JPS62119486A - Radar altitude measuring system - Google Patents

Abstract

PURPOSE:To measure the altitude of a target without increasing the size of an antenna by interlocking a plurality of two-dimensional radars and determining the altitude of the target from the distance data of the target from two points and the bearing data of the target from one of the two points. CONSTITUTION:When a two-dimensional radar 2 finds a target aircraft and measures its distance and bearing, the radar 2 transmits the data thus obtained to another radar 1 by a microwave communication apparatus 7 and the radar 1, receiving the data, and emits a beam to the target in synchronism with the radar 2. An altitude calculating filter 5, incorporating the precise distance and bearing data of the target from the position of the radar 1 and the precise distance data of the target from the position of the radar 2, the latter data being received from the radar 2, calculates altitude of the target.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radar height measurement method in an air traffic control radar.

[Conventional technology]

Conventionally, there are two ways to measure the altitude of an aircraft: an aircraft equipped with a transponder transmits the barometric altimeter values back to the ground using mode C of a secondary radar, and a three-dimensional radar that measures the altitude based on the elevation angle and distance of the aircraft. There was something to measure altitude.

[Problem that the invention seeks to solve]

Among the conventional technologies mentioned above, the method using secondary radar has the limitation that the aircraft must be equipped with a transponder, and the method using the same three-dimensional radar measures altitude from distance and elevation angle. Therefore, in order to reduce the altitude error over long distances, the antenna must be made larger, resulting in a larger system.

SUMMARY OF THE INVENTION An object of the present invention is to provide a radar height measurement method that eliminates such drawbacks, eliminates the need for a transponder, and allows altitude measurement without using a three-dimensional radar.

[Failure to solve the problem]

The configuration of the present invention includes a first two-dimensional radar having an electronic scanning antenna that measures the direction and distance of the target with high precision, and a plurality of second two-dimensional radars having mechanical scanning antennas that measure the distance of the target with high precision. In a radar height measurement method for a radar system equipped with a two-dimensional radar, the first
The distance and direction of the target are measured at almost the same time by each pair of radars, and the distance and direction of the target are measured at almost the same time by each pair of radars. It is characterized by measuring the altitude of the target geometrically from the data.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. Radar 1 is a two-dimensional radar with an electronic scanning two-dimensional antenna that measures the direction and distance of target P with high precision. Radar 2 is a radar radar that measures only the distance to the target with high precision and performs scanning using mechanical rotation. It is a normal two-dimensional radar with a two-dimensional antenna, and has a transmitter 8 and a receiver 3, respectively. MTI4. Monitoring instruction device6. The two-dimensional radar 2 includes a microwave communication device 7 and an altitude calculation filter 5 . When this two-dimensional radar 2 discovers the target aircraft and measures its distance and direction, it transmits the data to the radar 1 using the microwave communication device 7, and the radar 1 that receives it synchronizes with the radar 2 toward the target. Fire a beam as shown below. The altitude calculation filter 5 inputs precise data on the distance and direction of the target from the position of the radar 1 and precise data on the distance of the target from the position of the radar 2 received from the radar 2, and calculates the altitude of the target. Calculate.

Next, the quantitative relationship between input data and target altitude will be explained.

Figure 2 shows these radars 1. FIG. 2 is a diagram showing the relationship between parameters of the position of radar 2 on the earth. Altitude of target P and direct distance R81 of target P from first radar 5t(1)
and the direct distance R of the target P from the second radar 8 (t2)
Assuming that SS is the azimuth angle at which the radar Sl and the target P look at the radar Sl, the relationship with the three input data is expressed as shown in the following equation.

h=r(I A)+r"(A"1)+R%1+h'
...11) However, 1, d stn-; r=-ro (r (correction of H) taking into account the refraction of radio waves)
h'...The antenna heights of radar and radar 2 are the same), ro...radius of the earth, d...direct distance between radar and radar 2 ( Fig. 3 shows an iso-precision diagram regarding the accuracy of height obtained by calculating the relationship between the error of range) and Po...the vertical point lowered from the target to the ground surface. Here Rst
, The measurement error of R82 is 15m1 The measurement error of angle θ is 0
03°, and the radars Sl and S are shown to have equal precision Iw (maximum error of 90 m (F), 180 m (of hl and 270 m)) relative to each other. 200 km from this figure
Radar 81 installed remotely. The maximum error is 2 between S
It can be seen that the target altitude can be measured within a range of 70mρ).

In addition, in order to keep the measurement error of the altitude of the eye IP within a certain range, the target position P relative to the position of the electronic scanning radar S1 must be
It can be seen that the position of the paired mechanical scanning two-dimensional radar S2 must be appropriately selected.

FIG. 4 shows an example in which the range of error that can be measured is expanded to 270 m (up to 270 m) by selecting the radar S2' located at a different position depending on the target position.

That is, radar 79. / and Radar S! It can be seen that by combining this, it is possible to measure the height of a target in a different area (dotted line range) with the same accuracy.

[Effects of the Invention] As explained above, the present invention links a plurality of two-dimensional radars including an electronic scanning two-dimensional radar to obtain target distance data from two points and target direction from one of the points. By determining the altitude of the target from the data, the altitude of the target can be measured without increasing the size of the antenna, and the altitude of an aircraft without a transponder can be measured.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. Figure 2 is a conceptual diagram showing the geometric relationship of each input data in the case of Figure 1, and Figure 3 is a diagram with equal accuracy that can be measured using the pair of electronic scanning radar and mechanical scanning radar in Figure 1. FIG. 4 is a plan view of a contour line for nine cases in which two mechanical scanning radars are arranged in FIG. 1. 1...Electronic scanning two-dimensional radar, 2...
Mechanical scanning two-dimensional radar, 3...Receiver, 4.
...MTI. 5...Altitude calculation filter, 6...Monitoring instruction device, 7...Microwave communication device, 8.
...Transmission device. @Momo P tough f11 counterfeit Ecal γ

Claims (1)

[Claims] A first two-dimensional radar having an electronic scanning antenna that measures the direction and distance of the target with high precision, and a plurality of second two-dimensional radars having mechanical scanning antennas that measure the distance of the target with high precision. In the radar height measurement method of a radar system, the combination of the first radar and the second radar paired with each other is changed depending on the position of the tracking target, and each of the paired radars measures the distance of the target at approximately the same time. This radar height measurement method is characterized in that the height of the target is measured geometrically from two sets of data from both paired radars.