We know that second-generation anti-tank missiles usually use infrared tracking goniometers. The infrared sensitive device of the guidance station tracks the radiation source of the infrared generator of the missile tail in flight to measure the angle error between the missile and the guidance station. Wires send control commands to the missile. In order to combat second-generation anti-tank missiles, modern foreign main battle tanks are generally equipped with infrared jammers. By emitting strong infrared radiation, two infrared radiation sources can appear in the anti-tank missile guidance station, causing confusion in tracking instructions and causing the missile to Fall to the ground. This jamming method is very effective. For most second-generation anti-tank missiles, the infrared jammer can make the missile land in a flash.By using a TV CCD goniometer, the HJ-73 can counteract any infrared jammer.
In order to enhance its anti-jamming capabilities, China has applied TV CCD guidance to its improved Hongjian-73 missile and used a CCD goniometer to measure and track missile flight errors.A TV CCD goniometer is used, which can combat any infrared jammer.
The A and B models of the Red Arrow 73 （HJ-73）both use backward infrared angle measurement and have poor anti-interference capabilities. During the test in Pakistan, the local military did not use an infrared jammer at all, but only set up some battlefield interference conditions, such as fire and heavy smoke to render the missile ineffective.
The Red Arrow 73C(HJ-73c）uses CCD TV angle measurement and uses anti-interference technologies such as spectrum recognition, background cancellation and adaptive gate, which greatly improves battlefield survivability.
Use the follow-up launcher to allow the shooter to maintain a certain distance from the missile using the sight. This greatly reduces the probability of casualties from enemy artillery counterattacks, and more importantly, it can be used on various vehicle-mounted launch platforms.
Another addition is the addition of an infrared thermal imager, which greatly improves night combat capabilities, but this is not standard equipment. Many Red Arrow 73Cs do not have night combat capabilities.
The Red Arrow 73D(HJ-73D) is a product of further optimizing the aerodynamic design of the warhead and missile based on the C-type. Canards are added to the head to improve flight stability.
The Red Arrow-73E uses wireless command transmission, and there are no wires.
（Cross-sectional view of the CCD structure in the Red Arrow 73 (HJ-73)goniometer）
Red Arrow 73C/D adopts the method of tracer tube + spectral identification. The specific method is to install a tracer tube on the missile body. When the missile is launched, the tracer tube is also ignited and continues to emit light of a specific spectrum. The goniometer uses spectral recognition technology. The specific implementation method of spectral recognition here is background cancellation. The picture below is a cross-sectional view of the Red Arrow 73C/D goniometer. From the picture below, you can see that light enters the goniometer lens. After that, it was divided into two paths by the spectroscope, which went to the CCD1 camera and the CCD2 camera for imaging respectively.There is a filter in front of the CCD1 and CCD2 cameras. The spectral characteristics of the two filters are opposite. The filter in front of CCD2 is only sensitive to the spectrum of the light emitted by the tracer tube on the projectile, while the filter in front of CCD1 The filter is insensitive to the light emitted by the tracer tube, but can pass light with other spectral characteristics. Finally, the electrical signals generated by the two optical signals in the electronic system are subtracted and output. The background light and interference light are eliminated, leaving only the missile signal. At this time, even though the space and time characteristics of the interference source are exactly the same as those of the missile, As long as there are differences in spectral characteristics, they can be identified using this technology.At the same time, adaptive gate technology is used, which means that the focal length of the lens gradually increases as the missile flies, and the field of view becomes smaller as the focal length increases. At this time, many interferences cannot enter the field of view of the goniometer, and therefore cannot interfere with the goniometer.
（CCP Soldier using rangefinder）
（The tracer tube on the missile is used to emit light of a specific frequency）
Precisely because TV angle measurement technology has strong anti-interference capabilities, many improved versions of second-generation anti-tank missiles have gradually adopted this technology, such as the latest improved version of HJ 8, HJ 8L. In addition to weight reduction, Another biggest improvement is to abandon the infrared angle measurement that the Red Arrow 8 series has always used, and instead use TV and thermal imaging cameras to measure angles. The second-generation semi-anti-tank missile Red arrow 9(HJ-9) equipped by our army also uses TV angle measurement.