For direct GPS reception, start with a right-hand circularly polarized (RHCP) antenna that covers the required signals. A linear GPS antenna can still be a real integration option when its installed reception meets the application’s needs, but it is not equivalent merely because the frequency and connector match. When comparing two RHCP antennas, use their gain and polarization information over the viewing angles and bands you need—not just the word “RHCP” or a single figure at zenith.
This is an antenna-selection decision for a team retaining its GNSS receiver. A requirement to suppress external RF interference is an additional equipment decision, not a result established by the polarization label.
What the polarization label tells a buyer
GPS signals arrive with RHCP. A receiving antenna with the matching polarization can use that signal more effectively than an otherwise comparable linear antenna. Linear reception is not automatically impossible: an ideal linear antenna receiving an ideal circularly polarized wave has a polarization mismatch loss of about 3 dB. That is one loss mechanism, not a prediction of the total difference between two finished products. Their patterns, efficiency and installation also differ. The u-blox GNSS antenna application note, sections 3 and 4, discusses these choices for its receiver designs.
Do not confuse circular polarization with an all-direction reception guarantee. An antenna still has a radiation pattern. Turning a platform can change which part of that pattern faces the satellites, even if the antenna remains RHCP.
Linear GPS antennas are real products, not interchangeable substitutes
Taoglas lists the ALA.01 active GPS/Galileo loop antenna as linearly polarized. Its description emphasizes a narrow profile and placement options around the device board. The same supplier lists its Inception L1/L5 patch antenna as RHCP. These are examples of different commercial design choices—not a controlled performance comparison or a ResiNav supply offer.
The useful purchasing question is therefore not “Can a linear antenna ever receive GPS?” It is “Does its documented installed performance meet this receiver and platform requirement, and what integration work does the alternative require?”
If an existing enclosure only accommodates the narrow option, retain it as a candidate when the supplier’s integration evidence and your application requirements support it. Do not call it a drop-in equivalent to an RHCP assembly. If navigation reception is the priority and suitable mounting space is available, prefer a documented RHCP option rather than accepting polarization mismatch solely to minimize the antenna body. The receiver manufacturer’s guidance remains part of that decision.
Compare RHCP offers beyond a single number
Axial ratio describes how close the polarization is to circular. The ideal is 1:1, or 0 dB; a lower value is closer to circular under the stated measurement conditions. It is not an amplifier-gain figure, a positioning-accuracy result or a jammer-suppression rating. Taoglas’ antenna-parameter guide separates polarization, axial ratio and gain.
A value specified at zenith describes the direction directly above the antenna’s stated reference orientation. It does not establish the same value across the whole sky or all supported bands. For a moving platform, compare the documented angles against the mounting orientation and operating attitudes that matter to the task. A good top-down figure cannot settle a requirement that includes reception well away from that direction.
This is a way to make the comparison fair, not a universal axial-ratio threshold. NovAtel’s antenna-selection guidance also treats signal coverage, antenna gain and application constraints as separate selection factors. Use the requirements of the receiver and application being purchased, not another supplier’s numerical limits as a specification for ResiNav.
Three choices that change the shortlist
These are purchasing rules, not test results or a ranking of antenna brands.
A worked quotation decision
Hypothetical example: a team keeps its existing receiver and compares two antenna offers for an outdoor mobile platform. Both cover the required signals and fit the initial mechanical envelope. Offer A provides an RHCP declaration and a zenith axial-ratio figure. Offer B provides RHCP gain and axial-ratio information over the viewing range specified by the team. Assume no other material difference has yet been established.
For that stated requirement, B has the stronger basis for an evaluation shortlist. This does not prove B will produce a better position in service. A can remain a conditional alternative, but its price must not be treated as including the missing characterization unless that work is explicitly offered. The buyer can now compare a documented antenna package with an antenna-plus-additional-evidence package, instead of treating two RHCP labels as the same deliverable.
If the platform actually remains in a mounting condition addressed by both offers, the missing wider-angle information may not decide this purchase. Select evidence for the operating requirement rather than buying the longest specification sheet.
Keep the interference-protection order separate
Polarization selection helps define the antenna reception path. It does not, by itself, establish rejection of a particular interfering transmitter, spoofing detection or a protected navigation output. For the choice between reflected-signal reception improvements and external RF mitigation, use the existing multipath versus interference buying guide.
When the requirement is GNSS interference protection, continue to the ResiNav product catalogue, compare the published signals and interfaces of the relevant model, and use that product’s enquiry route. Keep any antenna-polarization or installed-pattern requirement alongside the protection requirement. An unpublished model-level value remains unconfirmed; the ordinary antenna examples above do not establish ResiNav polarization performance, bare-antenna supply or compatibility with a named receiver.
The result should be a clear shortlist and quotation boundary: the reception hardware being selected, the installation it is being judged in, and any separate protection function the order must contain.
NEXT STEP
Turn available platform information into an engineering review.
Use the Technology centre to frame the discussion, review relevant application scenarios, then send the available platform and receiver details for confirmation.