES are errors such as multiple-path propagation and dynamic influences;NES is the phase ambiguity at an initial time t0 and triple difference is formed from the carrier phases determined at the initial time (t0) and a current time (t where t>
t0) according to the formula
space="preserve" listing-type="equation">ovΔ
.o slashed.={ ¥
.sub.F (t)-.o slashed..sub.R (t)!- .o slashed..sub.F.sup.j (t)-.o slashed..sub.R.sup.j (t)!}-{ .o slashed..sub.F (t.sub.0)-.o slashed..sub.R (t.sub.0)!- .o slashed..sub.F.sup.i (t.sub.0)-.o slashed..sub.R.sup.j (t.sub.0)!}where .o slashed. is the carrier phase, Δ
is the difference shown in square brackets,∇
is the difference shown in wavy brackets,δ
is the difference between the sets of wavy brackets,t is the current time, t0 is the initial time, φ
Ri (t) is the carrier phase of the satellite Si measured at the reference station Ref at time t,φ
Fi (t) is the carrier phase of the satellite Si measured at the user receiver F at time t,φ
Rj (t) is the carrier phase of the satellite Sj measured at the reference station Ref at time t,φ
Fj (t) is the carrier phase of the satellite Sj measured at the user receiver F at time t,φ
Ri (t) is the carrier phase of the satellite Si measured at the reference station Ref at initial time t0,φ
Fi (t0) is the carrier phase of the satellite Si measured at the user receiver F at initial time t0,φ
Rj (t0) is the carrier phase of the satellite Sj measured at the reference station Ref at initial time t0,φ
Fj (t0) is the carrier phase of the satellite Sj measured at the user receiver F at initial time t0,characterized in that the positions of the user receiver at times t and t0 are determined from the triple difference using an analytical method with at least six triple-difference equations that have been linearized around an estimation point, wherein the position of the user receiver at an initial time (t0) is evaluated statistically based on its temporally-unchanged characteristic, that the values of the position at the initial time (t0), which have been determined with the use of the position solution with six unknowns, are smoothed by low-pass filtering, the statistically-evaluated position of the user receiver at the initial time (t0) is inserted as a known position into the observation equations, and only the current position of the user receiver is subsequently determined at a predefinable, current time (t). - View Dependent Claims (2, 3, 4, 5, 6)
- 3. Satellite navigation method according to claim 1, characterized in that an estimation value is used for determining the initial position of the user receiver.
- 4. Satellite navigation method according to claim 1, characterized in that the user receiver is attached to an aircraft.
- 5. Satellite navigation method according to claim 1, characterized in that at least one stationary reference station (Ref) having a known position is set up in the vicinity of a runway as a landing aid for aircraft.
- 6. Satellite navigation method according to one claim 1, characterized in that, in addition to the reference station (Ref), at least one pseudo-satellite station is set up in the vicinity of the runway.
- space="preserve" listing-type="equation">.o slashed..sub.E.sup.S=( 1/λ
Specification
-
- Resources
-
Current AssigneeNFS Navigations-und Flugfuhrungs-Systeme GmbH
-
Original AssigneeNFS Navigations-und Flugfuhrungs-Systeme GmbH
-
InventorsGu, Xiaogang
-
Primary Examiner(s)Blum, Theodore M.
-
Application NumberUS08/727,653Time in Patent Office755 DaysField of Search342/357, 364/449.7, 701/213US Class Current342/357.31CPC Class CodesG01S 19/04 providing carrier phase dataG01S 19/07 providing data for correcti...G01S 19/15 Aircraft landing systems
