Unmanned Aerial platforms have been effectively used in recent conflicts across the globe.
UAVs provide unmatched advantage of size, cost and scale; thus, they are widely adopted.
In order to be effective a UAV Must have following key features
- Robust Data Link
- Reliable & Secure long range Radio data link is must; the radio link must provide
data rate enough to transport the control messages and video feed. - Must support key network topologies: Point-to-Point, Relay, Autonomous Mesh network.
- Must be resilient against EW (Electronic warfare) Techniques like Jamming and spoofing.
- Reliable & Secure long range Radio data link is must; the radio link must provide
- Dependable Navigation
- A Navigation system that works well in heavy EW environment.
Major C-UAS systems target above two mentioned key areas to make the UAVs in-effective using
EW techniques like Jamming & Spoofing. Majority of UAVs currently available use the
off-the-shelf modules for both data link and navigation, the challenges with such modules are:
- Fixed or hardwired implementation:
- These modules have fixed implementation of data link and navigation which were
originally targeted for Leisurely applications like photo filming. - The hardware is based on either FGPA or ASICs which are hardwired, it is not possible
to extend the functionality to make it secure and EW resistant.
- These modules have fixed implementation of data link and navigation which were
- Black box implementations:
- In most of the cases the ASIC and the Firmware are like a black box to UAV OEMs, and it
is not possible implement solutions to challenges mentioned above. - For example, it is not possible to update the waveform used for communication, or
antenna pattern for GNSS navigation.
- In most of the cases the ASIC and the Firmware are like a black box to UAV OEMs, and it
The challenges mentioned above can be solved using Software Defined Radio (SDR) for UAV applications. Software defined Radio (SDR) is well known technology in communication industry; it enables following key outcomes:
- Customizable Secured Comms Link
- Non SDR comms platform use either application specific ASICs or FPGAs to implement a
given protocol like WIFI, LTE etc. - Hardware built for LTE in most cases can’t be used for WIFI and Vise-a-versa.
- However, Software defined radio give’s ability to implement a completely new
application specific Physical layer and MAC layer enabling wide variety of
communication protocols. - Thus, it is suited to define and implement custom and secured communication protocol
for sensitive areas like defence.
- Non SDR comms platform use either application specific ASICs or FPGAs to implement a
- Future proof design
- Since the Radio is completely controlled by firmware, the firmware can be updated to
implement the requirements that may arise in future without any change in hardware.
- Since the Radio is completely controlled by firmware, the firmware can be updated to
At Flextride we have a versatile SDR radio called FLEXTRIDE SDR, it is well suited for defense and military, UAV/UGV applications. Following are the key features of this platform:
- No Chinese hardware of software/firmware is used
- We own and understand the hardware & Firmware of SDR completely.
- The SDR can be customized to suit a particular use case of application.
- No risk of hidden Trojan Horses.
- SDR board uses the SOCs (system on chip) for reputed chip makers, so no doubts about reliability of underlying chips.
- Fully customizable platform:
- We develop custom protocol starting at Physical later ensuring that communication link implemented by FLEXTRIDE SDR remains a guarded secret.
FLEXTRIDE-SDR – Introduction
FLEXTRIDE-SDR platform is a small form factor self-sufficient SDR which includes all the major components of comms system i.e. Application processor, Modem including DSP processors, Radio Transceiver.
This SDR does not need a host computer to work (which is required for most of SDR platforms available in market), So it can work as independent Radio module.
This SDR platform supports following key features:
- 1X2 RF transceiver
- Fully Programmable DSP (digital signal processing) cores.
- Frequency range:
- Platform shown above supports 100-5800 Mhz
- 5, 10, 20 MHz bandwidth to provide high data rate capacity
Block diagram of the system (SDR platform shown above) is shown below:
Figure 2 SDR block architecture diagram
FLEXTRIDE-SDR high level architecture is shown in block diagram above.
It mainly consists of following components:
- Application core:
- A powerful set of Arm based cores.
- Rich set of interfaces including Camera/Video, Display/HDMI,
Cryptography hardware accelerators, ethernet for backhaul connectivity. - Custom application and a part of SDR radio stack runs on this core.
It has enough processing power to handle both loads.
- Modem
- Modem handles all the Digital signal processing of signals received
from the RF transceiver. - It includes hardware vector signal processor to efficiently process
the SDR payload and convert it to Radio signals. - The Digital signal processor is fully programmable, that means that
the waveform structure, type, modulation is all coded in C language
and uploaded as firmware on the modem. - Fully programmable modem enables development of a secure, and may be
custom physical layer protocol which is not used in any other wireless
technology like WIFI, LTE. - For defence applications this is really important, because using this
platform a highly secure and secret communication channel can be build
which will be difficult to hack, because the protocol is not known to anybody.
- Modem handles all the Digital signal processing of signals received
- RF transceiver & Front-end module:
- Zero-IF transceiver(s) supporting frequency ranges: 100-5800 MHz
- RF transceiver supports highly integrated Front-end module supporting
variable gain at front-end.
FLEXTRIDE-SDR platform is agile, scalable and secure. It also supports temper proof firmware, that means the firmware is signed with pre-known cryptographic keys and any attempt to replace the firmware will make the platform non-functional thus securing the hardware from any malicious updates.
Multiple use cases in both defense and civilian space can be implemented using FLEXTRIDE-SDR platform, for each use-case a custom firmware needs to be developed but the hardware remains same (as long as supported frequency range remains same).
FLEXTRIDE-SDR based key product applications
Secured EW Resistant Radio Data link
RF data link is essential when two parties need to communicate using wireless medium securely, without any pre-requisite of existing cellular network. Such a radio link can be used for:
- Hand-held Radio for communication between soldiers in tough terrain where there is no other
communication infra is available. - Comms between two equipment in field, for example exchanging video or data feed.
Here applications of such a link are vast, for example:- UAV to Ground control and comms communication
- Comms between UAV, UGV and control and command centre.
- Comms between Multiple equipment/UAVs forming an autonomous mesh network.
FLEXTRIDE-SDR along with FLEXTRIDE SDR firmware implements a radio data link which provides:
- 1T1R Antenna configuration
- 20 Mbps data throughput
- Encrypted payload at MAC layer itself (Secured Comms)
- Frequency hopping Physical layer (EW resistant comms)
The hardware and software architecture are scalable and they can be scaled up to support up to 4T4R Antenna configuration &100 Mbps data throughput
Two network topologies are supported – Point to Point & Autonomous Mesh network.
Point-to-Point & Relay
Figure 3 Point-to-Point UAV communication
FLEXTRIDE-SDR device implements a secure communication link between UAV & Ground station,
also it can act as Relay node to communicate to a device which is not in line of site (NLOS).
The example above shows the application of integrating FLEXTRIDE-SDR into UAV/UGV, but same
concept can be used to create hand held device that can be used by soldiers to securely exchange
video, and data.
The link bandwidth is sufficient to exchange high quality (HD) video stream, as the link
supports up-to 20 Mbps (Mega bits per second) throughput rate.
Autonomous Mesh Network
UAVs are also widely used in large groups called drone swarms. In such formation it is very
much desirable that there is an autonomous mesh network that can be created on-the-go between
each drone which is part of swarm, something like this:
Figure 4 Autonomous Mesh network
The Mesh network provides various advantages:
- Reliability – UAVs can talk to each other and there could be multiple downlink connections
to the ground. So, if one link fails, other can take over. - Optimized bandwidth & control – All the UAVs don’t talk to ground, they talk to each
other, only few UAVs talk to ground thus it makes managing swarm more efficient.
FLEXTRIDE-SDR & firmware supports autonomous mesh formation, also it supports inter-mesh
communication, it can be extended to non-UAV use cases where there are multiple mesh networks
that communicate with each other and to the backbone.
FLEXTRIDE-SDR Radio software stack
The Key differentiator of FLEXTRIDE SDR is: The ability to customize even lowest layer of
comms stack. This gives us advantages:
- Implement custom Layer 1 protocols – It makes the system very tough to hack.
- Updatable waveforms – The system is future proof because we can update the waveform that
is used by changing firmware.
Figure 5 FLEXTRIDE-SDR protocol stack
The User interface on FLEXTRIDE-SDR device provides mechanism to feed Video or Data to be
transmitted to the Peer FLEXTRIDE-SDR user.
Firmware in FLEXTRIDE-SDR implements a custom-made MAC (Medium access layer) and PHY
(Physical layer) that is defined jointly between the customer and our engineers, thus making it a secret implementation.
Since the MAC & PHY protocol are not following any open wireless standards like WIFI, LTE, it will be difficult for any adversary to intercept this communication.
The firmware is designed to be secure and EW resistant by using two techniques:
- Encryption: All the payload is encrypted at the MAC layer.
- Frequency hopping: Physical layer supports frequency hopping to avoid EW jamming.
The communication channel is divided in multiple narrow channels, and the transmitter & receiver changes these narrow channels continuously at a configurable granularity (in order of Milli seconds).
The comms module can hop the frequencies in range of 100-3500 Mhz, it can be extended up to
5800 MHz also.
This blog gives brief overview of capabilities Flextride has for SDR based communication solutions. Reach out to us for any SDR based solution requirement, contact@flextride.com