From Impact to Screen: The Science Inside a Launch Monitor

A launch monitor does one job that matters: it works out how the ball left the club, then uses that to predict where it goes. It does this in two stages. A sensor captures the ball for a fraction of a second around impact, and software turns those readings into launch numbers such as ball speed, launch angle and spin. A flight model then uses those numbers to estimate apex, carry, curve and roll.

Indoors, that second stage produces most of the distance figures you see. Nothing in a simulator room sees the whole flight, because the screen or net stops the ball within feet. Every carry and total distance on a simulator screen is a model output. The numbers closest to impact, like ball speed and spin, are the ones the sensor actually reads.

How we put this together: we compared published manufacturer specs, retailer listings and owner reports. Links may earn us a commission.

The short version: a sensor, a few milliseconds and a physics model

Every launch monitor does three jobs. First it captures the ball, and on some units the club, in a short window around impact. Second it converts the raw signal into launch numbers. Third it passes those numbers into a flight model that predicts carry, curve and roll.

The capture step is where products differ. Doppler radar reads the frequency shift of a reflected microwave signal. Photometric systems use high-speed cameras to photograph the ball, and sometimes the clubhead, in the first few inches of flight. Some hybrid units combine radar and cameras to cover each method's weak spots. At the budget end, some swing analyzers use infrared light gates built into a mat. Those mostly detect the club passing over sensors and estimate ball flight without ever seeing the ball, which matters for the buying decision later in this article.

The model step works on the same idea everywhere, but the details differ by maker. Two units can read identical ball speed and launch and still show different carry, because each has its own drag and lift assumptions and its own default conditions.

By the end you should be able to tell which numbers a unit reads directly, which it works out with arithmetic, and which it predicts. That tells you which figures to lean on for club fitting and which to treat as a guide.

Following one 7-iron from contact to the simulator screen

The timeline below follows one shot using illustrative numbers. They describe a typical-looking strike. They are not a measurement of any particular golfer or unit.

Step 1, address. The ball sits on a mat in front of the sensor. A camera unit sees it in its frame and arms itself. A radar unit waits for a moving target and starts tracking once the club sends the ball away.

Step 2, impact. Club and ball stay in contact for a very short time. The figure most often cited is around half a millisecond, or about 0.0005 seconds. That is far too short for the eye to follow, which is why every one of these systems depends on fast sensors.

Step 3, capture window. A camera unit takes a burst of images during the first few inches of flight. A radar unit keeps tracking for as long as the ball stays in range. Indoors that is only a few feet of flight. Outdoors, high-end radar can follow much more of the real trajectory.

Step 4, launch numbers. Say the sensor reads a ball speed of 115 mph, a launch angle of 18 degrees and a spin rate of 6,500 rpm. Those are the direct readings for this example, and they are what the unit reports before any physics happens.

Step 5, flight model. The software takes those inputs, adds the conditions settings (temperature, altitude and ground firmness), and applies drag and lift to predict apex, carry, curve and roll. Nothing in this step is sensed. It is calculation.

Step 6, display. The numbers appear with a rendered ball flight. Depending on the unit and the connection, this typically takes a second or two.

Takeaway. Two units fed identical launch data can still show different carry, because their flight models and conditions settings differ. When you see a gap like that, compare the inputs first. Ball speed, launch and spin are where the sensors do their work. Carry is only as good as the model sitting on top of them.

Radar units: reading the echo off a moving ball

A Doppler radar unit sends out microwave signals and listens for the echo. A moving ball reflects that signal back at a slightly different frequency. The size of the shift tells the unit how fast the ball is moving toward or away from the antenna, and that gives ball speed.

Direction comes from timing. Radar units use several receive antennas. The reflected signal reaches each one at a slightly different moment and phase, so the unit can work out the ball's angle both vertically (launch) and horizontally (direction). Spin is harder. As the ball rotates, the reflection varies in small ways, and the unit reads spin from those variations. The signal is weaker on short indoor tracks and on low-spin shots, which is why spin is the number radar users tend to question first.

That has practical consequences. Radar has to look at the ball from behind, down the target line, and it needs enough flight in view to work with. Indoors, most radar units want the sensor several feet behind the ball and open room in front of it. FlightScope's Mevo+ guidance sits in the region of 7 to 8 feet behind the ball, with 8 feet or more to the screen. Treat that as a starting point, and check current maker documentation before you plan a room around it.

Some radar units also ask for a small metallic dot or sticker on the ball when used indoors, to strengthen the spin signal. The Mevo+ is one example. Check the instructions for the model you're considering, because this requirement changes from unit to unit.

Outdoors, the picture changes. High-end radar such as TrackMan can follow a large part of the real flight, which is why radar has a long history on ranges and tours. TrackMan calls its approach OERT, short for optically enhanced radar tracking. FlightScope calls its radar-plus-camera approach Fusion Tracking. Which current models use each one is worth checking on the maker's site, since product lines change.

If you want the head-to-head, read radar versus camera launch monitors compared, or browse radar-based launch monitors for the current field.

Camera units: photographing the ball in its first inches

Camera units take a different route. High-speed cameras fire a burst of images of the ball right after impact. Stereo or multi-camera setups triangulate its position in three dimensions. Ball speed and launch angles come from how far the ball moves between frames and the time between those frames.

Spin works differently. Camera units track surface features such as dimples, logos or markings as they rotate from frame to frame. Because the unit reads the rotation directly, camera makers often describe spin as measured rather than inferred. That is one reason camera units are popular for spin data.

Club data is a separate matter. On many camera units, club speed and face information come from reflective markers stuck on the clubface. Foresight's GCQuad and Uneekor's overhead units are examples of this approach, but requirements vary by model, so check the spec sheet for the one you plan to buy.

Mounting styles split the category in two. Floor units sit at the side of the ball facing the golfer. Foresight's GC3 and GCQuad, Bushnell's Launch Pro and SkyTrak all follow this layout. Overhead units mount on the ceiling. Foresight's GCHawk and Falcon and the Uneekor EYE XO family are in this group.

The consequences are straightforward. Camera units have a small footprint and don't need the long depth that radar does. The trade-off is that they need consistent lighting and a clean lens. Overhead units also need enough ceiling height and a fixed hitting position under the unit. The GCQuad is described as using four cameras and the GC3 as using three, but confirm camera counts against Foresight's spec sheets before you rely on them.

For the four-camera design in more detail, read the GCQuad four-camera review. If overhead mounting appeals to you, the best overhead launch monitors roundup covers that category.

Hybrids and infrared club sensors

Hybrids pair radar and cameras so each covers the other's weak spot. SkyTrak+ adds Doppler radar to the original SkyTrak camera system, mainly to add club data. Check the SkyTrak+ spec sheet for exactly what the radar contributes and which club metrics you get. The SkyTrak+ hybrid camera and radar review goes through the details.

Infrared light-gate systems sit at the other end. These are sensor strips built into a mat. OptiShot 2 is one example, using an array of infrared sensors. As the clubhead passes over them, the system reads the club and estimates ball flight without ever seeing the ball. These are swing trainers and casual game devices, not true ball-tracking launch monitors. They can help with swing feedback, but the ball numbers are estimates.

Phone-based options exist too. Before you decide whether a phone is good enough, read can a phone replace a launch monitor?

Measured, derived or modeled: sorting the numbers on your screen

Most screens show more numbers than the sensor actually saw. Sorting them into three buckets makes the trust question much easier.

Category	Metrics	How the number is produced
Measured	Ball speed, vertical launch, horizontal launch, spin rate (directly on camera units, on radar units when the signal is strong enough), club speed on most units	The sensor observes it
Derived	Smash factor (ball speed divided by club speed), spin loft (dynamic loft minus angle of attack), face to path (face angle minus club path)	Arithmetic on measured values
Modeled	Carry, total distance, roll, apex height, descent angle, lateral landing, hang time	Output of the flight model, always indoors
Unit dependent	Spin axis, angle of attack, club path, face angle, dynamic loft, impact location	Some units measure these, some infer them, and some only offer them through a paid upgrade

The practical rule is this. When you're chasing distance gains, judge by ball speed, launch and spin first. Carry is only as good as the model and the conditions settings behind it. If carry moves while ball speed stays flat, the change usually came from the model or the conditions, not from your swing.

If you want to see how one unit's metrics are produced, every Mevo+ metric and how it is produced walks through its list.

Why the sensing method decides your room layout

This is the buying decision most people actually face, and the sensing method settles most of it. Each method asks something different of your room.

Radar behind the ball needs depth. Plan the unit-to-ball distance plus the ball-to-screen distance, then add walk-around space. For example, 8 feet behind the ball plus 10 feet from the ball to the screen comes to 18 feet before any walk-around space. That figure is illustrative, so check it against the spec for the unit you're buying and the screen you have.

Floor camera units sit beside the ball, on the far side from the golfer. Depth is driven mostly by the safe ball-to-screen distance. Left- and right-handed players need the unit moved to the other side of the ball, which means a small setup change each time the hitter switches.

Overhead camera units clear the floor and never need a swap for lefties. The price is ceiling height and a fixed hitting position under the unit. If the room has a low ceiling, check the requirement carefully before you commit. The golf simulator ceiling height guide and room size planning cover the planning side.

Lighting matters as well. Cameras want even, steady light without harsh glare. Radar is largely indifferent to light, but it is sensitive to space and to reflective clutter in the room.

Setup	Sensing	Depth need	Ceiling need	Lighting sensitivity	Lefty swap
Radar behind the ball	Doppler radar	Deep: unit behind ball plus ball-to-screen distance	Check per model	Low, but sensitive to clutter	Check per model
Floor camera beside the ball	Photometric	Moderate: driven by ball-to-screen distance	Check per model	High: needs even light	Move the unit to the other side
Overhead camera	Photometric	Small floor footprint, no floor clutter	Needs adequate height	High: needs even light	None, but needs a fixed hitting position

Compare launch monitors by budget ↗

Where accuracy gets lost (and how setup wins it back)

Accuracy is usually lost in setup and in the ball, not in the sensor's spec sheet. Work through this list before you blame the unit.

• Level the unit and aim it down the target line. A unit that is a degree or two off shifts every horizontal number.
• Use the ball the unit expects. Radar indoors may need metallic dots, and camera units prefer clean balls. Foam and limited-flight balls confuse both types.
• Expect the weakest data at very low speeds and very high spin. Chips and flop wedges are where many units struggle.
• Set lighting for camera units. Keep it even and keep reflective surfaces out of the frame.
• Match the conditions settings to the course or range you want to mimic before comparing carry.
• Read maker claims as marketing. Some high-end makers cite accuracy around 1 percent on ball speed. Check the figure for the specific maker and model before relying on it. Budget units tend to vary more by shot type.
• Look for independent comparisons and owner reports. They are a better guide than a single headline number.

For a wider look at what accuracy means in a simulator, read what simulator accuracy really means. If the data looks wrong, why launch monitor data goes wrong covers the usual causes.

A short history: tour equipment to pocket radars

Early launch monitors were large and expensive. Club fitters and tour players used them mainly, and they were built around the same measurement methods that later became consumer categories.

Radar and camera methods developed side by side. TrackMan, a radar system from Denmark, and Foresight Sports, a camera system from the US, became reference brands in their respective approaches. FlightScope built both pro and consumer radar units, which is part of why its name turns up across the whole market.

The consumer era opened when SkyTrak brought camera tracking to home users at a lower price. FlightScope's Mevo and Mevo+, Garmin's Approach R10 and Rapsodo's MLM2 PRO pushed prices down further. Today the category runs from pocket-sized portable units through to fixed systems for dedicated sim rooms.

The main trends right now are overhead cameras, hybrid sensing and subscription software. Each one changes what you pay for and where the unit can sit.

Matching a sensing method to how you practice

If you're still deciding whether a unit is worth buying at all, is a launch monitor worth buying? answers that first. Once you've decided, use this as a quick filter.

• Mostly outdoors on a range: radar suits you. It can follow more of the real flight, and its performance doesn't depend on the lighting in your space.
• Garage or spare room with limited depth: a floor camera unit is the usual pick, since it doesn't need the long depth radar does.
• Low ceiling or tight width: check overhead needs carefully. A floor camera may be the safer choice.
• Shared bay with left- and right-handed players: an overhead camera avoids moving the unit between hitters.
• Budget under a few hundred dollars: expect more of the numbers to be estimated. The launch monitors under $500 guide covers this price band.
• Wants detailed club data: check whether it is included or a paid upgrade. The launch monitors with detailed club data roundup sorts this out.

See radar and camera picks ↗

What readers ask once they know how the tech works

Why do two launch monitors show different carry for the same swing?

Carry is a model output, not a direct reading. Each maker uses its own drag and lift model and its own default conditions for temperature, altitude and ground firmness. Small differences in measured spin can move carry too, so when you cross-check two units, compare ball speed, launch angle and spin first.

Can I use foam or limited-flight practice balls with a launch monitor?

Usually not for reliable numbers. Foam and limited-flight balls leave the face and fly differently from a regular golf ball. Camera units can misread spin on them, radar can lose the ball, and the flight models assume a standard ball. Real balls in good condition give the most meaningful data.

Do launch monitors read putts?

Many home units and simulator software include putting modes. Very low ball speeds are harder to capture, especially for radar indoors. Some camera systems offer putting analysis, though that depends on the model, and budget units may only report speed and direction.

Is a sensor mat that only tracks the club a real launch monitor?

Infrared club-tracking mats never see the ball. They estimate ball flight from the club's speed and its face and path readings. That is fine for casual play and swing feedback, but not for gapping clubs or fitting equipment.

Do the altitude and temperature settings change my numbers?

They change the modeled flight, meaning carry and total distance, not the measured launch numbers. Higher altitude and warmer air are thinner, so the model shows more carry. Set them to match the course or range you want to mimic.