# Surveying in GNSS-Denied Areas: How the CHCNAV ViLi i100 Ends the Signal Struggle **By Sam Hough** · 2026-03-30 ## Surveying Without a Signal: How the CHCNAV ViLi i100 Changes the Game in GNSS-Denied Areas Every surveyor and site engineer knows that sinking feeling. You’re on-site, the weather is actually holding up, and your deadline is looming - then your GNSS receiver starts jumping around like it’s possessed. Maybe you’re tucked into a narrow alleyway between Victorian brickwork. Perhaps you’re under a dense summer tree canopy. Or you’ve just walked into the "urban canyon" of a new high-rise that has turned your satellite connection into digital confetti. For decades, the industry answer to GNSS-denied environments has been "the long way round": break out the total station, establish control points, and watch your productivity plummet. But what if your receiver simply kept working when the satellites vanished? The **CHCNAV ViLi i100** aims to do exactly that. After getting hands-on with this Visual-LiDAR GNSS RTK receiver, it’s clear this isn't just an incremental update, it’s a genuine shift in how we handle "impossible" sites. ### The GNSS Problem We Don’t Like to Talk About Let’s be honest: traditional GNSS receivers have a massive blind spot. They are flawless in an open field, but the moment you step under a bridge, into a forest, or near a glass-fronted skyscraper, things get dicey. **Multipath errors,** where signals bounce off buildings to create "ghost" positions, can ruin a dataset before you even realise there’s an issue. In fully obstructed areas, most receivers simply give up. This isn't just a minor annoyance; it’s a logistical nightmare for urban construction, infrastructure inspections, and woodland topography. Usually, this means more gear, more man-hours, and more budget. #### The ViLi i100 takes a different path. * * * ### How the ViLi i100 Holds Accuracy Without Satellites The "magic" under the hood is CHCNAV’s **SFix 2.0 engine**. It’s a sophisticated bit of sensor fusion that blends data from: - A **1,408-channel** GNSS receiver - A **96-line LiDAR scanner** (firing 860,000 points per second) - A **200 Hz IMU** for tracking tilt and movement - An array of high-res cameras When the sky is clear, it’s a standard high-precision RTK rover (±30mm). But when you walk into a "black spot," the system doesn't lose its cool. It references its last known "good" position and uses the LiDAR and IMU to "dead reckon" your movement. The LiDAR creates a real-time 360° map of your surroundings to fix your location. You get **5 cm accuracy** within a 20-metre radius, even with zero satellite visibility. In plain English? You can walk under a motorway bridge, map the abutments, and walk out the other side without ever losing your fix. ### Total Isolation: No GNSS, No Mobile Signal, No Problem Most "hybrid" units still scream for a phone signal to get NTRIP corrections. The ViLi i100 is a different beast. Thanks to internal **SLAM (Simultaneous Localisation and Mapping)** technology, it can work completely offline. Whether you’re in a deep basement, a remote Scottish glen, or a rural site where 4G is a myth, the i100 maintains its precision locally. It’s genuine surveying freedom-no more holding your phone in the air praying for a single bar of signal. ![Construction surveyor walking on-site using a CHCNAV GNSS receiver and rugged tablet mounted on a survey pole, supplied by PQS Tech.](https://cdn.shopify.com/s/files/1/0966/9283/0582/files/DSC02599.jpg?v=1774617193) * * * ### Visual-LiDAR: Capturing Points You Can’t Reach One of the most practical features we found was **contactless surveying**. Usually, if you want a point, your pole has to touch it, or you have to get the total station out. That’s fine until you need to measure a live dual carriageway, a feature behind security fencing, or a high-level utility connection. The ViLi i100 uses an **8 MP telephoto camera** to extract points from photos. You snap the image, pick your points in the software, and the system calculates 3D coordinates with 5 cm accuracy from up to 15 metres away. It’s a massive win for safety and site access. ### Real-Time 3D Clouds and Instant Volume Calcs The i100 isn't just a rover with a backup plan; it’s a handheld SLAM laser scanner. It builds a 3D point cloud as you walk. For earthworks, this is a game-changer. You can calculate stockpile volumes on-site with **99.98% accuracy**. No waiting to get back to the office to process data—you get the numbers while you’re still standing in the mud. ![Close-up of a surveyor pointing at a CHCNAV rugged tablet displaying 3D topographical survey data and cut volumes, equipment by PQS Tech.](https://cdn.shopify.com/s/files/1/0966/9283/0582/files/DSC02613.jpg?v=1774617109) * * * ### Is It Actually Faster? CHCNAV claims a **50% boost in workflow efficiency**. While that sounds like marketing fluff, the maths actually holds up when you look at the "hidden" time-wasters: - **Zero setup time** for GNSS-denied zones (no total station tripod dance). - **Faster stakeouts** using the dual-camera AR (Augmented Reality) view—you literally see the design point overlaid on the ground through your screen. - **Fewer re-visits** because you can capture "unreachable" points the first time. ### Who Is This For? If your work is 100% open farmland, this might be overkill. But the ViLi i100 is a "must-have" for: - **Urban Site Teams** dealing with high-rise shadows. - **Infrastructure Engineers** working in tunnels or under bridges. - **Utility Surveyors** in heavily wooded residential areas. - **Earthworks Contractors** needing instant volume checks. ### Making the Right Choice At **PQS Tech**, we know that gear is only as good as the problems it solves. The surveying market is flooded with options, but the ViLi i100 sits in that "sweet spot": advanced enough for the toughest environments, but intuitive enough for daily use. **Would you like to see how the ViLi i100 handles your most challenging site?** [Get in touch](https://pqstech.com/pages/contact "Get In Touch") with our team today to arrange a hands-on demo or to chat about our flexible hire options. **Tags:** chc i100, chcnav, GNSS Denied Environments, gps multipath, i100, SFix, Signal loss solutions, Surveying Under Tree Canopy, Urban Canyon Surveying --- > Source: [PQS Tech](https://pqstech.com/blogs/news/surveying-in-gnss-denied-areas)