Determination of phase ambiguities in satellite ranges

• US 5,359,332 A
• Filed: 12/31/1992
• Issued: 10/25/1994
• Est. Priority Date: 12/31/1992
• Status: Expired due to Fees

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Deaver, Phillip, Dreier, Scott, Allison, Michael T.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US07/999,099
• Time in Patent Office: 663 Days
• Field of Search: 342/352, 342/356, 342/357, 342/358, 342/457
• US Class Current: 342/357.42
• CPC Class Codes: G01S 19/04 providing carrier phase data

Abstract

A method for accurately determining the position of a roving receiver positioned on or above the Earth'"'"'s surface, relative to the position of a reference receiver whose position is known with sufficient accuracy, using measurements of signal phase transmitted at one or more carrier frequencies and received from each of four or more satellites in a Satellite Positioning System (SPS). Phase double differences are formed, using the reference and roving receivers and any two satellites drawn from four or more satellites, using phase information obtained from either or both of the two carrier signal frequencies. Phase correction information, in the form of estimates of integer wavelength ambiguities, is then obtained from two sets of ambiguity estimates computed with the roving receiver antenna in each of two specified positions, with the reference receiver antenna lying between and being collinear with the two roving receiver-antenna positions. If the distance between the reference receiver antenna position and the two roving receiver antenna positions is sufficiently small, a set of estimates at only one of the roving receiver positions may suffice. If an azimuth angle measuring device is incorporated in the apparatus, a set of estimates at only one roving receiver position may again suffice. The method produces a set of simultaneous equations that can be solved for the coordinates of a roving receiver located at an arbitrary position. The reference receiver antenna is positioned at a fixed location and orientation while the roving antenna is correctly positioned at each of two specified locations and orientations. A Global Positioning System (GPS) or a Global Orbiting Navigational System (GLONASS) may serve as the SPS.

Claims

1. A method for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System, the method comprising the steps of:

(1) providing a reference receiver and antenna, denoted receiver number 1, whose antenna position r(ref) is known with predetermined accuracy, at a sequence of predetermined times;

(2) providing a roving receiver and antenna, denoted receiver number 2, with a first roving receiver antenna position r(rov, +d, L) that is displaced from the reference receiver antenna position by a distance +d in a first direction along a selected line L also containing the reference receiver antenna position, where d need not be determined;

(3) providing a plurality of n satellites (n≧

4), numbered i=1, 2, . . . , n, at predetermined heights above the Earth'"'"'s surface, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f=f_L1 and f=f_L2 ;

(4) determining an effective signal frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/λ

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 =c/λ

_L1 and f_L2 =c/λ

_L2, for the Satellite Positioning System, where c is the velocity of light and λ

_cp is the corresponding effective wavelength;

(5) determining a phase integer estimate N<sub>e;

i</sub>,i'"'"';

j,j'"'"'(1) for the roving receiver located at a first roving receiver antenna position r(rov, +d, L), for satellites number i and i'"'"' and receivers number j and j'"'"' from the relation

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"'(1) =Δ

R.sub.i,i'"'"';

j,j'"'"' (1)/λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp (1),

where Δ

R_i,i'"'"';

j,j'"'"' (1) is a double difference range value defined by the relation

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' (1)=(R.sub.i,j (1)-R.sub.i'"'"',j (1))-(R.sub.i,j'"'"' (1)-R.sub.i'"'"',j'"'"' (1) ),

and R_i,j (1) is the theoretical range or distance from receiver number j to satellite number i for the first roving receiver antenna position, assuming that d≈

0 for this determination, and Φ

_i,i'"'"';

j,j'"'"';

cp (1) is a phase variable determined by the relation

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp (1)=[β

.sub.i,j;

cp (1)-β

.sub.i'"'"',j;

cp(1) ]-[β

.sub.i,j'"'"';

cp (1)-β

.sub.i'"'"',j'"'"';

cp(1) ],

where β

_i,j;

cp (1) is an effective phase, measured from satellite number i to receiver number j of a carrier signal with effective frequency f_cp ;

(6) determining a phase integer estimate N<sub>e;

i</sub>,i'"'"';

j,j'"'"'(2) for the roving receiver located at a second roving receiver antenna position r(rov, -d, L), for satellites number i and i'"'"' and receivers number j and j'"'"' from the relation

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"'(2) =Δ

R.sub.i,i'"'"';

j,j'"'"' (2)/λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp (2),

where Δ

R_i,i'"'"';

j,j'"'"' (1) is a double difference range value defined by the relation

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' (2)=(R.sub.i,j (2)-R.sub.i'"'"',j (2))-(R.sub.i,j'"'"' (2)-R.sub.i'"'"',j'"'"' (2)),

and R_i,j (2) is the theoretical range or distance from receiver number j to satellite number i for the first roving receiver antenna position, assuming that d=0 for this determination, and Φ

_i,i'"'"';

j,j'"'"';

cp (2) is a phase variable determined by the relation

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp (2)=[β

.sub.i,j;

cp (2)-β

.sub.i'"'"',j;

cp(2) ]-[β

.sub.i,j'"'"';

cp (2)-β

.sub.i'"'"'j'"'"';

cp(2) ],

where β

_i,j;

cp (2) is an effective phase, measured from satellite number i to receiver number j of a carrier signal with effective frequency f_cp ; and

(7) determining the desired phase integers N_i,i'"'"';

j,j'"'"' for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[(N.sub.e;

i,i'"'"';

j,j'"'"' (1)+N.sub.e;

i,i'"'"';

j,j'"'"' (2))/2+0.5].

2. A method for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System, the method comprising the steps of:

(1) providing a reference receiver and antenna, denoted receiver number 1, whose antenna position r(ref) is known with predetermined accuracy, at a sequence of predetermined times;

(2) providing a roving receiver and antenna, denoted receiver number 2, with a roving receiver antenna position r(rov, d, L) that is displaced from the reference receiver antenna position by a distance d in a first direction along a selected line L also containing the reference receiver antenna position, where d need not be determined;

(3) providing a plurality of n satellites (n≧

4), numbered i=1, 2, . . . , n, at predetermined heights above the Earth'"'"'s surface, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f=f_L1 and f=f_L2 ;

(4) determining an effective signal frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/λ

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 =c/λ

_L1 and f_L2 =c/λ

_L2, for the Satellite Positioning System, where c is the velocity of light, λ

_cp is the corresponding effective wavelength and the distance d is less than λ

_cp /2;

(5) determining a phase integer estimate N<sub>e;

i</sub>,i'"'"';

j;

j'"'"' for the roving receiver located at the roving receiver antenna position r(rov, d, L), for satellites number i and i'"'"' and receivers number j and j'"'"' from the relation

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' =Δ

R.sub.i,i'"'"';

j,j'"'"' /λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp,

where Δ

R_i,i'"'"';

j,j'"'"' (1) is a double difference range value defined by the relation

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' =(R.sub.i,j -R.sub.i'"'"',j)-(R.sub.i,j'"'"' -R.sub.i'"'"',j'"'"'),

and R_i,j is the theoretical range or distance from receiver number j to satellite number i for the first roving receiver antenna position, assuming that d≈

0 for this determination, and Φ

_i,i'"'"';

j,j'"'"';

cp is a phase variable determined by the relation

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp =[β

.sub.i,j;

cp -β

.sub.i'"'"',j;

cp ]-[β

.sub.i,j'"'"';

cp -β

.sub.i'"'"',j'"'"';

cp ],

where β

_i,j;

cp is an effective phase, measured from satellite number i to receiver number j of a carrier signal with effective frequency f_cp ; and

(6) determining the desired phase integers N_i,i'"'"';

j,j'"'"' for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[N.sub.e;

i,i'"'"';

j,j'"'"' +0.5].

3. A method for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System, the method comprising the steps of:

(1) providing a reference receiver and antenna, denoted receiver number 1, whose antenna position r(ref) is known with predetermined accuracy, at a sequence of m predetermined times;

(2) providing a roving receiver and antenna, denoted receiver number 2, whose antenna position r(rov, d, L) is displaced from the reference receiver antenna position by a known distance d in a first direction along a selected line L containing the reference receiver antenna position;

(3) determining the azimuthal angle Ψ

of the line L with respect to a chosen north direction;

(4) from the known geodetic coordinates (latitude₁, longitude₁, altitude₁) of the reference receiver antenna position, determining the geodetic coordinates of the roving receiver antenna (latitude₂, longitude₂, altitude₂) according to the relations

space="preserve" listing-type="equation">latitude.sub.2 =latitude.sub.1 +(360°

d cos Ψ

)/(2π

R),

space="preserve" listing-type="equation">longitude.sub.2 =longitude.sub.1 +(360°

d sin Ψ

)/(2π

R cos(latitude.sub.1)),

space="preserve" listing-type="equation">altitude.sub.2 =altitude.sub.1 ;

(5) providing a plurality of n satellites (n≧

4), numbered i=1,2, . . . , n, at predetermined heights above the Earth'"'"'s surface, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f=f_L1 and f=f_L2 ;

(6) determining an effective frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/λ

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 =c/λ

_L1 and f_L2 =c/λ

_L2, for the Satellite Positioning System,where c is the velocity of light and λ

_cp is the corresponding effective wavelength;

(7) determining a phase integer estimate N<sub>e;

i</sub>,i'"'"';

j,j'"'"' for the roving receiver located at the roving receiver antenna position r(rov, d, L), for satellites number i and i'"'"' and receivers number j and j'"'"' from the relation

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' =Δ

R.sub.i,i'"'"';

j,j'"'"' /λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp,

where Δ

R_i,i'"'"';

j,j'"'"' (1) is a double difference range value defined by the relation

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' =(R.sub.i,j -R.sub.i'"'"',j)-(R.sub.i,j'"'"' -R.sub.i'"'"',j'"'"'),

and R_i,j is the theoretical range or distance from receiver number j to satellite number i for the roving receiver antenna position r(rov, d, L), and Φ

_i,i'"'"';

j,j'"'"';

cp is a phase variable determined by the relation

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp =[β

.sub.i,j;

cp -β

.sub.i'"'"',j;

cp ]-[β

.sub.i,j'"'"';

cp -β

.sub.i'"'"',j'"'"',cp ],

where β

_i,j;

cp is an effective phase, measured from satellite number i to receiver number j of a carrier signal with effective frequency f_cp ; and

(8) determining the desired phase integers N_i,i'"'"';

j,j'"'"' for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[N.sub.e;

i,i'"'"';

j,j'"'"' +0.5].

4. A method for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System, the method comprising the steps of:

(1) providing a reference receiver and antenna, denoted receiver number 1, whose antenna position r(ref) is known with predetermined accuracy, at a sequence of m predetermined times;

(2) providing a roving receiver and antenna, denoted receiver number 2, whose antenna position r(rov, +d, L) is displaced from the reference receiver antenna position by an arbitrary distance +d in a first direction along a selected line L also containing the reference receiver antenna position, where d need not be determined;

(3) providing a plurality of n satellites (n≧

4), numbered i =1,2, . . . , n, at predetermined heights above the Earth'"'"'s surface, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f=f_L1 and f=f_L2 ;

(4) determining an effective signal frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/λ

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 =c/λ

_L1 and f_L2 =c/λ

_L2, for the Satellite Positioning System, where c is the velocity of light and λ

_cp is the corresponding effective wavelength;

(5) performing steps (6)-(11) for the roving receiver located at a first roving receiver antenna position r(rov, +d, L);

(6) determining a plurality of n theoretical distance values R₁,1, R₂,1, . . . , R_n,1 from each of the n satellites to the roving receiver antenna at the sequence of predetermined times, where R_I,J is the distance between satellite number I, with Cartesian coordinates (x_I,y_I,z_I), and receiver antenna number J, with coordinates (x_J,y_J,z_J) (I=1, 2, . . . , n;

J=1,

     2), given by R_I,J =[(x_I -x_J)² +(y_I -y_J)² +(z_I -z_J)² ]^1/2, where each theoretical distance value is determined from a knowledge of the position of a satellite and of an estimate of a position of the roving receiver antenna, assuming that d≈

0 for this determination;

(7) determining a plurality of n theoretical distance values R₁,2, R₂,2, . . . , R_n,2 from each of the satellites to the reference receiver antenna at the sequence of predetermined times, where each theoretical distance value is determined from a knowledge of the position of a satellite and of the position of the reference receiver antenna, where the position of the reference receiver antenna is known with sufficient accuracy at each of the predetermined sequence of times;

(8) forming theoretical range double difference values Δ

R_i,i'"'"';

j,j'"'"' (1) (i,i'"'"'=1,2, . . . , n;

i≠

i'"'"';

j,j'"'"'=1,2;

j≠

j'"'"') for the reference and roving receiver antenna positions, defined by the relations

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' (1)=(R.sub.i,j (1)-R.sub.i'"'"',j (1))-(R.sub.i,j'"'"' (1)-R.sub.i'"'"',j'"'"' (1))

for the pair of satellites number i and i'"'"' and the pair of receiver antennas number j and j'"'"';

(9) measuring the effective phase β

<sub>ij;

cp</sub> (1) from satellite number i of a carrier signal with effective frequency f=f_cp received at receiver antenna number j (i=1,2, . . . , n;

j=1,

     2);

(10) forming double difference phase variables

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp (1)=[β

.sub.i,j;

cp (1)-β

.sub.i'"'"',j;

cp(1) ]-[β

.sub.i,j'"'"';

cp (1)-β

.sub.i'"'"',j'"'"';

cp (1)]

for the satellites number i and i'"'"' and the receiver antennas number j and j'"'"', using the effective signal frequency f=f_cp ;

(11) determining phase integer estimates N<sub>e;

i</sub>,i'"'"';

j,j'"'"' by the relations

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' (1)=Δ

R.sub.i,i'"'"';

j,j'"'"' (1)/λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp (1);

(12) performing steps (6)-(11) for the roving receiver antenna located at a second roving receiver antenna position r(rov, -d, L) that also lies on the line L, where the reference receiver antenna position lies between, and equidistant from, the first and second roving receiver antenna positions on the line L, to obtain the double difference range values Δ

R_i,i'"'"';

j,j'"'"' (2) defined by

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' (2)=(R.sub.i,j (2)-R.sub.i'"'"',j (2))-(R.sub.i,j'"'"' (2)-R.sub.i'"'"',j'"'"' (2)),

measured carrier phase variables β

_i,j;

cp (2), double difference phase variables Φ

_i,i'"'"';

j,j'"'"';

cp (2) defined by

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp (2)=[β

.sub.i,j;

cp (2)-β

.sub.i'"'"',j;

cp (2)]-[β

.sub.i,j'"'"';

cp (2)-β

.sub.i'"'"',j'"'"';

cp(2) ],

and phase integer estimates N<sub>e;

i</sub>,i'"'"';

j,j'"'"' (2) given by

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' (2)=Δ

R.sub.i,i'"'"';

j,j'"'"';

cp (2)/λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp (2); and

(13) determining the desired phase integers for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[(N.sub.e;

i,i'"'"';

j,j'"'"' (1)+N.sub.e;

i,i'"'"';

j,j'"'"' (2))/2+0.5].

5. The method of claim 4, further comprising the step of choosing said integer n equal to four.

6. The method of claim 4, further comprising the step of

(14) solving the n-1 simultaneous equations given by

7. The method of claim 4, further comprising the step of choosing said effective frequency, and of said corresponding effective phases β

_i,i'"'"';

j,j'"'"';

cp, drawn from the group consisting of the L1 carrier frequency f_L1 the L2 carrier frequency f_L2 the wide lane frequency f_w =f_L1 -f_L2, and the narrow lane frequency f_n =f_L1 +f_L2 .

8. A method for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System, the method comprising the steps of:

(1) providing a reference receiver and antenna, denoted receiver number 1, whose antenna position r(ref) is known with predetermined accuracy, at a sequence of m predetermined times;

(2) providing a roving receiver and antenna, denoted receiver number 2, whose antenna position r(rov, d, L) is displaced from the reference receiver antenna position by a distance d in a first direction along a selected line L also containing the reference receiver antenna position, where d need not be determined;

(3) providing a plurality of n satellites (n≧

4), numbered i=1, 2, . . . , n, at predetermined heights above the Earth'"'"'s surface, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f=f_L1 and f=f_L2 ;

(4) determining an effective frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/λ

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 =c/λ

_L1 and f_L2 =c/λ

_L2 for the Satellite Positioning System, where c is the velocity of light, where λ

_cp is the corresponding effective wavelength, and where the distance d is less than half the effective wavelength (d<

λ

_cp /2);

(5) determining a plurality of n theoretical distance values R₁,1, R₂,1, . . . , R_n,1 from each of the n satellites to the roving receiver antenna at the sequence of predetermined times, where R_I,J is the distance between satellite number I, with Cartesian coordinates (x_I,y_I,z_I), and receiver antenna number J, with coordinates (x_J,y_j,z_J) (I=1, 2, . . . , n;

J=1,

     2), given by R_I,J =[(x_I -x_J)² +(y_I -y_J)² +(z_I -z_J)² ]^1/2, where each theoretical distance value is determined from a knowledge of the position of a satellite and an estimate of a position of the roving receiver antenna, assuming that d≈

0 for this determination;

(6) determining a plurality of n theoretical distance values R₁,2, R₂,2, . . . , R_n,2 from each of the satellite to the reference receiver antenna at the sequence of predetermined times, where each theoretical distance value is determined from a knowledge of the position of a satellite and of the position of the reference receiver antenna, where the position of the reference receiver antenna is known with sufficient accuracy at each of the predetermined sequence of times;

(7) forming theoretical range double difference values Δ

R_i,i'"'"';

j,j'"'"' (i,i'"'"'=1,2, . . . , n;

i≠

i'"'"';

j,j'"'"'=1,2;

j≠

j'"'"') for the reference and roving receiver antenna positions, defined by the relations

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' =(R.sub.i,j -R.sub.i'"'"',j)-(R.sub.i,j'"'"' -R.sub.i'"'"',j'"'"')

for the pair of satellites number i and i'"'"' and the pair of receiver antennas number j and j'"'"';

(8) measuring the effective phase β

<sub>ij;

cp</sub> from satellite number i of a carrier signal with effective frequency f=f_cp received at receiver antenna number j (i =1,2, . . . , n;

j=1,

     2);

(9) forming double difference phase variables

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp =[β

.sub.i,j;

cp -β

.sub.i'"'"',j;

cp ]-[β

.sub.i,j'"'"';

cp -β

.sub.i'"'"',j;

cp ]

for the satellites number i and i'"'"' and the receiver antennas number j and j'"'"', using the effective signal frequency f=f_cp ;

(10) determining phase integer estimates N<sub>e;

i</sub>,i'"'"';

j,j'"'"' by the relations

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' =Δ

R.sub.i,i'"'"';

j,j'"'"' /λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp ; and

(11) determining the desired phase integers for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[N.sub.e;

i,i'"'"';

j,j'"'"' +0.5].

9. The method of claim 8, further comprising the step of choosing said integer n equal to four.

10. The method of claim 8, further comprising the step of

(12) solving the n-1 simultaneous equations given by

11. The method of claim 8, further comprising the step of choosing said effective frequency, and of said corresponding effective phases β

_i,i'"'"';

j,j'"'"';

cp, drawn from the group consisting of the L1 carrier frequency f_L1, the L2 carrier frequency f_L2, the wide lane frequency f_w =f_L1 -f_L2, and the narrow lane frequency f_n =f_L1 +f_L2.

12. A method for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System, the method comprising the steps of:

(1) providing a reference receiver and antenna, denoted receiver number 1, whose antenna position r(ref) is known with predetermined accuracy, at a sequence of m predetermined times;

(2) providing a roving receiver and antenna, denoted receiver number 2, whose antenna position r(rov, d, L) is displaced from the reference receiver antenna position by a known distance d in a first direction along a selected line L containing the reference receiver antenna position;

(3) determining the azimuthal angle Ψ

of the line L with respect to a chosen north direction;

(4) from the known geodetic coordinates (latitude₁, longitude₁, altitude₁) of the reference receiver antenna position, determining the geodetic coordinates of the roving receiver antenna (latitude₂, longitude₂, altitude₂) according to the relations

space="preserve" listing-type="equation">latitude.sub.2 =latitude.sub.1 +(360°

d cos Ψ

)/(2π

R),

space="preserve" listing-type="equation">longitude.sub.2 =longitude.sub.1 +(360°

d sin Ψ

)/(2π

R cos(latitude.sub.1)),

space="preserve" listing-type="equation">altitude.sub.2 =altitude.sub.1 ;

(5) providing a plurality of n satellites (n≧

4), numbered i=1, 2, . . . , n, at predetermined heights above the Earth'"'"'s surface, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f=f_L1 and f=f_L2 ;

(6) determining an effective frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/λ

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 =c/λ

_L1 and f_L2 =c/λ

_L2, for the Satellite Positioning System, where c is the velocity of light and λ

_cp is the corresponding effective wavelength;

(7) determining a plurality of n theoretical distance values R₁,2, R₂,2, . . . , R_n,2 from each of the satellites to the reference receiver antenna at the sequence of predetermined times, where each theoretical distance value is determined from a knowledge of the position of a satellite and of the position of the reference receiver antenna, where the position of the reference receiver antenna is known with sufficient accuracy at each of the predetermined sequence of times;

(8) determining a plurality of n theoretical distance values R₁,1, R₂,1, . . . , R_n,1 from each of the n satellites to the roving receiver antenna at the sequence of predetermined times, using the geodetic coordinates for this antenna determined in step (4), where R_I,J is the distance between satellite number I, with Cartesian coordinates (x_I,y_I,z_I), and receiver antenna number J, with coordinates (x_J,y_J,z_J) (I=1, 2, . . . , n;

J=1,

     2), given by R_I,J =[(x_I -x_J)² +(y_I -y_J)² +(z_I -z_J)² ]^1/2 ;

(9) forming theoretical range double difference values Δ

R_i,i'"'"';

j,j'"'"' (i,i'"'"'=1,2, . . . , n;

i≠

i'"'"';

j,j'"'"'=1,2;

j≠

j'"'"') for the reference and roving receiver antenna positions, defined by the relations

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' =(R.sub.i,j -R.sub.i'"'"',j)-(R.sub.i,j'"'"' -R.sub.i'"'"',j'"'"')

for the pair of satellites number i and i'"'"' and the pair of receiver antennas number j and j'"'"';

(10) measuring the effective phase β

<sub>ij;

cp</sub> from satellite number i of a signal with effective frequency f=f_cp received at receiver antenna number j (i=1,2, . . . , n;

j=1,

     2);

(11) forming double difference phase variables

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp =[β

.sub.i,j;

cp -β

.sub.i'"'"',j;

cp ]-[β

.sub.i,j'"'"';

cp -β

.sub.i'"'"',j'"'"';

cp ]

for the satellites number i and i'"'"' and the receiver antennas number j and j'"'"', using the effective signal frequency f=f_cp ;

(12) determining phase integer estimates N<sub>e;

i</sub>,i'"'"';

j,j'"'"' by the relations

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' =Δ

R.sub.i,i'"'"';

j,j'"'"' /λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp ; and

(13) determining the desired phase integers for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[N.sub.e;

i,i'"'"';

j,j'"'"' +0.5].

13. The method of claim 12, further comprising the step of choosing said integer n equal to four.

14. The method of claim 12, further comprising the step of

(13) solving the n-1 simultaneous equations given by

15. The method of claim 12, further comprising the step of choosing said effective frequency, and of said corresponding phases β

_i,i'"'"';

j,j'"'"';

cp, drawn from the group consisting of the L1 carrier frequency f_L1, the L2 carrier frequency f_L2, the wide lane frequency f_w =f_L1 -f_L2, and the narrow lane frequency f_n =f_L1 +f_L2.

16. Apparatus for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System (SPS), the apparatus comprising:

a reference receiver and associated antenna for receiving SPS signals from a plurality of n satellites (n≧

4), numbered i=1, 2, . . . , n, that are part of the SPS, where the position of the reference receiver antenna is known with sufficient accuracy;

a roving receiver and associated antenna for receiving SPS signals from the plurality of n satellites that are part of the SPS, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f_L1 =c/λ

_L1 and f_L2 =c/λ

_L2, where c is the velocity of light;

antenna positioning means for positioning the roving receiver antenna at a first selected position and then at a second selected position on a selected line containing the reference receiver antenna, where the reference receiver antenna lies between and at a distance d from the first and the second selected roving receiver antenna positions, where d need not be determined;

signal processing means, connected to the reference receiver antenna and to the roving receiver antenna;

(1) for determining an effective frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/α

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 and f_L2, for the Satellite Positioning System, where λ

_cp is the corresponding effective wavelength;

(2) for receiving the SPS signals received by the reference receiver antenna and by the roving receiver antenna at the first selected position and the second selected position;

(3) for determining a plurality of n theoretical distance values R₁,1, R₂,1, . . . , R_n,1 from each of the n satellites to the roving receiver antenna at the sequence of predetermined times, where R_I,J is the distance between satellite number I, with Cartesian coordinates (x_I,y_I,z_I), and receiver antenna number J, with coordinates (x_J,y_J,_J) (I=1, 2, . . . , n;

J=1,

     2), given by R_I,J =[(x_I -x_J)² +(y_I -y_J)² +(z_I -z_J)² ]^1/2, where each theoretical distance value is determined from a knowledge of the position of a satellite and of an estimate of a position of the roving receiver antenna, assuming that d≈

0 for this determination;

(4) for determining a plurality of n theoretical distance values R₁,2, R₂,2, . . . , R_n,2 from each of the satellites to the reference receiver antenna at the sequence of predetermined times, where each theoretical distance value is determined from a knowledge of the position of a satellite and of the position of the reference receiver antenna, where the position of the reference receiver antenna is known with sufficient accuracy at each of the predetermined sequence of times;

(5) for forming theoretical range double difference values Δ

R_i,i'"'"';

j,j'"'"' (1) (i,i'"'"'=1,2, . . . , n;

i≠

i'"'"';

j,j'"'"'=1,2;

j≠

j'"'"') for the reference and roving receiver antenna positions, defined by the relations

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' (1)=(R.sub.i,j (1)-R.sub.i'"'"',j (1))-(R.sub.i,j'"'"' (1)-R.sub.i'"'"',j'"'"' (1))

for the pair of satellites number i and i'"'"' and the pair of receiver antennas number j and j'"'"', assuming that d≈

0 for this determination;

(6) for measuring the effective phase β

<sub>ij;

cp</sub> (1) from satellite number i of a carrier signal with effective frequency f=f_cp received at receiver antenna number j(i=1,2, . . . , n;

j=1,

     2);

(7) for forming double difference phase variables

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp (1)=[β

.sub.i,j;

cp (1)-β

.sub.i'"'"',j;

cp (1)]-[β

.sub.i,j'"'"';

cp (1)-β

.sub.i'"'"',j'"'"';

cp (1)]

for the satellites number i and i'"'"' and the receiver antennas number j and j'"'"', using the effective signal frequency f=f_cp ;

(8) for determining phase integer estimates N<sub>e;

i</sub>,i'"'"';

j,j'"'"' by the relations

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' (1)=Δ

R.sub.i,i'"'"';

j,j'"'"' (1)/λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp (1);

(9) for performing steps (2)-(8) for the roving receiver antenna located at a second roving receiver antenna position r(rov, -d, L) that also lies on the line L, where the reference receiver antenna position lies between, and equidistant from, the first and second roving receiver antenna positions on the line L, to obtain the double difference range values Δ

R_i,i'"'"';

j,j'"'"' (2) defined by

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' (2)=(R.sub.i,j (2)-R.sub.i'"'"',j (2))-(R.sub.i,j'"'"' (2)-R.sub.i'"'"',j'"'"' (2)),

measured carrier phase variables β

_i,j;

cp (2), double difference phase variables Φ

_i,i'"'"';

j,j'"'"';

cp (2) defined by

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp (2)=[β

.sub.i,j;

cp (2)-β

.sub.i'"'"',j;

cp(2) ]-[β

.sub.i,j'"'"';

cp (2)-β

.sub.i'"'"',j'"'"';

cp(2) ],

and phase integer estimates N<sub>e;

i</sub>,i'"'"';

j,j'"'"' (2) given by

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' (2)=Δ

R.sub.i,i'"'"';

j,j'"'"';

cp (2)/λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp (2); and

(10) for determining the desired phase integers for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[(N.sub.e;

i,i'"'"';

j,j'"'"' (1)+N.sub.e;

i,i'"'"';

j,j'"'"' (2))/2 +0.5].

17. The apparatus of claim 16, wherein said integer n is equal to four.

18. The apparatus of claim 16, wherein said signal processor also solves n-1 simultaneous equations given by

19. The apparatus of claim 16, wherein said effective frequency, and said corresponding effective phases β

_i,i'"'"';

j,j'"'"';

cp, is drawn from the group consisting of the L1 carrier frequency f_L1, the L2 carrier frequency f_L2, the wide lane frequency f_w =f_L1 f_L2, and the narrow lane frequency f_n =f_L1 +f_L2.

20. Apparatus for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System (SPS), the apparatus comprising:

a reference receiver and associated antenna for receiving SPS signals from a plurality of n satellites (n≧

4), numbered i=1, 2, . . . , n, that are part of the SPS, where the position of the reference receiver antenna is known with sufficient accuracy;

a roving receiver and associated antenna for receiving SPS signals from the plurality of n satellites that are part of the SPS, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f_L1 =c/λ

_L1 and fL2=c/λ

_L2, where c is the velocity of light;

antenna positioning means for positioning the roving receiver antenna at a selected position spaced apart from the reference receiver antenna position by a distance d that is less than λ

_cp /2, where d need not be otherwise determined and λ

_cp is an effective wavelength defined below;

signal processing means, connected to the reference receiver antenna and to the roving receiver antenna;

(1) for determining a frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/λ

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 and f_L2, for the Satellite Positioning System, where λ

_cp is the corresponding effective wavelength;

(2) for receiving the SPS signals received by the reference receiver antenna and by the roving receiver antenna at a selected position;

(3) for determining a plurality of n theoretical distance values R₁,1, R₂,1, . . . , R_n,1 from each of the n satellites to the roving receiver antenna at the sequence of predetermined times, where R_I,J is the distance between satellite number I, with Cartesian coordinates (x_I,y_I,z_I), and receiver antenna number J, with coordinates (x_J,y_J,z_J) (I=1, 2, . . . , n;

J=1,

     2), given by R_I,J =[(x_I -x_J)² +(y_I -y_J)² +(z_I -z_J)² ]^1/2, where each theoretical distance value is determined from a knowledge of the position of a satellite and of an estimate of a position of the roving receiver antenna, assuming that d≈

0 for this determination;

(4) for determining a plurality of n theoretical distance values R₁,2, R₂,2, . . . , R_n,2 from each of the satellites to the reference receiver antenna at the sequence of predetermined times, where each theoretical distance value is determined from a knowledge of the position of a satellite and of the position of the reference receiver antenna, where the position of the reference receiver antenna is known with sufficient accuracy at each of the predetermined sequence of times;

(5) for forming theoretical range double difference values Δ

R_i,i'"'"';

j,j'"'"' (i,i'"'"'=1,2, . . . , n;

i≠

i'"'"';

j,j'"'"'=1,2;

j≠

j'"'"') for the reference and roving receiver antenna positions, defined by the relations

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' =(R.sub.i,j -R.sub.i'"'"',j)-(R.sub.i,j'"'"' -R.sub.i'"'"',j'"'"')

for the pair of satellites number i and i'"'"' and the pair of receiver antennas number j and j'"'"';

(6) for measuring the effective phase β

<sub>ij;

cp</sub> from satellite number i of a carrier signal with effective frequency f=f_cp received at receiver antenna number j (i=1,2, . . . , n;

j =1,

     2);

(7) for forming double difference phase variables

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp =[β

.sub.i,j;

cp -β

.sub.i'"'"',j;

cp ]-[β

.sub.i,j'"'"';

cp 1728 β

.sub.i'"'"',j'"'"';

cp ]

for the satellites number i and i'"'"' and the receiver antennas number j and j'"'"', using the signal frequency f=f_cp ;

(8) for determining phase integer estimates N<sub>e;

i</sub>,i'"'"';

j,j'"'"' by the relations

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' =Δ

R.sub.i,i'"'"';

j,j'"'"' /λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp ; and

(9) for determining the desired phase integers for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[N.sub.e;

i,i'"'"';

j,j'"'"' +0.5].

21. The apparatus of claim 20, wherein said integer n is equal to four.

22. The apparatus of claim 20, wherein said signal processor also solves n-1 simultaneous equations given by

23. The apparatus of claim 20, wherein said effective frequency, and said corresponding effective phases β

_i,i'"'"';

j,j'"'"';

cp, is drawn from the group consisting of the L1 carrier frequency f_L1, the L2 carrier frequency f_L2, the wide lane frequency f_w =f_L1 -f_L2, and the narrow lane frequency f_n =f_L1 +f_L2 .

24. Apparatus for determining and removing the phase integer ambiguities associated with determination of position of a receiver that is part of a Satellite Positioning System (SPS), the apparatus comprising:

a reference receiver, denoted receiver number 1, and associated antenna for receiving SPS signals from a plurality of n satellites (n≧

4), numbered i=1, 2, . . . , n, that are part of the SPS, where the position of the reference receiver antenna is known with sufficient accuracy;

a roving receiver, denoted receiver number 2, and associated antenna for receiving SPS signals from the plurality of n satellites that are part of the SPS, where each satellite transmits a predetermined signal at a predetermined sequence of times at each of at least two carrier signal frequencies f_L1 =c/λ

_L1 and fL2=c/λ

_L2, where c is the velocity of light, where the roving receiver antenna position r(rov, d, L) is displaced from the reference receiver antenna position by a known distance d in a first direction along a selected line L containing the reference receiver antenna position;

antenna positioning means for positioning the roving receiver antenna at a selected position spaced apart from the reference receiver antenna position by a selected distance d along the line L, where the line L makes a known azimuthal angle Ψ

with respect to a chosen north direction;

signal processing means, connected to the reference receiver antenna and to the roving receiver antenna;

(1) for determining, from the known geodetic coordinates (latitude₁, longitude₁, altitude₁) of the reference receiver antenna position, the geodetic coordinates of the roving receiver antenna (latitude₂, longitude₂, altitude₂) according to the relations

space="preserve" listing-type="equation">latitude.sub.2 =latitude.sub.1 +(360°

d cos Ψ

)/(2π

R),

space="preserve" listing-type="equation">longitude.sub.2 =longitude.sub.1 +(360°

d sin Ψ

)/(2π

R cos(latitude.sub.1)),

space="preserve" listing-type="equation">altitude.sub.2 =altitude .sub.1 ;

(2) for determining an effective frequency f_cp =α

₁ f_L1 +α

₂ f_L2 =c/λ

_cp, expressed as a selected linear combination of the two carrier frequencies f_L1 =c/λ

_L1 and f_L2 =c/λ

_L2, for the Satellite Positioning System, where c is the velocity of light and λ

_cp is the corresponding effective wavelength;

(3) for determining a plurality of n theoretical distance values R₁,2, R₂,2, . . . , R_n,2 from each of the satellites to the reference receiver antenna at the sequence of predetermined times, where each theoretical distance value is determined from a knowledge of the position of a satellite and of the position of the reference receiver antenna, where the position of the reference receiver antenna is known with sufficient accuracy at each of the predetermined sequence of times;

(4) for determining a plurality of n theoretical distance values R₁,1, R₂,1, . . . , R_n,1 from each of the n satellites to the roving receiver antenna at the sequence of predetermined times, using the geodetic coordinates for this antenna determined in step (1), where R_I,J is the distance between satellite number I, with Cartesian coordinates (x_I,y_I,z_I), and receiver antenna number J, with coordinates (x_J,y_J,z_J) (I=1, 2, . . . , n;

J=1,

     2), given by R_I,J =[(x_I -x_J)² +(y_I -y_J)² +(z_I -z_J)² ]^1/2 ;

(5) for forming theoretical range double difference values Δ

R_i,i'"'"';

j,j'"'"' (1) (i,i'"'"'=1,2, . . . , n;

i≠

i'"'"';

j,j'"'"'=1,2;

j≠

j'"'"') for the reference and roving receiver antenna positions, defined by the relations

space="preserve" listing-type="equation">Δ

R.sub.i,i'"'"';

j,j'"'"' =(R.sub.i,j -R.sub.i'"'"',j)-(R.sub.ij'"'"' -R.sub.i'"'"',j'"'"')

for the pair of satellites number i and i'"'"' and the pair of receiver antennas number j and j'"'"';

(6) for measuring the effective phase β

<sub>ij;

cp</sub> from satellite number i of a signal with effective frequency f=f_cp received at receiver antenna number j (i=1,2, . . . , n;

j=1,

     2);

(7) for forming double difference phase variables

space="preserve" listing-type="equation">Φ

.sub.i,i'"'"';

j,j'"'"';

cp =[β

.sub.i,j;

cp -β

.sub.i'"'"',j;

cp ]-[β

.sub.i,j'"'"';

cp -β

.sub.i'"'"',j'"'"';

cp ]

for the satellites number i and i'"'"' and the receiver antennas number j and j'"'"', using the effective signal frequency f=f_cp ;

(8) for determining phase integer estimates N<sub>e;

i</sub>,i'"'"';

j,j'"'"' by the relations

space="preserve" listing-type="equation">N.sub.e;

i,i'"'"';

j,j'"'"' =Δ

R.sub.i,i'"'"';

j,j'"'"' /λ

.sub.cp +Φ

.sub.i,i'"'"';

j,j'"'"';

cp ; and

(9) for determining the desired phase integers for the reference and roving receiver antennas by the relations

space="preserve" listing-type="equation">N.sub.i,i'"'"';

j,j'"'"' =floor[N.sub.e;

i,i'"'"';

j,j'"'"' +0.5].

25. The apparatus of claim 24, wherein said integer n is equal to four.

26. The apparatus of claim 24, wherein said signal processor also solves n-1 simultaneous equations given by

27. The apparatus of claim 24, wherein said effective frequency, and said corresponding effective phases β

_i,i'"'"';

j,j'"'"';

cp, is drawn from the group consisting of the L1 carrier frequency f_L1, the L2 carrier frequency f_L2, the wide lane frequency f_w =f_L1 -f_L2, and the narrow lane frequency f_n =f_L1 +f_L2.