Compaction of SATPS information for subsequent signal processing

• US 5,731,786 A
• Filed: 12/29/1994
• Issued: 03/24/1998
• Est. Priority Date: 12/29/1994
• Status: Expired due to Fees

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Abraham, Charles, Loomis, Peter Van Wyck, Schipper, John F.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US08/367,051
• Time in Patent Office: 1,181 Days
• Field of Search: 342/357
• US Class Current: 342/357.25
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]

Abstract

A method for characterization of data measurements made on signals received from a plurality of SATPS satellites that facilitates post-processing of these data to determine pseudoranges, code phases, carrier phases, pseudorange rate corrections, carrier phase corrections, spatial location, velocity and time coordinates and other variables of interest for an SATPS user. The SATS may be any satellite-based location determination system, such as GPS or GLONASS. The approach uses six indices h1, h2, h3, h4, h5 and h6, with the first index h1 including the total solution coordinates (t_n,x_n,y_n,z_n) for the location fix time t=t_n at which measurements are made, and the spatial location and velocity coordinates. The second and third indices h2 and h3 specify the in-view satellite constellation that provided the SATPS signals and the IODC parameter. The fourth index h4 represents the specific parameter set used to model the ephemeris, almanac and clock correction parameters needed for the M satellites for a given coordinate fix. The fifth index h5 represents the parameter set used to model signal propagation delay through the ionosphere and troposphere. The sixth index h6 represents the location solution method and method parameters used to determine the spatial location, location fix time, clock bias and/or velocity coordinates for each coordinate fix. For each time stamp value in the index h1, information specified by the six indices may be used to reconstruct the information needed to determine pseudoranges, pseudorange rates, carrier phase signals, corrections to these variables, and other quantities of interest in an SATPS. The information specified by the six indices may a minimal set in which information specified by one index is not also specified by another index. Another method uses selected portions of the information specified by the collective indices h1, h2, h3, h4, h5 and h6, using a collective index H that may be divided into index segments.

Claims

1. A method for characterization and use of data measurements made on signals received from a plurality of SATPS satellites that facilitates subsequent processing of these data and determination of a spatial location corresponding to these measurements, the method comprising the steps of:

receiving SATPS signals at an SATPS antenna from each satellite in a selected constellation of M SATPS satellites (M≧

3), where the SATPS signals can be used to determine location fix coordinates (t_n,x_n,y_n,z_n), consisting of a location fix time t=t_n and the corresponding location coordinates (x_n,y_n,z_n) for the SATPS antenna that are determined from the SATPS signals received from the selected constellation of M SATPS satellites at the location fix time t=t_n ;

filtering the received SATPS signals to produce selected signal bit information by removing redundant signal bit information, and storing the selected signal bit information;

associating each signal bit of the selected signal bit information with at least one of six information indices, numbered h1, h2, h3, h4, h5 and h6, where the six information indices are associated with the following information;

a first index h1 that specifies, for each location fix, the total solution coordinates (t_n,x_n,y_n,z_n) for that location fix;

a second index h2 that specifies each of the satellites in a selected constellation of M satellites, with M≧

4, for a location fix determined for at least two distinct location fix times;

a third index h3 that specifies IODC parameter for the selected constellation of M SATPS satellites for the location fix time t=t_n ;

a fourth index h4 that specifies at least one of (1) the ephemeris parameters, (2) the almanac parameters, and (3) the clock correction parameters that were used in determining the total solution coordinates (t_n,x_n,y_n,z_n);

a fifth index h5 that specifies at least one of (1) the ionospheric model parameters and (2) the tropospheric model parameters that were used in determining the signal propagation time delays and the total solution coordinates (t_n,x_n,y_n,z_n); and

a sixth index h6 that specifies the location solution method and the location solution method parameters used in determining the total solution coordinates (t_n,x_n,y_n,z_n);

when corrected pseudorange data or corrected carrier phase data corresponding to the total solution coordinates (t_n,x_n,y_n,z_n) are required, reading the total solution coordinates (t_n,x_n,y_n,z_n) into a digital computer that is programmed to determine at least one of pseudorange data and carrier phase data from a set of total solution coordinates (t_n,x_n,y_n,z_n), reading the information associated with at least one of the six indices h1, h2, h3, h4, h5 and h6 associated with the total solution coordinates (t_n,x_n,y_n,z_n) into the computer, and causing the computer to reconstruct at least one of the required pseudorange data and the required carrier phase data from the information associated with the six indices;

receiving differential SATPS correction signals associated with at least one location fix time t=t_n1 ;

correcting the reconstructed pseudorange data or reconstructed carrier phase data, using the received differential SATPS correction signals for the at least one location fix time t=t_n1 ; and

using the corrected reconstructed pseudorange data or corrected reconstructed carrier phase data to determine and display at least one corrected location coordinate t_n, x_n, y_n, and z_n for the at least one location fix time t=t_n1.

2. The method of claim 1, further comprising the steps of:

determining and storing the velocity coordinates (v_x,n,v_y,n,v_z,n) from signals received from said selected constellation of M SATPS satellites for said location fix time t=t_n ; and

constructing an augmented first index h1'"'"' that specifies said total coordinates (t_n,x_n,y_n,z_n) and the velocity coordinates (v_x,n,v_y,n,v_z,n) for said location fix time t=t_n, and replacing said index h1 by the augmented index h1'"'"'.

3. The method of claim 1, wherein said step of determining said second index comprises the steps of:

assigning a consecutive set of integers k=0, 1, 2, . . . , K-1 to a selected set of SATPS satellites that includes said M satellites that form said constellation at time t=t_n ; and

defining said index h2=h2(t_n) as a sum ##EQU10## where a_k,n =1 if satellite number k is part of said constellation at time t=t_n and a_k,n =0 otherwise, and A, B and C are selected constants with A≠

0 and w is a selected constant different from 1.

4. The method of claim 1, further comprising the step of selecting said fourth index h4=h4(t_n) from a selected subset of the following parameters used to describe the path followed by a satellite that is part of the SATPS:

{CODE, WN, L2/P, SV Accuracy, SVHealth, T_GD (sec), IODC, t_oc (sec), a_f2 (sec^-1), a_f1, a_f0 (sec), IODE, C_rc (meters), C_sc (meters), Δ

n(sec^-1), M_o, C_uc (rad), C_sc (rad), ε

, A^1/2 (meters^1/2), t_os (sec), C_ic (rad), C_is (rad), OMEGA_o, OMEGADOT(sec^-1), i_o, ω

, t_oe (sec), e, Φ

_k, δ

u_k, IDOT, C_us (rad), C_rs (rad), δ

1, SVConfig, A0(sec), A1, Δ

t_LS (sec.sub.), Δ

t_LSF (sec), t_ot (sec), WN_t, WN_LSF, DN}.

5. The method of claim 1, further comprising the step of selecting said fifth index h5=h5(t_n) from a selected subset of the following parameters used to describe the path followed by a satellite that is part of the SATPS:

{(α

₀, α

₁, α

₂, α

₃, β

₀, β

₁, β

₂, β

₃, t_oa, WN₈, a_f0 (sec), a_f1, A₀ (sec), A₁,a, b, f(sec^-1), E, A, φ

_m, t_ot (sec), DN, WN, WN_LSF, WN_t, φ

_u, λ

_u }.

6. The method of claim 1, further comprising the step of selecting said sixth index h6=h6(t_n) from a selected subset of the following parameters used to describe the path followed by a satellite that is part of the SATPS:

{K, M_i, π

_i ;

t_n, x_n, y_n, z_n }, where K is the number of satellites in the present constellation, M_i refers to the method used to determine the location solution from the SATPS signals received, π

_i is the set of parameters to be used with the method M_i, and (t_n,x_n,y_n,z_n) are the temporal and spatial coordinates for the present location determined at the location fix time t=t_n.

7. The method of claim 1, further comprising the step of selecting said fourth index h4 and said fifth index h5 so that no information specified by one of these two indices is also specified by the other of these indices.

8. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with said index h1 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said tour location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n);

adding to said selected signal bit information associated with at least one of said index h2 and said index h3 each time additional SATPS signals are received that causes at least of (1) said selected constellation of M satellites and (2) said IODC parameter for said selected constellation of M satellites to change; and

adding to said selected signal bit information associated with at least one of said index h4, said index h5 and said index h6 each time additional SATPS signals are received that causes at least of (1) said set of ephemeris parameters, (2) said set of almanac parameters, (3) said set of clock correction parameters, (4) said set of ionospheric parameters, (5) said set of tropospheric parameters and (6) said location solution method or said location solution method parameters used in determining said total solution coordinates to change.

9. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1 and said index h2 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes said selected constellation of M satellites to change;

adding to said selected signal bit information associated with said index h3 each time additional SATPS signals are received that causes said IODC parameter for said selected constellation of M satellites to change; and

adding to said selected signal bit information associated with at least one of said index h4, said index h5 and said index h6 each time additional SATPS signals are received that causes at least of (1) said set of ephemeris parameters, (2) said set of almanac parameters, (3) said set of clock correction parameters, (4) said set of ionospheric parameters, (5) said set of tropospheric parameters and (6) said location solution method or said location solution method parameters used in determining said total solution coordinates to change.

10. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1 and said index h3 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes said IODC parameter for said selected constellation of M satellites to change;

adding to said selected signal bit information associated with said index h2 each time additional SATPS signals are received that causes said selected constellation of M satellites to change; and

adding to said selected signal bit information associated with at least one of said index h4, said index h5 and said index h6 each time additional SATPS signals are received that causes at least of (1) said set of ephemeris parameters, (2) said set of almanac parameters, (3) said set of clock correction parameters, (4) said set of ionospheric parameters, (5) said set of tropospheric parameters and (6) said location solution method or said location solution method parameters used in determining said total solution coordinates to change.

11. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1, said index h2 and said index h3 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes at least of (1) said selected constellation of M satellites and (2) said IODC parameter for said selected constellation of M satellites to change; and

adding to said selected signal bit information associated with at least one of said index h4, said index h5 and said index h6 each time additional SATPS signals are received that causes at least of (1) said set of ephemeris parameters, (2) said set of almanac parameters, (3) said set of clock correction parameters, (4) said set of ionospheric parameters, (5) said set of tropospheric parameters and (6) said location solution method or said location solution method parameters used in determining said total solution coordinates to change.

12. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1, said index h3 and said index h4 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes at least one of (1) said IODC parameter for said selected constellation of M satellites, (2) said set of ephemeris parameters, (3) said set of almanac parameters, (4) said set of clock correction parameters to change;

adding to said selected signal bit information associated with said index h2 each time additional SATPS signals are received that causes said selected constellation of M satellites to change; and

adding to said selected signal bit information associated with at least one of said index h5 and said index h6 each time additional SATPS signals are received that causes at least of (1) said set of ionospheric parameters, (2) said set of tropospheric parameters and (3) said location solution method or said location solution method parameters used in determining said total solution coordinates to change.

13. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with said index h1 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes at least one of (1) said set of ionospheric parameters and (2) said set of tropospheric parameters to change

adding to said selected signal bit information associated with at least one of said index h2 and said index h3 each time additional SATPS signals are received that causes at least of (1) said selected constellation of M satellites and (2) said IODC parameter for said selected constellation of M satellites to change; and

adding to said selected signal bit information associated with at least one of said index h4 and said index h6 each time additional SATPS signals are received that causes at least of (1) said set of ephemeris parameters, (2) said set of almanac parameters, (3) said set of clock correction parameters and (4) said location solution method or said location solution method parameters used in determining said total solution coordinates to change.

14. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1, said index h2 and said index h6 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes at least one of (1) said selected constellation of M satellites and (2) said location solution method or said location solution method parameters used in determining said total solution coordinates to change;

adding to said selected signal bit information associated with said index h3 each time additional SATPS signals are received that causes said IODC parameter for said selected constellation of M satellites to change; and

adding to said selected signal bit information associated with at least one of said index h4 and said index h5 each time additional SATPS signals are received that causes at least of (1) said set of ephemeris parameters, (2) said set of almanac parameters, (3) said set of clock correction parameters, (4) said set of ionospheric parameters and (5) said set of tropospheric parameters to change.

15. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1, said index h2, said index h3, said index h5 and said index h6 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes at least of (1) said selected constellation of M satellites, (2) said IODC parameter for said selected constellation of M satellites, (3) said set of ionospheric parameters, (4) said set of tropospheric parameters and (5) said location solution method or said location solution method parameters used in determining said total solution coordinates to change; and

adding to said selected signal bit information associated with said index h4 each time additional SATPS signals are received that causes at least of (1) said set of ephemeris parameters, (2) said set of almanac parameters, (3) said set of clock correction parameters to change.

16. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1, said index h2, said index h3, said index h4 and said index h6 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes at least of (1) said selected constellation of M satellites, (2) said IODC parameter for said selected constellation of M satellites, (3) said set of ephemeris parameters, (4) said set of almanac parameters, (5) said set of clock correction parameters and (5) said location solution method or said location solution method parameters used in determining said total solution coordinates to change; and

adding to said selected signal bit information associated with said index h5 each time additional SATPS signals are received that causes at least of (1) said set of ionospheric parameters and (2) said set of tropospheric parameters to change.

17. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1, said index h2, said index h3, said index h4 and said index h5 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes at least of (1) said selected constellation of M satellites, (2) said IODC parameter for said selected constellation of M satellites, (3) said set of ephemeris parameters, (4) said set of almanac parameters, (5) said set of clock correction parameters and (6) said set of ionospheric parameters and (7) said set of tropospheric parameters to change; and

adding to said selected signal bit information associated with said index h6 each time additional SATPS signals are received that causes said location solution method or said location solution method parameters used in determining said total solution coordinates to change.

18. The method of claim 1, further comprising the steps of:

adding to said selected signal bit information associated with at least one of said index h1, said index h2, said index h3, said index h4, said index h5 and said index h6 each time additional SATPS signals are received that can be used to determine a set of location fix coordinates (t_n,x_n,y_n,z_n) in which at least one of said four location fix coordinates, t_n, x_n, y_n, and z_n, has changed from a preceding set of said location coordinates (t_n,x_n,y_n,z_n), or that causes at least of (1) said selected constellation of M satellites, (2) said IODC parameter for said selected constellation of M satellites, (3) said set of ephemeris parameters, (4) said set of almanac parameters, (5) said set of clock correction parameters, (6) said set of ionospheric parameters, (7) said set of tropospheric parameters and (8) said location solution method or said location solution method parameters used in determining said total solution coordinates to change.

19. A method for characterization and use of data measurements made on signals received from a plurality of SATPS satellites that facilitates subsequent processing of these data and determination of a spatial location corresponding to these measurements, the method comprising the steps of:

receiving SATPS signals at an SATPS antenna from each satellite in a selected constellation of M SATPS satellites (M≧

3), where the SATPS signals can be used to determine location fix coordinates (t_n,x_n,y_n,z_n), consisting of a location fix time t=t_n and the corresponding location coordinates (x_n,y_n,z_n) for the SATPS antenna that are determined from the SATPS signals received from the selected constellation of M SATPS satellites at the location fix time t=t_n ;

filtering the received SATPS signals to produce selected signal bit information by removing redundant signal bit information, and storing the selected signal bit information;

associating each signal bit of the selected signal bit information with an information index H that specifies, for each location fix, the total solution coordinates (t_n,x_n,y_n,z_n) for that location fix, consisting of a location fix time t=t_n and the corresponding spatial location coordinates (x_n,y_n,z_n) that are determined from signals received from the selected constellation of M SATPS satellites for each location fix time, where the index H also includes at least one of the following parameters;

v_x,n, v_y,n, v_z,n ;

SC, P;

IODC;

CODE, WN, L2/P, SV Accuracy, SVHealth, T_GD (sec), t_oc (sec), a_f2 (sec^-1), a_f1, a_f0 (sec), IODE, C_rc (meters), C_sc (meters), Δ

n(sec^-1), M_o, C_uc (rad), C_sc (rad), ε

, A^1/2 (meters^1/2), t_os (sec), C_ic (rad), C_is (rad), OMEGA_o, OMEGADOT(sec^-1), i_o, ω

, t_oe (sec), e, Φ

_k, δ

u_k, IDOT, C_us (rad), C_rs (rad), δ

1, SVConfig, A0(sec), A1, Δ

t_LS (sec), Δ

t_LSF (sec), t_ot (sec), WN_t, WN_LSF, DN;

α

₀, α

₁, α

₂, α

₃, β

₀, β

₁, β

₂, β

₃, MP_tropo, t_oa, WN₈, a_f0 (sec), a_f1, a, b, f(sec^-1), E, A, φ

_m, t_ot (sec), WN_LSF, WN_t, φ

_u, λ

_u ;

K, M_i, and π

_i ;

when corrected pseudorange data or corrected carrier phase data corresponding to the total solution coordinates (t_n,x_n,y_n,z_n) are required, reading the total solution coordinates (t_n,x_n,y_n,z_n) into a digital computer that is programmed to determine at least one of pseudorange data and carrier phase data from a set of total solution coordinates (t_n,x_n,y_n,z_n), reading the information associated with the index H associated with the total solution coordinates (t_n,x_n,y_n,z_n) into the computer, and causing the computer to reconstruct at least one of the required pseudorange data and the required carrier phase data from the information associated with the six indices;

receiving differential SATPS correction signals associated with at least one location fix time t=t_n1 ;

correcting the reconstructed pseudorange data or reconstructed carrier phase data, using the received differential SATPS correction signals for the at least one location fix time t=t_n1 ; and

using the corrected reconstructed pseudorange data or corrected reconstructed carrier phase data to determine and display at least one corrected location coordinate t_n, x_n, y_n, and z_n for the at least one location fix time t=t_n1.

20. The method of claim 19, further comprising the step of dividing said index H into a first segment H1 that refers to or contains said total solution coordinates (t_n,x_n,y_n,z_n) and at least one other of said parameters that is likely to change each time said location fix time t=t_n changes, and at least one other index segment H2 that contains only parameters that are likely to change less often than every time said location fix time t=t_n changes.

21. The method of claim 20, further comprising the step of determining and storing the velocity coordinates (v_x,n,v_y,n,v_z,n) from signals received from said selected constellation of M SATPS satellites, as part of said index H1, for said location fix time t=t_n.