Method for determining object movement data

• US 6,204,804 B1
• Filed: 10/29/1999
• Issued: 03/20/2001
• Est. Priority Date: 10/30/1998
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Andersson, Bengt Lennart
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US09/429,016
• Time in Patent Office: 508 Days
• Field of Search: 342/59, 342/104, 342/107, 342/109, 342/113, 342/114, 342/115, 342/118, 342/134, 342/139, 342/147, 342/149, 342/175, 342/194-197, 342/25, 342/52, 342/58, 342/60
• US Class Current: 342/113
• CPC Class Codes: G01S 13/53 performing filtering on a single spectral line and associated with one or more range gates with a phase detector or a frequency mixer to extract the Doppler information, e.g. pulse Doppler radar G01S13/5244 takes precedence
• CPC Class Codes: G01S 13/589 measuring the velocity vector
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations

Abstract

The velocity vector of a moving object is precisely determined by using radar measurements of the angle to and the radial speed of a moving object. This can be done in a radar system comprising one or more units. The technique also makes it possible to precisely determine the range to a moving object from a single moving radar unit.

Claims

1. A method for determining movement information of a moving object from data provided by a radar system comprising at least one radar unit (F1, F2), whereby

the at least one radar unit (F1, F2) is scanning objects in a given plane and is determining the radial speed (v₁, v₂) of the moving object, the at least one radar unit (F1, F2) is furthermore determining the angle (β

₁, β

₂) to the moving object with respect to a predetermined co-ordinate system, whereby

two measurements of said radial speed (v₁, v₂) and said angle (β

₁, β

₂) are performed by means of the at least one radar unit (F1, F2) at two different positions, whereby

the angle (α

) of the velocity vector (v, α

) of an object with respect to the predetermined co-ordinate system is determined according to $\mathrm{\alpha <br><br>}={\mathrm{tg}}^{-1}<br><br>\left(\frac{v_2<br><br>\cos <br><br>\left({\mathrm{\beta <br><br>}}_1\right)-v_1<br><br>\cos <br><br>\left({\mathrm{\beta <br><br>}}_2\right)}{v_1<br><br>\sin <br><br>\left({\mathrm{\beta <br><br>}}_2\right)-v_2<br><br>\sin <br><br>\left({\mathrm{\beta <br><br>}}_1\right)}\right)$

 

and the speed (v) of the velocity vector (v, α

) is determined according to $v=-\text{\hspace{1em}<br><br>}<br><br>\frac{v_1}{\cos <br><br>\left(\mathrm{\alpha <br><br>}-{\mathrm{\beta <br><br>}}_1\right)}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{or}<br><br>\text{\hspace{1em}<br><br>}<br><br>v=-\text{\hspace{1em}<br><br>}<br><br>\frac{v_2}{\cos <br><br>\left(\mathrm{\alpha <br><br>}-{\mathrm{\beta <br><br>}}_2\right)}.<br><br>\text{\hspace{1em}<br><br>}$

2. The method according to claim 1, wherein said measurements (v₁, v₂;

β

₁, β

₂) are performed simultaneously using two radar units (F1, F2) being displaced at an angle from one another with regard to the object, whereby

the radar units (F1, F2) comprise communication means for transferring the measurements.

3. The method according to claim 1, wherein

the measurements (v₁, v₂;

β

₁, β

₂) are performed at least at two different points in time (t₁, t₂) and space by a single moving radar unit (F1).

4. The method according to claim 3, wherein the distance (a) the radar unit or units (F1/F2) travels between the points in time (t₁, t₂) at which the measurements (v₁, v₂;

β

₁, β

₂) are performed is determined according to navigation equipment associated with the radar unit or units (F1) and wherein

the distance (R) from the radar unit to the object at the position where the first measurement is made is determined according to $R=\frac{a}{\sin <br><br>\left({\mathrm{\beta <br><br>}}_1-{\mathrm{\beta <br><br>}}_2\right)}·<br><br>\left(\cos <br><br>\left({\mathrm{\beta <br><br>}}_2\right)-\frac{s}{a}·<br><br>\sin <br><br>\left(\mathrm{\alpha <br><br>}-{\mathrm{\beta <br><br>}}_2\right)\right),$

 

and where the distance the object is travelling between the points in time (t₁, t₂) is calculated from said determination of the speed (v) of the velocity vector (v, α

) of the moving object according to

5. The method of claim 3, wherein the determination of the velocity vector (v, α

) is performed when said velocity vector remains constant during the time between the measurements.

6. The method according to claim 1, wherein the measurements (v₁, v₂;

β

₁, β

₂) are performed at least at two different points in time (t₁, t₂) by a plurality of radar units (F1, F2) having communication means for transferring the measurements.

7. The method of claim 4, wherein the determination of the velocity vector (v, α

) is performed when said velocity vector remains constant during the time between the measurements.