AINS land surveyor system with reprocessing, AINS-LSSRP

• US 7,149,629 B1
• Filed: 10/05/2004
• Issued: 12/12/2006
• Est. Priority Date: 11/22/2000
• Status: Expired due to Term

• Current Assignee: Applanix Corporation, Inc.
• Original Assignee: Applanix Corporation, Inc.
• Inventors: Reid, Blake, Scherzinger, Bruno, Lithopoulos, Erik
• Primary Examiner(s): Bui, Bryan
• Assistant Examiner(s): Le, Toan M.
• Application Number:
  US10/959,249
• Time in Patent Office: 798 Days
• Field of Search: 702/5, 702/150, 701/200, 701/201, 701/207, 701/213, 701/214, 701/217, 701/220
• US Class Current: 702/5
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments

Abstract

A Land Surveyor System with Reprocessing is carried by a surveyor moving from a first known position at the start of a survey interval to a second known position at the end of the survey interval has an AINS (aided inertial navigation system) that provides a continuing sequence of time-indexed present position values. A Position Computing System uses a program that stores the sequence of time-indexed present position values in a memory. A reprocessing computer and program is activated at the second known position to access and process the continuing sequence of time-indexed present position values with a smoothing program to provide indexed and adjusted present position values for at least some of the time-indexed present position values. The system is packaged for transport and use by a surveyor. A switch permits the surveyor to signal that the unit is stationary as a reset for the AINS.

Claims

1. A Land Surveyor System with Reprocessing (LSSRP) comprising:

an Aided Inertial Navigation System (AINS) providing a sequence of time-indexed present position values in response to the LSSRP being moved from a first known position value at the start of a survey interval to a second known position value at the end of the survey interval,

a Position Computing System (PCS) coupled to receive and store the sequence of time-indexed present position values as a surveyor carries the LSSRP from the first known position to the second known position,

the PCS and the AINS being integrally coupled into a package, the package further comprising;

a means for inputting and time-indexing successive first and second known present position values at respective successive known present position fixes, each successive pair of known present position values establishing the beginning and end of a survey interval,

the PCS having a reprocessing computer and program means coupled to receive and store the successive time-indexed known present position fix values for processing the indexed present position values with a Modified Bryson-Frazier smoother (MBFS) algorithm to provide indexed and adjusted present position values for at least some of the indexed present position values between the first known position fix value at the start of the survey interval and the second known position fix value at the end of the survey interval.

2. The LSSRP of claim 1 wherein the AINS uses a Kalman filter responsive to at least two sources of aiding signals,

the PCS having an aiding signal selector algorithm characterized to select the most accurate aiding signal for use by the Kalman filter from all available aiding signals.

3. The LSSRP of claim 1 wherein the means for inputting and time-indexing successive first and second known present position values at respective successive known present position fixes further comprises:

an input/output interface device having a computer key pad and a read-out display electrically coupled to the PCS for inputting successive known present position values and for signaling the start of reprocessing after inputting each successive known present position value.

4. The LSSRP of claim 1 wherein the PCS coupled to receive and store the sequence of time-indexed present position values further comprises:

a mass storage memory for storing the sequence of time-indexed present position values.

5. The LSSRP of claim 4 wherein the mass storage memory for storing the sequence of time-indexed present position values is linked to the reprocessing computer and program mean by a radio link.

6. The LSSRP of claim 1 further comprising:

a switch means for signaling the AINS and the Kalman filter that the unit is stationary by use of an algorithm, running in the PCS reprocessing computer and program means, for deducing zero velocity from computed inertial velocity.

7. The LSSRP of claim 6 wherein

the switch means is a manually operated switch with the surveyor manually signals the AINS that the unit is stationary.

8. The LSSRP of claim 6 wherein the switch means comprises:

a mechanical closure coupled to the package and electrically coupled to the AINS to signal the AINS that the unit is stationary, the mechanical closure being transferred by operation of a lever or plunger contacting the ground.

9. The LSSRP of claim 1 wherein the reprocessing computer and program means smoothing algorithm is a modified Bryson-Frazier smoother (MBFS) mechanized using the following equations and definitions for steps and definitions:

data available to the MBFS at iteration k from the AINS-LSSRP Kalman filter;

Φ

(k;

k−

1) transition matrix from iteration k−

1 to iteration k,

H_k measurement matrix,

K_k Kalman gain,

S_k Kalman innovations covariance,

{overscore (ξ

)}_k innovations vector,

{overscore ({circumflex over (x)}_k⁻

, {overscore ({circumflex over (x)}_k⁺ Kalman estimated error state,

P_k⁻

, P_k⁺ Kalman generated estimation error VCV matrix,

and where,

the backwards extrapolation follows;

{overscore (λ

)}<sub>k−

1</sub>⁺=Φ

^T(k;

k−

1){overscore (λ

)}_k⁻

, 

 

(12)

Λ

<sub>k−

1</sub>⁺=Φ

^T(k;

k−

1)Λ

_k⁻

Φ

(k;

k−

1), 

 

(13)

and the adjoint measurement update follows;

{overscore (λ

)}_k⁻

=(I−

H_kK_k){overscore (λ

)}_k⁺−

H_kS_k<sup>−

1</sup>{overscore (ξ

)}_k,  

 

(14)

Λ

_k⁻

=(I−

H_kK_k)^TΛ

_k⁺(I−

H_kK_k)+H_k^TS_kH_k, 

 

(15)

and where;

{overscore (λ

)}_k⁻

is the a priori adjoint state vector,

Λ

_k⁻

is the a priori adjoint VCV matrix,

{overscore (λ

)}_k⁺ is the a posteriori state vector, and

{overscore (λ

)}_k⁺ is the a posteriori adjoint VCV matrix;

and where;

the smoothed state and estimation error VCV matrix is defined by;

{overscore (x)}_k^s={overscore (x)}_k⁻

−

P_k⁻

{overscore (λ

)}_k⁻

={overscore (x)}_k⁺−

P_k⁺{overscore (λ

)}_k⁺, 

 

(16)

P_k^s=P_k⁻

(I−

Λ

_k⁻

P_k⁻

)=P_k⁺(I−

Λ

_k⁺P_k⁺), 

 

(17)

and where the smoothed state vector is defined by;

10. A Land Surveyor System with Reprocessing (LSSRP) transported by a surveyor moving from a first known position at the start of a survey interval to a second known position at the end of the survey interval, the LSSRP comprising:

an Aided Inertial Navigation System (AINS) having a Kalman filter coupled to be responsive to at least a first source of aiding time-indexed values, the AINS providing a continuing sequence of time-indexed present position values,

a Position Computing System (PCS) having a program for storing the continuing sequence of time-indexed present position values in a memory,

the PCS further comprising a reprocessing computer and program means activated at the second known position to access and process the stored continuing sequence of time-indexed present position values with an optimal smoothing program to provide indexed and adjusted present position values for at least some of the continuing sequence of time-indexed present position values.

11. The Land Surveyor System with Reprocessing (LSSRP) of claim 10 wherein:

the PCS and the AINS are integrally coupled into a package carried by and used by a surveyor, the package further comprising;

an input/output interface device having a means for inputting and time-indexing the known present position values at respective successive known present position fixes, each successive pair of known present position values establishing the beginning and end of a survey interval.

12. The Land Surveyor System with Reprocessing (LSSRP) of claim 10 wherein

the program for storing the continuing sequence of time-indexed present position values in a memory is further characterized to output the time-indexed present position values of the PCS as the surveyor moves from the first known position to the second known position, the surveyor using the output time-indexed present position value to locate at least one predetermined stake position.

13. The LSSRP of claim 10 wherein

the PCS further comprises an aiding signal selector for analyzing the aiding position signals available to the AINS and for commanding the AINS to select and use the highest accuracy aiding position signal available.

14. The LSSRP of claim 13 wherein

the aiding signal selector for analyzing the aiding position signals available to the AINS monitors for loss of differential Global Position Satellite (GPS) and directs the AINS to not use differential GPS signals as aiding position signals until differential GPS is restored.

15. The LSSRP of claim 13 wherein

the aiding signal selector is further characterized to receive all aiding position signals and to select and provide the highest accuracy aiding position signal to the AINS for use as an input to the Kalman filter.

16. The LSSRP of claim 10 wherein the PCS further comprises:

a mass storage memory for storing the sequence of time-indexed present position values in an array of memory locations for later recall.

17. The LSSRP of claim 10 wherein the PCS and AINS package further comprises a switch means for signaling that the AINS that the unit is stationary.

18. The LSSRP of claim 10 further comprising:

a switch means for signaling the AINS and the Kalman filter that the unit is stationary by use of an algorithm, running in the PCS reprocessing computer and program means, for deducing zero velocity from computed inertial velocity.

19. The LSSRP of claim 17 wherein

the switch means is further characterized to be coupled to the package and electrically coupled to the AINS and to automatically signal the start of a Zero-velocity Update (ZUPD) on contact with the ground.

20. A Land Surveyor System with Reprocessing (LSSRP) to be carried or transported by a surveyor along a predetermined path or a zigzag pattern of parallel seismic lines to locate and record the position fixes of stakes that the surveyor positions in accordance with a pre-planned grid of predetermined locations comprising:

an AINS programmed to provide a sequence of time-indexed present position values in response to the LSSRP being moved from a first known position fix location or “

tie-down”

at the start of a survey interval to a second known position fix location or “

tie-down”

at the end of the survey interval,

a reprocessing computer running a reprocessing program to process the indexed present position values with a Modified Bryson-Frazier smoother (MBFS), the reprocessing computer and smoothing algorithm calculating and storing smoothed and corrected indexed and adjusted present position values at the end of each survey interval, the resulting smoothed and corrected indexed and adjusted present position values being used to correct the position value or fix location of at least one stake positioned between the first known position fix location at the start of the survey interval and the second known position fix location at the end of the survey interval.

21. The Land Surveyor System with Reprocessing (LSSRP) of claim 20 further comprising:

a Position Computing System (PCS) coupled to the AINS to receive and store the sequence of time-indexed present position values from the AINS as the surveyor moves the Land Surveyor System with Reprocessing (LSSRP) from the first known position fix location to the second known position fix location, the PCS and the AINS being integrally coupled into

a package, the package being carried by the surveyor, the package further comprising;

an input/output interface device having a means for inputting successive known present position fix location values at respective successive known present position fix locations, each successive pair of known present position values establishing the beginning and the end of a survey interval.

22. The Surveyor System with Reprocessing (LSSRP) of claim 21 further comprising

a switch means coupled to the PCS for signaling that the package is stationary.

23. The Surveyor System with Reprocessing (LSSRP) of claim 22 wherein the switch means comprises an algorithm running in the AINS and or the PCS for automatically signaling when the package is stationary.

24. The Surveyor System with Reprocessing (LSSRP) of claim 22 further comprising:

an aiding signal selector means coupled to at least two sources of aiding signals for analyzing the aiding position signals available for use by a Kalman filter and for automatically selecting the most accurate aiding signal for use by the Kalman filter from all available aiding signals.