Location estimation of one or more transmitters based on signals transmitted therefrom

• US 6,567,669 B1
• Filed: 05/16/2000
• Issued: 05/20/2003
• Est. Priority Date: 03/22/2000
• Status: Expired due to Term

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Groome, W. C. Andrew
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): Nguyen, Tu X
• Application Number:
  US09/571,237
• Time in Patent Office: 1,099 Days
• Field of Search: 455/450, 455/451, 455/452, 455/62, 455/456, 342/450, 342/452, 342/463, 342/465
• US Class Current: 455/456.6
• CPC Class Codes: G01S 5/02213 Receivers arranged in a network for determining the position of a transmitter

Abstract

A method is disclosed for estimating the location of a transmitter based on signals transmitted therefrom. The transmitted signals are received at a plurality of reception locations and are employed to compile data including a plurality of entries, where each entry includes a received signal level (RSL) of a received signal, a channel identification of the received signal, and position information corresponding to the respective reception location when the received signal was received. The entries are organized into groups according to channel identification, and, in each group, entries having the same position information are consolidated. Thereafter, for each entry, the distance DRT between the reception location and the transmitter is estimated, and the distance DRR between the reception location thereof and an adjacent reception location is also estimated. Then, for each group, the location of the transmitter corresponding to the channel identification of such group is estimated based on the distances DRT and DRR.

Claims

1. A method for estimating the location of a transmitter based on signals transmitted therefrom, the transmitted signals being received at a plurality of reception locations and being employed to compile data including a plurality of entries, each entry including a received signal level (RSL) of a received signal, a channel identification of the received signal, and position information corresponding to the respective reception location when the received signal was received, the method comprising:

organizing the entries into groups according to channel identification;

in each group, consolidating entries having the same position information;

for each entry, estimating the distance DRT between the reception location and the transmitter;

for each entry, estimating the distance DRR between the reception location thereof and an adjacent reception location; and

for each group, estimating the location of the transmitter corresponding to the channel identification of such group based on the distances DRT and DRR.

2. The method of claim 1 wherein estimating the location of the transmitter corresponding to the channel identification of such group based on the distances DRT and DRR for each group comprises:

for each entry;

employing the distances DRR and DRT thereof to form mirrored isosceles triangles, each having a common base with distance DRR and sides with distances DRT; and

estimating first and second isosceles location for the transmitter based on the formed mirrored isosceles triangles; and

for each group;

averaging the first isosceles locations thereof;

assessing the deviation of the first isosceles locations thereof;

averaging the second isosceles locations thereof;

assessing the deviation of the second isosceles locations thereof; and

determining from the deviations which of the first and second averaged locations is the location of the transmitter of such group.

3. The method of claim 1 wherein estimating the first and second isosceles locations for each group comprises estimating such locations such that the first isosceles locations are on one side of a path defined by the common bases and wherein the second isosceles locations are on the other side of such path.

4. The method of claim 1 wherein each of the first and second isosceles locations is expressed according to first and second coordinates, and wherein averaging comprises averaging the respective first coordinates to produce an averaged first coordinate and averaging the respective second coordinates to produce an averaged second coordinate.

5. The method of claim 4 wherein assessing the deviation comprises determining a first deviation of the respective first coordinates, determining a second deviation of the respective second coordinates, and determining a root mean square of the first and second deviations.

6. The method of claim 1 wherein consolidating entries comprises replacing each set of entries having the same position information with a consolidated entry having such position information and an average of the received signal levels in the set.

7. The method of claim 1 wherein estimating the distance DRT for each entry comprises estimating such distance by applying the received signal level for the entry and a set of assumed reference conditions to a distance estimating function.

8. The method of claim 7 wherein applying the set of assumed reference conditions comprises selecting the assumed reference conditions based on the type of transmitter and environment.

9. The method of claim 7 comprising applying the received signal level and the assumed reference conditions to the function:

$r=10^\left[\frac{1}{m}<br><br>\left(\mathrm{RSL}-\mathrm{P1}-10<br><br>\log <br><br>\left(\frac{P_t}{P_{\mathrm{ref}}}\right)-\mathrm{\alpha <br><br>log}<br><br>\left(\frac{h_t}{h_{\mathrm{ref}}}\right)\right)\right]$

where;

RSL=Received Signal Level (dBm)

P1=1 mile intercept (dBm)

P_t=Effective Radiated Power (ERP) of the site

P_ref=Reference ERP

m=slow fading decay slope (dB/decade)

r=the estimated distance

α

=coefficient applied to transmitter height adjustment

h_t=height above ground level of the base station transmit antenna; and

h_ref=reference height of the base station transmit antenna.

10. The method of claim 1 comprising estimating for each entry the distance between the reception location thereof and one of the reception location previous thereto and the reception location next thereafter.

11. A computer-readable medium having computer-executable instructions thereon for estimating the location of a transmitter based on signals transmitted therefrom, the transmitted signals being received at a plurality of reception locations and being employed to compile data including a plurality of entries, each entry including a received signal level (RSL) of a received signal, a channel identification of the received signal, and position information corresponding to the respective reception location when the received signal was received, the instructions comprising modules including:

a first module for organizing the entries into groups according to channel identification;

a second module for, in each group, consolidating entries having the same position information;

a third module for, for each entry, estimating the distance DRT between the reception location and the transmitter;

a fourth module for, for each entry, estimating the distance DRR between the reception location thereof and an adjacent reception location; and

a fifth module for, for each group, estimating the location of the transmitter corresponding to the channel identification of such group based on the distances DRT and DRR.

12. The medium of claim 11 wherein the fifth module comprises:

for each entry;

a first sub-module for employing the distances DRR and DRT thereof to form mirrored isosceles triangles, each having a common base with distance DRR and sides with distances DRT; and

a second sub-module for estimating first and second isosceles location for the transmitter based on the formed mirrored isosceles triangles; and

for each group;

a third sub-module for averaging the first isosceles locations thereof;

a fourth sub-module for assessing the deviation of the first isosceles locations thereof;

a fifth sub-module for averaging the second isosceles locations thereof;

a sixth sub-module for assessing the deviation of the second isosceles locations thereof; and

a seventh sub-module for determining from the deviations which of the first and second averaged locations is the location of the transmitter of such group.

13. The medium of claim 11 wherein the second sub-module estimates the first and second isosceles locations for each group such that the first isosceles locations are on one side of a path defined by the common bases and wherein the second isosceles locations are on the other side of such path.

14. The medium of claim 11 wherein each of the first and second isosceles locations is expressed according to first and second coordinates, and wherein the third and fifth sub-modules average the respective first coordinates to produce an averaged first coordinate and average the respective second coordinates to produce an averaged second coordinate.

15. The medium of claim 14 wherein the fourth and sixth sub-modules assess the deviation by determining a first deviation of the respective first coordinates, determining a second deviation of the respective second coordinates, and determining a root mean square of the first and second deviations.

16. The medium of claim 11 wherein the second module consolidates entries by replacing each set of entries having the same position information with a consolidated entry having such position information and an average of the received signal levels in the set.

17. The medium of claim 11 wherein the third module estimates the distance DRT for each entry by applying the received signal level for the entry and a set of assumed reference conditions to a distance estimating function.

18. The medium of claim 17 wherein the third module selects the assumed reference conditions based on the type of transmitter and environment.

19. The medium of claim 17 wherein the third module applies the received signal level and the assumed reference conditions to the function:

$r=10^\left[\frac{1}{m}<br><br>\left(\mathrm{RSL}-\mathrm{P1}-10<br><br>\log <br><br>\left(\frac{P_t}{P_{\mathrm{ref}}}\right)-\mathrm{\alpha <br><br>log}<br><br>\left(\frac{h_t}{h_{\mathrm{ref}}}\right)\right)\right]$

where;

RSL=Received Signal Level (dBm)

P1=1 mile intercept (dBm)

P_t=Effective Radiated Power (ERP) of the site

P_ref=Reference ERP

m=slow fading decay slope (dB/decade)

r=the estimated distance

α

=coefficient applied to transmitter height adjustment

h_t=height above ground level of the base station transmit antenna; and

h_ref=reference height of the base station transmit antenna.

20. The medium of claim 11 wherein the fourth module estimates the distance DRR between the reception location thereof and one of the reception location previous thereto and the reception location next thereafter.

21. A computer executing computer-executable instructions thereon for estimating the location of a transmitter based on signals transmitted therefrom, the transmitted signals being received at a plurality of reception locations and being employed to compile data including a plurality of entries, each entry including a received signal level (RSL) of a received signal, a channel identification of the received signal, and position information corresponding to the respective reception location when the received signal was received, the instructions comprising modules including:

a first module organizing the entries into groups according to channel identification;

a second module consolidating, in each group, entries having the same position information;

a third module, for each entry, estimating the distance DRT between the reception location and the transmitter;

a fourth module, for each entry, estimating the distance DRR between the reception location thereof and an adjacent reception location; and

a fifth module, for each group, estimating the location of the transmitter corresponding to the channel identification of such group based on the distances DRT and DRR.

22. The computer of claim 21 wherein the fifth module comprises:

for each entry;

a first sub-module employing the distances DRR and DRT thereof to form mirrored isosceles triangles, each having a common base with distance DRR and sides with distances DRT; and

a second sub-module estimating first and second isosceles location for the transmitter based on the formed mirrored isosceles triangles; and

for each group;

a third sub-module averaging the first isosceles locations thereof;

a fourth sub-module assessing the deviation of the first isosceles locations thereof;

a fifth sub-module averaging the second isosceles locations thereof;

a sixth sub-module assessing the deviation of the second isosceles locations thereof; and

a seventh sub-module determining from the deviations which of the first and second averaged locations is the location of the transmitter of such group.

23. The computer of claim 21 wherein the second sub-module estimates the first and second isosceles locations for each group such that the first isosceles locations are on one side of a path defined by the common bases and wherein the second isosceles locations are on the other side of such path.

24. The computer of claim 21 wherein each of the first and second isosceles locations is expressed according to first and second coordinates, and wherein the third and fifth sub-modules average the respective first coordinates to produce an averaged first coordinate and average the respective second coordinates to produce an averaged second coordinate.

25. The computer of claim 24 wherein the fourth and sixth sub-modules assess the deviation by determining a first deviation of the respective first coordinates, determining a second deviation of the respective second coordinates, and determining a root mean square of the first and second deviations.

26. The computer of claim 21 wherein the second module consolidates entries by replacing each set of entries having the same position information with a consolidated entry having such position information and an average of the received signal levels in the set.

27. The computer of claim 21 wherein the third module estimates the distance DRT for each entry by applying the received signal level for the entry and a set of assumed reference conditions to a distance estimating function.

28. The computer of claim 27 wherein the third module selects the assumed reference conditions based on the type of transmitter and environment.

29. The computer of claim 27 wherein the third module applies the received signal level and the assumed reference conditions to the function:

$r=10^\left[\frac{1}{m}<br><br>\left(\mathrm{RSL}-\mathrm{P1}-10<br><br>\log <br><br>\left(\frac{P_t}{P_{\mathrm{ref}}}\right)-\mathrm{\alpha <br><br>log}<br><br>\left(\frac{h_t}{h_{\mathrm{ref}}}\right)\right)\right]$

where;

RSL=Received Signal Level (dBm)

P1=1 mile intercept (dBm)

P_t=Effective Radiated Power (ERP) of the site

P_ref=Reference ERP

m=slow fading decay slope (dB/decade)

r=the estimated distance

α

=coefficient applied to transmitter height adjustment

h_t=height above ground level of the base station transmit antenna; and

h_ref=reference height of the base station transmit antenna.

30. The computer of claim 21 wherein the fourth module estimates the distance DRR between the reception location thereof and one of the reception location previous thereto and the reception location next thereafter.