A two-way RF command-video data link has been realised for HELINA missile which is intended to be fired from Advanced light helicopter (ALH). The missile-to-helicopter down-link used to pass the IR seeker video is stated to work in the S band and the helicopter-to-missile up-link to pass steering commands is stated to work in the C band. In addition, a DS-SS modulation scheme is expected to be used for the command up link while a conventional FM technique is said to have been used for video down-link respectively. The range of operation is in the region of 10 kms. Both the missile – and helicopter – borne trans-receiver units have been realised and their link performance evaluated by carrying out field tests and ground- based missile flight trials.
Helina is a fast track project spanning just 33 months to establish its full functionality with ALH. The 4 to 6 months time frame was given for realization of both the helicopter and the missile data link units.
The data link consists of helicopter-and missile-borne trans-receiver modules. The helicopter borne module is supposed to consist of a two-way C band command transmitter with antenna switching and an S band video receiver with input antenna switching mechanism.
Similarly, the missile-borne unit is expected to consist of a dual C band command receiver with linear AGC and an S band video transmitter with antenna switching logic.
ECCM has also been tested.
Two NAG missiles were fired from a ground launcher in full Helina configuration with RF data link. The range of operation was 4 km. Two hot targets separated by 30 m were erected at 4 km from launch point. The seeker was focused on first target when missile was launched. During missile flight the target video received via data-link was monitored by weapon system officer. Based on the target video. The track gate was shifted to the second target and lock command was issued using command link. It was stated that the officer could perform all the tasks within 10 seconds of missile flight from ground itself.
The field test to validate range of operation was carried out and a range of approximately 10 km was established. All the interface checks in full mission configuration were carried out and the LOAL principle was verified.
Helina’s flight duration is approximately 40 seconds