JPS5832350B2 - Method and device for measuring target detection and tracking performance of pulse search radar - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a means for accurately and objectively measuring target detection and tracking performance in a Nokirus search radar that has the function of automatically detecting and tracking multiple targets by digitizing received signals. What you do makes you old.

Conventionally, there has been no method for comprehensively measuring the target detection and tracking performance of pulse radars having the above functions.

That is, conventionally, a signal with the same transmission frequency, pulse width, and repetition frequency as the radar is injected from the front stage of the radar receiver, and then visually observed using a synchroscope or a radar-CPPI scope at the output end of the receiver. The only method available was to measure the minimum detectable signal level through confirmation.

With this method, it has not been possible to measure the target detection and tracking performance of a radar device equipped with a recent inter-sweve correlation processing device or inter-scan correlation processing device.

Therefore, an object of the present invention is to enable easy and accurate on-line measurement of the target detection and tracking performance of a pulse search radar having the above-mentioned functions, thereby understanding the target detection and tracking performance of the radar.

The present invention uses a pulse search radar that has the function of automatically detecting and tracking multiple targets by digitizing the radar reception signal, and uses a signal that has the same frequency and pulse width as the radar transmission wave. It has a device that can generate signals, and the number of hits generated by this device,
It is a device that can set the generation position and power level, and measures the target detection and tracking probability of the radar by injecting the generated signal from the front stage of the receiver. This method measures target detection and tracking performance by determining the corresponding injection peak power level Si.

What is shown in FIG. 1 is a block diagram of one embodiment of the present invention, and in the figure, the portion surrounded by a dashed line 11 is the portion included in the present system.

Reference numeral 1 is the antenna of the pulse generator, and 2 is its feeding system.

3 is a transmitter/receiver switch.

4 is an ultra-high frequency amplifier, a frequency converter, an intermediate double branch amplifier,
The receiver of the radar including the detector etc. is shown.

5 is an inter-sweep correlation processing device including a slicer that quantizes the receiver output video.

Reference numeral 6 denotes a device that further performs inter-scan correlation processing on the output signal of the inter-sweep correlation processing device 5.

7 is an output path for the final output signal of this pulselator device.

Reference numeral 8 denotes a device that performs input/output operations for the inter-scan correlation processing device 6, and is capable of extracting a portion of the output signal of the inter-scan correlation processing device 6 and typing out information regarding it.

In this system, a linear coupler 18 is provided in the middle of the power supply 2, and a pseudo target signal is injected from there to the receiver side.

The pseudo target signal to be injected is generated by the generator 12 in synchronization with the system trigger.

This generator 12 has a hit number designator 13, and can output a required number of hits with the same width γ as the transmission pulse width of the generator.

The generated position can be designated by the position designator 14 as the time t1 and azimuth θ1 from the system trigger.

The output signal from the generator 12 passes through a path 15 and is converted by a signal converter 16 into a high frequency signal having the same frequency fO as the transmission frequency of the radar, and passes through a path 17 to a coupler 1'8.
leading to.

The injected power level Si can be set in the signal converter 16.

What is shown in FIG. 2 is an example in which one pseudo target signal is generated.

An example will be shown in which the detection and tracking probability of a target is measured using this device.

Radar clutter - one pseudo target signal is injected into a noise area without human input.

The situation is shown in Figure 3a. The pulse width of this signal is γ,
Let the number of hits be n.

The signal passes through the receiver 4, the inter-sweep correlation processing device 5, and the inter-scan correlation processing device 6, and is output to the output path 7.

By performing the necessary operations on the inter-scan correlation processing device, the input/output device 8 can type out the trajectory of the pseudo target, and the detection and tracking probability of the target can be known.

The target detection and tracking probability is expressed as the ratio of the number of scans that detected and tracked the target among the typed-out tracks to the total number of scans.

The input power Si is sequentially changed from Sil to 5i5t, and the input/output device 8 is operated as many times as necessary for each power level.
By typing out the output data and calculating the ratio of the number of scans that detected and tracked the target to the total number of scans, you can find out the target detection rate corresponding to each level, and create a graph like the one shown in Figure 3. Obtainable.

However, the injected power value Si is the peak power value at the output end of the linear coupler 18.

As an example, if the detection probability is set to 50φ as the detection limit, then
The corresponding power value can be determined as Si6 in the figure.

If the detection and tracking probability referred to here is PT, it has the following meaning.

If PS is the detection probability of a single pulse signal at the output end of the slicer (1) and PD is the detection probability of a signal obtained by taking the correlation between humans (2), then However, n1m is a test standard for human correlation, and if m or more pulses are detected out of n hits, it is assumed that a signal is present.

PT is the probability of being established as a track in the inter-scan correlation processing device, and is expressed as follows.

PT=F(PD) ・・・・・・
(4) However, F is a function representing the tracking property.

Next, it will be explained that the maximum detection distance of the radar can be determined from the injected power value Si6 determined here.

The radar equation of the pulselator shown in FIG. 1 is theoretically given as follows.

σ: Target radar cross section ・・・・・・(10)
K: Boltzmann constant (11
)TO: Antenna noise temperature (assumed to be 290'K)
......(12)B: Bandwidth of receiver intermediate frequency...(13)NF: Receiver noise figure...(14)Ls: System loss caused by antenna rotation operation (pseudo Constant for correcting the difference between the target signal and the actual signal due to the horizontal beam pattern of the antenna) ・・・・・・(15) La: Atmospheric propagation loss ・・・・・・(16)
Lt: Transmission loss of transmission path (17)
Lr: Reception loss at 1 from the antenna to the receiver
......(18) (SO/NO),
: Minimum detectable signal power to noise power 1n power ratio --- (19) In the above, Equations (6) to (18) Equation 1 are known values, and the remaining (So/NO) , the maximum detection distance R can be calculated.

By the way, No is the receiver average output noise power, which is also a known value.

Therefore, if SO as the minimum detectable signal power is measured, this will represent the target detection and tracking performance as a number corresponding to the maximum detection distance.

Therefore, it will be proven below that Si6 obtained earlier represents SO.

The probability PT of being detected and tracked as a wake is given as PT=F(PD) in equation (4).

For example, if a tracking track is established by detecting the target twice, this is given by the following function.

PT=F(PD)−(PD)2 ・・・・・・(2
0) In the example of FIG. 3, the standard is PT=PT1=0.5 (50 excellent).

From equation (3), Pp = PS included in the right side of this equation is:
As shown in equation (1) above, this is the detection probability of a single pulse signal at the output end of the slicer.

Here, PS is given as follows.

It is required as.

On the other hand, an actual measurement value Si6 is obtained corresponding to the detection and tracking probability P T = P T1.

Therefore , and SO can be known from the value of Si6.

FIG. 4 shows a specific embodiment of this method and shows corresponding parts of the numerical values appearing in the above-mentioned formula.

1 is a pulse radar antenna, and 2 is its power supply system.

3 is a transmission/reception switch, 4 is a receiver, 51 is a slicer, 52
is an inter-sweep correlation processing device, 6 is an inter-scan correlation processing device, and 7 is an output path for the final output signal.

Reference numeral 9 denotes a typewriter that specifies any signal among the signals processed by the inter-scan correlation processing device 6 and prints the track data.

12 is a block diagram of a pseudo target generator. A distance is specified by a distance designation switch 121 and a distance signal matching circuit 122, and a direction is similarly designated by a direction designation switch 123 and a direction signal matching circuit 124.

On the other hand, the number of hits n is designated by the number of hits designation circuit 125.

The pulse width is γ.

These signals cause a pseudo signal trigger generator 126 to generate a required trigger signal.

This signal is used as a modulation signal for the high frequency signal modulator 162 of the signal converter 16, modulating the high frequency Cw signal from the high frequency signal generator 161, and creating a pulsed high frequency signal to be injected.

Reference numeral 163 is a terminal for monitoring the power level of the pulsed high frequency signal, and is for calibrating the level of Si.

Reference numeral 164 is a high frequency variable attenuator for adjusting Si, and the amount of attenuation is known.

17 is a transmission line for injection signals. This transmission loss is also a known value and is used for calibrating Si.

181 is a directional coupler whose coupling amount is known. As described above, according to the present invention, it is possible to quantitatively measure the target detection and tracking performance of a pulse search radar equipped with an inter-sweep correlation processing device and an inter-scan correlation processing device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention. FIG. 2 shows an example of generation of a pseudo target signal. FIG. 3 shows an example of measuring target detection and tracking limit performance. FIG. 4 shows a specific embodiment of this invention. In the figure, 1 is a radar antenna, 4 is a receiver, 12 is a pseudo target signal generator, 13 is a hit number designator, 14 is a position designator, and 16 is a signal converter.

Claims (1)

[Claims] 1. A receiver receives a reflected signal of a transmitted pulse signal by a target object, quantizes the received signal, and performs inter-sweep correlation processing and inter-scan correlation processing to detect and track the target. A pulse signal with a set number of hints n and a power level Si is injected as a pseudo target signal from the front stage of the radar receiver of the pulse search radar, and the output track data is used to detect a set number or more of the number of hits n. The target detection and tracking probability is determined from the ratio of the number of scans in which pulses are detected and the total number of scans, and the power level Si and the target detection and tracking probability are determined by sequentially changing the power level Si of the pseudo target signal. From the relationship, determine the value of the power level corresponding to the set target detection and tracking probability,
This power level value is converted to the minimum detectable signal power level defined by the rate equation, and the maximum detection distance is determined from this minimum detectable signal power level. 2. means for emitting a pulse signal having the same frequency as the radar transmission wave and having the same repetition frequency and pulse width as the transmission wave; a stage for setting the number of hits, generation position, and power level of the pulse signal; A pseudo target signal injection device for use in carrying out the method according to claim 1, further comprising means for injecting said pulse signal from the previous floor of a radar receiver.