Optical Radar Pods for UAV-Based Maritime Surveillance

By Mike Ball / 04 Aug 2021
Sentient Vision Systems UAV VIDAR pod
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Sentient Vision Systems UAV VIDAR pod

Sentient Vision Systems has released the following article explaining how its ViDAR (Visual Detection and Ranging) technology has been developed into a pod solution for UAVs (unmanned aerial vehicles) and other aircraft, providing wide-area maritime search and surveillance capabilities.

ViDAR, which stands for Visual Detection and Ranging, is the world’s first optical radar system. Developed by Sentient Vision Systems in Melbourne, Australia, ViDAR has developed a global track record for its ability to detect very small objects on the sea surface over a very wide area, in conditions up to Sea State 6. It enables operators to cover a search area 300 times greater than an aircraft without ViDAR.

Since 2016, Sentient has supplied ViDAR as an Artificial Intelligence (AI) software-based solution to customers as different as the US Coastguard, Australian Maritime Safety Authority (AMSA) and Fisheries and Oceans Canada. They’ve used ViDAR for Search and Rescue (SAR), maritime surveillance, law enforcement and for fisheries protection.

This year, in response to market demand, Sentient for the first time integrated ViDAR into a complete, podded solution, including sensors and processors, for operators of fixed wing aircraft, helicopters and UAS.

By offering a fully integrated pod, the company has achieved two things for the customer: firstly, it offers an unrivalled surveillance capability with minimal platform disruption that’s backed up by a single, dedicated hardware and software product support package. Secondly, it controls the quality and reliability of the ViDAR installation to deliver a more consistent, well-engineered installation and training process.

A pod has a number of advantages over a bespoke installation. Responsibility for initial integration, testing and weather-proofing of the sensors and processors resides with Sentient. For small operators, that’s important: many simply haven’t the resources to devote to ongoing engineering support and ‘tweaking’. It’s not quite ‘plug and play’, but it offers greater simplicity and high levels of assuredness to small operators and those entering this market for the first time.

A pod is also a very rapid, low-impact addition to an aircraft, so doesn’t affect its flight safety or its resale value. And a pod can be swapped rapidly between aircraft in a fleet, according to availability or mission requirements.

So how does it work? The ViDAR VMS-5 pod is fixed to the outside of an aircraft; it is equipped with multiple fixed, high-resolution cameras with a combined Field of View (FoV) of 180 degrees. From an altitude of 1,500ft at a speed of about 90kt, they scan a surface swath 3.2 nautical miles wide to find targets as small as a person in the water. If the mission objective is to find a suspicious boat with a low radar cross-section then the ViDAR swath can easily be increased to over 25nm from 5,000ft.

ViDAR comes with a mission planning tool where you can input what you’re looking for, and the planning tool will calculate the optimal altitude, speed and coverage area of the ViDAR package. So a ViDAR payload can provide a UAS manufacturer with a market edge when trying to meet an operator’s requirements.

One ViDAR operator, for example, sets a standard maritime search at 3,000ft MSL at 60 kts, providing a 15.94 nm swath in front of the UAS, while searching the water autonomously. If the search object changes, the mission specialist can change the parameters of the search, and the planning tool will automatically recalculate the optimum output.

If the target is within the sensors’ field of view ViDAR will spot it in the imagery feed, thanks to Sentient’s computer vision and AI-based software expertise, even in Sea State 6, and even when it’s something as small as a human head in the water that’s invisible to the operator. This increases the probability of detection to as much as 96% on first pass. The ViDAR software provides a thumbnail to the operator’s mission system showing the target and its location, enabling the operator to slew the platform’s primary sensor onto it for further inspection. Being middleware, ViDAR is mission-system agnostic so it can be integrated easily with any mission system specified by a customer.

The pods are offered initially with two sensor types: a 60 Megapixel Electro-Optic (E/O) installation and a 2.6 Megapixel HD Infrared (IR) sensor for night and bad weather operations. Size, Weight and Power (SWAP) demands are low: the pod weighs just 21 Kg, requires 18-48V DC power up to 400W, and is 865mm long and 305mm wide. Depending on the application the pods can also be equipped with a camera turret.

The VMS-5 version is all-inclusive; the pod can also be offered as a simpler day-only or night-only variant, or left- or right-handed to go on either or both wings of a light, high-wing aircraft.

The pod carries the sensors and processor mounted internally on a Line-Replaceable Unit (LRU) and requires only a power supply. The output via a single cable will go direct to the operator station as a direct feed, either to a carry-on laptop or for simple integration with an existing mission management system. More tightly integrated installations may also require access to the aircraft’s own IMU.

Operators get another benefit from using the VMS-5 pod: new generations of high-definition sensors and enhanced processors emerge every 18 months or so and the pod can accommodate these with minimal re-design.

The initial VMS-5 pod design and its universal mount for light aircraft and helicopters were proven on a Cessna 172 and AS350. But the company is designing a family of pods and working with partners to include conformal designs for bigger, faster aircraft such as the Viking Twin Otter, King Air 300 and even Boeing 737-based maritime patrol aircraft. The range will also extend across helicopters from the AS365 Dauphin, AW139 and AW189 right up to the AW101 Merlin and CH-149 Cormorant. Solutions for Medium Altitude, Long Endurance (MALE) UASs are also planned with pods using either NATO-standard mountings compatible with belly-mounted or under-wing external stores pylons or adopting a conformal style solution.

Despite the COVID-19 pandemic, Sentient Vision Systems has grown strongly over the past year. It’s able to integrate the podded systems cost-effectively and reliably in-house, both to maintain control over quality and reliability and also to ensure it protects and develops its IP. However, Sentient will also work with external specialists such as sensor, mission system and pod manufacturers who are the recognised subject matter experts in their field.

Once delivered to the customer, the pods are installed by the company’s own Field Integration and Training team (FIT) who also train the operators. Sentient Vision Systems’ ViDAR VMS optical radar pods allow a wide range of UAVs to quickly become effective Search and Rescue or Maritime Surveillance platforms.

Posted by Mike Ball Mike Ball is our resident technical editor here at Unmanned Systems Technology. Combining his passion for teaching, advanced engineering and all things unmanned, Mike keeps a watchful eye over everything related to the unmanned technical sector. With over 10 years’ experience in the unmanned field and a degree in engineering, Mike’s been heading up our technical team here for the last 8 years. Connect & Contact