Ranging method and apparatus
First Claim
1. A ranging method for measuring the distance between a measuring apparatus and a target employing the laser radar impulse transit time principle, comprising the following steps:
- (a) using a single receiver detector for producing start signals and stop signals for time interval measurements,(b) generating laser light impulses for directing said laser light impulses toward said target,(c) passing a first fraction of said laser light impulses through a first optical delay line to said receiver detector for providing a first reference signal (Ref.
1),(d) passing simultaneously a second fraction of said laser light impulses through a second optical delay line, which is longer than said first optical delay line, to said receiver detector for forming a second reference signal (Ref.
2),(e) transmitting the remainder of said laser light impulses to said target for producing a target reflected signal (ZS),(f) determining the range to said target by ascertaining a first target time difference between said first reference signal and said target reflected signal,(g) determing a second time difference between said first reference signal and said second reference signal for providing a calibration measure, and(h) forming the ratio of the first and second time differences as a value representing the actual target range or distance.
1 Assignment
0 Petitions
Accused Products
Abstract
A radar ranging system uses a laser transmitter and a single detector for producing the start and stop signals for the time interval measurement. Two reference signals are produced by passing two light portions, decoupled from the laser light to be transmitted to a target, through two different delay lines to the detector. The time difference between the first reference signal and a target signal is a measure for the range to be measured. The time difference between the two reference signals is used as a calibration measure for repeatedly calibrating the system. The true range is calculated by forming the ratio of the two time intervals.
-
Citations
12 Claims
-
1. A ranging method for measuring the distance between a measuring apparatus and a target employing the laser radar impulse transit time principle, comprising the following steps:
-
(a) using a single receiver detector for producing start signals and stop signals for time interval measurements, (b) generating laser light impulses for directing said laser light impulses toward said target, (c) passing a first fraction of said laser light impulses through a first optical delay line to said receiver detector for providing a first reference signal (Ref.
1),(d) passing simultaneously a second fraction of said laser light impulses through a second optical delay line, which is longer than said first optical delay line, to said receiver detector for forming a second reference signal (Ref.
2),(e) transmitting the remainder of said laser light impulses to said target for producing a target reflected signal (ZS), (f) determining the range to said target by ascertaining a first target time difference between said first reference signal and said target reflected signal, (g) determing a second time difference between said first reference signal and said second reference signal for providing a calibration measure, and (h) forming the ratio of the first and second time differences as a value representing the actual target range or distance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A ranging apparatus for measuring a distance between said apparatus and a target employing the laser radar impulse transit time principle, comprising:
-
(a) receiver means including a single receiver detector for producing start signals and stop signals for time interval measurements, (b) a laser light generator for generating laser light impulses for directing said laser light impulses toward said target, (c) a first optical delay line and first transmitter coupling means for passing a first fraction of said laser light impulses through said first optical delay line to said single receiver detector for providing a first reference signal (Ref.
1),(d) a second optical delay line and second transmitter coupling means for passing simultaneously a second fraction of said laser light impulses through said second optical delay line, which is longer than said first optical delay line, to said receiver detector for forming a second reference signal (Ref.
2),(e) laser light transmitting means for transmitting the remainder of said laser light impulses to said target for producing a target reflected signal (ZS), (f) first time measuring means (41) for measuring a first target time difference or interval for determining the range to said target by ascertaining said first target time difference between said first reference signal and said target reflected signal, (g) second time measuring means (42) for determining a second time difference between said first reference signal and said second reference signal for providing a calibration measure, and (h) means for forming the ratio of the first and second time differences as a value representing the actual target range or distance. - View Dependent Claims (10, 11, 12)
-
Specification