System and method for collection of global AIS and radar track information

• US 7,817,079 B1
• Filed: 04/17/2008
• Issued: 10/19/2010
• Est. Priority Date: 04/17/2008
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Funk, Clarence John
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Barker; Matthew M
• Application Number:
  US12/105,129
• Time in Patent Office: 915 Days
• Field of Search: 342/41
• US Class Current: 342/41
• CPC Class Codes: G01S 13/917 for marine craft or other waterborne vessels
• CPC Class Codes: G01S 13/937 of marine craft
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G08G 3/00 Traffic control systems for marine craft marking of navigational route B63B22/16, B63B51/00

Abstract

Methods and apparatuses are described that enable the automatic collection of maritime vessel location information within a global or regional framework by using a minimum network of vessels outfitted with non-intrusive AIS data collection systems. The network of vessels may comprise standard ships operating within their normal commercial or private tasks. By utilizing these non-specially tasked vessels and augmenting the received AIS reports with onboard radar/navigation information, accurate global or regional tracking information can be generated at a centralized location without incurring large costs.

Claims

1. A method for tracking a network of ships, comprising:

forming a network of a plurality of data collection ships (DCS);

receiving, from the plurality of the DCSes, Automatic Information System (AIS) reports provided by nearby ships'"'"' own-ship position information;

receiving radar intercepts of the nearby ships by the plurality of the DCSes;

filtering the received AIS reports, own-ship position information, and radar intercepts to generate smoothed ship track reports;

sampling of the smoothed ship track reports to create sampled track reports having a reduced data size;

generating sample track messages from the sampled track reports;

forwarding the sampled track messages to a central data processing facility (CDPF); and

correlating the forwarded messages to provide global tracking information on the DCSes and the nearby ships.

2. The method according to claim 1, wherein the receiving radar intercepts includes at least one of an automatic generation of radar intercept records on nearby ships, an automatic generation of own-ship track records, and an automatic generation of AIS track records and AIS header records from the received AIS reports.

3. The method according to claim 1, wherein the filtering is performed with a Kalman filter scheme.

4. The method according to claim 1, wherein the forwarding the sampled track messages is performed using a SATCOM system.

5. The method of claim 1, wherein the step of sampling step further comprises sampling the smoothed ship track reports at a data sampling interval Δ

t_i where the subscript i indicates that the data sampling interval is dependent on the behavior of a given ship track such that if a specific ship is maneuvering, the sampling intervals are shorter than the sampling interval for a different ship maintaining constant course and speed.

6. The method of claim 5 wherein the value of the data sampling interval Δ

t_i, determined for each track by the criteria that;

Δ

lat_i(t)=lat_i^KFi(t)−

lat_i<sup>Δ

ti</sup>(t)≦

error_lat,

Δ

lon_i(t)=lon_i^KFi(t)−

lon_i<sup>Δ

ti</sup>(t)≦

error_lon,

Δ

crs_i(t)=crs_i^KFi(t)−

crs_i<sup>Δ

ti</sup>(t)≦

error_crs, and

Δ

speed_i(t)=speed_i^KFi(t)−

speed_i<sup>Δ

ti</sup>(t)≦

error_speed

where Δ

lat_i, is the change in latitude of the specific ship, Δ

lon_i is the change in longitude of the specific ship, Δ

crs_i is the change in course of the specific ship, and Δ

speed_i is the change in speed of the specific ship.

7. The method of claim 6 wherein:

the subscript i denotes the estimate of the corresponding parameter from the filtered track for the i^th ship and the superscript Δ

t_i denotes the estimate of the corresponding parameter that can be determined by using a data-smoothing algorithm to interpolate among the sampled values during the time period t₁≦

t≦

t₂, where the value t₁ is the time of the first sample and t₂ is the time of the last sample for a given track; and

wherein the values for the four error terms, error_lat, error_lon, error_crs, and error_speed are selected to establish the quality of the track data stored in the databases used at the CDPF.

8. The method of claim 1 further comprising the step of reporting an AIS track header message by each DCS each time data from a different ship is collected.

9. A system to track a network of ships, comprising:

means for forming a network of a plurality of data collection ships (DCS);

means for receiving, by the plurality of the DCSes, Automatic Information System (AIS) reports provided by nearby ships'"'"' own-ship position information;

means for receiving radar intercepts and corresponding GPS data from the nearby ships by the plurality of the DCSes;

means for filtering the received AIS reports, own-ship position information, and radar intercepts to generate smoothed ship track reports;

means for sampling of the smoothed ship track reports to create sampled track reports having a reduced data size;

means for generating sample track messages from the sampled track reports;

means for forwarding the sampled track messages to a central data processing facility (CDPF); and

means for correlating the forwarded messages to provide global tracking information on the DCSes and the nearby ships.

10. The system according to claim 9, wherein the means for forwarding is a SATCOM system.

11. The system according to claim 9, wherein the means for filtering is a Kalman filtering scheme.

12. The system according to claim 9 wherein the means for means for sampling of the smoothed ship track reports samples the smoothed ship track reports at a data sampling interval Δ

t_i, where the subscript i indicates that the data sampling interval is dependent on the behavior of a given ship track such that if a specific ship is maneuvering, the sampling intervals are shorter than the sampling interval for a different ship maintaining constant course and speed.

13. The system of claim 12 wherein the value of the data sampling interval Δ

t_i, determined for each track by the criteria that;

Δ

lat_i(t)=lat_i^KFi(t)−

lat_i<sup>Δ

ti</sup>(t)≦

error_lat,

Δ

lon_i(t)=lon_i^KFi(t)−

lon_i<sup>Δ

ti</sup>(t)≦

error_lon,

Δ

crs_i(t)=crs_i^KFi(t)−

crs_i<sup>Δ

ti</sup>(t)≦

error_crs, and

Δ

speed_i(t)=speed_i^KFi(t)−

speed_i<sup>Δ

ti</sup>(t)≦

error_speed

where Δ

lat_i, is the change in latitude of the specific ship, Δ

lon_i is the change in longitude of the specific ship, Δ

crs_i is the change in course of the specific ship, and Δ

speed_i is the change in speed of the specific ship.

14. The system of claim 13 wherein:

the subscript i denotes the estimate of the corresponding parameter from the filtered track for the i^th ship and the superscript Δ

t_i denotes the estimate of the corresponding parameter that can be determined by using a data-smoothing algorithm to interpolate among the sampled values during the time period t₁≦

t≦

t₂, where the value t₁ is the time of the first sample and t₂ is the time of the last sample for a given track; and

wherein the values for the four error terms, error_lat, error_lon, error_crs, and error_speed are selected to establish the quality of the track data stored in the databases used at the CDPF.